A reverse-structured porous copper or porous silver with dealloying corrosion and a preparation method thereof

Abstract

The application discloses a kind of reverse structure porous copper or porous silver of dealloying corrosion and a preparation method thereof, and belongs to the technical field of porous metal material.The two principal curvatures (the two curvatures of the maximum and minimum of three-dimensional surface) k1, k2 (k1 < k2) of the pore wall surface of the porous copper and the porous silver are mainly distributed in the following range: in the rectangular coordinate system with k1 as the abscissa and k2 as the ordinate, k1 and k2 of the pore wall of the porous copper or the porous silver are mainly distributed in the following range: k1 < 0, k2 > 0 and its absolute value |k1| > |k2|, or k1 < 0, k2 < 0 and its absolute value |k1| > |k2|.The main idea of the application is to corrode the porous framework formed by dealloying in the bicontinuous phase material and retain a kind of reverse structure porous metal material.This method has the advantage that the reverse structure porous metal material prepared by the method exhibits more excellent mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of porous metal materials technology, specifically to a reverse-structure porous copper or porous silver with dealloying corrosion and its preparation method. Background Technology

[0002] Porous materials are a widely used type of structure-function integrated material. They possess properties such as low bulk density, large specific surface area, energy absorption and vibration damping, and noise reduction, finding applications in many areas including structure, buffering, vibration damping, thermal insulation, sound absorption, and filtration. The performance characteristics of porous materials, such as mechanical properties like strength and elastic modulus, and physical properties like thermal conductivity, electrical conductivity, and sound absorption coefficient, are all significantly related to their porous structure. These porosity-influencing factors include porosity, pore morphology, pore size, and their distribution. Controlling the pore structure characteristics of porous materials is a key prerequisite and effective means to obtain superior performance.

[0003] Dealloying corrosion is a rapidly developing technique for preparing porous and bicontinuous phase materials in recent years. Current dealloying methods include chemical or electrochemical corrosion, liquid dealloying corrosion, and evaporative dealloying. It generally involves two processes: the corrosion of the active component in the single-phase precursor alloy and the self-assembly of the remaining components into a three-dimensional continuous framework structure. During dealloying corrosion, the three-dimensional framework structure formed by the inert components (not corroded) suffers from drawbacks such as low connectivity and poor load-bearing efficiency, leading to weak mechanical properties in porous materials.

[0004] Porous copper and porous silver retain the high electrical and thermal conductivity of copper and silver metals, while possessing a porous structure and a large volumetric surface area, making them promising for applications in battery electrodes and heat dissipation materials. Summary of the Invention

[0005] The purpose of this invention is to provide a reverse-structure porous copper or porous silver obtained through dealloying corrosion and its preparation method. Based on existing dealloying corrosion processes, this invention prepares porous copper and porous silver with excellent structure and properties. The main idea of ​​this invention is to corrosion the porous framework formed by dealloying in a bicontinuous phase material, preserving a reverse-structure porous metallic material. The advantage of this method is that the reverse-structure porous metallic material prepared exhibits superior mechanical properties.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An inverse-structured porous copper or porous silver by dealloying corrosion, where the two principal curvatures of the pore wall surface of the porous copper or porous silver are the maximum curvature k2 and the minimum curvature k1 of the three-dimensional surface, and k1 < k2; in the rectangular coordinate system with k1 as the abscissa and k2 as the ordinate, the k1 and k2 of the pore wall of the porous copper or porous silver are mainly distributed (proportion greater than 50%) in the following ranges: k1 < 0, k2 > 0 and its absolute value |k1| > |k2| (this part of the pore wall shows a saddle-shaped pore channel) or k1 < 0, k2 < 0 and its absolute value |k1| > |k2| (this part of the pore wall shows a bowl-shaped concave surface); this curvature distribution can be adjusted by adjusting the porosity of the porous copper or porous silver.

[0008] The porous copper or porous silver is an open porous metal material with pores penetrating each other in three-dimensional space; the pore edges and pore sizes of the porous copper or porous silver are both less than 100 μm; the pore edges and pore sizes of the porous copper or porous silver can be controlled by adjusting the dealloying reaction temperature and time.

