CN113290242A

CN113290242A - Micro-nano porous functional device, additive manufacturing method and application thereof

Info

Publication number: CN113290242A
Application number: CN202110453993.8A
Authority: CN
Inventors: 蔡超; 魏毓; 魏青松; 史玉升
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2021-04-26
Filing date: 2021-04-26
Publication date: 2021-08-24

Abstract

The invention belongs to the crossing field of advanced manufacturing and nano material synthesis, and particularly relates to a micro-nano porous structure functional device, and an additive manufacturing method and application thereof. Firstly, alloy powder is processed into a porous alloy precursor by adopting an additive manufacturing technology, and then the porous alloy precursor is subjected to dealloying treatment so as to obtain a nano-pore structure on the surface and compound the nano-pore structure into a micro-nano porous structure. The porous functional device precursor with large specific surface area and suitable for the dealloying process can be prepared by adopting the additive manufacturing technology. The additive manufacturing/dealloying composite technology can conveniently prepare a functional device with a micro-nano porous structure and a controllable shape, and can meet more complex and changeable use requirements in more practical application compared with small-sized nanowires or films with nano porous structures.

Description

Micro-nano porous functional device, additive manufacturing method and application thereof

Technical Field

The invention belongs to the crossing field of advanced manufacturing and nano material synthesis, and particularly relates to a micro-nano porous structure functional device, an additive manufacturing method and application thereof, and more particularly relates to a micro-nano porous functional device manufactured in an additive manufacturing/dealloying composite mode, and preparation and application thereof.

Background

Dealloying is also called Dealloying (Dealloying), under a specific corrosion condition (chemical or electrochemical), due to the difference of electrochemical behaviors or element activities of elements in an alloy, relatively active elements are dissolved, and elements with lower activity spontaneously form a nano-scale porous structure with random distribution under the action of surface tension through self-assembly modes such as diffusion and aggregation.

In the catalytic reaction, the nano-scale porous structure can remarkably enhance the interaction between host molecules and guest molecules and provide a plurality of ultrahigh specific surfaces with a plurality of catalytic sites. The dealloying can realize the nano-porous of the metal material, so that the material has the advantages of small relative density, large specific surface area, good energy absorption performance and the like, and the porous material has the application which is difficult to be performed by a compact material. The technology is an important feasible method for producing the nano-porous metal structure, and is important for some emerging industrial applications, such as production of energy storage devices, sensors and catalytic media with high activity.

At present, the thin strip-shaped alloy is prepared by a method of quick solidification and strip spinning basically for preparing a precursor by dealloying, the process is complex, and the method is not suitable for batch production, so that the application of the method is limited. However, the material prepared by the method has small size, is inconvenient to use and collect, is easy to generate secondary pollution, and is difficult to apply to practical occasions. For example, in the sewage treatment process, the adopted nano-catalyst is in a powder state, and although the nano-catalyst has better catalytic performance in the use process, the nano-catalyst is in a powder state, so that the nano-catalyst is inconvenient to collect and easily causes secondary pollution to the treated water. The prior art can only prepare nanowire or film-shaped nano porous structure devices, can not obtain body type micro-nano porous structure devices with composite hole structures, and cannot meet the complicated and variable use requirements due to shape limitations.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a method for manufacturing a micro-nano porous functional device by additive manufacturing/dealloying, which combines additive manufacturing and dealloying, adopts additive manufacturing technology to manufacture a porous alloy precursor with large specific surface area, and then adopts dealloying technology to prepare nano porous catalytic particles on the surface of the precursor so as to obtain the high-performance micro-nano porous functional device with large specific surface area and a plurality of catalytic sites, and aims to solve the technical problems that the shape of nano materials such as a nano porous thin strip or a nano wire prepared by dealloying in the prior art is limited and cannot meet the complicated and variable application requirements.

