Method for preparing tungsten-copper composite material based on calcium thermal reduction and infiltration process

Abstract

The invention discloses a method for preparing a tungsten-copper composite material based on calcium thermal reduction and infiltration processes, and relates to the technical field of tungsten-copper composite material preparation. Firstly, tungsten oxide and calcium powder are blended, calcium thermal reduction treatment is conducted, then screening is conducted to remove impurity phase CaO with the large particle size, a tungsten powder raw material with multiple pores is obtained, the tungsten powder is pressed into a blank, presintering is conducted to prepare a high-pore tungsten framework, sintering infiltration is conducted on the high-pore tungsten framework and high-sphericity-degree copper powder prepared through gas atomization, and the high-sphericity-degree copper powder is obtained. The tungsten-copper composite material with high density and high thermal conductivity is obtained, and effective combination between tungsten and copper is achieved. Tungsten oxide is reduced through a calcium thermal reduction process with high reduction efficiency, the tungsten powder with high porosity is obtained, the binding site of copper in a tungsten framework can be effectively improved, the pore morphology can be improved, meanwhile, the wettability of copper liquid in the tungsten framework can be remarkably improved through the high-sphericity-degree copper powder prepared through gas atomization, and the high-sphericity-degree copper powder is obtained. The driving force of liquid copper infiltrating into the tungsten framework is increased, and the capillary action of the liquid copper on the tungsten framework can be improved through the infiltration process, and the bonding strength is improved.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of tungsten-copper composite materials, and in particular to a method for preparing a tungsten-copper composite material based on calcium thermal reduction and melt infiltration processes. Background Art

[0002] With the advancement of microelectronics technology, integrated circuit devices are developing rapidly in the direction of miniaturization and high density. The power per unit area is constantly increasing, and the heat generated per unit area is increasing, which has led to increasing requirements for packaging materials. Single traditional electronic packaging materials such as ceramics and metals can no longer meet the actual requirements of the microelectronics industry. The research and development of new packaging composite materials with high thermal conductivity, low expansion, excellent processing performance and mechanical properties has become a research hotspot in the industry. Tungsten copper material has the characteristics of high thermal conductivity and low expansion coefficient, and its thermal conductivity and thermal expansion coefficient can be adjusted by changing the ratio of W and Cu in the composite material, so that it can be well matched with ceramic materials, gallium arsenide, silicon wafers and other semiconductor components in electronic devices, preventing thermal fatigue damage caused by interface thermal stress, and at the same time can efficiently export the heat in the semiconductor. These excellent properties make it one of the preferred packaging materials for high-power integrated circuits.

[0003] Because W and Cu do not dissolve in each other, it is difficult to form a solid solution and an intermetallic compound. Therefore, the tungsten-copper composite material is a pseudo alloy formed by combining two different crystal structures of W (body-centered cubic structure) and Cu (face-centered cubic structure). It has the characteristics of high thermal conductivity of Cu and low expansion coefficient of W, and the physical properties of the material can be adjusted by adjusting the ratio of the two phases in the tungsten-copper composite material. The tungsten-copper packaging shell parts for electronic packaging require the material to have high thermal conductivity and airtightness. Since the thermal conductivity is proportional to the sintering degree, the sintering density is an important indicator for measuring the performance of tungsten-copper composite materials. At present, the copper infiltration method is mainly used to prepare tungsten-copper sheets. This method has the disadvantages of low raw material utilization and high processing cost. The melt infiltration method is currently a common method for preparing tungsten-copper alloys. It is to press tungsten powder into a blank, and then sinter it in hydrogen to form a porous tungsten skeleton containing pores. At a temperature higher than the melting point of copper, the porous tungsten skeleton is infiltrated with copper. Liquid copper fills the pores in the porous tungsten skeleton under the action of capillary force, thereby obtaining a dense tungsten-copper alloy. The prepared tungsten copper alloy has the characteristics of less impurities, higher density and better performance, and can obtain better sintering density.

[0004] Powder modification refers to the method of changing the properties of powder (such as morphology, particle size, specific surface area, surface friction, etc.) or interface characteristics by physical and chemical means. It is a key technology to optimize the performance of powder. Surface-modified powders obtained by treating oxide powders through a reduction process have been used in the manufacturing process of various alloys. Oxide powders have large surface roughness and a large contact area that can effectively provide contact pores. Reduction treatment will also retain the rough surface interface and maintain strong interface binding energy. Calcium, as a strong reducing agent, is usually better than other reducing agents, such as hydrogen or carbon, and can effectively reduce many metal oxides, including tungsten oxide (WO) which is difficult to reduce. 3 ), which helps to ensure the complete reduction reaction and improve the reduction efficiency. The reduction process is relatively simple, mainly relying on high temperature and calcium as a reducing agent, and does not require complex equipment or catalysts. This can reduce production costs and operational complexity. At the same time, the calcium oxide impurities generated during the reduction process are easy to remove. Calcium vapor will volatilize at 900°C, which can remove residual calcium during the sintering process and facilitate the purity of the reaction matrix.

