CN115595543A - A kind of MoAlB ceramic film with MAB phase structure and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of surface treatment, in particular to a MoAlB ceramic film with an MAB phase structure and a preparation method thereof, wherein the MoAlB ceramic film is prepared by adopting a two-step method of four-target magnetron sputtering ion plating and annealing heat treatment, and the preparation method comprises the following specific steps: s1, adopting MoB ₂ Carrying out sputtering deposition on the substrate material by using the Mo and double Al target four-target system to obtain a deposited film; and S2, carrying out annealing heat treatment on the deposited film to obtain the crystalline MoAlB ceramic film with a 222-type MAB phase structure. The MoAlB ceramic film with the MAB phase structure can be obtained at low temperature by adopting a two-step method of magnetron sputtering ion plating and annealing heat treatment; meanwhile, the control of the MoAlB film with specific components and microstructure can be realizedAnd the process is stable and easy to realize industrial production.

Description

A kind of MoAlB ceramic film with MAB phase structure and preparation method thereof

technical field

The invention relates to the technical field of surface treatment, in particular to a MoAlB ceramic film with a MAB phase structure and a preparation method thereof.

Background technique

With the rapid development of my country's aviation, aerospace and nuclear power and other fields, higher and higher requirements are put forward for the high temperature performance of materials. Traditional high-temperature alloy materials are limited by their melting points and cannot meet the requirements, and ceramic materials with better heat resistance have become the only choice. Derived from strong covalent and ionic bonding characteristics, transition metal carbides/nitrides/borides and their composites have attracted much attention as ultra-high temperature ceramic materials due to their high hardness, high melting point, and good corrosion resistance. However, intrinsic brittleness and poor oxidation resistance are the main bottlenecks for their service in high-temperature extreme environments, and they are also problems that the scientific community needs to overcome urgently. Therefore, it is particularly important to develop materials with both ceramic and metallic properties.

Inspired by the MAX phase material (abbreviation of M _n+1 AX _n , where M is a transition metal element, A is a group IIIA or IVA element, X is carbon or nitrogen, and n is 1, 2 and 3), in binary A ternary layered transition metal boride called "MAB phase" can also be formed by inserting a single or double layer of main group atoms (typically Al atoms) into borides. MAB phase (abbreviation of (MB)2 _x Al _y (MB ₂ )z, where B represents boron element, x is 1, 2..., y is 1, 2, 3..., z=0, 1, 2...) material It is a series of ternary layered borides, including MAB compounds and MAB solid solutions. The MAB phase is composed of MB atomic layers (MBene) and A atomic layers alternately arranged to form a laminated structure. The MB layers are connected by strong covalent bonds and ionic bonds, and the MA layers are connected by weaker metal bonds. This layered crystal structure and The weak interlayer bonding makes it have many excellent properties of metal and ceramics, such as high fracture toughness, high damage tolerance, excellent machinability, good high temperature oxidation resistance and ablation resistance.

As one of the MAB phases that has received much attention, MoAlB's double-layer "Al-rich" layer has the function of "reservoir", which can provide enough Al to form a continuous Al ₂ O ₃ protective film during the oxidation process, and is expected to become a high-temperature Candidate material for structural components and high temperature coatings. At the same time, good electrical conductivity/thermal performance and neutron shielding performance make it have great application potential in the fields of heating elements, electrode materials, electrical contacts, and nuclear material cladding layers.

So far, research on MoAlB materials has mainly focused on theoretical calculations, bulk and powder materials. The patent application number 201911300427.2 discloses a preparation method of dense MoAlB ceramic materials, its products and preparation of high-purity MoAlB ceramic powder Methods: A dense and high-purity MoAlB bulk material was prepared by plasma sintering at a temperature of 800-1200°C and a pressure of 50-100 MPa, and then pulverized to obtain a powder material. However, the preparation process requires excessive Al and high temperature, and it is difficult to realize the preparation of bulk MoAlB materials, and the energy consumption of the process is high, which limits its practical application.

