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Crystals
Volume 14
Issue 11
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Crystals, Volume 14, Issue 11 (November 2024) – 95 articles

Cover Story (view full-size image): The complex coacervation of polyacrylate and calcium ions or polyamines with phosphates has been uncovered as a fascinating approach to synthesizing multifunctional physically crosslinked hydrogels. We investigated the entire mechanism of calcium/polyacrylate, as well as phosphate/polyamine coacervation, starting from early dynamic ion complexation by the polymers, through the determination of the phase boundary and droplet formation, up to the growth and formation of thermodynamically stable macroscopic coacervate hydrogels. The exceptional properties of the coacervates obtained here, combined with the straightforward synthesis and the character of an ions reservoir, open a promising field of bioinspired composite materials for osteology and dentistry. View this paper
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9 pages, 5081 KiB  
Article
Pressure-Induced Structural Phase Transition and Fluorescence Enhancement of Double Perovskite Material Cs2NaHoCl6
by Tingting Yan, Linan Liu, Dongyang Xi, Lei Sun, Dinghan Jin and Han Li
Crystals 2024, 14(11), 1006; https://doi.org/10.3390/cryst14111006 - 20 Nov 2024
Viewed by 661
Abstract
Cs2NaHoCl6, a double perovskite material, has demonstrated extensive application potential in the fields of anti-counterfeiting and optoelectronics. The synthesis of Cs2NaHoCl6 crystals was achieved using a hydrothermal method, followed by the determination of their crystal structures [...] Read more.
Cs2NaHoCl6, a double perovskite material, has demonstrated extensive application potential in the fields of anti-counterfeiting and optoelectronics. The synthesis of Cs2NaHoCl6 crystals was achieved using a hydrothermal method, followed by the determination of their crystal structures through single crystal X-ray diffraction techniques. The material exhibits bright red fluorescence when exposed to ultraviolet light, confirming its excellent optical properties. An in situ high-pressure fluorescence experiment was conducted on Cs2NaHoCl6 up to 10 GPa at room temperature. The results indicate that the material possibly undergoes a structural phase transition within the pressure range of 6.9–7.9 GPa, which is accompanied by a significant enhancement in fluorescence. Geometric optimization based on density functional theory (DFT) revealed a significant decrease in the bond lengths and crystal volumes of Ho-Cl and Na-Cl across the predicted phase transition range. Furthermore, it was observed that the bond lengths of Na-Cl and Ho-Cl reach an equivalent state within this phase transition interval. The alteration in bond length may modify the local crystal field strength surrounding Ho3+, consequently affecting its electronic transition energy levels. This could be the primary factor contributing to the structural phase transition. Full article
(This article belongs to the Section Inorganic Crystalline Materials)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>Rietveld refinement of the experimental XRD pattern of synthesized Cs<sub>2</sub>NaHoCl<sub>6</sub>.</p> Full article ">Figure 2
<p>SEM images of Cs<sub>2</sub>NaHoCl<sub>6</sub>.</p> Full article ">Figure 3
<p>(<b>a</b>) Crystal structure of Cs<sub>2</sub>NaHoCl<sub>6</sub>; (<b>b</b>) Coordination of cesium ions in the unit cell.</p> Full article ">Figure 4
<p>(<b>a</b>) High-pressure fluorescence spectra of Cs<sub>2</sub>NaHoCl<sub>6</sub> in the range of 640 to 740 nm (<b>b</b>) High-pressure fluorescence spectra of Cs<sub>2</sub>NaHoCl<sub>6</sub> in the range of 900 to 1100 nm. The pressure dependence of the fluorescence peak positions of Cs<sub>2</sub>NaHoCl<sub>6</sub> in the range of 645~690 nm (<b>c</b>) and 945~1030 nm (<b>d</b>).</p> Full article ">Figure 5
<p>(<b>a</b>–<b>c</b>) The fluorescence emission intensity in the range of 640 to 700 nm under different pressures as pressure increases. (<b>d</b>) Pressure dependence of PL peak intensity of Cs<sub>2</sub>NaHoCl<sub>6</sub>.</p> Full article ">Figure 6
<p>(<b>a</b>) CIE chromaticity coordinates of Cs<sub>2</sub>NaHoCl<sub>6</sub>; the illustrations present images of the sample captured under natural light and 365 nm UV illumination. (<b>b</b>) The Cl-Cs-Cl bond angle, controlled by the Ho-Cl and Na-Cl bonds, respectively, changes under pressure. (<b>c</b>) Pressure dependence of Na-Cl and Ho-Cl bond lengths. (<b>d</b>) Pressure dependence of the lattice volume of Cs<sub>2</sub>NaHoCl<sub>6</sub>.</p> Full article ">
16 pages, 5415 KiB  
Article
Influence of Mechanical Activation on the Evolution of TiSiCN Powders for Reactive Plasma Spraying
by Lazat Baimoldanova, Bauyrzhan Rakhadilov, Aidar Kengesbekov and Rashid Kuanyshbai
Crystals 2024, 14(11), 1005; https://doi.org/10.3390/cryst14111005 - 20 Nov 2024
Viewed by 493
Abstract
In modern materials science and surface engineering, reactive plasma spraying (RPS) holds a key position due to its ability to create high-quality coatings with unique properties. The effectiveness of this process is largely determined by the physicochemical characteristics of the initial powder materials. [...] Read more.
In modern materials science and surface engineering, reactive plasma spraying (RPS) holds a key position due to its ability to create high-quality coatings with unique properties. The effectiveness of this process is largely determined by the physicochemical characteristics of the initial powder materials. This study examines the effects of mechanical activation for two compositions in the TiSiCN system and their impact on the quality and performance characteristics of RPS-produced coatings. It is shown that mechanical activation induces significant changes in the crystalline structure of the powders, reducing their particle size and increasing their specific surface area, thereby enhancing the reactivity of the materials during mechanochemical reactions. These changes contribute to the formation of dense and durable coatings with improved hardness and thermal stability. Thermogravimetric analysis (TGA) results confirm that the powders retain stable thermal properties and exhibit resistance to oxidation and decomposition. X-ray structural analysis reveals multiphase structures, including TiC, SiC, and TiCN, with the TiCN phase playing a key role in ensuring coating hardness. Additionally, SEM analysis showed that the TiSiCN-2-2 coating possesses a denser and more homogeneous structure with minimal pores and microcracks, providing superior mechanical strength and wear resistance compared to TiSiCN-1-2. Cross-sectional micrographs further revealed that the TiCN + Si coating has a greater average thickness (39.87 μm) and more uniform distribution compared to Ti + SiC (35.48 μm), indicating better application control and a more homogeneous material structure. Mechanical activation significantly influences the properties of powders, allowing for the determination of optimal parameters for RPS, which is a highly efficient method for creating coatings with unique performance characteristics. Full article
(This article belongs to the Section Hybrid and Composite Crystalline Materials)
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<p>Dependence of the increase in total energy on the magnitude of external stress (<b>left</b>) and the stepwise nature of strain accumulation under mechanical stress near the yield point (<b>right</b>) [<a href="#B18-crystals-14-01005" class="html-bibr">18</a>,<a href="#B19-crystals-14-01005" class="html-bibr">19</a>].</p> Full article ">Figure 2
<p>Schematic configuration of chamber.</p> Full article ">Figure 3
<p>SEM images of powders after activation: (<b>a</b>,<b>b</b>) Ti + SiC; (<b>c</b>,<b>d</b>) TiCN + Si. Activation time: (<b>a</b>,<b>c</b>) 30 min; (<b>b</b>,<b>d</b>) 60 min.</p> Full article ">Figure 4
<p>Thermogravimetric analysis (TGA) curves of multicomponent systems (powders), (<b>a</b>) Ti + SiC and (<b>b</b>) TiCN + SiC, by activation time: black line—30 min, red line—60 min.</p> Full article ">Figure 5
<p>X-ray diffraction pattern of Ti + SiC powder.</p> Full article ">Figure 6
<p>X-ray diffraction pattern of TiCN + Si powder.</p> Full article ">Figure 7
<p>SEM micrograph of TiSiCN coating surface: (<b>a</b>) TiSiCN-1-2; (<b>b</b>) TiSiCN-2-2.</p> Full article ">Figure 8
<p>Cross-sectional micrographs with coating thickness measurements for coatings: (<b>a</b>) TiSiCN-1-2; (<b>b</b>) TiSiCN-2-2.</p> Full article ">Figure 9
<p>X-ray diffraction pattern of TiSiCN-1-2 coating.</p> Full article ">Figure 10
<p>X-ray diffraction pattern of TiSiCN-2-2 coating.</p> Full article ">Figure 11
<p>Loading and unloading curves for the coating.</p> Full article ">
2 pages, 138 KiB  
Editorial
Advances in Green Nanocomposites: Design, Characterization and Applications
by Gianluca Viscusi
Crystals 2024, 14(11), 1004; https://doi.org/10.3390/cryst14111004 - 20 Nov 2024
Viewed by 636
Abstract
Nowadays, green nanocomposites are gaining interest in different application fields [...] Full article
(This article belongs to the Special Issue Advances in Green Nanocomposites: Design, Characterization and Applications)
10 pages, 5215 KiB  
Article
Enhancing Wireless Power Transfer Performance Based on a Digital Honeycomb Metamaterial Structure for Multiple Charging Locations
by Bui Huu Nguyen, Pham Thanh Son, Le Thi Hong Hiep, Nguyen Hai Anh, Do Khanh Tung, Bui Xuan Khuyen, Bui Son Tung, Vu Dinh Lam, Haiyu Zheng, Liangyao Chen and YoungPak Lee
Crystals 2024, 14(11), 999; https://doi.org/10.3390/cryst14110999 - 19 Nov 2024
Viewed by 690
Abstract
Enhancing the efficiency is an essential target of the wireless power transfer (WPT) technology. Enabling the WPT systems requires careful control to prevent power from being transferred to unintended areas. This is essential in improving the efficiency and minimizing the flux leakage that [...] Read more.
Enhancing the efficiency is an essential target of the wireless power transfer (WPT) technology. Enabling the WPT systems requires careful control to prevent power from being transferred to unintended areas. This is essential in improving the efficiency and minimizing the flux leakage that might otherwise occur. Selective field localization can effectively reduce the flux leakage from the WPT systems. In this work, we propose a method using a digital honeycomb metamaterial structure that has a property operation as a function of switching between 0 and 1 states. These cavities were created by strongly confining the field by using a hybridization bandgap that arose from wave interaction with a two-dimensional array of local resonators on the metasurface. A WPT efficiency of 64% at 13.56 MHz was achieved by using the metamaterial and improved to 60% compared to the system without the metamaterial with an area ratio of Rx:Tx~1:28. Rx is the receiver coil, and Tx is the transmitter one. Full article
(This article belongs to the Section Hybrid and Composite Crystalline Materials)
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Figure 1
<p>(<b>a</b>) Schematic of MM slab including 37 unit cells. (<b>b</b>) Top and bottom of the 5T-SR hexagonal unit cells. (<b>c</b>) Unit cell circuit model. (<b>d</b>) Reflection coefficient and (<b>e</b>) reflection phase of the unit cell at the ON (<span class="html-italic">C</span><sub>ON</sub> = 145.6 pF) and OFF states (<span class="html-italic">C</span><sub>OFF</sub> = 195.6 pF).</p> Full article ">Figure 2
<p>Schematic of the WPT-MM system with control panel.</p> Full article ">Figure 3
<p>The circuit model of the WPT-MM system.</p> Full article ">Figure 4
<p>H-field intensity distribution (simulations with CST). (<b>a</b>) Free space and (<b>b</b>) metamaterial with a cavity.</p> Full article ">Figure 5
<p>H-field intensity distribution in the x–y plane. (<b>a</b>) One unit cell ON. (<b>b</b>) Three unit cells ON. (<b>c</b>) Five unit cells ON.</p> Full article ">Figure 6
<p>Experimental configuration for the proposed WPT-MM system.</p> Full article ">Figure 7
<p>Comparison of the measurement and simulation results. (<b>a</b>) Transmission coefficient (<span class="html-italic">S</span><sub>21</sub>) and (<b>b</b>) PTE.</p> Full article ">Figure 8
<p>Measured relative field amplitude via transmission coefficient. (<b>a</b>) One unit cell ON, (<b>b</b>) three unit cells ON, and (<b>c</b>) five unit cells ON.</p> Full article ">
19 pages, 4523 KiB  
Article
Cr3+ Doping Effects on Structural, Optical, and Morphological Characteristics of BaTiO3 Nanoparticles and Their Bioactive Behavior
by Efracio Mamani Flores, Bertha Silvana Vera Barrios, Julio César Huillca Huillca, Jesús Alfredo Chacaltana García, Carlos Armando Polo Bravo, Henry Edgardo Nina Mendoza, Alberto Bacilio Quispe Cohaila, Francisco Gamarra Gómez, Rocío María Tamayo Calderón, Gabriela de Lourdes Fora Quispe and Elisban Juani Sacari Sacari
Crystals 2024, 14(11), 998; https://doi.org/10.3390/cryst14110998 - 19 Nov 2024
Viewed by 840
Abstract
This study investigates the effects of chromium (Cr3+) doping on BaTiO3 nanoparticles synthesized via the sol–gel route. X-ray diffraction confirms a Cr-induced cubic-to-tetragonal phase transition, with lattice parameters and crystallite size varying systematically with Cr3+ content. UV–visible spectroscopy reveals [...] Read more.
This study investigates the effects of chromium (Cr3+) doping on BaTiO3 nanoparticles synthesized via the sol–gel route. X-ray diffraction confirms a Cr-induced cubic-to-tetragonal phase transition, with lattice parameters and crystallite size varying systematically with Cr3+ content. UV–visible spectroscopy reveals a monotonic decrease in bandgap energy from 3.168 eV (pure BaTiO3) to 2.604 eV (5% Cr3+-doped BaTiO3). Raman and FTIR spectroscopy elucidate structural distortions and vibrational mode alterations caused by Cr3+ incorporation. Transmission electron microscopy and energy-dispersive X-ray spectroscopy verify nanoscale morphology and successful Cr3+ doping (up to 1.64 atom%). Antioxidant activity, evaluated using the DPPH assay, shows stable radical scavenging for pure BaTiO3 (40.70–43.33%), with decreased activity at higher Cr3+ doping levels. Antibacterial efficacy against Escherichia coli peaks at 0.5% Cr3+ doping (10.569 mm inhibition zone at 1.5 mg/mL), decreasing at higher concentrations. This study demonstrates the tunability of structural, optical, and bioactive properties in Cr3+-doped BaTiO3 nanoparticles, highlighting their potential as multifunctional materials for electronics, photocatalysis, and biomedical applications. Full article
(This article belongs to the Special Issue Synthesis and Characterization of Oxide Nanoparticles)
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Figure 1
<p>(<b>a</b>) Thermogravimetric analysis and (<b>b</b>) differential scanning calorimetry of pure and Cr<sup>3+</sup>-doped BaTiO<sub>3</sub>.</p> Full article ">Figure 2
<p>(<b>a</b>) X-ray diffraction patterns of pure and doped BaTiO<sub>3</sub> and (<b>b</b>) amplification of XRD peaks within the 44–46.5° range.</p> Full article ">Figure 3
<p>Raman spectra of (<b>a</b>) Pristine BaTiO<sub>3</sub> and (<b>b</b>) Cr<sup>3+</sup>-doped BaTiO<sub>3</sub>.</p> Full article ">Figure 4
<p>FTIR spectra of pure and Cr<sup>3+</sup>-doped BaTiO<sub>3</sub>.</p> Full article ">Figure 5
<p>(<b>a</b>) UV–visible diffuse reflectance spectrum. (<b>b</b>) Kubelka–Munk plot for bandgap calculation.</p> Full article ">Figure 6
<p>Photoluminescence spectrums of pure and Cr<sup>3+</sup>-doped BaTiO<sub>3</sub><b>.</b></p> Full article ">Figure 7
<p>Transmission electron microscopy microphotography of (<b>a</b>) BaTiO<sub>3</sub>, (<b>b</b>) BaTiO<sub>3</sub>-0.3%Cr<sup>3+</sup>, (<b>c</b>) BaTiO<sub>3</sub>-0.5%Cr<sup>3+</sup>, (<b>d</b>) BaTiO<sub>3</sub>-1%Cr<sup>3+</sup>, (<b>e</b>) BaTiO<sub>3</sub>-3%Cr<sup>3+</sup>, and (<b>f</b>) BaTiO<sub>3</sub>-5%Cr<sup>3+</sup>.</p> Full article ">Figure 8
<p>Antioxidant activity of pure and Cr<sup>3+</sup>-doped BaTiO<sub>3.</sub></p> Full article ">
11 pages, 5167 KiB  
Article
Unveiling the Bluish Green Chalcedony Aquaprase™—The Study of Its Microstructure and Mineralogy
by Sara Monico, Ilaria Adamo, Valeria Diella, Yianni Melas, Loredana Prosperi and Nicoletta Marinoni
Crystals 2024, 14(11), 1003; https://doi.org/10.3390/cryst14111003 - 19 Nov 2024
Viewed by 480
Abstract
A bluish green chalcedony (a micro to crypto polycrystalline form of silica) from Africa has been marketed with the trademark AQUAPRASETM. A multimethodological approach, combining gemological analyses, thin section examination, scanning electron microscopy, X-ray powder diffraction, Raman spectroscopy, and trace elements [...] Read more.