In order to achieve the aim, the invention provides a method for manufacturing a micro-nano porous functional device by additive manufacturing/dealloying composite, which comprises the following steps:

(1) obtaining an integral porous alloy precursor by additive manufacturing of alloy powder or alloy element mixed powder, wherein the pore distribution of the integral porous alloy precursor has a three-dimensional net structure;

(2) and (2) performing dealloying treatment on the porous alloy precursor obtained in the step (1), wherein in the dealloying treatment process, the surface of the porous alloy precursor is subjected to dealloying and dissolving of the alloying element component, and meanwhile, the retained element component spontaneously forms a nano porous structure on the surface of the porous alloy precursor under the action of surface tension, so that a micro-nano porous functional device is obtained.

Preferably, the additive manufacturing is selective laser melting, selective electron beam melting, laser near net shape forming, electron beam fuse deposition shaping, or arc additive manufacturing.

Preferably, step (1) comprises the following sub-steps:

(1-1) processing a three-dimensional CAD model of a target porous alloy precursor by slicing software, converting the three-dimensional CAD model into an STL file, and transmitting information of the STL file to additive manufacturing equipment;

and (1-2) performing additive manufacturing on alloy powder or mixed powder of alloy elements by using the additive manufacturing equipment according to the STL file information to obtain a porous alloy precursor.

Preferably, the porous alloy precursor prepared in the step (1) is subjected to ultrasonic cleaning and drying, and then is subjected to dealloying treatment in the step (2).

Preferably, the pores in the porous alloy precursor obtained in the step (1) are one or more of micron-sized pores, submicron-sized pores and millimeter-sized pores; the porous alloy precursor has a dimension in any dimension greater than 1 millimeter.

Preferably, the size of pores in the porous alloy precursor obtained in the step (1) is 500-1500 μm.

Preferably, the three-dimensional CAD model of the target porous alloy part precursor in the step (1-1) is designed into a three-dimensional reticular porous structure, and the three-dimensional reticular porous structure is preferably a minimal curved surface structure or a cross truss-shaped grid structure.

Preferably, step (2) is performed by means of electrochemical corrosion or by dealloying in a corrosive solution.

Preferably, the time of the dealloying treatment is not greater than 48 hours.

Preferably, when the porous alloy precursor is placed in a corrosive solution for dealloying in the step (2), the corrosive solution is a dilute acid solution or a dilute alkali solution.

According to another aspect of the invention, the micro-nano porous functional device prepared by the method is provided.

According to another aspect of the invention, the invention provides an application of the micro-nano porous functional device in preparation of a porous catalytic material.

Generally, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:

(1) the invention provides a method for manufacturing a micro-nano porous functional device by additive manufacturing/dealloying composite. The precursor of the functional device in the step of dealloying is prepared in an additive manufacturing mode, and the porous alloy precursor with large specific surface area can be obtained. The micro-nano porous functional device prepared by the 3D printing/dealloying composite technology can be conveniently customized into various shapes, and compared with a nanowire or a nano porous film, the shape is controllable, and more complicated and changeable use requirements can be met.

(2) According to the invention, by adopting an additive manufacturing technology, the overall dimension of the obtained precursor can be controlled, and the alloy precursor with a porous structure can be obtained at the same time, so that the time can be reduced and the efficiency of dealloying treatment can be improved when the precursor is used in the subsequent dealloying process.

(3) According to the invention, a porous alloy precursor is obtained by adopting an additive manufacturing technology, more nano-scale holes can be obtained after the porous alloy precursor is used for dealloying, and the nano-scale holes and a porous structure prepared by the additive manufacturing technology are compounded to form a micro-nano porous structure. The method has the advantages that not only are more nanopores generated by dealloying on the surface of the outermost layer of the alloy precursor, but also corrosive solution can enter micro or millimeter pores of the porous alloy precursor, and more nanopores are generated by dealloying on the surface of the inner pores of the porous alloy precursor, so that the specific surface area of a prepared device is improved, and experiments prove that the method can effectively improve the catalytic effect of a functional device.

(4) When the porous alloy precursor is manufactured by additive manufacturing, the generation effect of nano porous catalytic particles in the dealloying process can be improved by optimizing the porous structure design of the 3D model, and the application performance of the finally prepared micro-nano structure device is improved.

