Preparation method of porous metal copper

Abstract

The invention provides a preparation method of porous metal copper, which comprises the following steps: S1, adding copper oxide powder and a pore-forming agent into an organic solvent, and stirring and mixing to obtain slurry; in the slurry, the mass percentages of the copper oxide, the pore-forming agent and the organic solvent are 60%-70%, 0-10% and 20%-30% respectively; s2, printing the slurry through a steel mesh to obtain a biscuit; s3, the biscuit is sintered in a reducing atmosphere, the sintering temperature ranges from 600 DEG C to 900 DEG C, the sintering time ranges from 2 h to 8 h, and a sintered body is obtained after cooling; and S4, the sintered body is cleaned and freeze-dried, and the porous metal copper is obtained. According to the technical scheme, by controlling the technological parameters such as the size of the copper oxide, the content of the pore forming agent and the size and shape of the steel mesh, the prepared porous metal copper is controllable in pore size, size and proportion, the process is simple, the cost is low, and batch preparation of the porous copper can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of porous metal materials, and in particular to a method for preparing porous metal copper. Background Art

[0002] Currently, the main methods for preparing porous copper metal include melt foaming, electrochemical deposition, and hydrogen bubble templates. The melt foaming method offers simple processes, low costs, and suitability for large-scale production. However, the pore structure is uncontrollable, energy consumption is high, and foaming agent residues often remain in the pores, affecting mechanical properties. The electrochemical deposition method offers controllable pores and a uniform structure, but the process is complex, template removal is difficult, and pore structure can be easily damaged. Furthermore, the electrolyte can easily cause environmental pollution. The hydrogen bubble template method does not require a physical template, offers a simple process, and adjustable porosity. However, dynamic bubble control is difficult, pore connectivity is poor, and deposition efficiency is low.

[0003] Chinese Patent 202210208914.3 discloses a solid-phase preparation method for porous copper. Copper hydroxide powder is first pressed into green sheets, and then the copper hydroxide is sintered in a reducing atmosphere to produce flaky porous copper. This method produces the porous copper directly through a solid-phase reaction, without the addition of any other pore-forming or templating agents. However, the pore size, dimensions, and proportions of the porous copper produced by this method are uncontrollable, and the copper hydroxide used as the raw material is easily decomposed upon heating, making it unsuitable for large-scale production. Chinese Patent 201710469236.3 discloses a three-dimensional nanoporous copper, its preparation method, and application. Using polystyrene colloidal crystals as a template, copper is electrodeposited into the interstices of polystyrene microspheres. The polystyrene colloidal crystal template is then removed at high temperature to obtain the three-dimensional nanoporous copper. However, this method requires up to a week for the emulsion to evaporate, making the preparation process complex. The etching solution is highly corrosive liquid sulfuric acid, posing a risk of environmental pollution. Furthermore, the shape and size of the resulting porous copper are uncontrollable. Summary of the Invention

[0004] In response to the above technical problems, the present invention discloses a method for preparing porous metallic copper. By controlling process parameters such as copper oxide size, pore-forming agent content, steel mesh size and shape, porous metallic copper with controllable pore size is prepared; it solves the problems of high raw material cost, complex preparation process and uncontrollable pore size of porous metallic copper in the prior art.

[0005] To this end, the technical solution adopted in the present invention is:

[0006] A method for preparing porous metallic copper comprises the following steps:

[0007] Step S1, adding copper oxide powder and a pore-forming agent to an organic solvent and stirring and mixing to obtain a slurry; in the slurry, the mass percentages of copper oxide, pore-forming agent, and organic solvent are 60% to 70%, 0% to 10%, and 20% to 30%, respectively;

[0008] Step S2, printing the slurry through a steel screen to obtain a green blank;

[0009] Step S3, sintering the green body in a reducing atmosphere at a temperature of 600° C. to 900° C. for 2 hours to 8 hours, and obtaining a sintered body after cooling;

[0010] Step S4: washing and freeze-drying the sintered body to obtain porous metallic copper.

