Copper metal foam and preparation method thereof

Abstract

The invention discloses copper metal foam and a preparation method of the copper metal foam, the copper metal foam comprises a copper-based supporting body and foamy copper supported by the supporting body, and the copper-based supporting body comprises at least one of a copper net and a copper foil. In the application, the copper-based support body is arranged to provide support for the foamy copper, so that the strength of the copper metal foam can be improved while the lightweight of the material is met, a new-generation multifunctional material solution is provided for the fields of new energy, 5G communication and the like, and the copper metal foam is suitable for the fields of new energy battery current collectors, electromagnetic shielding devices, environment-friendly catalytic carriers and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of copper-based material preparation, in particular to copper metal foam and a preparation method of copper metal foam. Background Art

[0002] Copper foam is a new type of multifunctional material with a large number of connected or unconnected pores evenly distributed in a copper matrix. While retaining the ductility, electrical conductivity and thermal conductivity of metallic copper, it also has the advantages of low density, high porosity, large specific surface area and good chemical stability. It has broad application prospects in filtration, catalysis, sensing, energy and other fields.

[0003] However, with the increasing demand for lightweight and high-strength materials, existing copper foam cannot meet the needs, especially in some scenarios, which require copper foam to have a larger porosity and higher strength.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide copper metal foam and a method for preparing the copper metal foam, so as to improve the strength of the material under the premise of the same porosity.

[0006] The present invention is achieved in that:

[0007] In a first aspect, the present invention provides a copper metal foam comprising a copper-based support and copper foam supported by the support, wherein the copper-based support comprises at least one of a copper mesh and a copper foil.

[0008] In an optional embodiment, the surface roughness Ra of the copper-based support in contact with the copper foam is 1.2-2.5 μm;

[0009] Alternatively, a surface of the copper-based support in contact with the foamed copper is provided with dendrites, and the dendrite length is 10-20 μm.

[0010] In an optional embodiment, the copper-based support has a thickness of 0.05-0.2 mm;

[0011] And / or, the copper-based support is provided with a through hole;

[0012] And / or, the copper-based support body includes a surface support body provided on one side of the copper foam; and / or, the copper-based support body includes a middle support body provided in the middle of the copper foam;

[0013] In an optional embodiment, the size of the through hole is 30-200 mesh;

[0014] And / or, when the surface support and the middle support exist at the same time, the thickness of the surface support is smaller than the thickness of the middle support.

[0015] In a second aspect, the present invention provides a method for preparing copper metal foam, wherein the assembled layered composite is sequentially preheated, pre-sintered, sintered, cooled and cleaned to obtain the copper metal foam; the layered composite includes a copper-based support and a powder blend layer for generating foamed copper, wherein the powder blend includes copper powder, a pore-forming agent, a binder and water.

[0016] In an optional embodiment, the powder blend satisfies at least one of the following characteristics ag:

[0017] a. The volume ratio of copper powder and pore-forming agent is 2-8:8-2;

[0018] b. The pore-forming agent is a water-soluble chloride salt;

[0019] c. The binder is polyvinyl alcohol;

[0020] d. The mass fraction of the binder in the powder blend is less than 5%;

[0021] e. The viscosity of the powder blend is 300-500mPa·s;

[0022] f. The average particle size ratio of the copper powder and the pore-forming agent is 1: 1-3;

[0023] g. The particle size of the pore-forming agent is 100-300 μm.

[0024] In an optional embodiment, the heating rate in the preheating stage is 5-10°C / min, and the temperature is raised to 280-320°C.

[0025] In an optional embodiment, the pressure in the pre-sintering stage is 8-12 MPa, the temperature is 740-760° C., the holding time is 1.5-2.5 h, and the atmosphere is an inert gas.

[0026] In an optional embodiment, the temperature of the main sintering stage is 930° C.-950° C., the pressure is 15-25 MPa, the holding time is 2.5-3.5 hours, and the atmosphere is hydrogen.

[0027] In an optional embodiment, the heating rate in the pre-sintering stage is 2-5°C / min;

[0028] and / or, the heating rate in the main sintering stage is 2-5°C / min;

[0029] and / or, cleaning is performed by ultrasonic-assisted cleaning, with water being the cleaning agent;

[0030] And / or, after cleaning, the process further includes drying and nickel plating, and the nickel layer obtained in the nickel plating step has a thickness of 0.1-0.5 μm.

