Tungsten-coated copper anti-oxidation material and preparation method thereof

Abstract

The invention discloses a tungsten-coated copper anti-oxidation material and a preparation method thereof, and relates to the technical field of coating materials. The invention discloses a preparation method of a tungsten-coated copper anti-oxidation material. The preparation method comprises the following steps that S1, copper powder is cleaned and subjected to first drying, and clean copper powder is obtained; s2, tungsten salt, a surfactant, clean copper powder and water are mixed and stirred, and a mixture is obtained; s3, the mixture is filtered and dried for the second time, and copper powder with tungsten salt adsorbed on the surface is obtained; and S4, the copper powder with the tungsten salt adsorbed on the surface is calcined in a reducing atmosphere, and the tungsten-coated copper anti-oxidation material is obtained. The tungsten-coated copper anti-oxidation material prepared through the method has good oxidation resistance and conductivity and is suitable for being applied to multiple fields.

Description

Technical Field

[0001] The present invention relates to the technical field of coating materials, and in particular to a tungsten-coated copper anti-oxidation material and a preparation method thereof. Background Art

[0002] Copper powder has good electrical and thermal conductivity and is widely used in catalysts, metal coatings and other fields. It is a key raw material for advanced circuit integration of high-density printed circuit boards (PCBs) interconnection. It is also important in high-performance lubricants for low-speed, heavy-loaded bearings, gears and other parts in the fields of wind power and metallurgy. However, copper powder is prone to oxidation in the air. This oxidation problem seriously affects the performance of copper powder in products. For example, in the field of conductive pastes, the high conductivity of the product depends on the conductive network formed after the copper powder is sintered; if the copper powder is oxidized, sintering at the same temperature will not form an effective sintering neck, resulting in a significant decrease in conductivity.

[0003] Generally, a dense passivation layer is coated on the surface of copper powder to prevent the copper powder from directly contacting oxygen. The passivation layer can be an organic layer, such as CN114453578B discloses a method for modifying copper powder, which utilizes the coordination of 2-mercaptobenzothiazole or methylbenzotriazole with copper to form a hydrophobic and dense coating layer, thereby improving the anti-oxidation and corrosion resistance of the copper powder; the passivation layer can also be an inorganic material, such as CN117548669A discloses a method for preparing silver-coated copper powder, which obtains silver-coated copper powder with excellent conductivity and anti-oxidation properties by coating a dense silver layer on the surface of copper powder.

[0004] Although the above method can improve the oxidation resistance of copper powder at room temperature, organic coating cannot improve the oxidation resistance of copper powder at high temperature. The cost of silver-coated copper is relatively high. In addition, most existing coating methods have complex processes, which is not conducive to large-scale application. Summary of the invention

[0005] The main purpose of the present invention is to provide a tungsten-coated copper anti-oxidation material and a preparation method thereof, so as to solve the problems in the prior art of poor high-temperature oxidation resistance of copper powder, high preparation cost of anti-oxidation copper powder and complex preparation process.

[0006] In order to achieve the above object, according to a first aspect of the present invention, a method for preparing a tungsten-coated copper anti-oxidation material is provided, comprising the following steps:

[0007] S1, washing and first drying the copper powder to obtain clean copper powder;

[0008] S2, mixing tungsten salt, surfactant, clean copper powder and water, stirring to obtain a mixture;

[0009] S3, filtering the mixture and performing a second drying to obtain copper powder with tungsten salt adsorbed on the surface;

[0010] S4, calcining the copper powder with tungsten salt adsorbed on the surface under a reducing atmosphere to obtain a tungsten-coated copper antioxidant material.

[0011] Furthermore, in S1, the copper powder is cleaned with an alkaline solution, an acid solution, and water in sequence, wherein the alkaline solution is at least one of a sodium hydroxide solution, a potassium hydroxide solution, and an ammonia solution; and the acid solution is at least one of a sulfuric acid solution, a hydrochloric acid solution, and a nitric acid solution.

[0012] Furthermore, in S1, the temperature of the cleaning with the alkaline solution is 60°C to 80°C, and the time is 0.5h to 2h.

[0013] Furthermore, in S1, ultrasonic assistance is used during cleaning with the acid solution, and the cleaning time with the acid solution is 3 minutes to 10 minutes.

[0014] Furthermore, in S1, washing is performed with water until it becomes neutral.

[0015] Furthermore, in S1, the temperature of the first drying is 25°C to 80°C, and the time of the first drying is 2h to 5h.