[0009] The preparation method of the inverse-structured porous copper or porous silver by dealloying corrosion includes the following steps:

[0010] (1) Preparation of chromium / copper bicontinuous phase material or nickel / silver bicontinuous phase material: Using pure copper as the dealloying corrosion medium, dissolve the manganese in a chromium-manganese alloy with a certain composition ratio to obtain a chromium / copper bicontinuous phase material; using pure silver as the dealloying corrosion medium, dissolve the copper in a nickel-copper alloy with a certain composition ratio to obtain a nickel / silver bicontinuous phase material;

[0011] (2) Preparation of inverse-structured porous copper material or inverse-structured porous silver material by dealloying corrosion: Chemically or electrochemically dissolve the chromium phase in the chromium / copper bicontinuous phase material in step (1) to obtain an inverse-structured porous copper material by dealloying corrosion; chemically or electrochemically dissolve the nickel phase in the nickel / silver bicontinuous phase material in step (1) to obtain an inverse-structured porous silver material by dealloying corrosion.

[0012] In step (2), the dissolved chromium phase in the chromium / copper bicontinuous phase material is formed by the dealloying of manganese in the chromium-manganese alloy; the dissolved nickel phase in the nickel / silver bicontinuous phase material is formed by the dealloying of copper in the nickel-copper alloy.

[0013] The content of residual manganese in the porous copper is less than 30% atomic percentage; the content of residual copper in the porous silver is less than 10% atomic percentage.

[0014] Compared with the existing dealloying technology and the porous metal materials prepared by it, the present invention has the following beneficial effects:

[0015] (1) The reverse-structure porous metal material with dealloying corrosion proposed in this invention has higher structural connectivity than porous metal materials formed by dealloying, thus possessing higher load-bearing efficiency and superior mechanical properties.

[0016] (2) The reverse-structure porous metal material with dealloying corrosion proposed in this invention can avoid the influence of structural defects generated by dealloying on its mechanical properties. For example, the breakage of pore edges and structural spheroidization caused by surface diffusion during the dealloying process will cause a significant decrease in the mechanical properties of the porous material formed by dealloying, but these effects will not reduce the mechanical properties of the reverse-structure porous material.

[0017] (3) The reverse structure porous metal material with dealloying corrosion proposed in this invention has many pores and edges that are lamellar, which is more conducive to the load-bearing efficiency of the porous material and can make it achieve higher strength and elastic modulus. Attached Figure Description

[0018] Figure 1 This is a scanning electron microscope image of the dual continuous phase chromium / copper dual continuous phase material obtained in Example 1 of the present invention.

[0019] Figure 2 This is a scanning electron microscope image of the inverse-structure porous copper material obtained in Example 1 of the present invention.

[0020] Figure 3 The image shows the distribution of principal curvature of the three-dimensional inverse porous copper and its pore wall surface obtained by X-ray tomography in Embodiment 1 of the present invention; wherein: (a) three-dimensional inverse porous copper; (b) distribution of principal curvature of the pore wall surface.

[0021] Figure 4 This is a scanning electron microscope image of the bicontinuous nickel / silver bicontinuous phase material obtained in Example 2 of the present invention.

[0022] Figure 5 The diagram shows the compositional distribution of nickel and silver in the bicontinuous nickel / silver bicontinuous phase material obtained in Example 2 of the present invention; wherein: (a) silver; (b) nickel.

[0023] Figure 6 This is a scanning electron microscope image of the inverse porous silver obtained in Example 2 of the present invention.

[0024] Figure 7 The image shows the distribution of principal curvature of the three-dimensional inverse porous silver and its pore wall surface obtained by X-ray tomography in Embodiment 2 of the present invention; wherein: (a) three-dimensional inverse porous silver; (b) distribution of principal curvature of the pore wall surface.

[0025] Figure 8This section compares the Young's modulus data of the inverse porous copper obtained in Example 1 and the inverse porous silver obtained in Example 2 of the present invention with those of porous metallic materials prepared by other methods. The horizontal axis represents the relative density of the porous material, which is the ratio of the density of the porous material to the density of the solid in the porous material. The vertical axis represents the ratio of the Young's modulus of the porous material to the Young's modulus of the solid in the porous material. Solid circles represent inverse porous copper; solid triangles represent inverse porous silver; hollow pentagons represent porous copper prepared by the foaming method; hollow squares represent positive porous iron-chromium alloys prepared by dealloying corrosion; and dashed lines represent the prediction results of the Gibson-Ashby theoretical model.