[0031] The present invention has the following beneficial effects:

[0032] In this application, by providing a copper-based support body to provide support for the copper foam, the strength of the copper metal foam can be improved while meeting the lightweight requirements of the material, providing a new generation of multifunctional material solutions for new energy, 5G communications and other fields. It is suitable for new energy battery collectors, electromagnetic shielding devices, environmentally friendly catalytic carriers, high-power laser diodes, GaN radio frequency amplifiers, power electronic modules, aerospace electronic equipment, high heat flux density electronic devices, high-energy laser systems, special power and energy equipment, aerospace, advanced manufacturing and processing and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 This is a schematic diagram of the structure of the layered composite in Example 1 of the present application. DETAILED DESCRIPTION

[0035] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0036] An embodiment of the present invention provides a copper metal foam, comprising a copper-based support and foamed copper supported by the support, wherein the copper-based support comprises at least one of a copper mesh and a copper foil.

[0037] In this application, by setting a copper-based support body to provide support for the foam copper, the strength of the copper metal foam can be improved while meeting the lightweight requirements of the material, providing a new generation of multifunctional material solutions for new energy, 5G communications and other fields, and is suitable for new energy battery collectors, electromagnetic shielding devices and environmentally friendly catalytic carriers and other fields.

[0038] In an optional embodiment, the surface roughness Ra of the copper-based support in contact with the copper foam is 1.2-2.5 μm; specifically, the surface of the copper-based support can be etched with a FeCl (40 wt%) + HCl (5 wt%) solution, which is beneficial to enhancing the bonding force between the copper-based support and the copper foam, thereby helping to improve the strength of the copper metal foam.

[0039] In an optional embodiment, the surface of the copper-based support in contact with the copper foam is provided with dendrites, and the dendrite length is 10-20 μm; specifically, electrochemical dendrite formation can be used to generate dendrites on the surface of the copper metal foam, wherein the electrolyte used for electrochemical dendrite formation can be a copper sulfate solution, and the generation of dendrites is beneficial to improving the interlocking ability between the copper metal foam and the copper-based support, thereby helping to improve the strength of the copper metal foam.

[0040] In an optional embodiment, the copper-based support has a thickness of 0.05-0.2 mm.

[0041] And / or, the copper-based support is provided with through holes; specifically, a needle roller punching device can be used to punch holes in a copper-based support such as copper foil, so that the holes on the copper foil are evenly distributed, which is beneficial to improving the uniformity of the voids in the foam copper and reducing thermal deformation of the copper foil.

[0042] And / or, the copper-based support body includes a surface support body arranged on one side of the copper foam; and / or, the copper-based support body includes a middle support body arranged in the middle of the copper foam; generally, if the copper-based support body is arranged in the middle of the copper foam, the middle support body needs to be electrochemically dendrite-treated, and if the copper-based support body is arranged on one side of the copper foam, it can be etched or electrochemically dendrite-treated.

[0043] In an optional embodiment, the size of the through holes is 30-200 meshes; usually, the through holes are evenly distributed on the copper-based support, and the size and number of the through holes on the copper-based support will affect the porosity and compressive strength of the foamed copper.

[0044] And / or, when the surface support and the middle support exist at the same time, the thickness of the surface support is smaller than the thickness of the middle support.

[0045] An embodiment of the present invention also provides a method for preparing copper metal foam, wherein the assembled layered composite is sequentially preheated, pre-sintered, sintered, cooled and cleaned to obtain the copper metal foam; the layered composite includes a copper-based support and a powder blend layer for generating foamed copper, wherein the powder blend includes copper powder, a pore-forming agent, a binder and water.

[0046] In an optional embodiment, the powder blend satisfies at least one of the following characteristics ag:

[0047] a. The volume ratio of copper powder to pore-forming agent is 2-8:8-2. The amount of pore-forming agent used is related to the target strength of the copper metal foam. In theory, the higher the pore-forming agent content, the higher the porosity.

[0048] b. The pore-forming agent is a water-soluble chloride salt, such as sodium chloride;

[0049] c. The binder is polyvinyl alcohol;

[0050] d. The mass fraction of the binder in the powder blend is less than 5%;

[0051] e. The viscosity of the powder blend is 300-500mPa·s; the oil flow powder blend is spread on the copper-based support and initially shaped;

[0052] f the average particle size ratio of the copper powder and the pore-forming agent is 1: 1-3, which is conducive to uniform mixing of the pore-forming agent and the copper powder;

[0053] g. The particle size of the pore-forming agent is 100-300 μm.

[0054] In an optional embodiment, the heating rate in the preheating stage is 5-10°C / min, and the temperature is raised to 280-320°C. The main purpose of this stage is to remove the binder.