A bluish green chalcedony (a micro to crypto polycrystalline form of silica) from Africa has been marketed with the trademark AQUAPRASETM. A multimethodological approach, combining gemological analyses, thin section examination, scanning electron microscopy, X-ray powder diffraction, Raman spectroscopy, and trace elements chemical analyses by LA–ICP–MS, was carried out to characterize this material from a gemological and mineralogical point of view. The chalcedony samples consist of a mixture of quartz and moganite, as shown by the X-ray powder diffraction analysis and Raman spectroscopy. “Aquaprase” showed a strong microstructural zoning in terms of grain size, from macrocrystalline to micro and crypto, and morphology. Trace element variations correlated well with the different colored areas of the samples. In particular, the main chromophore ion present in the bluish green areas of the “aquaprase” chalcedony was chromium, followed by iron and nickel, so this chalcedony could be included in the group of chromium-bearing chalcedony. Rayleigh light scattering contributed to the blue hue of the gems. Full article
(This article belongs to the Special Issue Gems Decoded: Bridging Gemology, Mineralogy, Crystallography and Geology)
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Figure 1
<p>Some selected cut aquaprase chalcedony samples (from 6.28 5 to 12.59 ct) investigated in the present study. On the left there are the bluish green samples (<span class="html-italic">AQ_type I</span>), whereas on the right the sample showing in reflected light a blue “turquoise”-like color (<span class="html-italic">AQ_type II</span>).</p> Full article ">Figure 2
<p>One aquaprase chalcedony sample (<span class="html-italic">AQ_type II</span>) (<b>a</b>) as viewed in transmitted and (<b>b</b>) in reflected lights collected by a dark field gemological microscope. Note the “cloudy” aspect of the stones. Photos by Ludovica Faldi (IGI).</p> Full article ">Figure 3
<p>Aquaprase chalcedony samples (<span class="html-italic">AQ_type II</span>) showing color zoning and banding when observed in transmitted light. (<b>a</b>) the contact boundary between the blue clouds and the white areas, (<b>b</b>) opaque and brown inclusions between blue clouds and white areas and (<b>c</b>) banding. Photos by Ludovica Faldi (IGI).</p> Full article ">Figure 4
<p>Diffraction patterns of an <span class="html-italic">AQ_type I</span> sample (<b>a</b>) from 10° to 60° 2θ and (<b>b</b>) an enlargement from 18° to 32° 2θ of a selected sample, showing the presence of quartz and moganite in aquaprase chalcedony. Dashed blue lines indicate the position of the main peaks of quartz, while red lines indicate the position of the main peaks of moganite.</p> Full article ">Figure 5
<p>Normalized Raman spectra of the aquaprase chalcedony sample (<span class="html-italic">AQ_type I</span>) in the 300–700 nm range, showing main peaks of quartz at 465 cm<sup>−1</sup> and moganite at 501 cm<sup>−1</sup>.</p> Full article ">Figure 6
<p>Thin section of an aquaprase samples: (<b>a</b>) <span class="html-italic">AQ_ type I</span> and (<b>b</b>) <span class="html-italic">AQ_type II</span>. In the <span class="html-italic">AQ_type I</span>, (<b>a</b>) the right part of the figure is characterized by cryptocrystalline quartz (A), whereas the left part presents microcrystalline quartz (B). In the <span class="html-italic">AQ_type II</span>, (<b>b</b>) the right and lower part of the figure are dominated by cryptocrystalline quartz (A), whereas the upper left part consists of microcrystalline and feathery quartz (B). Bands of fibrous quartz are observable between microcrystalline and cryptocrystalline quartz (C). Crossed Nicols observation, gray scale, 2.5× magnification.</p> Full article ">Figure 7
<p>Backscattered electron (BSE) images of a bluish green portion of an aquaprase chalcedony sample (<span class="html-italic">AQ_type I</span>). (<b>a</b>) a panoramic view of the sample and (<b>b</b>) a particular of irregular darker branched and spherical bodies in the background mass.</p> Full article ">
15 pages, 4409 KiB  
Article
Corrosion Inhibition of PAAS/ZnO Complex Additive in Alkaline Al-Air Battery with SLM-Manufactured Anode
by Guangpan Peng, Yuankun Geng, Chenhao Niu, Hanqian Yang, Weipeng Duan and Shu Cao
Crystals 2024, 14(11), 1002; https://doi.org/10.3390/cryst14111002 - 19 Nov 2024
Cited by 1 | Viewed by 903
Abstract
In order to improve the electrochemical activity and discharge performance of aluminum–air batteries and to reduce self-corrosion of the anode, an SLM-manufactured aluminum alloy was employed as the anode of the Al-air battery, and the influence of PAAS and ZnO inhibitors taken separately [...] Read more.
In order to improve the electrochemical activity and discharge performance of aluminum–air batteries and to reduce self-corrosion of the anode, an SLM-manufactured aluminum alloy was employed as the anode of the Al-air battery, and the influence of PAAS and ZnO inhibitors taken separately or together on the self-corrosion rate and discharge performance of the Al-air battery in a 4 M NaOH solution were investigated. The experimental result indicated that the effect of a composite corrosion inhibitor was stronger than that of a single corrosion inhibitor. The addition of the compound inhibitor not only promoted the activation of the anode but also formed a more stable composite protective film on the surface of the anode, which effectively slowed down the self-corrosion and improved the utilization rate of the anode. In NaOH/PAAS/ZnO electrolytes, the dissolution of the Al6061 alloy was mainly controlled by the diffusion of the electric charge in the corrosion products or the zinc salt deposition layer. Meanwhile, for the Al-air battery, the discharge voltage, specific capacity, and specific energy increased by 21.74%, 26.72%, and 54.20%, respectively. In addition, the inhibition mechanism of the composite corrosion inhibitor was also expounded. The excellent discharge performance was due to the addition of the composite corrosion inhibitor, which promoted the charge transfer of the anode reaction, improved the anode’s activity, and promoted the uniform corrosion of the anode. This study provides ideas for the application of aluminum–air batteries in the field of new energy. Full article
(This article belongs to the Section Materials for Energy Applications)
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<p>Schematic of the electrochemical testing equipment.</p> Full article ">Figure 2
<p>Schematic of the discharge testing equipment.</p> Full article ">Figure 3
<p>Schematic of XRD and SEM equipment.</p> Full article ">Figure 4
<p>Self-corrosion behavior of the Al6061 anode in different electrolyte systems.</p> Full article ">Figure 5
<p>OCP of the Al6061 anode in different electrolyte systems.</p> Full article ">Figure 6
<p>Polarization curve of Al6061 anode in different electrolyte systems.</p> Full article ">Figure 7
<p>EIS of the Al6061 anode in different electrolyte systems: (<b>a</b>) NaOH and NaOH + PAAS; (<b>b</b>) NaOH + ZnO and NaOH + PAAS + ZnO.</p> Full article ">Figure 8
<p>Equivalent circuit of the Al6061 anode in different electrolyte systems: (<b>a</b>) NaOH and NaOH + PAAS; (<b>b</b>) NaOH + ZnO and NaOH + PAAS + ZnO.</p> Full article ">Figure 9
<p>Discharge curve of the Al-air battery in different electrolyte systems.</p> Full article ">Figure 10
<p>Battery performance parameters of Al6061 anode in different porous electrolytes.</p> Full article ">Figure 11
<p>Surface morphology of the Al6061 anode after discharge in different electrolyte systems: (<b>a</b>) NaOH; (<b>b</b>) NaOH + PAAS; (<b>c</b>) NaOH + ZnO; (<b>d</b>) NaOH + PAAS + ZnO.</p> Full article ">Figure 12
<p>Element composition of the corresponding area in <a href="#crystals-14-01002-f011" class="html-fig">Figure 11</a> and EDS atlas of point A to point F: (<b>a</b>) point A, B and C; (<b>b</b>) point D, E and F.</p> Full article ">Figure 13
<p>XRD pattern of surface corrosion products of the Al6061 anode after discharge in different electrolytes.</p> Full article ">Figure 14
<p>Inhibition mechanism of the Al6061 anode in different electrolyte systems.</p> Full article ">
15 pages, 5644 KiB  
Article
The Influence of Ultrasonic Irradiation of a 316L Weld Pool Produced by DED on the Mechanical Properties of the Produced Component
by Dennis Lehnert, Christian Bödger, Philipp Pabel, Claus Scheidemann, Tobias Hemsel, Stefan Gnaase, David Kostka and Thomas Tröster
Crystals 2024, 14(11), 1001; https://doi.org/10.3390/cryst14111001 - 19 Nov 2024
Viewed by 651
Abstract
Additive manufacturing of metallic components often results in the formation of columnar grain structures aligned along the build direction. These elongated grains can introduce anisotropy, negatively impacting the mechanical properties of the components. This study aimed to achieve controlled solidification with a fine-grained [...] Read more.
Additive manufacturing of metallic components often results in the formation of columnar grain structures aligned along the build direction. These elongated grains can introduce anisotropy, negatively impacting the mechanical properties of the components. This study aimed to achieve controlled solidification with a fine-grained microstructure to enhance the mechanical performance of printed parts. Stainless steel 316L was used as the test material. High-intensity ultrasound was applied during the direct energy deposition (DED) process to inhibit the formation of columnar grains. The investigation emphasized the importance of amplitude changes of the ultrasound wave as the system’s geometry continuously evolves with the addition of multiple layers and assessed how these changes influence the grain size and distribution. Initial tests revealed significant amplitude fluctuations during layer deposition, highlighting the impact of layer deposition on process uniformity. The mechanical results demonstrated that the application of ultrasound effectively refined the grain structure, leading to a 15% increase in tensile strength compared to conventionally additively manufactured samples. Full article
(This article belongs to the Section Crystalline Metals and Alloys)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>Schematics of the DED process [<a href="#B1-crystals-14-01001" class="html-bibr">1</a>].</p> Full article ">Figure 2
<p>Experimental setup inside the DMG MORI LASERTEC 65 3D.</p> Full article ">Figure 3
<p>Schematic representation of the process strategy for the individual tracks with different ultrasonic amplitudes (given in µm).</p> Full article ">Figure 4
<p>(<b>A</b>) Schematic representation of the process strategy of the volumes; (<b>B</b>) Dimension and position of the volumes on the substrate.</p> Full article ">Figure 5
<p>Dimensions of the tensile test specimen.</p> Full article ">Figure 6
<p>(<b>A</b>) Minimum Feret diameter of the reference samples without (black) and with (red) ultrasound with standard deviations; (<b>B</b>) Maximum Feret diameter of the reference samples without (black) and with (red) ultrasound with deviations; and (<b>C</b>) Microscopic view of reference sample without ultrasound (<b>C1</b>) and with ultrasound (<b>C2</b>).</p> Full article ">Figure 7
<p>Single tracks with different amplitudes (<b>A</b>) and corresponding surface roughness (<b>B</b>).</p> Full article ">Figure 8
<p>Microstructure (EBSD) images with and without ultrasound (<b>A</b>); Grain sizes at different deflection amplitudes (<b>B</b>).</p> Full article ">Figure 9
<p>Comparison of the tensile strength (<b>A</b>) and elongation at break (<b>B</b>) of the samples produced with and without ultrasound.</p> Full article ">Figure 10
<p>Grain sizes for the top and bottom area of samples A and B (<b>A</b>) and the respective EBSD for sample B (<b>B</b>).</p> Full article ">Figure 11
<p>Metallurgical evaluation of the microscopic images from samples without current control (<b>A</b>) and with current control (<b>B</b>) showing the relative density.</p> Full article ">
11 pages, 6860 KiB  
Article
Effect of Powder Preparation Techniques on Microstructure, Mechanical Properties, and Wear Behaviors of Graphene-Reinforced Copper Matrix Composites
by Doan Dinh Phuong, Pham Van Trinh, Phan Ngoc Minh, Alexandr A. Shtertser and Vladimir Y. Ulianitsky
Crystals 2024, 14(11), 1000; https://doi.org/10.3390/cryst14111000 - 19 Nov 2024
Viewed by 610
Abstract
In this study, the effect of powder preparation techniques on microstructure, mechanical properties, and wear behaviors of graphene-reinforced copper matrix (Gr/Cu) composites was investigated. The composite powders were prepared by two different techniques including high-energy ball (HEB) milling and nanoscale dispersion (ND). The [...] Read more.
In this study, the effect of powder preparation techniques on microstructure, mechanical properties, and wear behaviors of graphene-reinforced copper matrix (Gr/Cu) composites was investigated. The composite powders were prepared by two different techniques including high-energy ball (HEB) milling and nanoscale dispersion (ND). The obtained results showed that the ND technique allows the preparation of the composite powder with a smaller and more uniform grain size compared to the HEB technique. By adding Gr, the mechanical properties and wear resistance of the composite were much improved compared to pure Cu. In addition, the composite using the powder prepared by the ND technique exhibits the best performance with the improvement in hardness (40%), tensile strength (66%) and wear resistance (38%) compared to pure Cu. This results from the uniform grain size of the Cu matrix and the good bonding between Cu matrix and Gr. The strengthening mechanisms were also analyzed to clarify the contribution of the powder preparation techniques on the load transfer strengthening mechanisms of the prepared composite. Full article
(This article belongs to the Special Issue Processing, Structure and Properties of Metal Matrix Composites)
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<p>Schematic view of the preparation process for Gr/Cu powder by using high energy ball milling (HEB-Approach 1) and nanoscale dispersion (ND, Approach 2).</p> Full article ">Figure 2
<p>SEM images of (<b>a</b>) Cu powder and (<b>b</b>) graphene powders.</p> Full article ">Figure 3
<p>Sintering process of Gr/Cu composite by hot isostatic pressing technique.</p> Full article ">Figure 4
<p>SEM images and EDS spectra of Gr/Cu powder prepared by using different techniques (<b>a</b>) HEB and (<b>b</b>) ND.</p> Full article ">Figure 5
<p>SEM images of Gr/Cu composite using powder prepared by using different techniques: (<b>a</b>) HEB and (<b>b</b>) ND.</p> Full article ">Figure 6
<p>EBSD inverse pole figure (IPF) maps of (<b>a</b>) pure Cu (HEB), (<b>b</b>) Gr/Cu (HEB), (<b>c</b>) pure Cu (ND), and (<b>d</b>) Gr/Cu (ND).</p> Full article ">Figure 7
<p>(<b>a</b>) XRD patterns and (<b>b</b>) crystallite size of pure Cu and Gr/Cu with powder prepared by HEB and ND techniques.</p> Full article ">Figure 8
<p>(<b>a</b>) Microhardness and (<b>b</b>) tensile strength of pure Cu and Gr/Cu with powder prepared by HEB and ND techniques.</p> Full article ">Figure 9
<p>Contribution of strengthening mechanisms to the yield strength of Gr/Cu composites with powder prepared by HEB technique.</p> Full article ">Figure 10
<p>Contribution of strengthening mechanisms to the yield strength of Gr/Cu composites with powder prepared by ND technique.</p> Full article ">Figure 11
<p>(<b>a</b>,<b>b</b>) Friction coefficient and (<b>c</b>) wear rate of pure Cu and Gr/Cu with powder prepared by HEB and ND techniques.</p> Full article ">
13 pages, 5902 KiB  
Article
Modulation of Surface Elastic Waves and Surface Acoustic Waves by Acoustic–Elastic Metamaterials
by Chang Fu and Tian-Xue Ma
Crystals 2024, 14(11), 997; https://doi.org/10.3390/cryst14110997 - 18 Nov 2024
Viewed by 812
Abstract
Metamaterials enable the modulation of elastic waves or acoustic waves in unprecedented ways and have a wide range of potential applications. This paper achieves the simultaneous manipulation of surface elastic waves (SEWs) and surface acoustic waves (SAWs) using two-dimensional acousto-elastic metamaterials (AEMMs). The [...] Read more.