[0011] In this technical solution, by adjusting the size of copper oxide and the size of the pore-forming agent, the particle size of the porous metallic copper can be controlled, especially porous metallic copper below 30 microns can be obtained; the steel screen printing used in step S2 has a significant improvement effect, and the length, width and height of the porous copper can be controlled to obtain porous copper with almost uniform shape, which is suitable for batch sample preparation. In addition, the thickness of the obtained porous copper is controllable and thinner than that of the general method; the porous copper obtained in step S4 has a small pore size and is easily oxidized by heating and drying in air; the freeze-drying temperature is low, which can effectively prevent copper oxidation.

[0012] As a further improvement of the present invention, in step S1, the copper oxide is in the shape of at least one of sphere, flake, and rod. Furthermore, the copper oxide has a particle size of 0.5 μm to 100 μm.

[0013] As a further improvement of the present invention, in step S1, the pore-forming agent is at least one of sodium chloride and potassium chloride. Furthermore, the particle size of the pore-forming agent is 10 μm-100 μm.

[0014] As a further improvement of the present invention, the organic solvent is terpineol, ethylene glycol or ethanol.

[0015] As a further improvement of the present invention, step S1 uses a paste mixer for stirring and mixing, and the stirring speed is 150-750 r·min -1 , mixing time is 3-10min.

[0016] As a further improvement of the present invention, in step S2, the thickness of the blank is 0.1 mm to 0.3 mm.

[0017] As a further improvement to the present invention, the mesh shape of the steel mesh is square, circular, or triangular. Furthermore, the mesh diameter of the steel mesh is 1 mm to 20 mm, and the thickness of the steel mesh is 20 μm to 1000 μm. By using different mesh shapes, such as square, circular, or triangular, the mesh size of the steel mesh can be varied to adjust the size, proportion, and proportion of the porous copper metal pores.

[0018] As a further improvement of the present invention, in step S3, the heating rate is 1-5°C / min, and the cooling rate is 5-10°C / min. Further, the heating rate is 5°C / min, and the cooling rate is 10°C / min.

[0019] As a further improvement of the present invention, in step S3, the reducing atmosphere is hydrogen, carbon monoxide, formic acid, or a mixed gas of hydrogen and nitrogen.

[0020] As a further improvement of the present invention, in step S4, the cleaning is performed by ultrasonic cleaning using deionized water, 5% formic acid solution, and anhydrous ethanol in sequence. Furthermore, each cleaning time is 3 to 6 minutes. Furthermore, each cleaning time is 5 minutes. This cleaning process can effectively remove impurities such as organic matter, inorganic matter, and oxides from porous copper, covering a wider range of objects and achieving better cleaning results.

[0021] As a further improvement of the present invention, in step S4, the freeze-drying temperature is -45 to -55°C, the freeze-drying time is 10 to 12 hours, and the freeze-drying method is vacuum protection. This technical solution can better prevent the porous copper from being oxidized.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The technical solution of the present invention combines stencil printing with process parameters such as copper oxide size, pore-forming agent content, and stencil size and shape to produce porous copper with adjustable pore size. Compared to traditional porous copper production methods, the method of the present invention reduces costs, simplifies the process, and enables mass production of porous copper. The resulting porous copper has the advantage of controllable pore size, proportion, and ratio, enabling manufacturers to carry out large-scale, personalized customization. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart for preparing porous metallic copper according to an embodiment of the present invention.

[0025] Figure 2 Schematic diagram of the paste mixing state in step S1 of an embodiment of the present invention.

[0026] Figure 3 Schematic diagram of the slurry after printing in step S2 of an embodiment of the present invention.

[0027] Figure 4 It is a schematic diagram of the sintered body after sintering in step S3 of an embodiment of the present invention.

[0028] Figure 5 Schematic diagram of porous metal copper after cleaning in step S4 of an embodiment of the present invention.

[0029] Figure 6 This is a scanning electron microscope image of the microscopic morphology of the porous metallic copper obtained in an embodiment of the present invention.

[0030] The reference numerals include: 1-copper oxide, 2-pore former, 3-organic solvent, 4-reaction container, 5-porous metallic copper. DETAILED DESCRIPTION

[0031] The preferred embodiments of the present invention are described in further detail below.