[0016] Furthermore, in S2, the tungsten salt is first dissolved in water to obtain a tungsten salt solution, and then the clean copper powder is added to the tungsten salt solution to form a dispersion; and then a surfactant is added to the dispersion and stirred to obtain a mixture.

[0017] Furthermore, in S2, the mass ratio of the tungsten salt to the clean copper powder is 1:100 to 1:10.

[0018] Furthermore, in S2, the mass ratio of the surfactant to the clean copper powder is 1:50 to 1:5.

[0019] Furthermore, in S2, the concentration of the tungsten salt in the tungsten salt solution is 1 mM to 10 mM.

[0020] Furthermore, in S2, the stirring time is 0.5 h to 3 h.

[0021] Furthermore, in S2, the tungsten salt is at least one of ammonium metatungstate, sodium tungstate, phosphotungstic acid, and ammonium paratungstate.

[0022] Furthermore, in S2, the surfactant is at least one of mercaptoethylamine, 3-(trimethoxymethylsilyl)propylamine (APTMS), and cysteine.

[0023] Furthermore, in S3, the temperature of the second drying is 25° C. to 60° C., and the time of the second drying is 1 h to 5 h.

[0024] Furthermore, in S4, the calcination temperature is 300° C. to 500° C., and the calcination time is 1 h to 3 h.

[0025] Furthermore, in S4, the reducing atmosphere is a mixture of hydrogen and an inert gas; the inert gas is at least one of nitrogen, argon and helium.

[0026] According to a second aspect of the present invention, a tungsten-coated copper anti-oxidation material is provided. The tungsten-coated copper anti-oxidation material is prepared by the preparation method according to the first aspect of the present invention.

[0027] By applying the technical solution of the present invention, dirt on the surface of copper powder can be removed by cleaning it, thereby improving the uniformity of coating; in addition, by mixing tungsten salt, surfactant and clean copper powder, copper powder with tungstate uniformly adsorbed on the surface can be formed, and finally reduction calcination is carried out in a reducing atmosphere to obtain a tungsten-coated copper antioxidant material with good oxidation resistance and conductivity. The oxidation resistance of the tungsten-coated copper material at high temperature is also significantly higher than that of the uncoated copper powder. The preparation process is simple, the cost is low, and it is easy to industrialize production. It can be applied to electronics, aerospace, high-temperature alloys and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of a method for preparing a tungsten-coated copper anti-oxidation material according to an embodiment of the present invention;

[0029] Figure 2 The scanning electron microscope image and EDX spectrum image of the tungsten-coated copper anti-oxidation material in Example 1 of the present invention;

[0030] Figure 3 The scanning electron microscope image and EDX spectrum image of the tungsten-coated copper anti-oxidation material in Example 2 of the present invention;

[0031] Figure 4 This is a scanning electron microscope image of the copper powder in Comparative Example 1;

[0032] Figure 5 These are scanning electron microscope images of the tungsten-coated copper antioxidant materials in (a) Example 1, (b) Example 2, and (c) Comparative Example 2 after aging at 85° C. for 10 hours. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0034] As described in the background of the present invention, the existing copper powder has poor oxidation resistance. After coating, the high temperature oxidation resistance of the copper powder is still poor, and the coating cost is relatively high and the process is complicated. In order to solve the above technical problems, in a typical embodiment of the present invention, a method for preparing a tungsten-coated copper anti-oxidation material is provided, and its preparation flow chart is as follows: Figure 1 As shown, the following steps are included:

[0035] S1, washing and first drying the copper powder to obtain clean copper powder;

[0036] S2, mixing tungsten salt, surfactant, clean copper powder and water, stirring to obtain a mixture;

[0037] S3, filtering the mixture and performing a second drying to obtain copper powder with tungsten salt adsorbed on the surface;

[0038] S4, calcining the copper powder with tungsten salt adsorbed on the surface under a reducing atmosphere to obtain a tungsten-coated copper antioxidant material.

[0039] In S1, cleaning the copper powder can remove organic matter, oxides and other contaminants on the surface of the copper powder, which helps to form copper powder with tungstate uniformly adsorbed on the surface, which is helpful for preparing tungsten-coated copper antioxidant materials with good antioxidant properties. In S2, water is used as a solvent to avoid the environmental pollution problems that may be caused by the use of organic solvents in traditional coating processes; in addition, in S2 and S3, the process of mixing, stirring, filtering and drying using tungsten salts and surfactants is relatively simple, easy to industrialize, and does not require complex secondary coating, thereby reducing production costs. In S4, by calcining the copper powder with tungstate adsorbed on the surface in a reducing atmosphere, a tungsten-coated copper antioxidant material with tungsten uniformly coated on the surface can be formed. The tungsten coating layer has good stability and is more firmly bonded to the copper powder. It can effectively isolate the copper powder and the air, which helps to improve the high-temperature antioxidant properties of the copper powder.