[0055] In an alternative embodiment, the pre-sintering stage is performed at a pressure of 8-12 MPa, a temperature of 740-760°C, a holding time of 1.5-2.5 hours, and an inert gas atmosphere, such as argon. Argon can stabilize the chloride structure and promote diffusion bonding of the metal powder through chemical inertness and physical heat transfer optimization.

[0056] In an alternative embodiment, the main sintering stage is performed at a temperature of 930°C-950°C, a pressure of 15-25 MPa, a holding time of 2.5-3.5 hours, and a hydrogen atmosphere. Atomic diffusion and grain boundary migration achieve metallurgical bonding between particles, stabilizing the pore structure. After the main sintering, the temperature can be gradually reduced to 200°C and the pressure to 0 MPa to mitigate microcracks caused by thermal stress.

[0057] In an optional embodiment, the heating rate in the pre-sintering stage is 2-5°C / min; slow heating is conducive to the full removal of organic matter;

[0058] and / or, the heating rate in the main sintering stage is 2-5°C / min;

[0059] And / or, cleaning is performed by ultrasonic assisted cleaning, the cleaning agent is water; the ultrasonic frequency may be 40 kHz, the water may be deionized water at 70° C., and the cleaning time may be 1-5 hours.

[0060] And / or, after cleaning, the process further includes drying and nickel plating. The nickel layer obtained in the nickel plating step has a thickness of 0.1-0.5 μm, which is beneficial to improving the corrosion resistance of the material.

[0061] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0062] Example 1:

[0063] This embodiment provides a method for preparing a copper metal foam material, comprising the following steps:

[0064] (1) According to Figure 1 Assemble a layered composite, the layered composite comprising, from bottom to top, a copper foil (0.2 mm), a powder blend layer (0.6 mm), a copper mesh (0.2 mm), a powder blend layer (0.6 mm), and a copper foil (0.2 mm), wherein the powder blend comprises copper powder, a pore-forming agent (sodium chloride), a binder (polyvinyl alcohol), and water, wherein:

[0065] The volume ratio of copper powder to pore-forming agent is 1:1, the concentration of polyvinyl alcohol is 3 vol% (the volume ratio of polyvinyl alcohol to water is 3:97), the copper powder particle size is 50 μm, the pore-forming agent particle size is 100 μm, and the viscosity of the powder blend is 400 Pa·s;

[0066] The copper foil is evenly distributed with through holes, with a pore size of about 50 μm and a through-hole coverage of 15%. The surface is etched with FeCl (40 wt%) + HCl (5%) to a Ra of 2 μm.

[0067] The mesh size of the copper mesh is about 100 μm, the mesh coverage of the copper mesh is 30%, and the average length of the dendrites on the copper mesh is 15 μm.

[0068] (2) preheating, pre-sintering, main sintering, cooling, cleaning and nickel plating the assembled layered composite body in sequence to obtain the copper metal foam; specifically comprising:

[0069] The assembled layered composite body and the mold are placed in a vacuum hot press furnace and vacuumed to 10 -1 Pa below, preheat to 300℃ at a heating rate of 5-10℃ / min and keep warm for 60 minutes;

[0070] Slowly increase the temperature (2-5℃ / min), maintain the pressure in the furnace at 10MPa and the temperature at 740-760℃, protect with argon, and keep warm for 2 hours for pre-sintering;

[0071] Slowly increase the temperature (2-5℃ / min), maintain the pressure in the furnace at 20MPa, the temperature at 950℃, H protection, keep warm for 3 hours, and then carry out the main sintering;

[0072] Gradual cooling to 200°C and pressure to 0 MPa;

[0073] Use 60-80℃ deionized water, ultrasonic assisted (40kHz) cleaning, time 3h;

[0074] Chemical nickel plating is performed on the surface of the copper metal foam material, and the thickness of the nickel layer is 0.3 μm.

[0075] Example 2:

[0076] This embodiment provides a method for preparing a copper metal foam material, which differs from Example 1 only in that the pressure in the furnace during the main sintering stage is 15 MPa.

[0077] Example 3:

[0078] This embodiment provides a method for preparing a copper metal foam material, which differs from Example 1 only in that the pressure in the furnace during the main sintering stage is 25 MPa.

[0079] Example 4:

[0080] This embodiment provides a method for preparing a copper metal foam material, which differs from Example 1 only in that the volume ratio of copper powder to pore-forming agent is 3:7.

[0081] Example 5:

[0082] This embodiment provides a method for preparing a copper metal foam material, which differs from Example 1 only in that the volume ratio of copper powder to pore-forming agent is 7:3.