Metamaterials enable the modulation of elastic waves or acoustic waves in unprecedented ways and have a wide range of potential applications. This paper achieves the simultaneous manipulation of surface elastic waves (SEWs) and surface acoustic waves (SAWs) using two-dimensional acousto-elastic metamaterials (AEMMs). The proposed AEMMs are composed of periodic hollow cylinders on the surface of a semi-infinite substrate. The band diagrams and the frequency responses of the AEMMs are numerically calculated through the finite element approach. The band diagrams exhibit simultaneous bandgaps for the SEWs and SAWs, which can also be effectively tuned by the modification of AEMM geometry. Furthermore, we construct the AEMM waveguide by the introduction of a line defect and hence demonstrate its ability to guide the SEWs and SAWs simultaneously. We expect that the proposed AEMMs will contribute to the development of multi-functional wave devices, such as filters for dual waves in microelectronics or liquid sensors that detect more than one physical property. Full article
(This article belongs to the Section Hybrid and Composite Crystalline Materials)
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<p>Schemes of the AEMM unit cells for the elastic (<b>a</b>) and acoustic (<b>b</b>) waves. (<b>c</b>) Cross-section view of the AEMM unit cell. (<b>d</b>) The first Brillouin zone of the square lattice.</p> Full article ">Figure 2
<p>Band diagrams of the AEMM unit cell for the elastic (<b>a</b>) and acoustic (<b>b</b>) waves. (<b>c</b>) Displacement distributions and deformations of the SEW modes marked in (<b>a</b>). (<b>d</b>) Pressure distributions of the SAW modes marked in (<b>b</b>).</p> Full article ">Figure 3
<p>Transmission spectra of the SEWs (<b>a</b>) and SAWs (<b>b</b>) in the finite-sized AEMM along the <math display="inline"><semantics> <mi mathvariant="normal">Γ</mi> </semantics></math>X direction.</p> Full article ">Figure 4
<p>Distributions of the displacement (<b>a</b>) and pressure (<b>b</b>) fields of the finite-sized AEMM at different excitation frequencies.</p> Full article ">Figure 5
<p>Band diagrams of the AEMM unit cell with different cylinder heights, where the upper and lower panels are the results of the elastic and acoustic waves, respectively.</p> Full article ">Figure 6
<p>Transmission curves of the SEWs (<b>upper panel</b>) and SAWs (<b>lower panel</b>) along the <math display="inline"><semantics> <mi mathvariant="normal">Γ</mi> </semantics></math>X direction for different cylinder heights.</p> Full article ">Figure 7
<p>Schemes of the AEMM supercells with a line defect for the elastic (<b>a</b>) and acoustic (<b>b</b>) waves.</p> Full article ">Figure 8
<p>Band diagrams of the AEMM supercell for the elastic (<b>a</b>) and acoustic (<b>b</b>) waves, where the direction of wave propagation is the <math display="inline"><semantics> <mi mathvariant="normal">Γ</mi> </semantics></math>X direction.</p> Full article ">Figure 9
<p>(<b>a</b>) Displacement distributions and deformations of the SEW modes marked in <a href="#crystals-14-00997-f008" class="html-fig">Figure 8</a>a. (<b>b</b>) Pressure distributions of the SAW modes marked in <a href="#crystals-14-00997-f008" class="html-fig">Figure 8</a>b.</p> Full article ">Figure 10
<p>Schemes for calculating the frequency responses of the AEMM waveguide: (<b>a</b>) solid domain and (<b>b</b>) air domain.</p> Full article ">Figure 11
<p>(<b>a</b>) Transmission curves of the SEWs in the AEMM waveguide, where the normalized frequencies corresponding to marker points 1, 2 are 0.257, 0.293. (<b>b</b>) Transmission curves of the SAWs in the AEMM waveguide, where the normalized frequencies corresponding to marker points I, II are 0.30, 0.36.</p> Full article ">Figure 12
<p>Distributions of the displacement (<b>a</b>) and pressure (<b>b</b>) fields of the AEMM waveguide at different excitation frequencies.</p> Full article ">
15 pages, 7053 KiB  
Article
Effects of Temperature and Secondary Orientations on the Deformation Behavior of Single-Crystal Superalloys
by Sujie Liu, Cui Zong, Guangcai Ma, Yafeng Zhao, Junjie Huang, Yi Guo and Xingqiu Chen
Crystals 2024, 14(11), 996; https://doi.org/10.3390/cryst14110996 - 18 Nov 2024
Cited by 1 | Viewed by 627
Abstract
The tensile behavior of single-crystal superalloys was investigated at room temperature (RT) and 850 °C, focusing on various secondary orientations. Transmission electron microscopy (TEM) and quasi in situ electron backscatter diffraction (EBSD) were employed to study the deformation mechanisms across length scales. Deformation [...] Read more.
The tensile behavior of single-crystal superalloys was investigated at room temperature (RT) and 850 °C, focusing on various secondary orientations. Transmission electron microscopy (TEM) and quasi in situ electron backscatter diffraction (EBSD) were employed to study the deformation mechanisms across length scales. Deformation at 850 °C enhanced the tensile ductility of the samples, evidenced by the more uniform coverage of dislocations across the γ and γ′ phases, and the fracture mode switched from pure cleavage at room temperature to mixed mode due to accelerated void growth. The influence of secondary orientations on mechanical properties is insignificant at room temperature. However, the ductility of the different secondary orientation samples shows significant variations at 850 °C, among which the one with [001] rotated 37° demonstrated superior ductility compared to others. Full article
(This article belongs to the Special Issue Microstructure and Mechanical Behaviour of Structural Materials)
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<p>(<b>a</b>) Schematic diagram of the four secondary orientations of 5°, 37°, 47°, and 57°, sampled on the ingot; (<b>b</b>) geometry of the tension sample with the location for the EBSD scans indicated by the box.</p> Full article ">Figure 2
<p>Microstructures of the alloy: (<b>a</b>) SEM image; (<b>b</b>) the carbide area fraction varies with different secondary orientations; (<b>c</b>) EDS images indicating the carbide compositions.</p> Full article ">Figure 3
<p>True stress–strain curves for different secondary orientations at (<b>a</b>) RT and (<b>b</b>) 850 °C.</p> Full article ">Figure 4
<p>Fracture surface of the samples tested at (<b>a</b>,<b>b</b>) RT and (<b>c</b>,<b>d</b>) 850 °C. Note that the images are presented at different magnifications.</p> Full article ">Figure 5
<p>TEM bright-field images after fracture at RT. (<b>a</b>,<b>b</b>) Dislocations accumulated in the γ-channel and sheared into the γ′ along the &lt;110&gt; direction. (<b>c</b>) Anti-phase boundaries formed by partial dislocation pairs (red arrow) and stacking faults in the γ′ phases.</p> Full article ">Figure 6
<p>STEM images and corresponding EDS elemental mapping (at. %) at RT. The encircled regions indicate local segregation of γ′ stabilizers: Co, Cr, and Re.</p> Full article ">Figure 7
<p>TEM bright-field images after fracture at 850 °C. (<b>a</b>) Curved dislocations distributed uniformly in the γ and γ′ phases, (<b>b</b>) irregular dislocation network at the γ/γ′ interface. The white triangles indicate partial dislocation pairs, (<b>c</b>) screw dislocations cross slip into γ′, and (<b>d</b>) partial dislocation pairs cut into γ′ by cross-slip, indicated by the red triangles.</p> Full article ">Figure 8
<p>STEM images and corresponding EDS elemental mapping (at.%) at 850 °C.</p> Full article ">Figure 9
<p>Quasi in situ observation of the GND density distribution of different secondary orientations during RT tensile tests at strains of 0%, 3%, 8%, and 12%.</p> Full article ">Figure 10
<p>Quasi in-situ observation of the GND density distribution of different secondary orientations during 850 °C tensile tests at strains of 0%, 3%, 8%, and 18%.</p> Full article ">Figure 11
<p>(<b>a</b>,<b>b</b>) The work hardening rate variations among secondary orientations at (<b>a</b>) RT and (<b>b</b>) 850 °C. (<b>c</b>,<b>d</b>) indicate the evolution of the GND density growth rate vs. strain for different secondary orientations at (<b>c</b>) RT and (<b>d</b>) 850 °C.</p> Full article ">
12 pages, 2023 KiB  
Article
A Revival of Molecular Surface Electrostatic Potential Statistical Quantities: Ionic Solids and Liquids
by Jane S. Murray, Kevin E. Riley and Tore Brinck
Crystals 2024, 14(11), 995; https://doi.org/10.3390/cryst14110995 - 17 Nov 2024
Viewed by 766
Abstract
In this paper, we focus on surface electrostatic potentials and a variety of statistically derived quantities defined in terms of the surface potentials. These have been shown earlier to be meaningful in describing features of these potentials and have been utilized to understand [...] Read more.
In this paper, we focus on surface electrostatic potentials and a variety of statistically derived quantities defined in terms of the surface potentials. These have been shown earlier to be meaningful in describing features of these potentials and have been utilized to understand the interactive tendencies of molecules in condensed phases. Our current emphasis is on ionic salts and liquids instead of neutral molecules. Earlier work on ionic salts has been reviewed. Presently, our results are for a variety of singly charged cations and anions that can combine to form ionic solids or liquids. Our approach is computational, using the density functional B3PW91/6-31G(d,p) procedure for all calculations. We find consistently that the average positive and negative surface electrostatic potentials of the cations and anions decrease with the size of the ion, as has been noted earlier. A model using computed statistical quantities has allowed us to put the melting points of both ionic solids and liquids together, covering a range from 993 °C to 11 °C. Full article
(This article belongs to the Section Inorganic Crystalline Materials)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>Computed electrostatic potentials on the 0.001 au iso-density contours of (<b>a</b>) hydrazine, (<b>b</b>) the hydrazinium cation, and (<b>c</b>) NH<sub>2</sub>NH<sup>−</sup>. The frameworks are shown in gray within the surfaces. The surface of (<b>a</b>) has both positive and negative values of V<sub>S</sub>(<b>r</b>); those of (<b>b</b>,<b>c</b>) are completely positive and negative, respectively. The color ranges, in kcal/mol, are therefore necessarily different for each. The color ranges for (<b>a</b>) are red, greater than 15; yellow, from 15 to 0; green, from 0 to −15; blue, more negative than −15. The color ranges for (<b>b</b>) are red, greater than 150; yellow, from 150 to 125; green, from 125 to 100; blue, less than 100. The color ranges for (<b>c</b>) are red, less negative than −110; yellow, from −110 to −130; green, from −130 to −150; blue, more negative than −150.</p> Full article ">Figure 2
<p>The quantum chemically computed electrostatic potential (V<sub>QC</sub>(r)) compared with the electrostatic potential of a point charge (V<sub><span class="html-italic">q</span></sub>(r)) as functions of the distance (r) from the nucleus for the ions Na<sup>+</sup> and F<sup>−</sup>. The distance of the iso-density contour (<span class="html-italic">ρ</span>(r) = 0.001 au) that is used to compute V<sub>S</sub>(<b>r</b>) is marked in both plots.</p> Full article ">Figure 3
<p>Computed electrostatic potentials on the 0.001 au iso-density contours of (<b>a</b>) EA<sup>+</sup> and (<b>b</b>) [BMIM]<sup>+</sup>. The frameworks are shown in gray within the surfaces. The color ranges, in kcal/mol, are for (<b>a</b>) red, greater than 150; yellow, from 150 to 125; green, from 125 to 100; blue, less than 100. The color ranges for (<b>b</b>) are red, greater than 100; yellow, from 100 to 80; green, from 80 to 60; blue, less than 60.</p> Full article ">Figure 4
<p>Computed electrostatic potentials on the 0.001 au iso-density contours of (<b>a</b>) BF<sub>4</sub><sup>−</sup> and (<b>b</b>) PF<sub>6</sub><sup>−</sup>. The color ranges, in kcal/mol, are for (<b>a</b>) red, less negative than −129; yellow, from −129 to −133; green, from −133 to −137; blue, more negative than −137. The color ranges for (<b>b</b>) are red, less negative than −113; yellow, from −113 to −117; green, from −117 to −121; blue, more negative than −12.</p> Full article ">Figure 5
<p>Plot of predicted melting points using Equation (8) vs. experimentally determined melting points for the seventeen ionic systems in <a href="#crystals-14-00995-t003" class="html-table">Table 3</a>. R = 0.997.</p> Full article ">
12 pages, 3593 KiB  
Article
Lattice Dynamics of Ni3-xCoxB2O6 Solid Solutions
by Svetlana N. Sofronova, Maksim S. Pavlovskii, Svetlana N. Krylova, Alexander N. Vtyurin and Alexander S. Krylov
Crystals 2024, 14(11), 994; https://doi.org/10.3390/cryst14110994 - 17 Nov 2024
Viewed by 576
Abstract
On the one hand, Ni3-xCoxB2O6 solid solutions are promising anode materials for lithium batteries, and on the other hand, they have antiferromagnetic properties. This study examines the lattice dynamics of Ni3-xCoxB2O6 [...] Read more.
On the one hand, Ni3-xCoxB2O6 solid solutions are promising anode materials for lithium batteries, and on the other hand, they have antiferromagnetic properties. This study examines the lattice dynamics of Ni3-xCoxB2O6 solid solutions for x = 0, 1, 2, 3 by means of quantum chemistry and Raman spectroscopy. The vibrational spectra of the compound NiCo2B2O6 have been studied using the polarized Raman spectroscopy method. Good agreement was found between the theoretical and experimental results. As expected, the largest change in frequencies was observed in the modes where the vibrations of the metal ion had a large amplitude. The substitution of cobalt by nickel does not lead to the appearance of soft modes. This fact indicates that the structures of the solid solutions are stable. Full article
(This article belongs to the Section Inorganic Crystalline Materials)
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<p>The crystal structure of kotoite. The 2a and 4f crystallographic positions of the transition metal ions are shown by different colors.</p> Full article ">Figure 2
<p>The dispersion curves of frequencies for Co<sub>2</sub>Ni(BO<sub>3</sub>)<sub>2</sub> (<b>a</b>) and CoNi<sub>2</sub>(BO<sub>3</sub>)<sub>2</sub> (<b>b</b>).</p> Full article ">Figure 2 Cont.