Drawings

FIG. 1 is a flow chart of a method for manufacturing a micro-nano porous functional device by additive manufacturing/dealloying composite manufacturing.

FIG. 2 is a diagram of a method for manufacturing micro-nano porous SnO by applying the method of the invention in example 1₂Schematic representation of a catalytic device. The content (a) is SnO₂A schematic front view of a micron porous precursor of the catalytic device; the content (b) is SnO₂A three-dimensional schematic diagram of a catalytic device micron porous precursor alloy; the content (c) is micro-nano porous SnO after dealloying₂A three-dimensional schematic of a catalytic device; wherein the black areas represent cubic microporous SnO obtained after SLM printing₂Precursor profile, white areas represent the nanopore structure that appears on the precursor after dealloying.

FIG. 3 is a schematic diagram of a device for manufacturing a micro-nano porous Ni-Mo alloy by using the method of the invention in example 2. The content (a) is a three-dimensional schematic diagram of a precursor of a micron porous Ni-Mo alloy device; content (b) is a front view of a micron porous Ni-Mo alloy device precursor; content (c) is a cross-sectional view of a front view of a micron porous Ni-Mo alloy device precursor; content (d) is a schematic diagram of a micro-nano porous Ni-Mo alloy device slice after alloy removal; wherein, the solid line represents the outline of the micron porous Ni-Mo alloy device after SLM printing, and the dotted line represents the micro-nano porous structure formed on the alloy framework after alloy removal.

FIG. 4 is a scanning image of the micro-nano porous Cu catalytic device prepared in example 3;

fig. 5 is an SEM image of the micro-nano porous Cu catalytic device prepared in example 3.

Fig. 6 is a high-magnification SEM image of the micro-nano porous Cu catalytic device prepared in example 3.

Fig. 7 is a comparison graph of catalytic oxidation effects of the micro-nano porous Cu catalytic device prepared in example 3 and the same material with the same mass and other structure.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides a method for manufacturing a micro-nano porous functional device by additive manufacturing/dealloying composite, which comprises the following steps:

The additive manufacturing method according to the present invention may be various metal additive manufacturing methods, such as Selective Laser Melting (SLM), Electron Beam Selective Melting (EBM), Laser Engineered Net Shaping (LENS), Electron Beam fuse deposition (EBFF), or arc and arc additive manufacturing (WAAM).

Take selective melting of laser as an example. The SLM is one of 3D printing technologies, and materials are accumulated layer by layer to form and manufacture a solid part under the control of a computer according to CAD three-dimensional data of the part, so that a cutter, a clamp and a plurality of processing procedures are not needed. The technology can form and manufacture a two-dimensional thin layer structure every time, greatly reduces the forming and manufacturing difficulty of a three-dimensional complex structure, can form and manufacture any complex structure theoretically, and belongs to a free forming and manufacturing process. Moreover, the more complex the part is, the more significant the effect of high efficiency of its forming and manufacturing. By utilizing the characteristic of the SLM technology, the invention adopts the SLM to manufacture the precursor of the functional device in the step of dealloying, thereby overcoming the problem of difficult manufacture of complex shapes.

In the SLM technology, laser energy is concentrated on a small scanning spot, metal powder can be rapidly melted together, so that a precursor of a functional device has a phase structure of a unidirectional solid solution, a uniform microstructure and component distribution, and the treatment effect of dealloying is improved. By adopting the SLM technology, the shape and the size of the obtained precursor can be controlled, and the alloy precursor with a micron or millimeter porous structure can be obtained at the same time, so that the time can be reduced in the subsequent dealloying process, and the dealloying treatment efficiency can be improved. The large-specific-surface-area micro-porous precursor can obtain more nano-scale holes after being subjected to dealloying, and the nano-porous precursor and the micro-porous structure prepared by the SLM technology are compounded to form a micro-nano porous structure. The shape of the micro-nano porous functional device prepared by the 3D printing/dealloying composite technology provided by the invention can be conveniently customized into various shapes, and compared with a nanowire or a nano porous structure film, the shape is controllable, and more complicated and changeable use requirements can be met. According to the invention, firstly, a micrometer or millimeter porous framework is obtained by additive manufacturing, and a large number of nano holes are obtained on the surface of the precursor framework by further matching with a dealloying technology, which is equivalent to integrating a nano porous film on the prepared porous device framework, so that the use is convenient.