[0026] Figure 9 This section compares the yield strength data of the inverse-structure porous copper obtained in Example 1 and the inverse-structure porous silver obtained in Example 2 of the present invention with porous metallic materials prepared by other methods. The horizontal axis represents the relative density of the porous material, which is the ratio of the density of the porous material to the density of the solid in the porous material. The vertical axis represents the ratio of the yield strength of the porous material to the yield strength of the solid in the porous material. Solid circles represent inverse-structure porous copper; solid triangles represent inverse-structure porous silver; hollow pentagrams represent porous copper prepared by the foaming method; hollow squares represent positive-structure porous iron-chromium alloys prepared by dealloying corrosion; and dashed lines represent the prediction results of the Gibson-Ashby theoretical model. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. The reverse-structure porous copper and porous silver with dealloying corrosion proposed in this invention include, but are not limited to, the following embodiments.

[0028] Example 1

[0029] In this embodiment, reverse-structure porous copper undergoing dealloying corrosion is prepared using the following specific process:

[0030] (1) According to the atomic ratio of chromium to manganese of 60:40, weigh the raw materials of pure chromium and pure manganese, and mix the two pure metals thoroughly and evenly by electric arc melting to prepare a solid solution alloy with an atomic ratio of chromium to manganese of 60:40.

[0031] (2) Place the chromium-manganese alloy under the protection of high-purity argon gas, heat it to 950℃ and hold it at that temperature for more than 50 hours, then remove it and cut it into 7×15×50mm pieces using wire cutting. 3 The blocks are ready for use; the cut alloy surfaces are polished clean and then cleaned with alcohol or acetone.

[0032] (3) Place the above chromium-manganese alloy block between two pure copper blocks and clamp it with two graphite blocks, and fix it tightly with screws and nuts; seal the above combination block in a quartz tube filled with pure argon gas, put it in an annealing furnace and heat it to 920°C for 90 hours, and then quench it with water to obtain a chromium / copper dual continuous phase material.

[0033] (4) Immerse the prepared chromium / copper bicontinuous phase material in 2 mol / L hydrochloric acid for a sufficient time to completely corrode the chromium phase therein, thereby obtaining a dealloyed corrosion inverse-structured porous copper material.

[0034] Figure 1 This is a scanning electron microscope photograph of the chromium / copper bicontinuous phase material prepared in step (3) of this embodiment, where the darker-colored part is the chromium phase and the lighter-colored part is the copper phase.

[0035] Figure 2 This is the dealloyed corrosion inverse-structured porous copper obtained after corroding the chromium phase in the chromium / copper bicontinuous phase material in step (4) of this embodiment.

[0036] Figure 3 This is the three-dimensional structure reconstructed by X-ray tomography and the distribution map of the principal curvature of the pore wall surface obtained by computer analysis for the dealloyed corrosion inverse-structured porous copper described in this embodiment. Figure 3 (a) is the three-dimensional structure; Figure 3 (b) is the distribution map of the principal curvature of the pore wall surface. Here, red indicates that the principal curvature represented by this place has a higher distribution density on the pore wall surface, while blue indicates that the principal curvature represented by this place has a lower distribution density on the pore wall surface.

[0037] The two principal curvatures (the maximum curvature k2 and the minimum curvature k1, k1 < k2) k1 and k2 of the pore wall surface of this inverse-structured porous copper mainly (the proportion is greater than 50%) are distributed in the following range: in a rectangular coordinate system with k1 as the abscissa and k2 as the ordinate: k1 < 0, k2 > 0 and its absolute value |k1| > |k2| or k1 < 0, k2 < 0 and its absolute value |k1| > |k2|.

[0038] Figure 8 The data represented by the solid circles includes the Young's modulus data of the dealloyed corrosion inverse-structured porous copper described in this embodiment. Except for the dealloyed corrosion inverse-structured porous copper with a relative density of approximately 0.31 described in this embodiment, inverse-structured porous coppers with different relative densities can be obtained by changing the composition of the master alloy, such as the chromium-manganese alloy composition in step (1) of this embodiment. The ratio of the Young's modulus of this inverse-structured porous copper to its solid Young's modulus is higher than that of the porous copper prepared by the foaming method and the positive-structured porous iron-chromium alloy prepared by dealloyed corrosion, indicating that this inverse-structured porous copper has a higher mechanical bearing efficiency. The ratio of the Young's modulus of this inverse-structured porous copper to its solid Young's modulus almost conforms to the theoretical prediction of the Young's modulus of porous materials proposed by Gibson and Ashby: where Y and Y s are the Young's moduli of the porous material and the solid respectively, is the relative density of the porous material.