[0005] After pre-sintering, the calcium-thermal reduced tungsten powder can obtain a tungsten skeleton with high porosity, and obtain surface roughness and bonding sites that the tungsten skeleton prepared by traditional ultrafine tungsten powder does not have, thereby improving the interface binding energy. By adopting the calcium-thermal reduction process and the melt infiltration process, surface-modified tungsten powder and tungsten-copper composite materials with high bonding strength can be effectively obtained in large quantities. The operation is simple and the efficiency is high, which has certain significance for the production and preparation of tungsten-copper composite materials.

[0006] In view of this, the present invention adopts tungsten oxide powder, calcium powder and gas atomized copper powder as raw materials, and after calcium thermal reduction treatment, the pressed green body is pre-sintered to obtain a tungsten skeleton, and the gas atomized copper powder is subjected to spark plasma sintering densification to obtain a tungsten-copper composite material prepared by calcium thermal reduction and infiltration process. Summary of the invention

[0007] The present invention proposes a method for preparing a tungsten-copper composite material based on calcium thermal reduction and melt infiltration process, and the main problem to be solved is that the tungsten obtained by reducing tungsten oxide as a raw material has a large roughness, which can effectively solve the significant difference in thermal expansion coefficient and the inherent immiscibility between W and Cu, which makes it difficult for W and Cu to be effectively bonded. At the same time, the tungsten oxide powder in the traditional hydrogen reduction process has problems such as high reduction temperature, low reaction rate, incomplete reaction, and more reaction products, which leads to defects such as poor performance of the tungsten powder obtained by hydrogen reduction of tungsten oxide powder. The present invention reduces tungsten oxide through a calcium thermal reduction process with high reduction efficiency to obtain tungsten powder with high porosity, which can effectively increase the binding sites of copper in the tungsten skeleton and improve the pore morphology. At the same time, the high sphericity copper powder prepared by gas atomization can significantly improve the wettability of copper liquid in the tungsten skeleton, increase the driving force of liquid copper infiltrating the tungsten skeleton, and the melt infiltration process can improve the capillary action of liquid copper in the tungsten skeleton and improve the bonding strength.

[0008] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is:

[0009] A method for preparing a tungsten-copper composite material based on a calcium thermal reduction and infiltration process comprises the following steps: tungsten oxide and calcium powder are mixed and subjected to a calcium thermal reduction treatment, followed by screening to remove the impurity phase CaO with a larger particle size, to obtain a tungsten powder raw material with more pores, the tungsten powder is pressed into a billet, and a tungsten skeleton is prepared by pre-sintering to obtain a tungsten skeleton with a certain surface roughness and high porosity, and the billet is subjected to spark plasma sintering and infiltration with high-sphericity copper powder prepared by gas atomization to obtain a tungsten-copper composite material with high density and high thermal conductivity, thereby achieving effective bonding between tungsten and copper.

[0010] As a preferred technical solution of the present invention, the preparation method specifically comprises the following steps:

[0011] Step 1: Calcium thermal reduction of tungsten oxide powder:

[0012] The tungsten oxide powder and calcium powder are mixed in a mixer, and then the mixed powder is placed in a tube furnace, and the temperature is increased and kept for a period of time. After the powder is taken out, it is placed in a sieving machine for sieving to obtain tungsten powder after calcium thermal reduction;

[0013] Step 2: Preparation of porous tungsten skeleton:

[0014] The tungsten powder after the calcium thermal reduction in step 1 is pressed into a green body with a certain diameter by using a hydraulic press, and then the green body is pre-sintered in a hydrogen atmosphere, and after being cooled in a furnace, a porous tungsten skeleton is obtained;

[0015] Step 3: Spark plasma sintering and infiltration:

[0016] The porous tungsten skeleton obtained in step 2 is subjected to spark plasma sintering with gas atomized copper powder to finally obtain a tungsten-copper composite material prepared by calcium thermal reduction and infiltration process.

[0017] As a further preferred technical solution of the present invention, in the preparation method:

[0018] In the step 1, the holding temperature in the tubular furnace is 800-1000° C., the holding time is 3-5 hours, and the mass ratio of calcium powder to tungsten oxide powder is 4-8:1.