MoAlB thin film materials can be prepared in a large area while meeting their performance requirements, the process temperature is low (<700°C) and the dependence on the substrate is low, so it has become one of the effective ways to replace bulk materials. Evertz et al. used the MoAlB composite target and heated the substrate by magnetron sputtering to prepare MoAlB thin films at low temperature, but the prepared thin films have poor crystallinity and low purity, and the preparation process has high requirements for equipment, which is difficult to produce. Film composition and microstructure are tuned. Therefore, the preparation of high-purity dense MoAlB thin films with controllable composition and structure is the key technology to promote the popularization and application of MoAlB thin films.

Contents of the invention

Aiming at the problems in the prior art that film components and microstructure are difficult to control, the present invention provides a MoAlB ceramic film with MAB phase structure and a preparation method thereof.

The present invention is achieved through the following technical solutions:

A method for preparing a MoAlB ceramic thin film with a MAB phase structure is prepared by using four-target magnetron sputtering ion plating and annealing heat treatment two-step method for preparation, and the specific steps are as follows:

S1, using the four-target system of MoB ₂ , Mo and double Al targets to perform sputtering deposition on the substrate material to obtain the as-deposited thin film;

S2, performing annealing heat treatment on the as-deposited film to obtain a crystalline MoAlB ceramic film with a 222-type MAB phase structure.

Preferably, in S1, the preparation method of the as-deposited thin film is as follows:

S11, selecting and cleaning the target and substrate materials;

S12, the substrate material is sputter-deposited under vacuum conditions to obtain a deposited thin film; during sputter deposition, the target combination mode is double Al targets facing each other, and MoB ₂ and Mo targets facing each other.

Preferably, in S11, the substrate material is single-crystal Al ₂ O ₃ polished on one side, and is ultrasonically cleaned in acetone solution and absolute ethanol solution in sequence.

Preferably, in S11, ion cleaning is used for cleaning the target. When the vacuum degree of the chamber is less than 7.33×10 ^-3 Pa, an inert gas is introduced, and the negative bias voltage of the substrate is adjusted to 300V-350V for 10min-20min.

Preferably, in S12, during sputtering deposition, the MoB ₂ target sputtering power is 700W-750W, the Mo target sputtering power is 150W-200W, the Al target sputtering power is 300W-350W, and the substrate negative bias voltage is 50V- 90V, the rotation speed of the workpiece holder is 3rpm~5rpm, the working pressure in the chamber is about 6.67~12.50×10 ^-2 Pa, when the vacuum degree in the chamber is less than 7.33×10 ^-3 Pa, inert gas is introduced into the chamber; the deposition time is 0.5h to 3h, the temperature in the chamber is 25°C to 100°C.

Preferably, in S1, the stoichiometric ratio of Mo:Al:B in the deposited thin film is 1:1:1.

Preferably, in S2, during the annealing heat treatment, the temperature range is 500°C-800°C, the holding time is 0.5h-1h, and the heating rate is less than 5°C/min.

Preferably, in S2, a protective atmosphere is introduced during the annealing heat treatment.

Preferably, in S2, the cooling method is furnace cooling.

A crystalline MoAlB ceramic film with a MAB phase structure prepared by a method for preparing a MoAlB ceramic film with a MAB phase structure.

Compared with the prior art, the present invention has the following beneficial effects:

In a method for preparing a MoAlB ceramic thin film with a MAB phase structure of the present invention, a two-step method of magnetron sputtering ion plating and annealing heat treatment can be used to obtain a MoAlB ceramic thin film with a MAB phase structure at a low temperature; at the same time, specific components and The controllable preparation of the microstructure MoAlB thin film is stable and easy to realize industrial production.

The preparation of MAB phase thin films by magnetron sputtering ion plating technology is a non-equilibrium process. Under the condition of lower than the synthesis temperature of bulk materials, high-quality thin films with high density, strong bonding force and controllable thickness can be obtained. In addition, the heat treatment process can achieve precise control of the phase composition and microstructure of the film.