In some embodiments, step (1) specifically includes the following sub-steps:

(1-1) processing a three-dimensional CAD model of a target porous alloy precursor by slicing software, converting the three-dimensional CAD model into an STL file, and transmitting information of the STL file to selective laser melting equipment;

and (1-2) carrying out selective laser melting on alloy powder or mixed powder of alloy elements by adopting the selective laser melting equipment according to the STL file information to prepare the porous alloy precursor.

In some embodiments of the present invention, a precursor alloy system and a dealloying etching solution are designed according to the application requirements of functional devices, and alloy powder used for the precursor can be prepared by methods such as gas atomization, and the like, and also element powder in each alloy system can be mechanically mixed according to the alloy proportion. In some embodiments of the invention, the powder corresponding to the alloying element to be removed is referred to as corrosion metal powder, the metal powder corresponding to the alloying element left after the dealloying treatment is referred to as main metal powder, and the corrosion metal powder and the main metal powder are mixed uniformly to obtain mixed alloy powder. And (3) putting the prepared powder into an SLM printer, adjusting parameters, and then manufacturing the micron porous precursor under the condition of protective atmosphere.

The design principle of the alloy system of the present invention is that the elemental reactivity of the alloying component being dealloyed should be significantly different from the elemental reactivity of the alloying component that is expected to be retained. In the dealloying treatment process, the SLM precursor is selectively corroded and dealloyed by dealloying, and the remaining one or more inert elements are self-assembled to form nano porous catalytic particles, so that the micro-nano porous functional device with large specific surface area and more catalytic particles is obtained. Dealloying is also called Dealloying (Dealloying), under a specific corrosion condition (chemical or electrochemical), due to the difference of electrochemical behaviors or element activities of elements in an alloy, relatively active elements are dissolved, and elements with lower activity spontaneously form a nano-scale porous structure with random distribution under the action of surface tension through self-assembly modes such as diffusion and aggregation. According to the invention, the micro-nano porous functional device is manufactured by an additive manufacturing/dealloying method, and the types of the alloy elements selected in the preparation of the precursor of the micro-nano porous functional device are the same as those of the alloy elements adopted when the dealloying method is adopted to obtain the nano-scale porous structure in the prior art. For example, a micron porous functional device precursor can be obtained by adopting CuTi pre-alloyed powder through SLM, and then Ti element components are removed through dealloying corrosion to obtain a Cu micro-nano porous functional device, or a micron porous functional device precursor can be obtained by adopting mixed powder of Ni powder, Mo powder and Al powder through SLM, and then Al element components are removed through dealloying corrosion to obtain a Ni-Mo alloy micro-nano porous functional device.

In some embodiments, the porous alloy precursor prepared in step (1) is subjected to ultrasonic cleaning and drying, and then subjected to dealloying in step (2).

The size of any dimension of the precursor of the integral porous alloy prepared in the step (1) is larger than 1 mm. The pores in the bulk porous alloy precursor are one or more of micron-sized pores, submicron-sized pores and millimeter-sized pores. In some embodiments, the porous alloy precursor obtained in step (1) has a pore size of 500-1500 μm.

According to the structure and application requirements of the target micro-nano functional device, three-dimensional CAD models of precursors of various porous target devices can be drawn. The three-dimensional CAD model of the target porous alloy part precursor in the step (1-1) of the invention is designed into a three-dimensional reticular porous structure, and the three-dimensional reticular porous structure is preferably an extremely-small curved surface structure or a crossed truss-shaped net frame structure. In some embodiments, the three-dimensional CAD model of the target microporous alloy part precursor in step (1) has a porous unit structure designed as a three-dimensional mesh porous structure such as a three-period extremely-small curved surface structure (TPMS) or a cross-truss grid structure. In experiments, the porous unit structure of the three-dimensional CAD model of the porous alloy precursor is designed into a minimal curved surface structure, so that the catalytic performance of the finally prepared micro-nano structure device can be improved. Because each part of the extremely-small curved surface structure is a continuous pore and the curvature coefficient of the interface at each part is zero, the conveying characteristic is enhanced, the flowing of guest molecules in the pores of the functional device in the actual catalytic process is facilitated, and the performance of the device is further improved.