[0039] Figure 9 The data represented by the solid circles include the yield strength data of the dealloyed corroded inverse porous copper with a relative density of approximately 0.31, as described in this embodiment, and other inverse porous coppers with relative densities. The ratio of the yield strength to the solid yield strength of this inverse porous copper is higher than that of porous copper prepared by foaming and positive porous iron-chromium alloys prepared by dealloying, indicating that this inverse porous copper possesses higher mechanical load-bearing efficiency. The ratio of the yield strength to the solid yield strength of this inverse porous copper almost matches the theoretical prediction of yield strength for porous materials proposed by Gibson and Ashby. Where σ and σ s The yield strengths are those of porous materials and solids, respectively. ρ represents the relative density of the porous material.

[0040] Example 2

[0041] In this embodiment, reverse-structure porous silver is prepared by dealloying corrosion. The specific process flow is as follows:

[0042] (1) According to the atomic ratio of nickel to copper of 60:40, pure nickel and pure copper raw materials are weighed and the two pure metals are fully and uniformly mixed by electric arc melting to prepare a solid solution alloy with an atomic ratio of nickel to copper of 60:40.

[0043] (2) The chromium-manganese alloy was placed under the protection of high-purity argon gas, heated to 950℃ and held for more than 50 hours. After being removed, it was compressed into a sheet with a thickness of 8mm, and then cut into 2×10×12mm pieces by wire cutting. 3 Prepare the blocks for later use; clean the cut alloy surface by grinding and washing with alcohol or acetone.

[0044] (3) Place the above nickel-copper alloy block between two pure silver blocks and clamp it with two graphite blocks, and fix it tightly with screws and nuts; seal the above combination block in a quartz tube filled with pure argon gas, put it in an annealing furnace and heat it to 920°C for 2.5 hours, and then quench it with water to obtain a nickel / silver dual continuous phase material.

[0045] (4) The prepared nickel / silver bicontinuous phase material is placed in a sulfuric acid solution of 1 mole per liter and a section of curled gold wire is used as the counter electrode. A potential of 0.5V is applied and allowed to etch the nickel phase completely for a sufficient period of time, thereby obtaining a reverse-structure porous silver material with dealloying corrosion.

[0046] Figure 4 The image shows a scanning electron microscope (SEM) image of the nickel / silver bicontinuous phase material prepared in step (3) of this embodiment, where the darker color represents the nickel phase and the lighter color represents the silver phase.

[0047] Figure 5 This is an example. Figure 5X-ray energy spectrum surface scan structure of the same area of the nickel / silver bicontinuous phase material shown Figure 5 (a) shows the distribution of silver Figure 5 (b) shows the distribution of nickel. It can be seen that the two-phase structure

[0048] Figure 6 Scanning electron microscope photograph of the inverse structure porous silver prepared in step (4) of this embodiment

[0049] Figure 7 Three-dimensional structure obtained by X-ray tomography reconstruction of the inverse structure porous silver of the dealloying corrosion described in this embodiment and the distribution map of the principal curvature of the pore wall surface obtained by computer analysis Figure 7 (a) is the three-dimensional structure Figure 7 (b) is the distribution map of the principal curvature of the pore wall surface. Among them, red indicates that the principal curvature represented by this place has a higher distribution density on the pore wall surface, while blue indicates that the principal curvature represented by this place has a lower distribution density on the pore wall surface

[0050] The two principal curvatures (the maximum curvature k2 and the minimum curvature k1, k1 < k2) k1 and k2 of the pore wall surface of this inverse structure porous silver are mainly (the proportion is greater than 50%) distributed in the following range: in the rectangular coordinate system with k1 as the abscissa and k2 as the ordinate: k1 < 0, k2 > 0 and its absolute value |k1| > |k2| or k1 < 0, k2 < 0 and its absolute value |k1| > |k2|

[0051] Figure 8 The data represented by the solid triangles in it include the Young's modulus data of the inverse structure porous silver of the dealloying corrosion described in this embodiment. Except for the inverse structure porous copper with a relative density of about 0.27 of the dealloying corrosion described in this embodiment, inverse structure porous copper with different relative densities can be obtained by changing the composition of the master alloy, such as the nickel-copper alloy composition in step (1) described in this embodiment. The ratio of the Young's modulus of this inverse structure porous silver to its solid Young's modulus is higher than that of the porous copper prepared by the foaming method and the positive structure porous iron-chromium alloy prepared by dealloying corrosion, indicating that this inverse structure porous silver has a higher mechanical bearing efficiency. The ratio of the Young's modulus of this inverse structure porous silver to its solid Young's modulus almost conforms to the theoretical prediction of the Young's modulus of porous materials proposed by Gibson and Ashby: Where Y and Y s are the Young's modulus of the porous material and the solid respectively is the relative density of the porous material