Description of drawings

Fig. 1 is a schematic diagram of 4 target magnetron sputtering ion plating equipment adopted in a kind of MoAlB ceramic film preparation method with MAB phase structure of the present invention;

Fig. 2 is the TG-DSC collection of illustrative plates of deposited state Mo-Al-B film sample described in comparative example 1 of the present invention;

Fig. 3 is the grazing incidence X-ray diffraction (GIXRD) collection of patterns (PDF#72-1277) of the comparative example of the present invention and embodiment film;

Fig. 4 is the surface and cross-sectional topography figure of deposition state Mo-Al-B thin film in comparative example 1 of the present invention;

Fig. 5 is the surface and cross-sectional topography diagram of crystalline MoAlB thin film in the embodiment 2 of the present invention;

Fig. 6 is a surface and cross-sectional morphology diagram of the crystalline MoAlB thin film in Example 3 of the present invention.

detailed description

The present invention will be further described in detail below in conjunction with specific embodiments, which are explanations of the present invention rather than limitations.

The invention discloses a method for preparing a MoAlB ceramic thin film with a MAB phase structure, which is prepared by a two-step method of four-target magnetron sputtering ion plating and annealing heat treatment, and the specific steps are as follows:

S1, use MoB ₂ , Mo and double Al target four-target system (using the equipment shown in Figure 1) to carry out sputter deposition on the substrate material, and obtain the stoichiometric ratio of Mo:Al:B as 1:1:1 The as-deposited thin film, the specific preparation process is as follows:

S11, selecting and cleaning the target and substrate materials;

The substrate material is single-crystal Al ₂ O ₃ (0001 crystal orientation) polished on one side. The size of the substrate material is 10mm×10mm, and the thickness is 430μm±20μm. Ultrasonic cleaning 10min ~ 20min.

Ion cleaning is used to clean the target. Before the experiment, the glass slide is placed on the biaxial workpiece holder in the chamber, and the power supply is connected for pre-sputtering. At this time, when the vacuum degree of the chamber is less than 7.33×10 ^-3 Pa, the The inert gas Ar (purity is 99.99%), the flow rate of the inert gas is 15Sccm~20Sccm, the negative bias voltage of the substrate is adjusted to 300V~350V, and the time is 10min~20min, the purpose is to clean the oxide and impurities on the surface of the target.

S12, the substrate material is sputtered and deposited under vacuum conditions to obtain a deposited thin film; during sputtering and deposition, the target combination method is double Al targets facing each other, and MoB ₂ and Mo targets facing each other. The specific operation steps are as follows: During sputtering deposition, put the pre-ultrasonic cleaned single crystal Al ₂ O ₃ substrate into the chamber, and when the vacuum degree of the chamber is less than 7.33×10 ^-3 Pa, the inert gas Ar is introduced to adjust the sputtering power of the target Value, deposited on a single crystal Al ₂ O ₃ substrate, about 0.75 ~ 4.5 μ m Mo: Al: B stoichiometric ratio to meet the 1:1:1 as-deposited film, that is, Mo-Al-B amorphous film .

The target combination method is double Al targets facing each other, MoB ₂ and Mo targets facing each other, MoB ₂ target sputtering power is 700W-750W, Mo target sputtering power is 150W-200W, Al target sputtering power is 300W-350W, The negative bias voltage of the substrate is 50V-90V, the rotation speed of the workpiece holder is 3rpm-5rpm, the working pressure in the chamber is about 6.67-12.50×10 ^-2 Pa, the deposition time is 0.5h-3h, and the temperature in the chamber is 25°C-100°C.

S2, the as-deposited film is annealed at 500°C-800°C, a protective atmosphere is introduced during the annealing heat treatment, the holding time is 0.5h-1h, the heating rate is less than 5°C/min, and the cooling method is furnace cooling, to obtain Crystalline MoAlB ceramic thin films with 222-type MAB phase structure.