In some embodiments, step (2) is performed by electrochemical etching or by dealloying in a corrosive solution. The time of the dealloying treatment is not more than 48 hours. In the dealloying process, the alloying element components on the surface of the porous alloy precursor are corroded and dissolved, and meanwhile, the retained element components spontaneously form a nano porous structure on the surface of the porous alloy precursor under the action of surface tension, so that a micro-nano porous functional device is obtained.

In some embodiments, the corrosive solution is a dilute acid solution or a dilute base solution. Specifically, according to the kind of the alloy element in the alloy precursor, a dilute acid solution of hydrochloric acid, hydrofluoric acid, sulfuric acid, and oxalic acid, or a dilute alkali solution of sodium hydroxide and potassium hydroxide may be used as the corrosive solution.

In some embodiments, the porous alloy precursor is put into a corrosive solution, a film is covered and air holes are formed to prevent the solution from volatilizing and remove gas after reaction in time, the solution is put into a fume hood and is kept stand for alloy removal, and the corrosion time is not more than 48 hours, preferably 10-24 hours; forming nano-porous on the surface layer of the micro-porous alloy precursor, and compounding to form a micro-nano porous structure. And finally, taking out the corroded device, slowly cleaning the device by using deionized water to prevent the micro-nano porous structure from being damaged, and drying the device after cleaning to finally obtain the target micro-nano porous functional device.

It is worth mentioning that the porous alloy precursor prepared by the additive manufacturing technology is placed in a corrosive solution for dealloying, and because the alloy precursor contains micron holes, submicron holes or millimeter holes with rich pore structures, the corrosive solution can corrode and dealloye the outermost surface of the alloy precursor, and can enter the alloy precursor through micropores and dealloye the inner pore surfaces of the alloy precursor, so that abundant micro-nano porous catalytic particles are formed in the integral structure of the alloy precursor, and a micro-nano porous functional device with a large specific surface area and multiple catalytic particles is obtained, and the requirements of practical application scenes are met.

The method provided by the invention is characterized in that the conventional dealloying technical route is improved, and the method has the main advantage that dealloying precursors with micron-sized or millimeter-sized pores can be obtained by additive manufacturing, while dealloying precursors such as strips, films, blocks and the like can only be obtained by conventional means. Compared with the common dealloying methods such as common blocks and powder which can be obtained by the conventional processing method, the dealloying method has the advantages that a large number of designed micron or millimeter holes are added to the precursor through additive manufacturing, the specific surface area is increased under the same mass, the dealloying can be carried out to form the nanometer holes, and the performance of the device is improved.

In the prior art, because the size of the thin film and the nanowire micro-nano structure device prepared by dealloying is micron-sized or even lower, compared with the millimeter-sized device prepared by additive manufacturing, the thin film and the nanowire micro-nano structure device prepared by the method are difficult to collect and use, and are easy to generate secondary pollution and the like. At present, most researches on the preparation of catalytic materials by dealloying are carried out on laboratory products, and the reason is that the researches are also based on the laboratory products. Compared with the bulk body, the precursor with micron or millimeter holes formed by the additive manufacturing technology has a large surface area, a large number of micron-sized holes are further formed on the surface of the framework under the action of dealloying, the surface area is further improved, the surface is changed into a nano-sized material, a large number of catalytic particles can be provided, and the catalytic effect is greatly improved compared with that of a common material. The nano-pores appear on the additive manufacturing framework with large surface area and have better catalytic performance. And because the catalyst is a shaped catalytic device, compared with powdery nanowires or a particularly thin dealloyed film, the catalyst is convenient to collect and use.