[0040] In some embodiments, in S1, the copper powder is washed with an alkaline solution, an acid solution, and water in sequence, wherein the alkaline solution is at least one of a sodium hydroxide solution, a potassium hydroxide solution, and an ammonia solution; and the acid solution is at least one of a sulfuric acid solution, a hydrochloric acid solution, and a nitric acid solution. After washing with the alkaline solution and the acid solution, the copper powder is washed with water until it becomes neutral.

[0041] Organic residues or oil stains on the surface of copper powder can be effectively removed by cleaning with alkaline solutions, such as sodium hydroxide solution, potassium hydroxide solution, and ammonia water. These organic substances may come from the production or storage process of copper powder. By cleaning, tungsten salt can be uniformly adsorbed on the surface of copper powder, promoting the formation of tungsten coating layer. The copper oxide layer formed on the surface of copper powder can be removed by cleaning with acid solutions, such as sulfuric acid solution, hydrochloric acid, and nitric acid solution, promoting the adsorption of tungstate on the surface of copper powder. Acid washing can ensure the cleanliness of the surface of copper powder and provide a good substrate for tungsten coating. After cleaning with alkaline solution and acid solution in turn, the active sites on the surface of copper powder will increase, which is conducive to the subsequent adsorption and coating process of tungsten salt, forming a more uniform and dense tungsten coating layer. Washing with water to neutral can keep copper powder in good chemical stability and improve reaction efficiency. The tungsten-coated copper antioxidant material formed after cleaning by the above method has good electrical conductivity and thermal conductivity, and the resistivity increases slowly during the aging process.

[0042] In some embodiments, the concentration of the alkali in the alkali solution is 2M to 5M. Within the above concentration range, it is sufficient to remove organic pollutants on the surface of the copper powder without damaging the copper powder itself.

[0043] In some embodiments, the acid concentration in the acid solution is 1 wt % to 10 wt %. Within the above range, oxides on the surface of the copper powder can be removed without damaging the copper powder itself.

[0044] In some embodiments, in S1, the temperature of the alkaline solution during cleaning is 60° C. to 80° C. and the time is 0.5 h to 2 h. Cleaning under such conditions can accelerate the reaction rate and enhance the cleaning effect.

[0045] In some embodiments, in S1, ultrasonic assistance is used during the cleaning with the acid solution, and the cleaning time with the acid solution is 3 minutes to 10 minutes. Compared with traditional immersion, ultrasonic assistance can achieve a cleaning effect in a shorter time, reducing time cost.

[0046] In some embodiments, in S1, the temperature of the first drying is 25° C. to 80° C., and the time of the first drying is 2 hours to 5 hours. Under the above conditions, the drying can be performed quickly without aging the copper powder, and the drying effect is good.

[0047] Typically but not limiting, the copper powder has a D50 particle size of 0.1 μm to 40 μm, and the copper powder is spherical or irregular in shape.

[0048] The copper powder has a good adsorption effect on tungsten salt under the action of surfactant, which is conducive to forming a uniform tungsten coating layer.

[0049] In some embodiments, in S2, a tungsten salt is first dissolved in water to obtain a tungsten salt solution, and then clean copper powder is added to the tungsten salt solution to form a dispersion; and then a surfactant is added to the dispersion and stirred to obtain a mixture.

[0050] Dissolving the tungsten salt first can ensure that it is completely dispersed in water to form a uniform tungsten salt solution, and then adding the clean copper powder to the tungsten salt solution will disperse the components better. Adding surfactants to the dispersion helps to make the tungsten salt evenly adsorbed on the surface of the copper powder, improve the chemical reaction efficiency, increase the adsorption rate of tungsten salt on the surface of the copper powder, reduce coating defects, and help improve the antioxidant properties of tungsten-coated copper antioxidant materials.

[0051] In some embodiments, in S2, the mass ratio of the tungsten salt to the clean copper powder is 1:100 to 1:10.

[0052] By limiting the mass ratio of tungsten salt and clean copper powder as above, a uniform and continuous tungsten coating layer can be formed, which helps to improve the oxidation resistance of the tungsten-coated copper antioxidant material. The copper-coated tungsten antioxidant material also has good electrical conductivity.