<p>The dispersion curves of frequencies for Co<sub>2</sub>Ni(BO<sub>3</sub>)<sub>2</sub> (<b>a</b>) and CoNi<sub>2</sub>(BO<sub>3</sub>)<sub>2</sub> (<b>b</b>).</p> Full article ">Figure 3
<p>A single crystal of Co<sub>2</sub>NiB<sub>2</sub>O<sub>6</sub>.</p> Full article ">Figure 4
<p>The angular dependence of the Raman spectra of Co<sub>2</sub>NiB<sub>2</sub>O<sub>6</sub> (<b>a</b>) low-wavenubers region (<b>b</b>) high-wavenumbers region.</p> Full article ">Figure 5
<p>The forms of the vibrational modes of the Co<sub>3</sub>B<sub>2</sub>O<sub>6</sub> crystal near 400 and 900 cm<sup>−1</sup>. (<b>a</b>) mode B<sub>1g</sub> 396.3 cm<sup>−1</sup>; (<b>b</b>) mode B<sub>2g</sub> 396.4 cm<sup>−1</sup>; (<b>c</b>) mode B<sub>1g</sub> 898.2 cm<sup>−1</sup>; (<b>d</b>) mode A<sub>1g</sub> 897.4 cm<sup>−1</sup>.</p> Full article ">Figure 6
<p>The comparison of the experimental Raman spectra of Ni<sub>3</sub>B<sub>2</sub>O<sub>6</sub> and Co<sub>2</sub>NiB<sub>2</sub>O<sub>6</sub> in the parallel polarizer–analyzer configuration. (<b>a</b>) 100–500 cm<sup>−1</sup>, (<b>b</b>) 500–1300 cm<sup>−1</sup>. The angle 0° denotes the initial position and 90° denotes the position of the crystal rotated by 90° to the incident light polarization.</p> Full article ">
19 pages, 14171 KiB  
Article
Mechanical, Tribological, and Corrosion Resistance Properties of (TiAlxCrNbY)Ny High-Entropy Coatings Synthesized Through Hybrid Reactive Magnetron Sputtering
by Nicolae C. Zoita, Mihaela Dinu, Anca C. Parau, Iulian Pana and Adrian E. Kiss
Crystals 2024, 14(11), 993; https://doi.org/10.3390/cryst14110993 - 17 Nov 2024
Cited by 1 | Viewed by 751
Abstract
This study investigates the effects of aluminum and nitrogen content on the microstructure, mechanical properties, and tribological performance of high-entropy coatings based on (TiCrAlxNbY)Ny systems. Using a hybrid magnetron sputtering technique, both metallic and nitride coatings were synthesized and evaluated. [...] Read more.
This study investigates the effects of aluminum and nitrogen content on the microstructure, mechanical properties, and tribological performance of high-entropy coatings based on (TiCrAlxNbY)Ny systems. Using a hybrid magnetron sputtering technique, both metallic and nitride coatings were synthesized and evaluated. Increasing the aluminum concentration led to a transition from a crystalline to a nanocrystalline and nearly amorphous (NC/A) structure, with the TiAl0.5CrNbY sample (11.8% Al) exhibiting the best balance of hardness (6.8 GPa), elastic modulus (87.1 GPa), and coefficient of friction (0.64). The addition of nitrogen further enhanced these properties, transitioning the coatings to a denser fine-grained FCC structure. The HN2 sample (45.8% nitrogen) displayed the highest hardness (21.8 GPa) but increased brittleness, while the HN1 sample (32.9% nitrogen) provided an optimal balance of hardness (14.3 GPa), elastic modulus (127.5 GPa), coefficient of friction (0.60), and wear resistance (21.2 × 10−6 mm3/Nm). Electrochemical impedance spectroscopy revealed improved corrosion resistance for the HN1 sample due to its dense microstructure. Overall, the (TiAl0.5CrNbY)N0.5 coating achieved the best performance for friction applications, such as break and clutch systems, requiring high coefficients of friction, high wear resistance, and durability. Full article
(This article belongs to the Special Issue Advances of High Entropy Alloys)
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<p>2ϴ/ϴ X-ray diffraction patterns corresponding to H1–H4 coatings.</p> Full article ">Figure 2
<p>AFM surface images (3 × 3 µm<sup>2</sup>) corresponding to (<b>a</b>) H1 and (<b>b</b>) H4 samples. Cross-sectional HR-SEM images corresponding to (<b>c</b>) H1 and (<b>d</b>) H4 samples.</p> Full article ">Figure 3
<p>Elemental cross-sectional mapping corresponding to H1 coating, 2.15 × 1.54 μm<sup>2</sup>.</p> Full article ">Figure 4
<p>(<b>a</b>) The averaged values of hardness (H) and Young’s modulus (E). (<b>b</b>) Wear rate. (<b>c</b>) Friction coefficient evolution.</p> Full article ">Figure 5
<p>(<b>a</b>) 2θ/θ X-ray diffraction patterns and (<b>b</b>) XRR experimental (scattered points) and simulated patterns (continuous lines) corresponding to samples H3, HN1, and HN2; (<b>c</b>) average mass density variation with nitrogen content.</p> Full article ">Figure 6
<p>AFM surface images (3 × 3 µm<sup>2</sup>) corresponding to (<b>a</b>) H3, (<b>b</b>) HN1, and (<b>c</b>) HN2 samples. Cross-sectional HR-SEM images corresponding to (<b>d</b>) H3, (<b>e</b>) HN1, and (<b>f</b>) HN2 samples.</p> Full article ">Figure 7
<p>Mechanical and tribological properties of (TiAl<sub>0.5</sub>CrNbY)N<sub>y</sub>/C45 (0 ≤ y ≤ 0.85). (<b>a</b>) Hardness (H) and Young’s modulus (E). (<b>b</b>) Coefficient of friction. (<b>c</b>) Wear rate.</p> Full article ">Figure 8
<p>SEM micrographs of wear tracks after tribological test corresponding to samples (<b>a</b>) H3 (×300), (<b>b</b>) HN1 (×500), and HN2 (×500). Figures (<b>d</b>) and (<b>e</b>) are magnified views (×1000) of (<b>b</b>) and (<b>c</b>), respectively.</p> Full article ">Figure 9
<p>(<b>a</b>) Nyquist, (<b>b</b>) Bode magnitude, and (<b>c</b>) phase diagrams.</p> Full article ">
9 pages, 6153 KiB  
Article
Thermal Regulation of the Acoustic Bandgap in Pentamode Metamaterials
by Jing Cheng, Shujun Liang and Yangyang Chu
Crystals 2024, 14(11), 992; https://doi.org/10.3390/cryst14110992 - 17 Nov 2024
Viewed by 526
Abstract
This study used the finite element method to investigate the acoustic bandgap (ABG) characteristics of three-dimensional pentamode metamaterial (PM) structures under the thermal environment, and a method for controlling the PM ABG based on external temperature variation is also proposed. The results indicate [...] Read more.
This study used the finite element method to investigate the acoustic bandgap (ABG) characteristics of three-dimensional pentamode metamaterial (PM) structures under the thermal environment, and a method for controlling the PM ABG based on external temperature variation is also proposed. The results indicate that the complete acoustic bandgap can be obtained for a PM in the thermal environment, which makes the PM combine the bandgap characteristics of phononic crystals. More than that, the bandwidth and locations of ABGs can be effectively manipulated by controlling the temperature. Considering the softening effect of thermal stresses, the ABG gradually moves to lower frequencies as the temperature increases. Based on this, different degrees of ABG tunability can be achieved by changing the thermal environment to propagate or suppress acoustic waves of different frequencies. This work provides the possibility for PMs to realize intelligent regulation of the bandgap. Full article
(This article belongs to the Special Issue Research and Applications of Acoustic Metamaterials)
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<p>Schematic illustration of the PM structure.</p> Full article ">Figure 2
<p>The band structure of the PM at (<b>a</b>) room temperature and (<b>b</b>) at 40 °C.</p> Full article ">Figure 3
<p>The band structure of the PM is affected by different factors. (<b>a</b>) Band structures. (<b>b</b>) Localized diagrams of the two bands. The red curve indicates the bandgap structure at room temperature. Pink dotted lines indicate that only thermal stresses are affected at 40 °C. The blue dotted line indicates the influence of both thermal stresses and thermally variable materials at 40 °C.</p> Full article ">Figure 4
<p>The thermal stress distribution of the PM in 40 °C. Unit: N/m<sup>2</sup>. (<b>a</b>) Normal thermal stresses in the <span class="html-italic">x</span>-direction. (<b>b</b>) Shear thermal stresses.</p> Full article ">Figure 5
<p>Variation in the band structure with temperature.</p> Full article ">Figure 6
<p>The band structure of the imaginary frequency and real wave number at different temperatures.</p> Full article ">Figure 7
<p>The trend of the complete bandgap with temperature.</p> Full article ">
3 pages, 172 KiB  
Editorial
Metal Oxides: Crystal Structure, Synthesis and Characterization
by Karolina Siedliska
Crystals 2024, 14(11), 991; https://doi.org/10.3390/cryst14110991 - 17 Nov 2024
Viewed by 669
Abstract
Solid metal oxides are widely recognized for their ubiquitous presence and multifaceted utility in everyday applications [...] Full article
(This article belongs to the Special Issue Metal Oxides: Crystal Structure, Synthesis and Characterization)
16 pages, 5705 KiB  
Article
Performance and Characterization of Additively Manufactured BST Varactor Enhanced by Photonic Thermal Processing
by Carlos Molina, Ugur Guneroglu, Adnan Zaman, Liguan Li and Jing Wang
Crystals 2024, 14(11), 990; https://doi.org/10.3390/cryst14110990 - 16 Nov 2024
Viewed by 824
Abstract
The demand for reconfigurable devices for emerging RF and microwave applications has been growing in recent years, with additive manufacturing and photonic thermal treatment presenting new possibilities to supplement conventional fabrication processes to meet this demand. In this paper, we present the realization [...] Read more.
The demand for reconfigurable devices for emerging RF and microwave applications has been growing in recent years, with additive manufacturing and photonic thermal treatment presenting new possibilities to supplement conventional fabrication processes to meet this demand. In this paper, we present the realization and analysis of barium–strontium–titanate-(Ba0.5Sr0.5TiO3)-based ferroelectric variable capacitors (varactors), which are additively deposited on top of conventionally fabricated interdigitated capacitors and enhanced by photonic thermal processing. The ferroelectric solution with suspended BST nanoparticles is deposited on the device using an ambient spray pyrolysis method and is sintered at low temperatures using photonic thermal processing by leveraging the high surface-to-volume ratio of the BST nanoparticles. The deposited film is qualitatively characterized using SEM imaging and XRD measurements, while the varactor devices are quantitatively characterized by using high-frequency RF measurements from 300 MHz to 10 GHz under an applied DC bias voltage ranging from 0 V to 50 V. We observe a maximum tunability of 60.6% at 1 GHz under an applied electric field of 25 kV/mm (25 V/μm). These results show promise for the implementation of photonic thermal processing and additive manufacturing as a means to integrate reconfigurable ferroelectric varactors in flexible electronics or tightly packaged on-chip applications, where a limited thermal budget hinders the conventional thermal processing. Full article
(This article belongs to the Special Issue Ceramics: Processes, Microstructures, and Properties)
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<p>(<b>a</b>) Diagram of IDC device fabricated with key dimensions labeled; (<b>b</b>) diagram depicting how BST is deposited to only cover the finger area; (<b>c</b>) microscope image of fabricated electrode layer; (<b>d</b>) SEM image of a device after BST deposition.</p> Full article ">Figure 2
<p>Diagram of ambient spray pyrolysis setup.</p> Full article ">Figure 3
<p>(<b>a</b>) Magnitude of the reflection coefficient (<span class="html-italic">S</span><sub>11</sub>) of the BST IDC device under a varied bias voltage (0–50 V), and (<b>b</b>) phase of the reflection coefficient of the BST IDC device under a varied bias voltage (0–50 V).</p> Full article ">Figure 4
<p>(<b>a</b>) Real part of the calculated <span class="html-italic">Z</span><sub>11</sub> (impedance) for different bias conditions, (<b>b</b>) imaginary part of the calculated <span class="html-italic">Z</span><sub>11</sub> (reactance) for different bias conditions, (<b>c</b>) calculated capacitance for the IDC device under different bias conditions, and (<b>d</b>) zoomed-in region of the calculated capacitance versus the frequency below 3 GHz.</p> Full article ">Figure 4 Cont.
<p>(<b>a</b>) Real part of the calculated <span class="html-italic">Z</span><sub>11</sub> (impedance) for different bias conditions, (<b>b</b>) imaginary part of the calculated <span class="html-italic">Z</span><sub>11</sub> (reactance) for different bias conditions, (<b>c</b>) calculated capacitance for the IDC device under different bias conditions, and (<b>d</b>) zoomed-in region of the calculated capacitance versus the frequency below 3 GHz.</p> Full article ">Figure 5
<p>(<b>a</b>) Tunability vs. frequency of a measured IDC device at various bias voltages, and (<b>b</b>) zoomed-in tunability vs. frequency for a reduced frequency range up to 3 GHz, over which the tunability exhibits quasi-constant values.</p> Full article ">Figure 6
<p>(<b>a</b>) Graph of the derived dielectric constant, and (<b>b</b>) zoomed-in dielectric constant graph.</p> Full article ">Figure 7
<p>Calculated <span class="html-italic">Q</span> Factor of the IDC device as a function of frequency under various bias voltages.</p> Full article ">Figure 8
<p>(<b>a</b>) Calculated loss tangent vs. frequency at a varied bias voltage (0–50 V), and (<b>b</b>) zoomed-in loss tangent vs. frequency at a reduced frequency range up to 3 GHz under a varied bias voltage (0–50 V).</p> Full article ">Figure 9
<p>SEM images of the BST film deposited on the IDC device at different magnifications: (<b>a</b>) 240× magnification, (<b>b</b>) 1000× magnification, (<b>c</b>) 4000× magnification, and (<b>d</b>) 8000× magnification.</p> Full article ">Figure 9 Cont.
<p>SEM images of the BST film deposited on the IDC device at different magnifications: (<b>a</b>) 240× magnification, (<b>b</b>) 1000× magnification, (<b>c</b>) 4000× magnification, and (<b>d</b>) 8000× magnification.</p> Full article ">Figure 10
<p>(<b>a</b>) Full span two-theta XRD scan of the BST film after the photonic thermal processing (unlabeled peaks correspond to Kβ), and (<b>b</b>) a comparison of XRD responses of as-deposited and thermally processed BST films.</p> Full article ">Figure 10 Cont.
<p>(<b>a</b>) Full span two-theta XRD scan of the BST film after the photonic thermal processing (unlabeled peaks correspond to Kβ), and (<b>b</b>) a comparison of XRD responses of as-deposited and thermally processed BST films.</p> Full article ">
14 pages, 4748 KiB  
Article
Growth and Characterization of High-Quality YTiO3 Single Crystals: Minimizing Ti4+ Containing Impurities and TiN Formation
by Yong Liu, David Wenhua Bi and Arnaud Magrez
Crystals 2024, 14(11), 989; https://doi.org/10.3390/cryst14110989 - 16 Nov 2024
Cited by 1 | Viewed by 603
Abstract
We report the growth of YTiO3 single crystals using different starting materials with the nominal compositions, (1) stoichiometric YTiO3; (2) oxygen deficient YTiO2.925; (3) oxygen deficient YTiO2.85, and different atmospheres, (1) 97%Ar/3%H2; (2) Ar; [...] Read more.