[0083] Example 6

[0084] This embodiment provides a method for preparing a copper metal foam material, which differs from the embodiment 1 only in that the copper mesh in the layered composite is omitted.

[0085] Example 7

[0086] This embodiment provides a method for preparing a copper metal foam material, which differs from the embodiment 1 only in that the two layers of copper foil in the layered composite are omitted.

[0087] Example 8

[0088] This embodiment provides a method for preparing a copper metal foam material, which is different from the embodiment 1 only in that no through-holes are provided on the copper foil.

[0089] Example 9

[0090] This embodiment provides a method for preparing a copper metal foam material. The only difference from Example 1 is that the copper mesh is not electrochemically dendrite-treated and is only etched with FeCl (40 wt %) + HCl (5%) to an Ra of 2 μm.

[0091] Comparative Example 1

[0092] This comparative example provides a method for preparing a copper metal foam material. The only difference from Example 1 is that no copper mesh and copper foil are provided, and the powder blend in Example 1 is directly placed in a mold. The powder blend is placed in a vacuum hot pressing furnace and preheated, pre-sintered, sintered, cooled, cleaned, and nickel-plated.

[0093] The porosity and compressive strength of the copper metal foam materials prepared in the above examples and comparative examples were tested, and the test results are shown in Table 1.

[0094] Table 1

[0095] Serial number Porosity% Compressive strength MPa Example 1 65 55 Example 2 75 35 Example 3 55 75 Example 4 60 50 Example 5 85 20 Example 6 65 30 Example 7 70 45 Example 8 50 65 Example 9 65 45 Comparative Example 1 70 10

[0096] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A copper metal foam, characterized in that The invention comprises a copper-based support body and a foam copper supported by the support body, wherein the copper-based support body comprises at least one of a copper mesh and a copper foil.

2. The copper metal foam according to claim 1, characterized in that The surface roughness Ra of the copper-based support in contact with the copper foam is 1.2-2.5 μm; Alternatively, a surface of the copper-based support in contact with the foamed copper is provided with dendrites, and the dendrite length is 10-20 μm.

3. The copper metal foam according to claim 1, characterized in that The copper-based support has a thickness of 0.05-0.2 mm; And / or, the copper-based support is provided with a through hole; And / or, the copper-based support body includes a surface support body arranged on one side of the copper foam; and / or, the copper-based support body includes a middle support body arranged in the middle of the copper foam.

4. The copper metal foam according to claim 3, characterized in that The size of the through hole is 30-200 mesh; And / or, when the surface support and the middle support exist at the same time, the thickness of the surface support is smaller than the thickness of the middle support.

5. A method for preparing the copper metal foam according to any one of claims 1 to 4, characterized in that: The assembled layered composite body is sequentially preheated, pre-sintered, mainly sintered, cooled and cleaned to obtain the copper metal foam; the layered composite body includes a copper-based support body and a powder blend layer for generating foamed copper, wherein the powder blend includes copper powder, a pore-forming agent, a binder and water.

6. The method for preparing copper metal foam according to claim 5, characterized in that: The powder blend satisfies at least one of the following characteristics ag: a. The volume ratio of copper powder and pore-forming agent is 2-8:8-2; b. The pore-forming agent is a water-soluble chloride salt; c. The binder is polyvinyl alcohol; d. The mass fraction of the binder in the powder blend is less than 5%; e. The viscosity of the powder blend is 300-500mPa·s; f. The average particle size ratio of the copper powder and the pore-forming agent is 1: 1-3; g. The particle size of the pore-forming agent is 100-300 μm.

7. The method for preparing copper metal foam according to claim 5, characterized in that: The heating rate in the preheating stage is 5-10℃ / min, and the temperature is raised to 280-320℃.

8. The method for preparing copper metal foam according to claim 5, characterized in that: The pressure in the pre-sintering stage is 8-12 MPa, the temperature is 740-760°C, the holding time is 1.5-2.5 hours, and the atmosphere is inert gas.

9. The method for preparing copper metal foam according to claim 5, characterized in that: The temperature of the main sintering stage is 930°C-950°C, the pressure is 15-25MPa, the holding time is 2.5-3.5 hours, and the atmosphere is hydrogen.

10. The method for preparing copper metal foam according to claim 5, characterized in that: The heating rate in the pre-sintering stage is 2-5°C / min; and / or, the heating rate in the main sintering stage is 2-5°C / min; and / or, cleaning is performed by ultrasonic-assisted cleaning, with water being the cleaning agent; And / or, after cleaning, the process further includes drying and nickel plating, and the nickel layer obtained in the nickel plating step has a thickness of 0.1-0.5 μm.

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