[0053] In some embodiments, in S2, the mass ratio of the surfactant to the clean copper powder is 1:50 to 1:5.

[0054] Surfactants can improve the wettability and dispersibility of the copper powder surface, ensuring good suspension of the copper powder in the solution; in addition, surfactants can reduce the energy barrier on the copper powder surface, and the active groups in the surfactants can electrostatically adsorb with the tungstate ions in the tungsten salt, promoting the adsorption of tungsten salt on the copper powder surface. A suitable surfactant to copper powder mass ratio can significantly improve the adsorption efficiency of tungsten salt on the copper powder surface, forming a dense coating layer, thereby enhancing the material's antioxidant properties.

[0055] In some embodiments, in S2, the concentration of the tungsten salt in the tungsten salt solution is 1 mM to 10 mM.

[0056] By properly setting the concentration of tungsten salt, a stable and uniform tungsten salt solution can be prepared, ensuring that the tungsten salt can be evenly covered on the surface of the copper powder during the subsequent coating process. In addition, the appropriate concentration can improve the coating efficiency.

[0057] By limiting the mass fraction of the surfactant, the wettability and dispersibility of the copper powder can be improved, and the uniformity and density of the coating layer can be enhanced.

[0058] In some embodiments, in S2, the stirring time is 0.5 h to 3 h. Under the above conditions, the tungsten salt can be uniformly adsorbed on the surface of the copper powder, which is conducive to forming a tungsten-coated copper antioxidant material with good oxidation resistance.

[0059] In some embodiments, in S2, the tungsten salt is at least one of ammonium metatungstate, sodium tungstate, phosphotungstic acid, and ammonium paratungstate; the surfactant is at least one of mercaptoethylamine, 3-(trimethoxysilyl)propylamine, and cysteine.

[0060] Ammonium metatungstate, sodium tungstate, phosphotungstic acid and ammonium paratungstate all have good water solubility, which enables them to disperse quickly in aqueous solution to form a uniform and stable solution, thus facilitating a uniform coating reaction with the surface of copper powder. High reactivity ensures the rapid formation of the tungsten coating layer and improves production efficiency. Surfactants such as mercaptoethylamine, APTMS and cysteine ​​have the characteristics of reducing surface tension, which can significantly improve the wettability of copper powder in tungsten salt solution, ensure that the coating reaction proceeds uniformly on the surface of copper powder, form a dense coating layer, and help reduce the sensitivity of tungsten-coated copper antioxidant materials to oxygen, while not affecting the conductivity of copper powder, enhancing the protective performance of the coating layer.

[0061] In some embodiments, in S3, the second drying temperature is 25°C to 60°C, and the second drying time is 1 hour to 5 hours.

[0062] Drying under the above conditions can significantly accelerate the evaporation of the solvent and shorten the entire drying time. This is particularly important for improving production efficiency and realizing industrial production. In addition, drying under the above conditions can maintain the stable adsorption of tungstate on the surface of copper powder and maintain the stability and density of the coating layer.

[0063] In some embodiments, in S4, the calcination temperature is 300° C. to 500° C., and the calcination time is 1 h to 5 h.

[0064] Calcination of copper powder with tungstate adsorbed on the surface will cause further chemical reaction to form a more dense and stable tungsten-coated copper antioxidant material. Under the above calcination conditions, the tungsten-coated copper antioxidant material also has good conductivity. In addition to ensuring the coating quality, it can also improve production efficiency and reduce energy consumption.

[0065] In some embodiments, in S4, the reducing atmosphere is a mixture of hydrogen and an inert gas; the inert gas is at least one of nitrogen, argon, and helium.

[0066] As a reducing agent, hydrogen can reduce tungsten oxide and tungstate to metallic tungsten at high temperature to form a coating with better conductivity. This process not only improves the oxidation resistance of the coating, but also makes it have good conductivity and corrosion resistance. In addition, in the mixed gas, inert gases (such as nitrogen, argon, and helium) can provide an environment isolated from air, effectively preventing copper powder from coming into contact with oxygen during high-temperature treatment and oxidizing, which helps to maintain the original properties of the copper powder and provide a guarantee for the performance of the final product.

[0067] In some embodiments, in S4, in the reducing atmosphere, the volume ratio of hydrogen to inert gas is 1:99 to 5:95.

[0068] Controlling the volume ratio of hydrogen to inert gas within the above range is to ensure that tungsten oxide or tungstate can be reduced to tungsten on the one hand, and to ensure the safety of the operation process on the other hand.