We report the growth of YTiO3 single crystals using different starting materials with the nominal compositions, (1) stoichiometric YTiO3; (2) oxygen deficient YTiO2.925; (3) oxygen deficient YTiO2.85, and different atmospheres, (1) 97%Ar/3%H2; (2) Ar; (3) forming gas 95%N2/5%H2, using the laser floating zone growth technique. The oxygen-deficient starting materials were prepared by mixing Y2O3, Ti2O3, and Ti powder according to the YTiO3-δ stoichiometry. The addition of Ti powder to the starting materials effectively reacts with the oxygen in the floating zone furnace chamber, reducing Ti4+ ion-containing impurities. High-quality YTiO3 single crystals with (2 0 0) facet were grown from the starting materials corresponding to the nominal composition YTiO2.925. YTiO3 single crystals grown from different starting materials are characteristic of oxygen content of 3 in both pure crystals and crystals containing impurities, revealed by the same oxygen occupancy in single crystal X-ray diffraction measurements. When forming gas was used, a golden TiN coating formed on the surface of rod. Full article
(This article belongs to the Special Issue Advances in Crystal Growth: Pioneering Materials for Tomorrow's Technologies)
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<p>(<b>a</b>) Rods are wrapped in a tantalum foil and sealed in quartz ampoules. (<b>b</b>) The grey rods after sintering at 1100 °C for 24 h. (<b>c</b>) The XRD pattern shows three phases: YTiO<sub>3</sub>, Y<sub>2</sub>O<sub>3</sub>, and Ti<sub>2</sub>O<sub>3</sub>, in the sintered rod.</p> Full article ">Figure 2
<p>(<b>a</b>) YTiO<sub>3</sub> single crystals grown from the starting materials YTiO<sub>3</sub> (growth rate 10 mm/h). (<b>b</b>) Laue X-ray diffraction pattern was performed on the surface of the rod after growth in the floating zone furnace. (<b>c</b>) The Laue pattern obtained from the surface of the rod. (<b>d</b>) The Laue X-ray diffraction measurement was performed on the cross-section of the rod. (<b>e</b>) The Laue pattern obtained from the cross-section of the rod. (<b>f</b>) The rod was titled until a symmetric Laue pattern was obtained. (<b>g</b>) The two-fold symmetric Laue pattern taken from the tilted rod.</p> Full article ">Figure 3
<p>Profile fitting of powder XRD data from the crystal grown from the starting materials with nominal composition YTiO<sub>3</sub> at a growth rate of 10 mm/h. The insets highlight the peaks assigned to the Y<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub> and Y<sub>2</sub>TiO<sub>5</sub> impurities, as indicated by the arrows. The red dotted line, Y<sub>obs</sub>, presents the raw data, the black solid line, Y<sub>calc</sub> by the Le Bail fitting using the HighScore plus program and ICDD PDF5+ data base, the red line Y<sub>obs</sub>-Y<sub>calc</sub>, <span class="html-italic">R</span><sub>wp</sub> and GOOF (goodness of fit) values indicate the quality of fitting. The blue vertical bars indicate the Bragg peak position in the calculated pattern.</p> Full article ">Figure 4
<p>(<b>a</b>) Crystal structure of orthorhombic YTiO<sub>3</sub>. (<b>b</b>) Pyrochlore Y<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub> structure with <math display="inline"><semantics> <mrow> <mi>F</mi> <mi mathvariant="normal">d</mi> <mover accent="true"> <mrow> <mn>3</mn> </mrow> <mo>¯</mo> </mover> <mi mathvariant="normal">m</mi> </mrow> </semantics></math> cubic space group. (<b>c</b>) Hexagonal Y<sub>2</sub>TiO<sub>5</sub> with space group <span class="html-italic">P</span>6<sub>3</sub>/mmc. The red, purple and grey spheres represent the O atoms, the Ti atoms, and the Y atoms, respectively.</p> Full article ">Figure 5
<p>(<b>a</b>) YTiO<sub>3</sub> single crystals grown from the starting materials with nominal composition YTiO<sub>2.925</sub> at a growth rate of 4 mm/h. The rod has two parallel flat surfaces. The inset shows the flat surface after polishing. (<b>b</b>) The XRD measurement reveals that the flat surface corresponds to the (2 0 0) plane. (<b>c</b>) The Laue X-ray diffraction measurement performed on the flat surface. (<b>d</b>) The two-fold symmetric Laue pattern obtained from the flat surface. (<b>e</b>) View of the rod tilted to obtain a symmetric Laue pattern. (<b>f</b>) The two-fold symmetric Laue pattern taken from the tilted rod.</p> Full article ">Figure 6
<p>Profile fitting of powder XRD data from the crystal grown from the starting materials with nominal composition YTiO<sub>2.925</sub> at a growth rate of 4 mm/h. The red dotted line, Y<sub>obs</sub>, presents the raw data, the black solid line, Y<sub>calc</sub> by the Le Bail fitting using the HighScore plus program and ICDD PDF5+ data base, the red line Y<sub>obs</sub>-Y<sub>calc</sub>, <span class="html-italic">R</span><sub>wp</sub> and GOOF (goodness of fit) values indicate the quality of fitting.</p> Full article ">Figure 7
<p>(<b>a</b>) The temperature dependence of the magnetic susceptibility of single-crystal crushed powder samples from the single crystals grown from the starting materials YTiO<sub>3</sub>, YTiO<sub>2.925</sub> and YTiO<sub>2.85</sub>. (<b>b</b>) The magnetic field dependence of magnetization for the same powder samples as those in (<b>a</b>). (<b>c</b>) Heat capacity as a function of temperature for the crystals grown from rods with an oxygen-deficient YTiO<sub>2.925</sub> composition.</p> Full article ">Figure 8
<p>(<b>a</b>) YTiO<sub>3</sub> single crystals grown from the starting materials YTiO<sub>2.85</sub> at 10 mm/h under Ar + H<sub>2</sub> atmosphere. A thin golden layer formed on the surface of the rod due to the air leak. (<b>b</b>) The XRD pattern shows the presence of TiN phase in the sample shown in (<b>a</b>). (<b>c</b>) A homogeneous gold-like coating on the YTiO<sub>3</sub> single crystal obtained when growth is performed under forming gas. (<b>d</b>) The XRD measurement was performed on the surface of the rod and TiN phase is identified.</p> Full article ">Figure 9
<p>(<b>a</b>) The temperature dependence of magnetization reveals the superconducting transition at about 4 K in the powder obtained by grinding the rod grown under forming gas. (<b>b</b>) The magnetic hysteresis loop measured at <span class="html-italic">T</span> = 3 K also evidences the presence of the TiN superconducting phase in the powder.</p> Full article ">
20 pages, 20721 KiB  
Article
Investigating Exchange Efficiencies of Sodium and Magnesium to Access Lithium from β-Spodumene and Li-Stuffed β-Quartz (γ-Spodumene)
by Joanne Gamage McEvoy, Yves Thibault and Dominique Duguay
Crystals 2024, 14(11), 988; https://doi.org/10.3390/cryst14110988 - 16 Nov 2024
Viewed by 706
Abstract
After the high-temperature pretreatment of α-spodumene to induce a phase transition to β-spodumene, a derivative of the silica polymorph keatite, often coexisting with metastable Li-stuffed β-quartz (γ-spodumene), the conventional approach to access lithium is through ion exchange with hydrogen using concentrated sulfuric [...] Read more.
After the high-temperature pretreatment of α-spodumene to induce a phase transition to β-spodumene, a derivative of the silica polymorph keatite, often coexisting with metastable Li-stuffed β-quartz (γ-spodumene), the conventional approach to access lithium is through ion exchange with hydrogen using concentrated sulfuric acid, which presents drawbacks associated with the production of low-value leaching residues. As sodium and magnesium can produce more interesting aluminosilicate byproducts, this study investigates Na+ ↔ Li+ and Mg2+ ↔ 2 Li+ substitution efficiencies in β-spodumene and β-quartz. Thermal annealing at 850 °C of the LiAlSi2O6 silica derivatives mixed with an equimolar proportion of Na endmember glass of equivalent stoichiometry (NaAlSi2O6) indicates that sodium incorporation in β-quartz is limited, whereas the main constraint for not attaining complete growth to a Na0.5Li0.5AlSi2O6 β-spodumene solid solution is co-crystallization of minor nepheline. For similar experiments in the equimolar LiAlSi2O6-Mg0.5AlSi2O6 system, the efficient substitution of Mg for Li is observed in both β-spodumene and β-quartz, consistent with the alkaline earth having an ionic radius closer to lithium than sodium. Ion exchange at lower temperatures was also evaluated by exposing coexisting β-spodumene and β-quartz to molten salts. In NaNO3 at 320 °C, sodium for lithium exchange reaches ≈90% in β-spodumene but less than ≈2% in β-quartz, suggesting that to be an efficient lithium recovery route, the formation of β-quartz during the conversion of α-spodumene needs to be minimized. At 525 °C in a molten MgCl2/KCl medium, although full LiAlSi2O6-Mg0.5AlSi2O6 solid solution is observed in β-quartz, structural constraints restrict the incorporation of magnesium in β-spodumene to a Li0.2Mg0.4AlSi2O6 stoichiometry, limiting lithium recovery to 80%. Full article
(This article belongs to the Collection Topic Collection: Mineralogical Crystallography)
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<p>Compositional space investigated in this study expressed in terms of [Si:Al]<sub>atomic</sub> relative to (<b>a</b>) [Na:Al]<sub>atomic</sub> and (<b>b</b>) [Mg<sub>0.5</sub>:Al]<sub>atomic</sub> ratios. The blue arrows represent the main substitutions in stuffed silica derivatives.</p> Full article ">Figure 2
<p>(<b>a</b>,<b>b</b>) Powder-XRD patterns, and (<b>c</b>,<b>d</b>) compositions of the synthesized endmember glasses.</p> Full article ">Figure 3
<p>Powder-XRD patterns and Raman spectra collected on the synthesized Li-stuffed silica derivatives: (<b>a</b>,<b>b</b>) β-quartz<sub>ss</sub> grown by thermal annealing of the lithium endmember glass; (<b>c</b>,<b>d</b>) β-spodumene<sub>ss</sub> crystallized from a Na-doped LiAlSi<sub>2</sub>O<sub>6</sub> melt.</p> Full article ">Figure 4
<p>(<b>a</b>) Compositions and molar proportions (in brackets) of the phases produced during the synthesis of the starting Li-stuffed silica derivatives. (<b>b</b>) BSE image of the β-quartz<sub>ss</sub> synthesis product emphasizing the minor residual glass cores accommodating the excess sodium from the kunzite precursor. (<b>c</b>) BSE image of the single-phase polycrystalline β-spodumene<sub>ss</sub> synthesis product. The slight contrast reflects variation in the orientation of the crystals.</p> Full article ">Figure 5
<p>Characteristics of the starting material consisting of mm-sized fragments with coexisting crystals of β-spodumene<sub>ss</sub> and β-quartz<sub>ss</sub>. (<b>a</b>) Powder-XRD pattern collected on a ground portion of the material. (<b>b</b>) BSE image obtained on a polished section across a representative fragment. (<b>c</b>) Raman spectra acquired on β-quartz<sub>ss</sub> and β-spodumene<sub>ss</sub> crystals displaying low and high intensity, respectively, in the BSE image shown in (<b>b</b>). (<b>d</b>) Compositions of β-quartz<sub>ss</sub> and β-spodumene<sub>ss</sub>.</p> Full article ">Figure 6
<p>Characteristics of the product from the solid-state crystallization experiment performed using the NaAlSi<sub>2</sub>O<sub>6</sub> glass and β-quartz<sub>ss</sub> endmembers. (<b>a</b>) Powder-XRD pattern collected on the ground portion of the recovered material. (<b>b</b>) BSE image obtained on a polished section across pellet fragments. (<b>c</b>) Representative β-quartz<sub>ss</sub> Raman spectra acquired on grains displaying low BSE intensity in (<b>b</b>). (<b>d</b>) Compositions (filled circles) and molar proportions (in brackets) of β-quartz<sub>ss</sub> and glass in the product. The empty squares represent the average compositions of the corresponding phases before the heat treatment.</p> Full article ">Figure 7
<p>XRD patterns with extended intensity scales to better visualize the amorphous hump, which expresses the relative contribution of the residual glass phase within the recovered products from the solid-state crystallization experiments using the NaAlSi<sub>2</sub>O<sub>6</sub> glass with (<b>a</b>) β-quartz<sub>ss</sub> and (<b>b</b>) β-spodumene<sub>ss</sub> endmembers. The indexed XRD patterns at full intensity can be found in <a href="#crystals-14-00988-f006" class="html-fig">Figure 6</a>a and <a href="#crystals-14-00988-f008" class="html-fig">Figure 8</a>a, respectively.</p> Full article ">Figure 8
<p>Characteristics of the product from the solid-state crystallization experiment performed using the NaAlSi<sub>2</sub>O<sub>6</sub> glass and β-spodumene<sub>ss</sub> endmembers. (<b>a</b>) Powder-XRD pattern collected on the ground portion of the recovered material. (<b>b</b>) BSE image obtained on a polished section across pellet fragments. The inset emphasizes the textural relationship of coexisting β-spodumene<sub>ss</sub>, nepheline, and glass. (<b>c</b>) Raman spectra acquired on grains of β-spodumene<sub>ss</sub> and nepheline. A reference spectrum of natural nepheline (Na<sub>0.66</sub>K<sub>0.27</sub>Ca<sub>0.04</sub>)AlSiO<sub>4</sub> from the RRUFF database (R060581) is also shown for comparison. (<b>d</b>) Compositions (filled circles) and molar proportions (in brackets) of β-spodumene<sub>ss</sub>, glass, and nepheline in the product. The empty squares represent the average compositions of β-spodumene<sub>ss</sub> and glass before the heat treatment.</p> Full article ">Figure 9
<p>Characteristics of the product from the solid-state crystallization experiment performed using the Mg<sub>0.5</sub>AlSi<sub>2</sub>O<sub>6</sub> glass and β-quartz<sub>ss</sub> endmembers. (<b>a</b>) Powder-XRD pattern collected on the ground portion of the recovered material. (<b>b</b>) BSE image obtained on a polished section across pellet fragments. (<b>c</b>) Representative β-quartz<sub>ss</sub> Raman spectra acquired on grains displaying low BSE intensity in (<b>b</b>). (<b>d</b>) Compositions (circles) and molar proportions (in brackets) of β-quartz<sub>ss</sub> and glass in the product. The empty circles indicate analyses performed on the β-quartz<sub>ss</sub> growth at the rim of the glass. The empty squares represent the average compositions of the corresponding phases before the heat treatment.</p> Full article ">Figure 10
<p>Characteristics of the product from the solid-state crystallization experiment performed using the Mg<sub>0.5</sub>AlSi<sub>2</sub>O<sub>6</sub> glass and β-spodumene<sub>ss</sub> endmembers. (<b>a</b>) Powder-XRD pattern collected on the ground portion of the recovered material. (<b>b</b>) BSE image obtained on a polished section across pellet fragments. (<b>c</b>) Raman spectra acquired on a representative β-spodumene<sub>ss</sub> grain. (<b>d</b>) Compositions of β-spodumene<sub>ss</sub> (red filled circles), β-quartz growth (green empty circles), and glass (blue filled circles) in the product. The molar proportions of glass and β phases (β-spodumene<sub>ss</sub> and β-quartz<sub>ss</sub> combined) are shown in brackets. The empty squares represent the average compositions of β-spodumene<sub>ss</sub> (red) and glass (blue) before the heat treatment.</p> Full article ">Figure 11
<p>Characteristics of the product from the Na<sub>0.5</sub>Li<sub>0.5</sub>AlSi<sub>2</sub>O<sub>6</sub> melt crystallization experiment. (<b>a</b>) Powder-XRD pattern collected on the ground portion of the recovered material. (<b>b</b>) BSE image emphasizing the growth habit of the β-spodumene<sub>ss</sub> crystals. (<b>c</b>) Raman spectra acquired on a representative β-spodumene<sub>ss</sub> crystal. (<b>d</b>) Compositions of β-spodumene<sub>ss</sub> and glass in the product. The blue empty square represents the average composition of the starting glass before the heat treatment.</p> Full article ">Figure 12
<p>Characteristics of the product from the Mg<sub>0.25</sub>Li<sub>0.5</sub>AlSi<sub>2</sub>O<sub>6</sub> melt crystallization experiment. (<b>a</b>) Powder-XRD pattern collected on the ground portion of the recovered material. (<b>b</b>) BSE image emphasizing complete crystallization dominated by β-spodumene<sub>ss</sub> and the euhedral habit of the minor mullite phase. (<b>c</b>) Raman spectra acquired on a representative β-spodumene<sub>ss</sub> crystal. (<b>d</b>) Compositions of β-spodumene<sub>ss</sub> in the product. The blue empty square represents the average composition of the starting glass before the heat treatment.</p> Full article ">Figure 13
<p>Characteristics of the product from the NaNO<sub>3</sub> molten salt exchange experiment performed on synthetic fragments with coexisting crystals of β-spodumene<sub>ss</sub> and β-quartz<sub>ss</sub>. (<b>a</b>) Powder-XRD pattern collected on the ground portion of the recovered material. (<b>b</b>) Raman spectra acquired on β-quartz<sub>ss</sub> and β-spodumene<sub>ss</sub> crystals after exchange. (<b>c</b>) BSE image and (<b>d</b>) quantitative WDS-EPMA map of the [Na:Al]<sub>atomic</sub> ratio across an exchanged fragment.</p> Full article ">Figure 14
<p>Characteristics of the product from the 0.6 MgCl<sub>2</sub>/0.4 KCl molten salt exchange experiment performed on synthetic fragments with coexisting crystals of β-spodumene<sub>ss</sub> and β-quartz<sub>ss</sub>. (<b>a</b>) Powder-XRD pattern collected on the ground portion of the recovered material. (<b>b</b>) Raman spectra acquired on β-quartz<sub>ss</sub> and β-spodumene<sub>ss</sub> crystals after exchange. (<b>c</b>) BSE image and (<b>d</b>) quantitative WDS-EPMA map of the [Mg<sub>0.5</sub>:Al]<sub>atomic</sub> ratio across an exchanged fragment.</p> Full article ">Figure 15
<p>Comparison of the powder-XRD patterns collected on the decrepitated spodumene concentrate before (pristine) and after exchange in molten (<b>a</b>) NaNO<sub>3</sub> and (<b>b</b>) 0.6 MgCl<sub>2</sub>/0.4 KCl. The peaks labeled “quartz” represent the contribution of the natural quartz mineral intergrown with α-spodumene in the concentrate.</p> Full article ">
12 pages, 1667 KiB  
Article
Supported and Free-Standing Non-Noble Metal Nanoparticles and Their Catalytic Activity in Hydroconversion of Asphaltenes into Light Hydrocarbons
by Leonid Kustov, Andrei Tarasov, Kristina Kartavova, Valery Khabashesku, Olga Kirichenko, Gennady Kapustin, Alexander Kustov, Evgeny Abkhalimov and Boris Ershov
Crystals 2024, 14(11), 987; https://doi.org/10.3390/cryst14110987 - 16 Nov 2024
Viewed by 647
Abstract
The hydroconversion of asphaltenes into light hydrocarbons catalyzed by supported and free-standing non-noble metal nanoparticles was studied. The activity of Ni or Co immobilized on microspherical oxide carriers and Co nanoparticles dispersed in a hydrocarbon solution of asphaltene was found to be higher [...] Read more.