[0032] A method for preparing porous copper metal is characterized in that the pore size is controllable and can be prepared in batches. Figure 1 As shown, the method includes the following steps:

[0033] Step S1: Add copper oxide ceramics and pore-forming agents into a reaction vessel, add an organic solvent, and stir in a paste mixer to obtain a slurry. The composition and weight percentage of the slurry are as follows: 60% to 70% copper oxide, 0% to 10% pore-forming agent, and 20% to 30% organic solvent. The schematic diagram of the mixed slurry is as follows: Figure 2 As shown, in a reaction container 4 , copper oxide 1 and a pore-forming agent 2 are uniformly dispersed in an organic solvent 3 .

[0034] Wherein, the pore-forming agent is an inorganic salt such as sodium chloride and potassium chloride.

[0035] Furthermore, the copper oxide may be in the shape of a sphere, a flake or a rod.

[0036] Furthermore, the copper oxide has a size of 0.5 μm-100 μm.

[0037] Furthermore, the size of the pore-forming agent is 10 μm-100 μm

[0038] Furthermore, the organic solvent is mainly terpineol, ethylene glycol, ethanol, etc.

[0039] Furthermore, the speed of the paste mixer is 150-750 r·min -1 , mixing time is 3-10min.

[0040] Step S2: The mixed slurry is screen printed to obtain a blank, such as Figure 3As shown. The shape of the steel mesh can be square, round, triangular, etc. The thickness of the blank is 0.1mm to 0.3mm. The mesh diameter of the steel mesh used is 1mm to 20mm. Figure 3 The shape of the middle mesh is square.

[0041] Step S3: Place the green billet in a tube furnace and sinter the green billet in a reducing atmosphere according to a certain sintering process, such as Figure 4 shown.

[0042] In the sintering process, the heating rate is 1-5°C / min, the sintering temperature is 600-900°C, the holding time is 2-8 hours, and the cooling rate is 5-10°C / min. The reducing atmosphere is hydrogen, carbon monoxide, formic acid, or a mixture of hydrogen and nitrogen.

[0043] Step S4: After the tube furnace is cooled, the sintered body is washed and freeze-dried in sequence to obtain porous metallic copper, such as Figure 5 shown.

[0044] The cleaning process is to use deionized water, 5% formic acid solution and anhydrous ethanol for ultrasonic cleaning in sequence for 5 minutes. The freeze drying temperature is -50°C, the time is 10 hours to 12 hours, and the freeze drying method is vacuum protection.

[0045] The above preparation method is described below in conjunction with specific examples.

[0046] Example 1

[0047] 45μm CuO ceramic powder was used as the raw material, 20μm NaCl was used as the pore-forming agent, and terpineol was used as the organic solvent. NaCl accounted for 5% by weight, terpineol accounted for 30% by weight, and the remainder was CuO ceramic powder. A paste mixer was used to mix the above materials for 5 minutes at a speed of 750 rpm. -1 .

[0048] After mixing, the paste was evenly printed onto a silicon nitride ceramic plate using a scraper to obtain a green blank with a size of 5 mm×5 mm×0.2 mm.

[0049] Place the green billet in a tube furnace, pass through a 95% N2 + 5% H2 atmosphere, and set the tube furnace heating rate to 5°C min -1 Sinter at 400℃ for 60min, keep the same heating rate, and sinter at 800℃ for 80min. Cooling rate is 10℃·min -1 .

[0050] After cooling, the prepared sample was ultrasonically cleaned with deionized water, 5% formic acid solution, and anhydrous ethanol to remove the pore-forming agent, thereby obtaining porous metallic copper.

[0051] The microstructure of the porous copper obtained by the above method is as follows: Figure 6 As shown, the pore size of the porous metallic copper presents a bimodal distribution, with the small pore size ranging from 1 to 5 μm and the large pore size ranging from 10 to 30 μm.

[0052] Example 2

[0053] The difference from Example 1 is that in Example 2, the addition ratio of NaCl is 7.5% of the weight of the mixed paste.

[0054] Example 3

[0055] The difference from Example 1 is that in Example 3, the addition ratio of NaCl is 10% of the weight of the mixed paste.