The invention also provides a micro-nano porous functional device prepared according to the method. The micro-nano porous functional device can be used for preparing a porous catalytic material, for example, the porous catalytic material is used for catalyzing hydrogen peroxide to generate hydroxyl radicals in sewage treatment and degrading organic matters in sewage, or is used for catalyzing hydrogen evolution reaction to electrolyze water to produce hydrogen.

The following are specific examples:

example 1:

tin dioxide (SnO)₂) Has excellent photocatalytic activityThe material can be used for wastewater treatment, can be used for gas sensors, solar cells and the like, and is an ideal material. The method is used for manufacturing SnO with micro-nano porous structure of 8mm multiplied by 8mm₂The catalytic device, as shown in fig. 1, comprises the following specific steps:

1. drawing a three-dimensional CAD model of a micron porous structure with the size of 8mm multiplied by 8mm, wherein the porous unit structure is designed to be a Gyroid three-period extremely-small curved surface structure, the size of the unit is 2mm multiplied by 2mm, and the porosity is 85%.

2. And (3) processing the designed Gyroid porous structure model by slicing software, outputting the Gyroid porous structure model as an STL format file, and conveying the STL format file to SLM equipment. CuSn alloy is selected as a precursor material of a catalytic device, and Cu and Sn are prepared in an atomic percentage of 7 by adopting a mechanical powder mixing mode: 3.

3. The alloy precursor of the device is shaped by SLM. The technological parameters of SLM forming of the CuSn prealloying powder are as follows: the scanning power is 250W, the scanning speed is 1000mm/s, the powder spreading thickness is 0.05mm, and the scanning interval is 0.1 mm. And introducing protective atmosphere in the printing process to prevent the CuSn precursor from being oxidized in the printing process.

4. Configuring 0.5 percent of HNO₃And (4) dealloying the alloy solution. Subjecting the SLM-formed CuSn precursor with the thickness of 8mm multiplied by 8mm to ultrasonic cleaning, and placing the precursor in HNO₃And performing dealloying treatment in the corrosive liquid. After being covered with the breathable film, the film was placed in a fume hood and allowed to stand for 12 hours.

5. In the process of dealloying, HNO₃Cu element can be removed from the surface of a CuSn precursor, the residual Sn element forms a nano porous structure through self-assembly on the surface of the precursor, and HNO is simultaneously carried out₃Oxidation of exposed Sn atoms to form SnO₂To realize nano-porous SnO₂Coating the microporous framework.

6. And taking out the device after the alloy is removed, slowly cleaning the device by using deionized water and absolute ethyl alcohol, and then drying the device in an oven at 80 ℃ for 2 hours to prevent the micro-nano porous structure from being damaged, thereby obtaining the target device.

FIG. 2 is a diagram of the production of small porous SnO using the method of the present invention in example 1₂Schematic representation of a catalytic device. Its content (a)) Is SnO₂A schematic front view of a micron porous precursor of the catalytic device; the content (b) is SnO₂A three-dimensional schematic diagram of a catalytic device micron porous precursor alloy; the content (c) is micro-nano porous SnO after dealloying₂A three-dimensional schematic of a catalytic device; wherein the black areas represent cubic microporous SnO obtained after SLM printing₂Precursor profile, white areas represent the nanopore structure that appears on the precursor after dealloying.

Example 2

At present, the industrial hydrogen production mainly depends on electrolytic water, and the Ni-Mo alloy can obtain better hydrogen evolution rate at lower price. The fine porous structure left by the dissolution of the active component in the dealloying process can enable the material to have extremely high specific surface area, can create abundant reaction sites for hydrogen evolution reaction, reduces the real current density of the electrode, and can obtain extremely high hydrogen evolution efficiency. Therefore, the invention is used for manufacturing the micro-nano porous Ni-Mo alloy electrode material with the thickness of 5mm multiplied by 5 mm. The method comprises the following specific steps:

1. a three-dimensional CAD model of a 5mm x 5mm micron porous Ni-Mo alloy electrode was drawn. In order to obtain a good dealloying effect, the alloy bracket is designed into a three-dimensional reticular porous structure, the diameter of a precursor framework is 1000 microns, and the size of pores among the frameworks is 1000 microns.