The hydroconversion of asphaltenes into light hydrocarbons catalyzed by supported and free-standing non-noble metal nanoparticles was studied. The activity of Ni or Co immobilized on microspherical oxide carriers and Co nanoparticles dispersed in a hydrocarbon solution of asphaltene was found to be higher than that of a comparative Pt-Pd/Al2O3 catalyst. The yield of light products (C5+) reached up to 91% on cobalt nanoparticles supported onto alumina microspheres. Full article
(This article belongs to the Special Issue Advances in Nanomaterials and Nanocomposites for Catalytic Applications)
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<p>Schematic representation of the molecular structure of asphaltene.</p> Full article ">Figure 2
<p>TPR-H<sub>2</sub> profiles of Al<sub>2</sub>O<sub>3</sub> (1), TiO<sub>2</sub> (2) carriers and 20%Co/Al<sub>2</sub>O<sub>3</sub> (3), 20%Ni/TiO<sub>2</sub> (4) catalyst precursors.</p> Full article ">Figure 3
<p>TEM images and size distributions of 5%Ni/Al<sub>2</sub>O<sub>3</sub> (<b>a</b>,<b>b</b>) and 7%Co/Al<sub>2</sub>O<sub>3</sub> (<b>c</b>,<b>d</b>).</p> Full article ">Figure 4
<p>TEM images of 5%Ni/TiO<sub>2</sub> (<b>a</b>) and 7%Co/TiO<sub>2</sub> (<b>b</b>).</p> Full article ">Figure 5
<p>XRD patterns of 5%Ni and 7%Co nanocatalysts on Al<sub>2</sub>O<sub>3</sub> and TiO<sub>2</sub> supports.</p> Full article ">Figure 6
<p>SEM image (<b>a</b>) and EDX elemental analysis (<b>b</b>) of the 5%Ni/TiO<sub>2</sub> catalyst. The contents of the elements determined by EDX: O, 43.00%, Ti, 51.73%, Ni, 5.27%.</p> Full article ">
19 pages, 12552 KiB  
Article
Atmosphere-Controlled Solvatomorphic Transitions of Ternary Copper(II) Coordination Compounds in Solid State
by Darko Vušak, Matea Primožić and Biserka Prugovečki
Crystals 2024, 14(11), 986; https://doi.org/10.3390/cryst14110986 - 15 Nov 2024
Viewed by 670
Abstract
Reactions of copper(II) sulfate with 2,2′-bipyridine (bpy) and l-serine (l-Hser) were investigated using different solution-based and mechanochemical methods. Four new ternary coordination compounds were obtained by solution-based synthesis, and three of them additionally via the liquid-assisted mechanochemical method: α-[Cu( [...] Read more.
Reactions of copper(II) sulfate with 2,2′-bipyridine (bpy) and l-serine (l-Hser) were investigated using different solution-based and mechanochemical methods. Four new ternary coordination compounds were obtained by solution-based synthesis, and three of them additionally via the liquid-assisted mechanochemical method: α-[Cu(l-Ser)(H2O)(bpy)]2SO4 (1a-α), β-[Cu(l-Ser)(H2O)(bpy)]2SO4 (1a-β), [Cu(l-Ser)(H2O)(bpy)]2SO4·6H2O (1a∙6H2O), and [Cu(l-Ser)(bpy)(CH3OH)]2SO4·2CH3OH (1b∙3CH3OH). The compounds were characterized by single-crystal and powder X-ray diffraction, infrared spectroscopy, and thermal analysis. Structural studies revealed two polymorphs (1a-α and 1a-β) and two solvatomorphs (1a∙6H2O and 1b∙3CH3OH). To investigate the stability of the compounds, crystalline samples were exposed to different conditions of relative humidity (RH) and an atmosphere of methanol vapours. Successful solid-state transformation of 1a∙6H2O into 1a-α was established at lower RH values, and vice versa at higher RH values, while both compounds partially transitioned to 1a-β in the atmosphere of methanol vapours. Compound 1b∙3CH3OH decomposed spontaneously into 1a-α by standing in the air. All of the investigated structural transformations were underpinned with proposed mechanisms. Additionally, 1a-α showed moderate in vitro antiproliferative activity toward a human breast cancer cell line (MCF-7), a human colon cancer cell line (HCT116), and a human lung cancer cell line (H460). Full article
(This article belongs to the Section Inorganic Crystalline Materials)
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Full article ">Figure 1
<p>Schematic diagram of solution-based syntheses and the main products. As stated in the Materials and Methods section, some byproducts also formed in the syntheses and were omitted from the scheme for clarity. Differences in crystal packings of unit cells of all four compounds are shown. Layers of complexes of different colours (blue and red) are separated by sulfate ions.</p> Full article ">Figure 2
<p>Schematic diagram of mechanochemical syntheses with powder X-ray diffraction patterns of the products of mechanochemical reactions. Blue PXRD patterns were experimentally measured, and red ones were calculated from crystal structure.</p> Full article ">Figure 3
<p>PXRD diffraction patterns of <b>1a-<span class="html-italic">α</span></b> (<b>left</b>) and <b>1a·6H<sub>2</sub>O</b> (<b>right</b>) after aging for 4 weeks in atmospheres of different relative humidities. Diffraction patterns separated by a broken line are not on the same intensity scale. Blue PXRD patterns were experimentally measured, and black ones were calculated from crystal structure.</p> Full article ">Figure 4
<p>PXRD patterns of <b>1a-<span class="html-italic">α</span></b> (red) and <b>1a·6H<sub>2</sub>O</b> (blue) after aging in an atmosphere of methanol vapours. PXRD patterns calculated from the single-crystal data are shown in black. Yellow triangles show diffraction peaks characterized as <b>1a-<span class="html-italic">β</span></b>. Diffraction patterns separated by a broken line are not on the same intensity scale. Single-crystal data for all compounds were measured at 100 K, so shifts of some diffraction maxima are possible.</p> Full article ">Figure 5
<p>π-stacked pillars in <b>1a·6H<sub>2</sub>O</b>, <b>1a-<span class="html-italic">α</span></b>, <b>1a-<span class="html-italic">β</span></b>, and <b>1b∙3CH<sub>3</sub>OH</b>.</p> Full article ">Figure 6
<p>(<b>a</b>) Comparison of propagation of water molecules through hydrogen bonding along the <span class="html-italic">a</span>-axis in <b>1a·6H<sub>2</sub>O</b> and [Cu(<span class="html-small-caps">l</span>-ser)(H<sub>2</sub>O)(phen)]<sub>2</sub>SO<sub>4</sub>∙6H<sub>2</sub>O; (<b>b</b>) 1D channels of solvent molecules (water in blue, methanol in pink) in <b>1a·6H<sub>2</sub>O</b> and <b>1b∙3CH<sub>3</sub>OH</b>.</p> Full article ">Figure 7
<p>Differences in the structures of <b>1a-<span class="html-italic">α</span></b> and <b>1a-<span class="html-italic">β</span></b>. π-stacked layers of complex cations and a simplified view of propagation of hydrogen bonds are shown in the top pictures. Brown lines represent hydrogen bonds formed by complex cations, and light blue lines represent hydrogen bonds formed by sulfate ions. The difference in the relative angles of the π-stacked layers is shown in the bottom pictures.</p> Full article ">Figure 8
<p>Distribution of interatomic contacts as a fraction of the Hirshfeld surface of each symmetrically independent cation (top graph) and average values for all cations (bottom lines) in <b>1a-<span class="html-italic">α</span></b> and <b>1a-<span class="html-italic">β.</span></b></p> Full article ">Figure 9
<p>Movements of 1D π-stacked pillars and sulfate ions (<b>top</b>) and the change in the coordination of water molecules (<b>bottom</b>) during <b>1a·6H<sub>2</sub>O⇄1a-<span class="html-italic">α</span></b> transformation. Possible movements of water molecules are shown with blue dashed lines.</p> Full article ">Figure 10
<p>Movements of 1D π-stacked pillars and sulfate ions during the <b>1b·3CH<sub>3</sub>OH→1a-<span class="html-italic">α</span></b> transition.</p> Full article ">
18 pages, 6573 KiB  
Article
Preliminary Spectroscopic Observations of Marble-Hosted Rubies, Marginal Host Marbles, and Transition Zones Between Marbles and Rubies on Samples from Afghanistan, Myanmar, and Pakistan
by Chen Fan, Yung-Chin Ding and Wing-Tak Lui
Crystals 2024, 14(11), 985; https://doi.org/10.3390/cryst14110985 - 15 Nov 2024
Viewed by 685
Abstract
This study focusses on the spectroscopic observation of marbles, rubies and the transition zone between ruby and its hosted marble that may distinguish the origin of ruby. Samples of ruby-bearing marble were obtained from Afghanistan, Myanmar, and Pakistan. Energy-dispersive X-ray fluorescence was used [...] Read more.
This study focusses on the spectroscopic observation of marbles, rubies and the transition zone between ruby and its hosted marble that may distinguish the origin of ruby. Samples of ruby-bearing marble were obtained from Afghanistan, Myanmar, and Pakistan. Energy-dispersive X-ray fluorescence was used to analyze the chemical compositions. Although the content of other elements in the marble varied with the origin, the Cl content was quite constant. A diagram of the trace elements Fe and Ga was used to determine the origins of the marble-hosted rubies. X-ray diffraction was used to verify the structure phases, where trioctahedral mica, plagioclase, quartz, and alkali feldspar were found in marbles. Ultraviolet–visible spectrophotometry was used for rubies, where a 659 nm fluoresce peak was found in the Myanmar ruby sample, which could make Myanmar ruby redder and more sought after. The bonding of elements and inclusions of the samples were analyzed using Fourier transform infrared spectroscopy, Raman spectroscopy, and photoluminescence. A FTIR peak at 630 cm−1 is found to be useful in judging the temperature of ruby formation. Scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to analyze the variation of the transition zone, which revealed that the boundary was a gradation zone. Concentrations of Al203 increased in this zone, but CaCO3 concentrations decreased. Full article
(This article belongs to the Collection Topic Collection: Mineralogical Crystallography)
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<p>Samples collected in this study (A1–A5 were from Jagdalek Afghanistan; M1–M6 were from Mogok Myanmar; and P1–P5 were from Hunza Pakistan).</p> Full article ">Figure 2
<p>The Ti-Cl content of marble XRF results is compared with log-log coordinates.</p> Full article ">Figure 3
<p>The XRD results for marble samples. The numbers 1–6 in red show the secondary phases.</p> Full article ">Figure 4
<p>A typical FTIR spectrum of marble.</p> Full article ">Figure 5
<p>A typical Raman spectrum of marble.</p> Full article ">Figure 6
<p>A typical 405 nm photoluminescence spectrum of marble.</p> Full article ">Figure 7
<p>A typical 532 nm photoluminescence spectrum of marble.</p> Full article ">Figure 8
<p>The Fe-Ga (ppma) diagrams for rubies.</p> Full article ">Figure 9
<p>The difference in the 659 nm peak between Myanmar and the other two origins.</p> Full article ">Figure 10
<p>Ruby FTIR 630 cm<sup>−1</sup> transmission peak.</p> Full article ">Figure 11
<p>A typical FTIR spectrum of ruby.</p> Full article ">Figure 12
<p>The typical Raman spectra of the ruby samples.</p> Full article ">Figure 13
<p>The 405 nm photoluminescence spectrum of ruby samples.</p> Full article ">Figure 14
<p>The 532 nm PL spectrum of ruby samples.</p> Full article ">Figure 15
<p>The boundary of ruby and host marble, shown in a blue circle.</p> Full article ">Figure 16
<p>SEM image of the boundary with the gap and test points labelled. The arrows indicate the gap between the ruby and the host marble. The numbers in the figure indicate the detecting points.</p> Full article ">Figure 17
<p>Al<sub>2</sub>O<sub>3</sub>%-CaCO<sub>3</sub>% distribution versus distance from center of gap.</p> Full article ">
9 pages, 2658 KiB  
Article
Performance Enhancement of MoSe2 and WSe2 Based Junction Field Effect Transistors with Gate-All-Around Structure
by Changlim Woo, Abdelkader Abderrahmane, Pangum Jung and Pilju Ko
Crystals 2024, 14(11), 984; https://doi.org/10.3390/cryst14110984 - 15 Nov 2024
Viewed by 793
Abstract
Recently, two-dimensional materials have gained significant attention due to their outstanding properties such as high charge mobility, mechanical strength, and electrical characteristics. These materials are considered one of the most promising solutions to overcome the limitations of semiconductor technology and are being utilized [...] Read more.