[0052] Figure 9The data represented by the solid triangle includes the yield strength data of the dealloyed corroded inverse porous silver with a relative density of approximately 0.27, as described in this embodiment, and other inverse porous silver with relative densities. The ratio of the yield strength to the solid yield strength of this inverse porous silver is higher than that of porous copper prepared by foaming and positive porous iron-chromium alloy prepared by dealloying, indicating that this inverse porous silver possesses higher mechanical load-bearing efficiency. The ratio of the yield strength to the solid yield strength of this inverse porous silver almost matches the theoretical prediction of yield strength for porous materials proposed by Gibson and Ashby. Where σ and σ s The yield strengths are those of porous materials and solids, respectively. ρ represents the relative density of the porous material.

Claims

1. A dealloyed, reverse-structured, porous copper or porous silver characterized in that: The two principal curvatures of the pore wall surface of the porous copper or the porous silver are three-dimensional surface maximum curvature k2 and minimum curvature k1, and k1 < k2; the principal curvatures can be used to represent the pore wall morphology; in a rectangular coordinate system with k1 as the horizontal coordinate and k2 as the vertical coordinate, the k1 and k2 of the porous copper or the porous silver pore wall are mainly distributed in range I or range II, wherein: range I is k1 < 0, k2 > 0 and the absolute value |k1| > |k2|, and range II is k1 < 0, k2 < 0 and the absolute value |k1| > |k2|. The porous copper or the porous silver is an open porous metal material with pores penetrating each other in three-dimensional space; the pore edge and pore size of the porous copper or the porous silver are both less than 100 μm; the pore edge and pore size of the porous copper or the porous silver can be controlled by adjusting the dealloying reaction temperature and time.

2. The dealloyed, etched inverse porous copper or silver of claim 1, wherein: The principal curvatures can be used to represent the pore wall morphology; when the k1 and k2 of the porous copper or the porous silver pore wall are mainly distributed in range I, the part of the pore wall appears as a saddle-shaped channel; when the k1 and k2 of the porous copper or the porous silver pore wall are mainly distributed in range II, the part of the pore wall appears as a bowl-shaped concave surface; the main distribution refers to the distribution proportion of k1 and k2 in range I or range II being greater than 50%.

3. The dealloyed, inverse-structured, porous copper or silver of claim 1, wherein: The curvature distribution of the pore wall surface of the porous copper or the porous silver can be adjusted by adjusting the porosity of the porous copper or the porous silver.

4. The method of claim 1, wherein the method is characterized by: The preparation method comprises the following steps: (1) preparation of a chromium / copper bicontinuous phase material or a nickel / silver bicontinuous phase material: dissolving manganese in a certain component ratio of chromium-manganese alloy to obtain a chromium / copper bicontinuous phase material by using pure copper as a dealloying corrosion medium; dissolving copper in a certain component ratio of nickel-copper alloy to obtain a nickel / silver bicontinuous phase material by using pure silver as a dealloying corrosion medium; (2) preparation of a reverse structure porous copper material or a reverse structure porous silver material by dealloying corrosion: dissolving the chromium phase in the chromium / copper bicontinuous phase material in step (1) by a chemical or electrochemical method to obtain a reverse structure porous copper material by dealloying corrosion; dissolving the nickel phase in the nickel / silver bicontinuous phase material in step (1) by a chemical or electrochemical method to obtain a reverse structure porous silver material by dealloying corrosion.

5. The method of claim 4, wherein the method is characterized by: In step (2), the dissolved chromium phase in the chromium / copper bicontinuous phase material is formed by dealloying manganese in the chromium-manganese alloy; the dissolved nickel phase in the nickel / silver bicontinuous phase material is formed by dealloying copper in the nickel-copper alloy.

6. The method of claim 4, wherein the method is characterized by: The content of dissolved manganese in the porous copper is less than 30% atomic percentage; the content of dissolved copper in the porous silver is less than 10% atomic percentage.

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