Comparative example 1

Magnetron sputtering ion plating technology is used to prepare Mo-Al-B amorphous film. During the process, a 4-target system is used for sputtering deposition. MoB ₂ , Mo, and Al targets are used as sputtering targets, and the target combination method is double Al targets. Opposite, MoB ₂ and Mo target are opposite.

S11, ion cleaning, the specific process parameters are: use a mechanical pump and a molecular pump to vacuum the chamber to <7.33×10 ^-3 Pa, then pass in an inert gas Ar (purity is 99.99%), the gas flow rate is 18Sccm, adjust the substrate Negative bias voltage to 350V, MoB ₂ target sputtering power 750W, Mo target sputtering power 200W, Al target sputtering power 350W, workpiece holder rotation speed 5rpm, working pressure in the chamber is about 1.12×10 ^-1 Pa, During the cleaning process, the temperature in the chamber is 25°C to 55°C, and the working time is 20 minutes, the purpose is to remove oxides and impurities on the surface of the target;

The substrate material is single-crystal Al ₂ O ₃ (0001 crystal orientation) polished on one side (size 10mm×10mm, thickness 430±20μm), and placed in acetone and absolute ethanol for 15 minutes of ultrasonic cleaning before deposition.

S12, put the ultrasonically cleaned single crystal Al ₂ O ₃ substrate into the chamber, and when the vacuum degree of the chamber is less than 7.33×10 ^-3 Pa, inject the inert gas Ar, adjust the sputtering power value of the target, and Deposit Mo-Al-B amorphous film on the surface of crystalline Al ₂ O ₃ substrate; the specific parameters are: the MoB ₂ target sputtering power is 728W, the Mo target sputtering power is 175W, the Al target sputtering power is 312W, and the Ar flow rate is 18Sccm , the substrate negative bias voltage is 65V, the rotating speed of the workpiece holder is 5rpm, the working pressure in the chamber is about 1.12×10 ^-1 Pa, the deposition time is 40min, the temperature in the chamber is 25℃～100℃ during the film deposition process, and the obtained film thickness is About 1 μm.

After the execution of the S12 process, when the temperature in the chamber dropped below 50°C, the samples were taken out for phase structure and cross-sectional morphology characterization. The thermal analysis (TG-DSC) results are shown in Figure 2, in which two crystallization exothermic peaks can be observed at 594.97°C and 661.04°C. The XRD results are shown in Figure 3. The XRD pattern of the as-deposited film presents a broad "steamed bread peak", indicating that the prepared Mo-Al-B film has a typical amorphous structure, and the adjustment of the composition is realized by using multiple targets. Further, the prepared thin film phase has higher purity. Referring to the cross-sectional morphology in the upper right corner of Figure 4, it can be observed that the surface of the film is flat and dense, and it is well bonded to the substrate.

Comparative example 2

The Mo-Al-B amorphous film was prepared by 4-target magnetron sputtering ion plating technology. In S12, single crystal Al ₂ O ₃ was used as the substrate material, and it was ultrasonically cleaned in acetone and absolute ethanol for 15 minutes before deposition. During the sputtering deposition process, the sputtering power of the MoB ₂ target was 728W, the sputtering power of the Mo target was 175W, the sputtering power of the Al target was 312W, the Ar flow rate was 18Sccm, the negative bias of the substrate was 65V, and the rotating speed of the workpiece holder was 5rpm. The working pressure is about 1.12×10 ^-1 Pa, the deposition time is 40 minutes, and the temperature in the chamber is 25°C-100°C during the film deposition process.