Recently, two-dimensional materials have gained significant attention due to their outstanding properties such as high charge mobility, mechanical strength, and electrical characteristics. These materials are considered one of the most promising solutions to overcome the limitations of semiconductor technology and are being utilized in various semiconductor device research. In particular, molybdenum diselenide (MoSe2) and tungsten diselenide (WSe2) are actively being developed for device applications due to their high electron mobility, optical properties, and electrical characteristics. In this study, we fabricated MoSe2 and WSe2-based junction field-effect transistors (JFET) and further deposited two-dimensional materials on the same device to fabricate and compare JFETs with a gate-all-around (GAA) structure. The research results showed that the GAA-structure JFET exhibited performance improvements in drain current, subthreshold swing (SS) transconductance (gm), and mobility, achieving enhancements ranging from a minimum of 1.2 times to a maximum of 10 times compared to conventional JFET. Full article
(This article belongs to the Special Issue Advanced Research in 2D Materials)
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<p>(<b>a</b>) SEM image of the fabricated MoSe<sub>2</sub>/WSe<sub>2</sub>/MoSe<sub>2</sub> device), (<b>b</b>) AFM 3D image of the device and (<b>c</b>–<b>e</b>) height profiles along the red and green.</p> Full article ">Figure 2
<p>(<b>a</b>) image of MoSe<sub>2</sub>/WSe<sub>2</sub>/MoSe<sub>2</sub> device (points 1 to 3 correspond to MoSe<sub>2</sub>, WSe<sub>2</sub> and MoSe<sub>2</sub>). (<b>b</b>–<b>d</b>) Raman spectroscopy of MoSe<sub>2</sub> and WSe<sub>2</sub>.</p> Full article ">Figure 3
<p>(<b>a</b>,<b>b</b>) shows a microscope image of fabricated JFET, (<b>c</b>,<b>d</b>) shows a microscope image of a fabricated JFET GAA-structure FET.</p> Full article ">Figure 4
<p>(<b>a</b>) image of fabricated device, (<b>b</b>) comparison of JFET and GAAJFET (WSe2 channel 1–3 line), (<b>c</b>,<b>d</b>) comparison of JFET and GAAJFET (PN junction MoSe<sub>2</sub>/WSe<sub>2</sub> 1–2 line, 2–3 line).</p> Full article ">Figure 5
<p>(<b>a</b>,<b>b</b>) each display the characteristics of the fabricated MoSe<sub>2</sub>/WSe<sub>2</sub> JFET. (<b>c</b>,<b>d</b>) illustrate schematic images of the device. (<b>e</b>) shows energy band diagram of the JFET device.</p> Full article ">Figure 6
<p>(<b>a</b>,<b>b</b>) each display the characteristics of the fabricated MoSe<sub>2</sub>/WSe<sub>2</sub>/MoSe<sub>2</sub> GAA-structure JFET. (<b>c</b>,<b>d</b>) illustrate schematic images of the device. (<b>e</b>) shows the energy band diagram of the GAA-structure JFET device.</p> Full article ">Figure 7
<p>(<b>a</b>) shows the current characteristics of the fabricated GAA-structure JFET, JFET. (<b>b</b>) show the mobility of JFET and GAA-structure JFET device. The inset shows transconductance (<b>c</b>) shows the percentage improvement value of SS, gm, mobility.</p> Full article ">
11 pages, 4471 KiB  
Article
Creep Behavior of a Single Crystal Nickel-Based Superalloy Containing High Concentrations of Re/Ru at an Intermediate Temperature
by Ning Tian, Tai Meng, Shulei Sun, Shunke Zhang and Danping Dang
Crystals 2024, 14(11), 983; https://doi.org/10.3390/cryst14110983 - 14 Nov 2024
Viewed by 818
Abstract
The deformation and damage mechanisms of a single crystal nickel-based superalloy containing 6.0%Re/5.0%Ru were studied through creep performance tests at 800 °C/860–880 MPa, microstructure and morphology observation, and dislocation configuration analyzation. It was found that, during the creep process at the intermediate temperature, [...] Read more.
The deformation and damage mechanisms of a single crystal nickel-based superalloy containing 6.0%Re/5.0%Ru were studied through creep performance tests at 800 °C/860–880 MPa, microstructure and morphology observation, and dislocation configuration analyzation. It was found that, during the creep process at the intermediate temperature, the γ′ phase does not form a raft-like structure. After a creep fracture, the distortion degree of the cubic γ′ phase becomes greater when the observation region is closer to the fracture. The alloy has a long creep life at 800 °C, and the dislocation slipping or climbing in the γ matrix is the deformation mechanism at the early and middle creep stages. At the later creep stage, the γ′ phase is sheared by dislocations. Because of the low stacking-fault energy of the alloy, the <110> superdislocation shearing into the γ′ phase can decompose on the {111} plane to form a (1/3) <112> partial dislocation and stacking-fault configuration or cross-slip to the {100} plane to form the Kear–Wilsdorf (K-W) lock, which greatly improves the creep resistance of the alloy. At the later creep stage, the primary/secondary slip systems in the alloy are activated alternately, resulting in micro-cracks at the intersection of the two slip systems. As the creep progresses, the initiated cracks spread and propagate in the γ matrix phase along a direction normal to the stress axis and connect with each other until creep fracture occurs. This is the fracture mechanism of the alloy during creep at the medium temperature. Full article
(This article belongs to the Section Crystal Engineering)
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<p>Microstructure of the alloy after full heat treatment.</p> Full article ">Figure 2
<p>Creep curves of the alloy.</p> Full article ">Figure 3
<p>Microstructure in different regions of the alloy. (<b>a</b>) Schematic diagram of the observation regions in the specimen, (<b>b</b>–<b>e</b>) SEM morphologies corresponding to regions A–D of the specimen, respectively.</p> Full article ">Figure 4
<p>Morphologies of the alloy after creep tests for different times under the applied stress of 860 MPa at 800 °C. (<b>a</b>) Crept for 60 h, (<b>b</b>) crept for 286 h up to fracture, and (<b>c</b>) two stacking faults with different expansion directions.</p> Full article ">Figure 5
<p>Dislocation configuration within the γ′ phase of the alloy after being crept up to fracture at 800 °C/860 MPa. (<b>a</b>) g = [<math display="inline"><semantics> <mrow> <mn>11</mn> <mo> </mo> <mover> <mn>3</mn> <mo>¯</mo> </mover> </mrow> </semantics></math>], (<b>b</b>) g = [<math display="inline"><semantics> <mrow> <mover> <mn>3</mn> <mo>¯</mo> </mover> <mo> </mo> <mn>11</mn> </mrow> </semantics></math>], (<b>c</b>) g = [020].</p> Full article ">Figure 6
<p>The crack initiation and propagation morphology in the alloy after creep for different times. (<b>a</b>) Crept for 200 h, (<b>b</b>) crept for 240 h, (<b>c</b>) crept for 286 h up to fracture, and (<b>d</b>) the local amplification of the creep fracture.</p> Full article ">Figure 7
<p>Schematic diagram of dislocations decomposing into different plane defects in L1<sub>2</sub>-Ni<sub>3</sub>Al.</p> Full article ">Figure 8
<p>Schematic diagram of crack initiation and propagation. (<b>a</b>) crack initiation (<b>b</b>) crack propagation.</p> Full article ">
13 pages, 3118 KiB  
Article
Preparation and Study of Poly(Vinylidene Fluoride-Co-Hexafluoropropylene)-Based Composite Solid Electrolytes
by Meihong Huang, Lingxiao Lan, Pengcheng Shen, Zhiyong Liang, Feng Wang, Yuling Zhong, Chaoqun Wu, Fanxiao Kong and Qicheng Hu
Crystals 2024, 14(11), 982; https://doi.org/10.3390/cryst14110982 - 14 Nov 2024
Cited by 1 | Viewed by 596
Abstract
Solid-state electrolytes are widely anticipated to revitalize lithium-ion batteries with high energy density and safety. However, low ionic conductivity and high interfacial resistance at room temperature pose challenges for practical applications. This study combines the rigid oxide electrolyte LLZTO with the flexible polymer [...] Read more.
Solid-state electrolytes are widely anticipated to revitalize lithium-ion batteries with high energy density and safety. However, low ionic conductivity and high interfacial resistance at room temperature pose challenges for practical applications. This study combines the rigid oxide electrolyte LLZTO with the flexible polymer electrolyte poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) to achieve effective coupling of rigidity and flexibility. The semi-interpenetrating network structure endows the PEL composite solid electrolyte with excellent lithium-ion transport capabilities, resulting in an ionic conductivity of up to 5.1 × 10−4 S cm−1 and lithium-ion transference number of 0.41. The assembled LiFePO4/PEL/Li solid-state battery demonstrates an initial discharge capacity of 132 mAh g−1 at a rate of 0.1 C. After 100 charge–discharge cycles, the capacity retention is 81%. This research provides a promising strategy for preparing composite solid electrolytes in solid-state lithium-ion batteries. Full article
(This article belongs to the Special Issue Research on Electrolytes and Energy Storage Materials)
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<p>The preparation process of PEL.</p> Full article ">Figure 2
<p>Images of (<b>a</b>,<b>b</b>) PE and (<b>c</b>,<b>d</b>) PEL solid electrolyte membranes.</p> Full article ">Figure 3
<p>Surface topography of (<b>a</b>,<b>c</b>) PE; (<b>b</b>,<b>d</b>) surface topography of PEL; (<b>e</b>,<b>g</b>) cross-sectional morphology of PE; and (<b>f</b>,<b>h</b>) cross-sectional morphology of PEL.</p> Full article ">Figure 4
<p>(<b>a</b>) X−ray diffraction spectra of LLZTO, PVDF−HFP, ETPTA, and PEL; (<b>b</b>) X−ray diffraction spectra of adding 0−20 wt.% LLZTO; FTIR infrared spectrum characterization diagram; (<b>c</b>) PE and PEL before and after UV photofixation; and (<b>d</b>) PE and PEL.</p> Full article ">Figure 5
<p>(<b>a</b>) Stress–strain plot of PE and PEL; EIS at room temperature; (<b>b</b>) PE electrolyte with different amounts of ETPTA added; (<b>c</b>) PEL electrolyte with different amounts of LLZTO added; (<b>d</b>) the linear sweep voltammetry of PE and PEL. Electrochemical impedance spectroscopy (EIS) and timing current method (CA) test the lithium-ion migration number of the assembled Li/Li symmetrical cells (<b>e</b>) PE and (<b>f</b>) PEL.</p> Full article ">Figure 6
<p>(<b>a</b>) Rate performance of LFP/PEL−PMEL/Li and LFP/PEL−PMEL/Li solid−state batteries at different rates; (<b>b</b>) first charge/discharge curves at different ratios of LFP/PEL−PMEL/Li; (<b>c</b>) cycling performance of the LFP/PEL−PMEL/Li and LFP/PEL−PMEL/Li solid−state batteries and (<b>d</b>) cyclic voltammetry curves of LFP/PEL−PMEL/Li solid−state batteries.</p> Full article ">
23 pages, 6021 KiB  
Article
Structural, Optical, Magnetic, and Dielectric Investigations of Pure and Co-Doped La0.67Sr0.33Mn1-x-yZnxCoyO3 Manganites with (0.00 < x + y < 0.20)
by Mansour Mohamed, A. Sedky, Abdullah S. Alshammari, Z. R. Khan, M. Bouzidi and Marzook S. Alshammari
Crystals 2024, 14(11), 981; https://doi.org/10.3390/cryst14110981 - 14 Nov 2024
Viewed by 622
Abstract
Here, we report the structural, optical, magnetic, and dielectric properties of La0.67Sr0.33Mn1-x-yZnxCoyO3 manganite with various x and y values (0.025 < x + y < 0.20). The pure and co-doped samples are [...] Read more.
Here, we report the structural, optical, magnetic, and dielectric properties of La0.67Sr0.33Mn1-x-yZnxCoyO3 manganite with various x and y values (0.025 < x + y < 0.20). The pure and co-doped samples are called S1, S2, S3, S4, and S5, with (x + y) = 0.00, 0.025, 0.05, 0.10, and 0.20, respectively. The XRD confirmed a monoclinic structure for all the samples, such that the unit cell volume and the size of the crystallite and grain were generally decreased by increasing the co-doping content (x + y). The opposite was true for the behaviors of the porosity, the Debye temperature, and the elastic modulus. The energy gap Eg was 3.85 eV for S1, but it decreased to 3.82, 3.75, and 3.65 eV for S2, S5, and S3. Meanwhile, it increased and went to its maximum value of 3.95 eV for S4. The values of the single and dispersion energies (Eo, Ed) were 9.55 and 41.88 eV for S1, but they were decreased by co-doping. The samples exhibited paramagnetic behaviors at 300 K, but they showed ferromagnetic behaviors at 10 K. For both temperatures, the saturated magnetizations (Ms) were increased by increasing the co-doping content and they reached their maximum values of 1.27 and 15.08 (emu/g) for S4. At 300 K, the co-doping changed the magnetic material from hard to soft, but it changed from soft to hard at 10 K. In field cooling (FC), the samples showed diamagnetic regime behavior (M < 0) below 80 K, but this behavior was completely absent for zero field cooling (ZFC). In parallel, co-doping of up to 0.10 (S4) decreased the dielectric constant, AC conductivity, and effective capacitance, whereas the electric modulus, impedance, and bulk resistance were increased. The analysis of the electric modulus showed the presence of relaxation peaks for all the samples. These outcomes show a good correlation between the different properties and indicate that co-doping of up to 0.10 of Zn and Co in place of Mn in La:113 compounds is beneficial for elastic deformation, optoelectronics, Li-batteries, and spintronic devices. Full article
(This article belongs to the Special Issue Crystal Structures and Magnetic Interactions of Magnetic Materials)
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<p>XRD patterns of the La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples.</p> Full article ">Figure 2
<p>SEM micrographs and grain size distribution of the La<sub>0.67</sub>Sr<sub>0.33</sub>M samples.</p> Full article ">Figure 2 Cont.
<p>SEM micrographs and grain size distribution of the La<sub>0.67</sub>Sr<sub>0.33</sub>M samples.</p> Full article ">Figure 3
<p>EDS compositional analysis of the La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples.</p> Full article ">Figure 3 Cont.
<p>EDS compositional analysis of the La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples.</p> Full article ">Figure 4
<p>FTIR spectra of La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples.</p> Full article ">Figure 5
<p>(<b>a</b>) Optical absorbance versus wavelength of the La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples. (<b>b</b>) (αhυ)<sup>2</sup> against hυ plots of the La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples.</p> Full article ">Figure 6
<p>The linear plots between (n<sup>2</sup> − k<sup>2</sup>) and (λ)<sup>2</sup> for La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples.</p> Full article ">Figure 7
<p>The linear plots between (n<sup>2</sup> − 1)<sup>−1</sup> and (hυ)<sup>2</sup> for La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples.</p> Full article ">Figure 8
<p>(<b>a</b>). Magnetization against applied field at 300 K for La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples. (<b>b</b>). The dependance of Magnetization on the applied field at 10 K for La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples.</p> Full article ">Figure 9
<p>(<b>a</b>,<b>b</b>). Magnetic hysteresis loops of La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples.</p> Full article ">Figure 10
<p>The zero-field-cooled (ZFC) field-cooled (FC) measurements at an applied magnetic field of 100 Oe for S3 where the blocking temperature T<sub>b</sub> = 60 K.</p> Full article ">Figure 11
<p>(<b>a</b>). The dependance of a real part of dialectic constant on the frequency (f) for La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples. (<b>b</b>). Ac conductivity versus frequency for La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples.</p> Full article ">Figure 12
<p>(<b>a</b>,<b>b</b>). Real and imaginary parts of electric modulus (M<sup>\</sup>, M<sup>\\</sup>) versus frequency for La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples.</p> Full article ">Figure 13
<p>(<b>a</b>,<b>b</b>). Cole-Cole plot of La<sub>0.67</sub>Sr<sub>0.33</sub>Mn<sub>1-x-y</sub>Zn<sub>x</sub>Co<sub>y</sub>O<sub>3</sub> samples.</p> Full article ">Figure 14
<p>Equivalent circuit of RC circuit for single and two successive semicircles.</p> Full article ">
12 pages, 894 KiB  
Article
Micro-Computed Tomographic Evaluation of the Shaping Ability of Vortex Blue and TruNatomyTM Ni-Ti Rotary Systems
by Batool Alghamdi, Mey Al-Habib, Mona Alsulaiman, Lina Bahanan, Ali Alrahlah, Leonel S. J. Bautista, Sarah Bukhari, Mohammed Howait and Loai Alsofi
Crystals 2024, 14(11), 980; https://doi.org/10.3390/cryst14110980 - 14 Nov 2024
Viewed by 723
Abstract
This study aimed to assess and evaluate the canal shaping ability of two different Ni-Ti rotary systems, Vortex Blue (VB) and TruNatomy (TN), using micro-computed tomography in extracted premolars. A total of 20 extracted bifurcated maxillary first premolars with two separate canals were [...] Read more.