[0069] In another typical embodiment of the present invention, a tungsten-coated copper anti-oxidation material is provided, which is prepared by the preparation method in the above embodiment of the present invention. The tungsten-coated copper anti-oxidation material has good anti-oxidation performance and electrical conductivity, and has good anti-oxidation performance at high temperature and a wide range of applications.

[0070] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0071] Example 1

[0072] An embodiment of the tungsten-coated copper anti-oxidation material of the present invention, the preparation method of the tungsten-coated copper anti-oxidation material of this embodiment is as follows:

[0073] S1, take 5g copper powder (D50 particle size is 40μm), add it to 50mL sodium hydroxide aqueous solution with a sodium hydroxide concentration of 2.5M, and stir it at 75℃ for 1h; after filtering, disperse it into 50mL sulfuric acid aqueous solution with a H2SO4 concentration of 5wt%, and ultrasonicate for 3min; after filtering, rinse the copper powder with water until neutral, and dry it in a vacuum drying oven at 25℃ for 3h to obtain 5g clean copper powder;

[0074] S2, adding ammonium metatungstate to water to form 15mL of ammonium metatungstate solution with a concentration of 10mM (the mass of ammonium metatungstate is 0.446g), then adding the above-mentioned clean copper powder to the ammonium metatungstate solution to obtain a dispersion; then dropping 0.5mL of APTMS solution with a mass fraction of 99% (the mass of APTMS is 0.51g) into the dispersion, stirring for 1h to obtain a mixture;

[0075] S3, filtering the mixture, and then placing it in a vacuum drying oven and drying it at 25° C. for 3 h to obtain copper powder with tungsten salt adsorbed on the surface;

[0076] S4, placing the copper powder with tungstate adsorbed on the surface in a tube furnace, calcining it under the condition of hydrogen and argon volume ratio of 5:95, raising the temperature to 300°C at a rate of 2°C / min, and keeping the temperature for 3h to obtain tungsten-coated copper antioxidant material.

[0077] Example 2

[0078] An embodiment of the tungsten-coated copper anti-oxidation material of the present invention, the preparation method of the tungsten-coated copper anti-oxidation material of this embodiment is as follows:

[0079] S1, take 5g copper powder (D50 particle size is 0.4μm), add it to 50mL sodium hydroxide aqueous solution with a sodium hydroxide concentration of 2.5M, and stir it at 60℃ for 1h; after filtering, disperse it into 50mL sulfuric acid aqueous solution with a H2SO4 concentration of 5wt%, and ultrasonicate for 3min; after filtering, rinse the copper powder with water until neutral, and dry it in a vacuum drying oven at 40℃ for 3h to obtain 5g clean copper powder;

[0080] S2, adding ammonium metatungstate to water to form 25mL of ammonium metatungstate solution with a concentration of 10mM (the mass of ammonium metatungstate is 0.743g), then adding the above-mentioned clean copper powder to the ammonium metatungstate solution to obtain a dispersion; then dropping 1mL of APTMS solution with a mass fraction of 99% (the mass of APTMS is 1.03g) into the dispersion, stirring for 0.5h to obtain a mixture;

[0081] S3, filtering the mixture, and then placing it in a vacuum drying oven and drying it at 60° C. for 1 h to obtain copper powder with tungsten salt adsorbed on the surface;

[0082] S4, placing the copper powder with tungstate adsorbed on the surface in a tube furnace, calcining it under the condition of hydrogen and argon volume ratio of 5:95, raising the temperature to 300°C at a rate of 2°C / min, and keeping the temperature for 3h to obtain tungsten-coated copper antioxidant material.

[0083] Example 3

[0084] An embodiment of the tungsten-coated copper anti-oxidation material of the present invention, the preparation method of the tungsten-coated copper anti-oxidation material of this embodiment is as follows:

[0085] S1, take 5g copper powder (D50 particle size is 0.4μm), add it to 50mL sodium hydroxide aqueous solution with a sodium hydroxide concentration of 2.5M, and stir it at 60℃ for 1h; after filtering, disperse it into 50mL sulfuric acid aqueous solution with a H2SO4 concentration of 5wt%, and ultrasonicate for 3min; after filtering, rinse the copper powder with water until neutral, and dry it in a vacuum drying oven at 25℃ for 3h to obtain 5g clean copper powder;