In S2, the as-deposited film was annealed at 500 °C in a high-temperature tube furnace. Before annealing, the inert Ar gas was introduced in advance to remove the oxygen in the pipeline, and the introduction time was 10 minutes. The specific parameters of the annealing heat treatment are: the heating rate is less than 5°C/min, the annealing temperature is 500°C, the holding time is 1h, and the cooling method is furnace cooling. At the same time, the protective atmosphere Ar is continuously introduced during the annealing heat treatment to prevent the oxidation of the film, and compared with the vacuum annealing heat treatment, the annealing heat treatment under an inert atmosphere can effectively prevent the evaporation of the Al element in the film. Its phase structure is shown in Figure 3. After annealing heat treatment at 500°C, the film still has an amorphous structure.

Example 1

The Mo-Al-B amorphous film was prepared by 4-target magnetron sputtering ion plating technology. In S12, single crystal Al ₂ O ₃ was used as the substrate material, and it was ultrasonically cleaned in acetone and absolute ethanol for 15 minutes before deposition. During the sputtering deposition process, the sputtering power of the MoB ₂ target was 728W, the sputtering power of the Mo target was 175W, the sputtering power of the Al target was 312W, the Ar flow rate was 18Sccm, the negative bias of the substrate was 65V, and the rotating speed of the workpiece holder was 5rpm. The working pressure is about 1.12×10 ^-1 Pa, the deposition time is 40 minutes, and the temperature in the chamber is 25°C-100°C during the film deposition process.

In S2, the as-deposited film was annealed at 600 °C in a high-temperature tube furnace. Before the annealing, the inert Ar gas was introduced in advance for 10 min. The specific parameters of the annealing heat treatment are: the heating rate is less than 5°C/min, the annealing temperature is 600°C, the holding time is 1h, and the cooling method is furnace cooling. Its phase structure is shown in Figure 3. After annealing heat treatment at 600°C, the film undergoes a crystallization transition, and the 222-type MAB phase characteristic diffraction peak appears in the spectral line, and the deposited Mo-Al-B amorphous film transforms into a Crystalline MoAlB ceramic film with MAB phase structure, this result is consistent with the crystallization exothermic peak at 594.97°C in the above thermal analysis spectrum.

Example 2

The Mo-Al-B amorphous film was prepared by 4-target magnetron sputtering ion plating technology. In S12, single crystal Al ₂ O ₃ was used as the substrate material, and it was ultrasonically cleaned in acetone and absolute ethanol for 15 minutes before deposition. During the sputtering deposition process, the sputtering power of the MoB ₂ target was 728W, the sputtering power of the Mo target was 175W, the sputtering power of the Al target was 312W, the Ar flow rate was 18Sccm, the negative bias of the substrate was 65V, and the rotating speed of the workpiece holder was 5rpm. The working pressure is about 1.12×10 ^-1 Pa, the deposition time is 40 minutes, and the temperature in the chamber is 25°C-100°C during the film deposition process.

In S2, the as-deposited film was annealed at 700 °C in a high-temperature tube furnace. Before the annealing, the inert Ar gas was introduced in advance for 10 min. The specific parameters of the annealing heat treatment are: the heating rate is less than 5°C/min, the annealing temperature is 700°C, the holding time is 1h, and the cooling method is furnace cooling. Referring to Figure 3, the crystallinity of the MoAlB film is higher after annealing at 700°C. Referring to Figure 5, the film is uniform, flat and dense.

Example 3

The Mo-Al-B amorphous film was prepared by 4-target magnetron sputtering ion plating technology. In S12, single crystal Al ₂ O ₃ was used as the substrate material, and it was ultrasonically cleaned in acetone and absolute ethanol for 15 minutes before deposition. During the sputtering deposition process, the sputtering power of the MoB ₂ target was 728W, the sputtering power of the Mo target was 175W, the sputtering power of the Al target was 312W, the Ar flow rate was 18Sccm, the negative bias of the substrate was 65V, and the rotating speed of the workpiece holder was 5rpm. The working pressure is about 1.12×10 ^-1 Pa, the deposition time is 40 minutes, and the temperature in the chamber is 25°C-100°C during the film deposition process.