2. And processing the designed three-dimensional CAD model by slicing software, keeping the three-dimensional CAD model as an STL file, and transmitting data information of the file to an SLM rapid prototyping machine. Preparing metal powder from Ni powder, Mo powder and Al powder according to the atomic ratio of 3:2:95, performing ball milling, pressing, uniformly mixing for 24 hours, and putting into an SLM printer.

3. According to the actual material components, selecting technological parameters (scanning power 300W, scanning speed 1000mm/s, powder spreading thickness 0.05mm, scanning distance 0.1mm and the like) suitable for SLM forming of the material, and then starting powder spreading to manufacture the precursor of the alloy workpiece. During the manufacturing process a protective atmosphere is fed into the SLM forming chamber to prevent the precursors from being oxidized during this process.

4. And processing the Ni-Mo alloy precursor with a micron porous structure.

5. Preparing a corrosion solution for dealloying, wherein the corrosion solution is 25% (mass fraction) of NaOH solution, can dissolve Al on the surface of the precursor of the alloy device to form a nanopore, and is compounded to form a micro-nano porous structure.

6. And (3) ultrasonically cleaning the precursor of the alloy device, and then placing the precursor into corrosive liquid for dealloying. After covering the corrosive liquid with the breathable film, placing the corrosive liquid in a fume hood for standing for 24 hours, and waiting for the end of the dealloying treatment.

7. And after the alloy removal is finished, taking out the workpiece, cleaning the workpiece by using deionized water and ethanol, and drying the workpiece in a forced air drying oven at 80 ℃ for 5 hours to obtain the device with the micro-nano porous structure.

FIG. 3 is a schematic diagram of a device for manufacturing a micro-nano porous Ni-Mo alloy by using the method of the invention in example 2. The content (a) is a three-dimensional schematic diagram of a precursor of a micron porous Ni-Mo alloy device; content (b) is a front view of a micron porous Ni-Mo alloy device precursor; content (c) is a cross-sectional view of a front view of a micron porous Ni-Mo alloy device precursor; content (d) is a schematic diagram of a micro-nano porous Ni-Mo alloy device slice after alloy removal; wherein, the solid line represents the outline of the micron porous Ni-Mo alloy device after SLM printing, and the dotted line represents the nano porous structure formed on the alloy skeleton after alloy removal.

Example 3

The nano pure Cu can catalyze hydrogen peroxide to generate hydroxyl radicals and degrade organic matters in sewage, so that the nano pure Cu is widely used for sewage purification. The method is used for manufacturing the Cu catalytic device with the micro-nano porous structure of 9mm multiplied by 9mm as an example, and comprises the following specific steps:

1. drawing a 9mm multiplied by 9mm micrometer porous structure three-dimensional CAD model, wherein the porous unit structure is designed to be a Diamond three-period minimum curved surface structure, the size of the unit size is 1.5mm multiplied by 1.5mm, and the porosity is 80%.

2. And (3) processing the designed Diamond porous structure model by slicing software, outputting the model as an STL format file, and transmitting the file to SLM equipment. CuTi alloy is selected as a precursor material of a catalytic device, and prealloy powder with Cu and Ti atomic percentages of 4:6 is prepared by adopting a mechanical powder mixing mode.

3. The alloy precursor of the device is shaped by SLM. The technological parameters of SLM forming of the CuTi pre-alloy powder are as follows: the scanning power is 250W, the scanning speed is 1000mm/s, the powder spreading thickness is 0.05mm, and the scanning interval is 0.1 mm. And introducing protective atmosphere in the printing process to prevent the CuTi precursor from being oxidized in the printing process.

4. 0.5% HF dealloying solution is prepared. And (3) ultrasonically cleaning a 9mm multiplied by 9mm CuTi precursor formed by SLM, and then placing the precursor into HF corrosive liquid for dealloying. After being covered with the breathable film, the film was placed in a fume hood and allowed to stand for 24 hours.