[0086] S2, adding ammonium metatungstate to water to form 15mL of ammonium metatungstate solution with a concentration of 5mM (the mass of ammonium metatungstate is 0.22g), then adding the above-mentioned clean copper powder to the ammonium metatungstate solution to obtain a dispersion; then dropping 0.2mL of APTMS solution with a mass fraction of 98% APTMS (the mass of APTMS is 0.204g) into the dispersion, stirring for 0.5h, to obtain a mixture;

[0087] S3, filtering the mixture, and then placing it in a vacuum drying oven and drying it at 40° C. for 1 h to obtain copper powder with tungsten salt adsorbed on the surface;

[0088] S4, placing the copper powder with tungstate adsorbed on the surface in a tube furnace, calcining it under the condition of hydrogen and argon volume ratio of 5:95, heating it to 370°C at a rate of 2°C / min, and keeping it warm for 1 hour to obtain a tungsten-coated copper antioxidant material.

[0089] Example 4

[0090] An embodiment of the tungsten-coated copper anti-oxidation material of the present invention, the preparation method of the tungsten-coated copper anti-oxidation material of this embodiment is as follows:

[0091] S1, take 5g copper powder (D50 particle size is 0.4μm), add it to 50mL sodium hydroxide aqueous solution with a sodium hydroxide concentration of 2.5M, and stir it at 60℃ for 1h; after filtering, disperse it into 50mL sulfuric acid aqueous solution with a H2SO4 concentration of 5wt%, and ultrasonicate for 3min; after filtering, rinse the copper powder with water until neutral, and dry it in a vacuum drying oven at 30℃ for 3h to obtain 5g clean copper powder;

[0092] S2, adding ammonium metatungstate to water to form 15mL of ammonium metatungstate solution with a concentration of 30mM (the mass of ammonium metatungstate is 1.338g), then adding the above-mentioned clean copper powder to the ammonium metatungstate solution to obtain a dispersion; then dropping 1mL of an APTMS solution with a mass fraction of 99% (the mass of APTMS is 1.03g) into the dispersion, stirring for 0.5h, to obtain a mixture;

[0093] S3, filtering the mixture, and then placing it in a vacuum drying oven and drying it at 25° C. for 1 h to obtain copper powder with tungsten salt adsorbed on the surface;

[0094] S4, placing the copper powder with tungstate adsorbed on the surface in a tube furnace, calcining it under the condition of hydrogen and argon volume ratio of 5:95, raising the temperature to 300°C at a rate of 2°C / min, and keeping the temperature for 3h to obtain tungsten-coated copper antioxidant material.

[0095] Example 5

[0096] An embodiment of the tungsten-coated copper anti-oxidation material of the present invention, the preparation method of the tungsten-coated copper anti-oxidation material of this embodiment is as follows:

[0097] S1, take 5g copper powder (D50 particle size is 0.4μm), add it to 50mL sodium hydroxide aqueous solution with a sodium hydroxide concentration of 2.5M, and stir it at 60℃ for 1h; after filtering, disperse it into 50mL sulfuric acid aqueous solution with a H2SO4 concentration of 5wt%, and ultrasonicate for 3min; after filtering, rinse the copper powder with water until neutral, and dry it in a vacuum drying oven at 60℃ for 2h to obtain 5g clean copper powder;

[0098] S2, adding ammonium metatungstate to water to form 15mL of ammonium metatungstate solution with a concentration of 10mM (the mass of ammonium metatungstate is 0.743g), then adding the above-mentioned clean copper powder to the ammonium metatungstate solution to obtain a dispersion; then dropping 2mL of an APTMS solution with a mass fraction of 99% (the mass of APTMS is 2.06g) into the dispersion, stirring for 0.5h to obtain a mixture;

[0099] S3, filtering the mixture, and then placing it in a vacuum drying oven and drying it at 25° C. for 1 h to obtain copper powder with tungsten salt adsorbed on the surface;

[0100] S4, placing the copper powder with tungstate adsorbed on the surface in a tube furnace, calcining it under the condition of hydrogen and argon volume ratio of 5:95, raising the temperature to 300°C at a rate of 2°C / min, and keeping the temperature for 3h to obtain tungsten-coated copper antioxidant material.