In S2, the as-deposited film was annealed at 800 °C in a high-temperature tube furnace. Before the annealing, the inert Ar gas was introduced in advance for 10 min. The specific parameters of the annealing heat treatment are: the heating rate is less than 5°C/min, the annealing temperature is 800°C, the holding time is 1h, and the cooling method is furnace cooling. At the same time, the protective atmosphere Ar is continuously introduced during the annealing heat treatment process. Its phase structure is shown in Figure 3. After annealing heat treatment at 800°C, the film has a crystalline structure and a high degree of crystallinity.

The invention also discloses a crystalline MoAlB ceramic thin film with MAB phase structure prepared by the method for preparing MoAlB ceramic thin film with MAB phase structure.

The above are only preferred embodiments of the present invention, and are not intended to limit the technical solutions of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solutions Some simple modifications and substitutions can also be made, and these modifications and substitutions also fall within the scope of protection covered by the claims.

Claims (10)

1. A preparation method of a MoAlB ceramic film with an MAB phase structure is characterized by adopting a two-step method of four-target magnetron sputtering ion plating and annealing heat treatment to prepare the MoAlB ceramic film, and comprises the following specific steps:

s1, adopting MoB ₂ Carrying out sputtering deposition on the substrate material by using the Mo and double Al target four-target system to obtain a deposited film;

and S2, carrying out annealing heat treatment on the deposited film to obtain the crystalline MoAlB ceramic film with a 222-type MAB phase structure.

2. The method according to claim 1, wherein in S1, the as-deposited film is prepared as follows:

s11, selecting and cleaning a target material and a substrate material;

s12, carrying out sputtering deposition on the substrate material under the vacuum degree condition to obtain a deposition state film; during sputtering deposition, the target combination mode is double Al targets oppositely arranged, moB ₂ Opposite the Mo target.

3. The method for preparing MoAlB ceramic film with MAB phase structure according to claim 2, wherein in S11, the substrate material is single crystal Al with single side polished ₂ O ₃ And ultrasonic cleaning in an acetone solution and an absolute ethyl alcohol solution sequentially.

4. The method for preparing MoAlB ceramic film with MAB phase structure according to claim 2, wherein in S11, the target cleaning is performed by ion cleaning, and the vacuum degree of the chamber is less than 7.33 x 10 ^-3 When Pa, inert gas is introduced, the negative bias of the matrix is adjusted to 300-350V for 10-20 min.

5. The method of claim 2, wherein in S12, during sputter deposition, moB is present ₂ The sputtering power of the target is 700W-750W, the sputtering power of the Mo target is 150W-200W, the sputtering power of the Al target is 300W-350W, the negative bias voltage of the substrate is 50V-90V, the rotating speed of the workpiece frame is 3 rpm-5 rpm, and the working air pressure in the chamber is about 6.67-12.50 multiplied by 10 ^-2 Pa, vacuum degree in the chamber less than 7.33X 10 ^-3 When Pa, introducing inert gas into the chamber; the deposition time is 0.5 h-3 h, and the temperature in the cavity is 25 ℃ to 100 ℃.

6. The method according to claim 1, wherein in S1, the ratio of Mo: al: the stoichiometric ratio of B is 1:1:1.

7. the method for preparing a MoAlB ceramic film with a MAB phase structure according to claim 1, wherein in S2, during annealing heat treatment, the temperature ranges from 500 ℃ to 800 ℃, the holding time ranges from 0.5h to 1h, and the heating rate is less than 5 ℃/min.

8. The method for preparing a MoAlB ceramic film with a MAB phase structure according to claim 1, wherein in S2, a protective atmosphere is introduced during the annealing heat treatment.

9. The method for preparing a MoAlB ceramic film with a MAB phase structure according to claim 1, wherein in S2, the cooling mode is furnace cooling.

10. A crystalline MoAlB ceramic thin film having a MAB phase structure prepared by the method of preparing a MoAlB ceramic thin film having a MAB phase structure according to any one of claims 1 to 9.

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