This study aimed to assess and evaluate the canal shaping ability of two different Ni-Ti rotary systems, Vortex Blue (VB) and TruNatomy (TN), using micro-computed tomography in extracted premolars. A total of 20 extracted bifurcated maxillary first premolars with two separate canals were randomly divided into two groups and prepared with either VB 35/0.04 (Dentsply Maillefer, Ballaigues, Switzerland) or TN Medium 36/0.03 (Dentsply Sirona). Pre- and post-instrumentation micro-CT scans were analyzed to measure the following parameters: percentage of untouched canal surface area, changes in canal surface area, changes in canal volume, structural model index (SMI), changes in canal angulation, changes in dentin thickness, transportation, and centering ability. Statistical analysis was performed with a significance level set at p-value < 0.05. Both VB and TN files showed a significant increase in the basic canal geometry parameters including canal surface area and canal volume. Both file systems showed no significant changes in SMI or dentin thickness after canal instrumentation (p > 0.05). Some degree of canal transportation and a similar centering ability ratio with no significant difference were observed in both file systems (p > 0.05). TN files showed less pre-cervical dentin removal when compared to VB files. A significant difference was found in the TN group regarding the dentin removal between coronal and apical thirds (p = 0.03). Both VB and TN files produced comparable root canal preparation with no considerable shaping mishaps and errors. Both files showed minimum canal transportation and minimum straightening of the canal curvature. TN files removed less pre-cervical dentin than apical dentin. Full article
(This article belongs to the Special Issue Shape Memory Alloys: Recent Advances and Future Perspectives)
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Figure 1
<p>Three-dimensional rendered images of teeth before instrumentation (<b>left</b> column) and after instrumentation (<b>right</b> column). In the right columns, touched root canal surface is presented with a gray color, and untouched root canal surface is presented with an orange color. B indicates buccal canal and palatal indicates palatal canal.</p> Full article ">Figure 2
<p>Cross-sectional images of the buccal and palatal canals after instrumentation at 3 mm, 5 mm, and 7 mm root areas. The buccal canal was treated with the TN file, and the palatal canal was treated with the VB file. The touched root canal surface is presented with a gray color, and the untouched root canal surface is presented with an orange color. B indicates buccal canal and palatal indicates palatal canal.</p> Full article ">Figure 3
<p>Three-dimensional images of the root canal showing canal angulation before instrumentation (<b>left</b> column) and after instrumentation (<b>right</b> column). (<b>A</b>,<b>C</b>) show root canal instrumented with TN files and canal angulation changed 1.43 degrees from 30.44° to 29.01°. (<b>B</b>,<b>D</b>) show canal instrumented with VB files and canal angulation changed 2.42 degrees from 26.28° to 23.86°. Root canal angulation is calculated by drawing two lines, one parallel with the long axis of the tooth and the other one extending from the apical foramen to intersect with the first line at the point where the canal starts to leave the long axis of the tooth [<a href="#B13-crystals-14-00980" class="html-bibr">13</a>].</p> Full article ">
16 pages, 4348 KiB  
Article
Understanding the Interface Characteristics Between TiB2(0001) and L12-Al3Zr(001): A First-Principles Investigation
by Xingzhi Pang, Loujiang Yang, Hang Nong, Mingjun Pang, Gaobao Wang, Jian Li, Zhenchao Chen, Wei Zeng, Zhihang Xiao, Zengxiang Yang and Hongqun Tang
Crystals 2024, 14(11), 979; https://doi.org/10.3390/cryst14110979 - 14 Nov 2024
Viewed by 676
Abstract
This study employs first-principles calculation methods to explore the characteristics of the TiB2(0001)/L12-Al3Zr(001) interface, including the atomic structure, adhesion work, interfacial energy, and electronic structure of various interface models. Considering four different terminations and three different stacking [...] Read more.
This study employs first-principles calculation methods to explore the characteristics of the TiB2(0001)/L12-Al3Zr(001) interface, including the atomic structure, adhesion work, interfacial energy, and electronic structure of various interface models. Considering four different terminations and three different stacking positions, twelve potential interface models were investigated. Surface tests revealed that a stable interface could be formed when a 9-layer TiB2(0001) surface is combined with a 7-layer ZrAl-terminated and a 9-layer Al-terminated Al3Zr(001) surface. Among these interfaces, the bridge-site stacking at the T/Al termination (TAB), hollow-site stacking at the Ti/ZrAl termination (TZH), top-site stacking at the B/Al termination (BAT), and hollow-site stacking at the B/ZrAl termination (BZH) were identified as the optimal structures. Particularly, the TAB interface exhibits the strongest adhesion strength and the lowest surface energy, indicating the highest stability. A Detailed analysis of the electronic structure further reveals that most interfaces predominantly exhibit covalent bonding, with the TAB, TZH, and BZH interfaces primarily featuring covalent bonds, while the BAT interface displays a combination of ionic and covalent bonds. The study ultimately ranks the stability of the interfaces from highest to lowest as TAB, BZH, TZH, and BAT. Full article
(This article belongs to the Special Issue Design, Development and Processing of Aluminium Alloys and Their Composite Materials)
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<p>Crystal structures of TiB<sub>2</sub> and Al<sub>3</sub>Zr: (<b>a</b>) TiB<sub>2</sub>; (<b>b</b>) Al<sub>3</sub>Zr.</p> Full article ">Figure 2
<p>Relationship between the surface energy and chemical potential: (<b>a</b>) the function of surface energy with boron chemical potential difference for the Ti-terminated and B-terminated TiB<sub>2</sub> surfaces; (<b>b</b>) the function of surface energy with aluminum chemical potential difference for the Al-terminated and ZrAl-terminated Al<sub>3</sub>Zr surfaces. Vertical dashed lines indicate the stability range of the compounds.</p> Full article ">Figure 3
<p>Twelve models for the TiB<sub>2</sub>/Al<sub>3</sub>Zr interface: (<b>a</b>) TAT interface; (<b>b</b>) TAB interface; (<b>c</b>) TAH interface; (<b>d</b>) BAT interface; (<b>e</b>) BAB interface; (<b>f</b>) BAH interface; (<b>g</b>) TZT interface; (<b>h</b>) TZB interface; (<b>i</b>) TZH interface; (<b>j</b>) BZT interface; (<b>k</b>) BZB interface; (<b>l</b>) BZH interface.</p> Full article ">Figure 3 Cont.
<p>Twelve models for the TiB<sub>2</sub>/Al<sub>3</sub>Zr interface: (<b>a</b>) TAT interface; (<b>b</b>) TAB interface; (<b>c</b>) TAH interface; (<b>d</b>) BAT interface; (<b>e</b>) BAB interface; (<b>f</b>) BAH interface; (<b>g</b>) TZT interface; (<b>h</b>) TZB interface; (<b>i</b>) TZH interface; (<b>j</b>) BZT interface; (<b>k</b>) BZB interface; (<b>l</b>) BZH interface.</p> Full article ">Figure 4
<p>The relationship between the twelve types of TiB<sub>2</sub>(0001)/Al<sub>3</sub>Zr(001) interfaces and varying chemical potentials of boron.</p> Full article ">Figure 5
<p>Differential charge density of the TiB<sub>2</sub>(0001)/Al<sub>3</sub>Zr(001) interfaces: (<b>a</b>) TAB interface; (<b>b</b>) BAT interface; (<b>c</b>) TZH interface; (<b>d</b>) BZH interface.</p> Full article ">Figure 6
<p>Partial density of states for the TiB<sub>2</sub>(0001)/Al<sub>3</sub>Zr(001) interfaces: (<b>a</b>) TAB interface; (<b>b</b>) BAT interface; (<b>c</b>) TZH interface; (<b>d</b>) BZH interface. Vertical dashed lines indicate the Fermi level.</p> Full article ">Figure 6 Cont.
<p>Partial density of states for the TiB<sub>2</sub>(0001)/Al<sub>3</sub>Zr(001) interfaces: (<b>a</b>) TAB interface; (<b>b</b>) BAT interface; (<b>c</b>) TZH interface; (<b>d</b>) BZH interface. Vertical dashed lines indicate the Fermi level.</p> Full article ">
12 pages, 4114 KiB  
Article
Intermolecular Interactions in Molecular Ferroelectric Zinc Complexes of Cinchonine
by Marko Očić and Lidija Androš Dubraja
Crystals 2024, 14(11), 978; https://doi.org/10.3390/cryst14110978 - 13 Nov 2024
Viewed by 618
Abstract
The use of chiral organic ligands as linkers and metal ion nodes with specific coordination geometry is an effective strategy for creating homochiral structures with potential ferroelectric properties. Natural Cinchona alkaloids, e.g., quinine and cinchonine, as compounds with a polar quinuclidine fragment and [...] Read more.
The use of chiral organic ligands as linkers and metal ion nodes with specific coordination geometry is an effective strategy for creating homochiral structures with potential ferroelectric properties. Natural Cinchona alkaloids, e.g., quinine and cinchonine, as compounds with a polar quinuclidine fragment and aromatic quinoline ring, are suitable candidates for the construction of molecular ferroelectrics. In this work, the compounds [CnZnCl3]·MeOH and [CnZnBr3]·MeOH, which crystallize in the ferroelectric polar space group P21, were prepared by reacting the cinchoninium cation (Cn) with zinc(II) chloride or zinc(II) bromide. The structure of [CnZnBr3]·MeOH was determined from single-crystal X-ray diffraction analysis and was isostructural with the previously reported chloride analog [CnZnCl3]·MeOH. The compounds were characterized by infrared spectroscopy, and their thermal stability was determined by thermogravimetric analysis and temperature-modulated powder X-ray diffraction experiments. The intermolecular interactions of the different cinchoninium halogenometalate complexes were evaluated and compared. Full article
(This article belongs to the Special Issue Polycrystalline Materials–from Design to (Micro)Structural Characterization and Applications)
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<p>Temperature-modulated PXRD experiments on the initial sample [CnZnBr<sub>3</sub>]·MeOH (black line) measured at 293 K. The diffractogram simulated from the single-crystal XRD data is given for comparison (gray line).</p> Full article ">Figure 2
<p>Asymmetric unit in [CnZnBr<sub>3</sub>]·MeOH with the atom numbering scheme. Displacement ellipsoids are drawn for a probability of 50% and hydrogen atoms are shown as spheres of arbitrary radii.</p> Full article ">Figure 3
<p>Hirshfeld surface mapped with normalized contact distance of (<b>a</b>) complex [CnZnBr<sub>3</sub>], (<b>b</b>) [CnZnBr<sub>3</sub>]·MeOH; (<b>d</b>) complex [CnZnCl<sub>3</sub>]; (<b>e</b>) [CnZnBr<sub>3</sub>]·MeOH. Fingerprint plots for all contacts in (<b>c</b>) [CnZnBr<sub>3</sub>]·MeOH; (<b>f</b>) [CnZnCl<sub>3</sub>]·MeOH.</p> Full article ">Figure 4
<p>Hydrogen bonding in [CnZnBr<sub>3</sub>]·MeOH: (<b>a</b>) cooperative hydrogen bond chain between methanol and [CnZnBr<sub>3</sub>]; (<b>b</b>) hydrogen bonding along the direction of the polar axis. Hydrogen contacts are shown as blue dashes; the coordination sphere around zinc is shown as a gray tetrahedron. The green line represents the two-fold screw axis.</p> Full article ">Figure 5
<p>Polarization–voltage loop measured on a [CnZnCl<sub>3</sub>]·MeOH 50 μm thick pellet sample.</p> Full article ">Figure 6
<p>Interactions between cinchoninium molecules related by two-fold screw axes in the structures of (<b>a</b>) cinchoninium tetrachlorocadmium(II) dihydrate (CINCDC) [<a href="#B40-crystals-14-00978" class="html-bibr">40</a>]; (<b>b</b>) bis(cinchoninium) tetrachlorocadmium(II) tetrachlorocopper(II) (WAFFUT) [<a href="#B42-crystals-14-00978" class="html-bibr">42</a>]; and (<b>c</b>) cinchoninium tribromozinc(II) methanol.</p> Full article ">
12 pages, 6747 KiB  
Article
Solution Strengthening and Short-Range Order in Cold-Drawn Pearlitic Steel Wires
by Gang Zhao, Jianyu Jiao, Yan Wu, Fengmei Bai, Hongwei Zhou, Jun Xue, Yixuan Zhu and Guangwen Zheng
Crystals 2024, 14(11), 977; https://doi.org/10.3390/cryst14110977 - 13 Nov 2024
Viewed by 577
Abstract
Pearlitic steel rods are subjected to cold-drawing processes to produce pearlitic steel wires with true strains ranging from 0.81 to 2.18. Tensile tests are utilized to attain mechanical properties of cold-drawn pearlitic steel wires. TEM and XRD investigations were performed on the microstructure [...] Read more.
Pearlitic steel rods are subjected to cold-drawing processes to produce pearlitic steel wires with true strains ranging from 0.81 to 2.18. Tensile tests are utilized to attain mechanical properties of cold-drawn pearlitic steel wires. TEM and XRD investigations were performed on the microstructure of the cold-drawn steel wires. With an increasing cold-drawn strain, both the interlamellar spacing and cementite lamellae thickness decrease, while the dislocation density significantly increases. The drawn wire has a tensile strength of 2170 MPa when the true stain reaches 2.18. Deformation-induced cementite dissolution occurs during cold-drawing progress, which releases many C atoms. The findings indicate that the supersaturation of C is heterogeneously distributed in the ferrite matrix. The ordered distribution of the released C in ferrite phases creates short-range order (SRO). SRO clusters and disordered Cottrell atmospheres contribute to solution strengthening, which, together with dislocation strengthening and interlamellar boundary strengthening, form an effective strengthening mechanism in cold-drawn pearlitic steel wires. Our work provides new insights into carbon redistribution and the mechanism of solution strengthening within ferrous phases. Full article
(This article belongs to the Special Issue Microstructure and Properties of Metals and Alloys)
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<p>(<b>a</b>) Schematic of the tensile specimens; (<b>b</b>) tensile stress–strain curves of wires with the different true stains; (<b>c</b>) tensile strength, yield strength and elongation vs drawn strains.</p> Full article ">Figure 2
<p>TEM images of wires in solution treatment before cold-drawing: (<b>a</b>) pearlitic in different colonies; (<b>b</b>,<b>c</b>) bright field (BF) and dark field (DF) images of complete lamellar; (<b>d</b>,<b>e</b>) BF and DF images of broken θ–Fe<sub>3</sub>C; (<b>f</b>) a SADP of lamellar in (<b>b</b>).</p> Full article ">Figure 3
<p>TEM images and corresponding EDS mapping of wires before and after cold-drawing: (<b>a</b>,<b>b</b>) ε = 0; (<b>c</b>,<b>d</b>) ε = 2.18.</p> Full article ">Figure 4
<p>TEM images of pearlitic structures: (<b>a</b>) wire rod; (<b>b</b>) ε = 0.81; (<b>c</b>) ε = 2.18; (<b>a1</b>,<b>b1</b>,<b>c1</b>) BF images; (<b>a2</b>,<b>b2</b>,<b>c2</b>) the corresponding DF images; (<b>a3</b>,<b>b3</b>,<b>c3</b>) dislocation configurations in α–Fe; (<b>a4</b>,<b>b4</b>,<b>c4</b>) SADP of the areas marked by circles in (<b>a3</b>,<b>b3</b>,<b>c3</b>).</p> Full article ">Figure 5
<p>Spacing of cold-drawn steel wire lamellae under different strains:(<b>a</b>) interlamellar spacing (ILS); (<b>b</b>) cementite lamellar thickness (CLT).</p> Full article ">Figure 6
<p>XRD patterns of cold-drawn wires.</p> Full article ">Figure 7
<p>The dislocation density (<span class="html-italic">ρ</span>) of the cold-drawn wires: (<b>a</b>) linear fitting plots for the diffraction patterns of the wires in <a href="#crystals-14-00977-f006" class="html-fig">Figure 6</a>: (<b>b</b>) <span class="html-italic">ρ</span> as the function of ε.</p> Full article ">Figure 8
<p>The calculated and experimental strengthening of cold-drawn pearlitic steel wires.</p> Full article ">Figure 9
<p>HRTEM images of α–Fe/θ–Fe<sub>3</sub>C interfaces at: (<b>a</b>) ε = 0, (<b>b</b>) ε = 2.18. (<b>a2</b>,<b>b2</b>) The FFT patterns of α–Fe and θ–Fe<sub>3</sub>C phases in (<b>a1</b>,<b>b1</b>), respectively; (<b>a3</b>,<b>b3</b>) magnified view of the yellow box areas in (<b>a1</b>,<b>b1</b>); and (<b>a4</b>,<b>b4</b>) the corresponding strain maps along the [100]<sub>α-Fe</sub> axis calculated by Strain++ software V1.8 for HRTEM images in (<b>a3</b>,<b>b3</b>).</p> Full article ">
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