[0101] Example 6

[0102] An embodiment of the tungsten-coated copper anti-oxidation material of the present invention, the preparation method of the tungsten-coated copper anti-oxidation material of this embodiment is as follows:

[0103] S1, take 5g copper powder (D50 particle size is 0.4μm), add it to 50mL sodium hydroxide aqueous solution with a sodium hydroxide concentration of 2.5M, and stir it at 60℃ for 1h; after filtering, disperse it into 50mL sulfuric acid aqueous solution with a H2SO4 concentration of 5wt%, and ultrasonicate for 3min; after filtering, rinse the copper powder with water until neutral, and dry it in a vacuum drying oven at 80℃ for 2h to obtain 5g clean copper powder;

[0104] S2, adding ammonium metatungstate to water to form 25mL of ammonium metatungstate solution with a concentration of 10mM (the mass of ammonium metatungstate is 0.743g), then adding the above-mentioned clean copper powder to the ammonium metatungstate solution to obtain a dispersion; then dropping 0.5mL of APTMS solution with a mass fraction of 99% APTMS (the mass of APTMS is 0.51g) into the dispersion, stirring for 0.5h to obtain a mixture;

[0105] S3, filtering the mixture, and then placing it in a vacuum drying oven and drying it at 40° C. for 1 h to obtain copper powder with tungsten salt adsorbed on the surface;

[0106] S4, placing the copper powder with tungstate adsorbed on the surface in a tube furnace, calcining it under the condition of hydrogen and argon volume ratio of 5:95, heating it to 650°C at a rate of 2°C / min, and keeping it warm for 1h to obtain tungsten-coated copper antioxidant material.

[0107] Comparative Example 1

[0108] A copper material, the preparation method of which is different from that of Example 1 only in that S2-S3 are not included, and specifically comprises the following steps:

[0109] Take 5g of copper powder (D50 particle size is 0.4μm), add it to 50mL of sodium hydroxide aqueous solution with a sodium hydroxide concentration of 2.5M, and stir it at 60℃ for 1h; after filtering, disperse it in 50mL of sulfuric acid aqueous solution with a H2SO4 concentration of 5wt%, and ultrasonicate for 3min; after filtering, rinse the copper powder with water until it is neutral, and dry it in a vacuum drying oven at 30℃ for 3h to obtain 5g of clean copper powder;

[0110] The clean copper powder was placed in a tubular furnace, calcined under the condition that the volume ratio of hydrogen to argon was 5:95, the temperature was raised to 300° C. at a rate of 2° C. / min, and the temperature was kept for 3 hours to obtain the copper material.

[0111] Comparative Example 2

[0112] A copper-coated tungsten antioxidant material, the preparation method of which is different from that of Example 2 only in that, in S2, ammonium metatungstate is added to water to form 15 mL of an ammonium metatungstate solution having a concentration of 0.1 mM ammonium metatungstate (the mass of ammonium metatungstate is 0.045 g).

[0113] Comparative Example 3

[0114] A copper-coated tungsten anti-oxidation material, the preparation method of which is different from that of Example 2 only in that no surfactant is added to the dispersion.

[0115] Performance Testing

[0116] 1) Morphology and element distribution: The surface morphology and surface element distribution of the tungsten-coated copper anti-oxidation material and copper powder in the embodiment and the comparative example were observed using a scanning electron microscope;

[0117] 2) Conductivity: Use a powder resistivity tester to test the resistivity of copper powder;

[0118] 3) High temperature oxidation resistance: The high temperature oxidation resistance of the tungsten-coated copper antioxidant material and copper powder in the comparative example was characterized by comparing the resistivity changes before and after accelerated aging in an oven at 85°C for 10 hours.

[0119] Table 1 shows the performance test results.

[0120] Table 1

[0121]

[0122]

[0123] It can be seen from the above test results that Examples 1 to 6 have better oxidation resistance than Comparative Example 1. At high temperatures, their resistivity growth rate is within 2000%, and they have good high-temperature oxidation resistance.

[0124] In addition, by comparing the test results of Examples 1 to 3 with those of Example 4, it can be found that too high a concentration of ammonium metatungstate in the ammonium metatungstate solution will also affect the adsorption effect of the tungsten salt, which may be caused by the uneven adsorption of the tungsten salt on the surface of the copper powder.

[0125] By comparing the test results of Examples 1 to 3 and Example 5, it can be found that, similarly, excessive use of surfactant will also affect the adsorption effect. Only when the mass ratio of surfactant to clean copper powder is 1:50 to 1:5 can the tungsten salt be evenly adsorbed on the surface of the copper powder, thereby improving the high-temperature oxidation resistance of the tungsten-coated copper antioxidant material.

[0126] By comparing the test results of Examples 1 to 3 and Example 6, it can be found that the tungsten-coated copper anti-oxidation material prepared at a calcination temperature in the range of 300 to 500° C. has better high-temperature oxidation resistance.