5. In the dealloying process, the HF can remove the Ti element from the surface of the CuTi precursor, and the residual Cu element forms a nano porous structure by self-assembly on the surface of the precursor, so that the nano porous Cu-coated micro porous frame is realized.

Fig. 4 is a schematic scanning view of the target device manufactured in example 3. Fig. 5 is a low-magnification SEM image of the target device prepared in this example, which has a large number of nano-scale pores on the surface under the network structure of micropores. FIG. 6 is a high-magnification SEM image of the target device with a large number of nano-scale pores. FIG. 7 is a graph comparing catalytic oxidation efficiency of the target device with other catalytic materials in the prior art in advanced oxidation technology, wherein no catalysis means that no catalytic substance is added, the dealloyed block means a regular square block of the same size prepared by additive manufacturing and dealloyed, the additive manufacturing precursor means a precursor obtained by additive manufacturing and not dealloyed, Cu²⁺Means Cu²⁺The homogeneous Fenton reagent, the copper powder refers to a copper powder reagent, and the functional device refers to the micro-nano porous functional device obtained by the scheme. The comparison with other same materials with the same mass shows that the catalytic efficiency of the micro-nano porous functional device is greatly improved.

In conclusion, the essence of the invention is that the dealloying treatment and the additive manufacturing technology are combined, the porous functional device precursor is manufactured by the additive manufacturing technology, the SLM precursor surface active elements are selectively corroded and removed by dealloying, and the remaining one or more inert elements are self-assembled to form the nano porous catalytic particles, so that the micro-nano porous functional device with large specific surface area and more catalytic particles is obtained, and the micro-nano porous functional device is more suitable for practical application scenes.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A method for additive manufacturing/dealloying composite manufacturing of micro-nano porous functional devices, characterized in that, comprising the steps:

(1) A bulk porous alloy precursor is obtained by additive manufacturing of alloy powder or alloy element mixed powder, and the pore distribution of the bulk porous alloy precursor has a three-dimensional network structure;

(2) performing dealloying treatment on the porous alloy precursor obtained in step (1). During the dealloying treatment, part of the alloy element components on the surface of the porous alloy precursor are corroded and dissolved, while the remaining element components are in Under the action of surface tension, a nanoporous structure is spontaneously formed on the surface of the porous alloy precursor, so as to obtain a micro-nano-porous functional device.

2. The method of claim 1, wherein the additive manufacturing is laser selective melting, electron beam selective melting, laser near net shaping, electron beam fuse deposition forming, or arc additive manufacturing.

3. The method of claim 1, wherein step (1) specifically comprises the following substeps:

(1-1) Convert the 3D CAD model of the target porous alloy precursor into an STL file after being processed by the slicing software, and transfer the STL file information to the additive manufacturing equipment;

(1-2) Using the additive manufacturing equipment to perform additive manufacturing on alloy powder or mixed powder of alloy elements according to the STL file information to obtain a porous alloy precursor.

4. The method of claim 1, wherein the pores in the porous alloy precursor obtained in step (1) are one or more of micron-scale pores, sub-micron-scale pores and millimeter-scale pores; The size of the porous alloy precursor in any dimension is greater than 1 mm.

5 . The method according to claim 1 , wherein the size of pores in the porous alloy precursor obtained in step (1) is between 500 and 1500 μm. 6 .

6 . The method according to claim 3 , wherein the three-dimensional CAD model of the precursor of the target porous alloy piece in step (1-1) is designed as a three-dimensional network porous structure, and the three-dimensional network porous structure is preferably Minimal surface structure or cross-truss-shaped grid structure.

7 . The method of claim 1 , wherein, in step (2), a dealloying treatment is performed by electrochemical corrosion or in a corrosive solution, and the time for the dealloying treatment is preferably not more than 48 hours. 8 .

8. The method of claim 1, wherein in step (2), when the porous alloy precursor is placed in a corrosive solution for dealloying treatment, the corrosive solution is a dilute acid solution or a dilute alkali solution.

9. The micro-nano porous functional device prepared by the method according to any one of claims 1 to 8.

10. The application of the micro-nano porous functional device according to claim 9 in the preparation of porous catalytic materials.