[0056] Example 4

[0057] The difference from Example 1 is that the particle size of NaCl in Example 4 is 30 μm.

[0058] Example 5

[0059] The difference from Example 1 is that the particle size of NaCl in Example 5 is 50 μm.

[0060] Example 6

[0061] The difference from Example 1 is that the particle size of the CuO ceramic powder in Example 6 is 1 μm.

[0062] Comparative Example 1

[0063] The difference from Example 1 is that in Comparative Example 1, only deionized water is used for cleaning.

[0064] The performance of the porous copper metal products obtained in Examples 1-7 and Comparative Example 1 was tested, and the specific test data are shown in Table 1.

[0065] Table 1 Performance test results of porous metal copper in Examples 1-7 and Comparative Example 1

[0066] Porosity / % Macropore diameter / μm Pore ​​diameter / μm Opening ratio / % Example 1 62.414 15.413 2.879 83.21 Example 2 70.488 15.625 3.214 84.05 Example 3 82.524 13.589 3.013 84.99 Example 4 64.873 19.463 4.632 83.42 Example 5 68.932 21.451 4.879 81.21 Example 6 56.245 13.606 2.537 76.85 Comparative Example 1 \ \ \ \

[0067] In Comparative Example 1 in the above table, since it was cleaned only with deionized water, the porous copper was oxidized and the pore structure could not be maintained after drying.

[0068] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and the specific implementation of the present invention cannot be considered to be limited to these descriptions.

[0069] For ordinary technicians in the technical field, without departing from the concept of the present invention, they can make several simple deductions or substitutions, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A method for preparing porous metallic copper, characterized in that: The steps include: Step S1, adding copper oxide powder and a pore-forming agent to an organic solvent and stirring and mixing to obtain a slurry; in the slurry, the mass percentages of copper oxide, pore-forming agent, and organic solvent are 60% to 70%, 0 to 10%, and 20% to 30%, respectively; Step S2, printing the slurry through a steel screen to obtain a green blank; Step S3, sintering the green body in a reducing atmosphere at a temperature of 600° C. to 900° C. for 2 hours to 8 hours, and cooling to obtain a sintered body; Step S4: washing and freeze-drying the sintered body to obtain porous metallic copper.

2. The method for preparing porous metallic copper according to claim 1, wherein: In step S1, the copper oxide is in a shape of at least one of sphere, flake, and rod, and has a particle size of 0.5 μm to 100 μm.

3. The method for preparing porous metallic copper according to claim 2, wherein: In step S1, the pore-forming agent is at least one of sodium chloride and potassium chloride, and the particle size of the pore-forming agent is 10 μm-100 μm; and the organic solvent is terpineol, ethylene glycol or ethanol.

4. The method for preparing porous metallic copper according to claim 3, wherein: Step S1: Mixing is performed using a paste mixer at a speed of 150-750 r / min. -1 , mixing time is 3-10min.

5. The method for preparing porous metallic copper according to claim 1, wherein: In step S2, the thickness of the blank is 0.1 mm to 0.3 mm; the mesh shape of the steel mesh is square, circular or triangular, the mesh diameter of the steel mesh is 1 mm to 20 mm, and the thickness of the steel mesh is 20 μm to 1000 μm.

6. The method for preparing porous metallic copper according to claim 1, wherein: In step S3, the heating rate is 1-5°C / min, and the cooling rate is 5-10°C / min.

7. The method for preparing porous metallic copper according to claim 1, wherein: In step S3, the reducing atmosphere is hydrogen, carbon monoxide, formic acid, or a mixture of hydrogen and nitrogen.

8. The method for preparing porous metallic copper according to claim 1, wherein: In step S4, the cleaning is performed by ultrasonic cleaning using deionized water, 5% formic acid solution, and anhydrous ethanol in sequence, and the time for each cleaning is 3 to 6 minutes.

9. The method for preparing porous metallic copper according to any one of claims 1 to 8, characterized in that: In step S4, the freeze-drying temperature is -45 to -55°C, the freeze-drying time is 10 to 12 hours, and the freeze-drying method is vacuum protection.

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