[0127] Figure 2 The scanning electron microscope image and EDX spectrum image of the tungsten-coated copper anti-oxidation material in Example 1 of the present invention show that the surface of the tungsten-coated copper anti-oxidation material is smooth and the uniformity of the tungsten coating layer is good; Figure 3 The scanning electron microscope image and EDX spectrum image of the tungsten-coated copper anti-oxidation material in Example 2 of the present invention are shown. Similarly, the surface is smooth and the tungsten coating layer is uniform. Figure 4 The scanning electron microscope image of the copper material in Comparative Example 1 shows that, since the surface of the copper powder without coating treatment is not protected by tungsten, sintering necks will be formed between the copper powder particles when calcined at the same temperature, and fusion will occur, thus destroying the original copper morphology; Figure 5 The scanning electron microscope images of the tungsten-coated copper antioxidant materials in (a) Example 1, (b) Example 2 and (c) Comparative Example 2 after aging at 85°C for 10 hours show that the tungsten-coated copper antioxidant materials in Examples 1 to 2 still have a smooth surface after high-temperature aging, while the tungsten-coated copper antioxidant material in Comparative Example 2 has more burrs on its surface and has poor high-temperature oxidation resistance.

[0128] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a tungsten-coated copper anti-oxidation material, characterized in that: The steps include: S1, washing and first drying the copper powder to obtain clean copper powder; S2, mixing tungsten salt, surfactant, the clean copper powder and water, and stirring to obtain a mixture; S3, filtering the mixture and performing a second drying to obtain copper powder with tungsten salt adsorbed on the surface; S4, calcining the copper powder with tungsten salt adsorbed on the surface under a reducing atmosphere to obtain the tungsten-coated copper antioxidant material.

2. The method for preparing the tungsten-coated copper anti-oxidation material according to claim 1, characterized in that: In S1, the copper powder is washed with an alkaline solution, an acid solution, and water in sequence, wherein the alkaline solution is at least one of a sodium hydroxide solution, a potassium hydroxide solution, and an ammonia solution; and the acid solution is at least one of a sulfuric acid solution, a hydrochloric acid solution, and a nitric acid solution.

3. The method for preparing the tungsten-coated copper anti-oxidation material according to claim 2, characterized in that: In S1, the temperature of the alkaline solution during cleaning is 60°C to 80°C, and the time is 0.5h to 2h; and / or, ultrasonic assistance is used during cleaning with the acid solution, and the cleaning time with the acid solution is 3min to 10min; and / or, the water is used to clean until neutral; And / or, the first drying temperature is 25° C. to 80° C., and the first drying time is 2 h to 5 h.

4. The method for preparing the tungsten-coated copper anti-oxidation material according to any one of claims 1 to 3, characterized in that: In S2, the tungsten salt is first dissolved in the water to obtain a tungsten salt solution, and then the clean copper powder is added to the tungsten salt solution to form a dispersion; and then the surfactant is added to the dispersion and stirred to obtain the mixture.

5. The method for preparing the tungsten-coated copper anti-oxidation material according to claim 4, characterized in that: In S2, in the mixture, the mass ratio of the tungsten salt to the clean copper powder is 1:100 to 1:10; and / or, the mass ratio of the surfactant to the clean copper powder is 1:50 to 1:5; and / or, the concentration of the tungsten salt in the tungsten salt solution is 1 mM to 10 mM; and / or, the stirring time is 0.5 h to 3 h.

6. The method for preparing the tungsten-coated copper anti-oxidation material according to claim 4, characterized in that: In S2, the tungsten salt is at least one of ammonium metatungstate, sodium tungstate, phosphotungstic acid, and ammonium paratungstate; and / or the surfactant is at least one of mercaptoethylamine, 3-(trimethoxysilyl)propylamine, and cysteine.

7. The method for preparing the tungsten-coated copper anti-oxidation material according to any one of claims 1 to 3, characterized in that: In S3, the temperature of the second drying is 25° C. to 60° C., and the time of the second drying is 1 hour to 5 hours.

8. The method for preparing the tungsten-coated copper anti-oxidation material according to any one of claims 1 to 3, characterized in that: In the step S4, the calcination temperature is 300° C. to 500° C., and the calcination time is 1 h to 3 h.

9. The method for preparing the tungsten-coated copper anti-oxidation material according to claim 8, characterized in that: In S4, the reducing atmosphere is a mixture of hydrogen and an inert gas; the inert gas is at least one of nitrogen, argon and helium.

10. A tungsten-coated copper anti-oxidation material, characterized in that: Prepared by the preparation method according to any one of claims 1 to 9.

Images