[0019] In the step 2, the pressure for pressing the embryo is 30-50 MPa, and the initial density of the embryo is controlled to be 50%-60%.

[0020] In the step 2, the pre-sintering temperature is 1300-1500° C., and the sintering time is 3-4 hours.

[0021] The specific steps of sintering densification in step three are as follows: loading a porous tungsten skeleton into a sintering mold, adding atomized copper powder on the surface of the tungsten skeleton with a rough porous structure, isolating the mold wall and the powder with carbon paper, placing it in a discharge plasma sintering furnace, and evacuating the sintering furnace; setting the initial pressure to 10MPa, starting sintering, heating from room temperature to 600°C and keeping it warm for 5min; then heating to 1000°C and keeping it warm for 5min, and manually pressurizing to a sintering pressure of 50MPa during the heating process; cooling with the furnace after the insulation is completed, taking out the product, and grinding the carbon paper on the surface with a grinder, and finally obtaining a tungsten-copper composite material prepared by calcium thermal reduction and infiltration process.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. Calcium is a strong reducing agent with a reducing ability that is generally superior to other reducing agents, such as hydrogen or carbon, and can effectively reduce many metal oxides, including tungsten oxide (WO 3 ), which helps to ensure the completeness of the reduction reaction and improves the reduction efficiency. The reduction process is relatively simple, mainly relying on high temperature and calcium as a reducing agent, and does not require complex equipment or catalysts, which can reduce production costs and operational complexity.

[0024] 2. During the calcium thermal reduction process, calcium will produce calcium vapor volatilization at 900℃, which helps to complete the reaction and avoid the contamination of tungsten powder by impurity calcium. The produced calcium oxide impurity has a large particle size and is easy to remove. Calcium oxide (CaO) can be reused or used as an industrial by-product for other purposes to improve economic value.

[0025] 3. Tungsten oxide is reduced as the raw material of tungsten powder. The surface of the prepared tungsten powder has a large roughness, which is conducive to the generation of multi-pores in the tungsten skeleton, improves the pore morphology, and can provide effective binding sites for copper liquid during the infiltration process.

[0026] 4. The copper powder used is prepared by gas atomization, and has the characteristics of high sphericity and good fluidity, and stable and reliable performance. Compared with electrolytic copper powder and flaky copper powder, it can significantly improve the wettability of copper liquid on the tungsten skeleton, and has a smaller bonding resistance with the tungsten skeleton, which increases the driving force for liquid copper to penetrate into the tungsten skeleton, and can fully combine with the rough pores on the inner surface of the tungsten skeleton to achieve high density.

[0027] 5. The infiltration process can melt the spherical copper powder with good fluidity at high temperature and use the liquid copper to fill and wet the structure through the gaps between the porous W frame particles under the action of capillary action. This technology can produce tungsten copper materials with relatively high density, strong bonding force and good comprehensive performance. Compared with the traditional liquid phase sintering preparation method, it avoids the shortcomings of uneven sample composition and unstable performance caused by component changes caused by liquid phase overflow or evaporation during liquid phase sintering. By controlling the infiltration process parameters such as pressure and flow rate, the process stability of the infiltration process can be stably controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a process flow chart for preparing a tungsten-copper composite material by using a calcium thermal reduction and melt infiltration process.

[0029] Figure 2 This is a SEM image of a porous tungsten skeleton of a tungsten-copper composite material prepared by the calcium thermal reduction and melt infiltration process of the present invention.

[0030] Figure 3 This is a surface EDS image of a tungsten-copper composite material prepared by the calcium thermal reduction and melt infiltration process of the present invention.

[0031] Figure 4 This is a SEM image of the fracture of a tungsten-copper composite material prepared by the calcium thermal reduction and melt infiltration process of the present invention.

[0032] Figure 5 This is an XRD diagram of a tungsten-copper composite material prepared by the calcium thermal reduction and melt infiltration process of the present invention.

[0033] Figure 6 It is a comparison chart of the mechanical properties of Example 1 and Comparative Example 1 of the tungsten-copper composite material prepared by the calcium thermal reduction and melt infiltration process of the present invention. DETAILED DESCRIPTION

[0034] See also Figure 1 As shown, the present invention proposes a method for preparing a tungsten-copper composite material based on calcium thermal reduction and infiltration process, taking tungsten oxide powder as a raw material, blending tungsten oxide with calcium powder, performing calcium thermal reduction treatment, and then sieving to remove the impurity phase CaO with a larger particle size to obtain a tungsten powder raw material with more pores, pressing the tungsten powder into a billet, pre-sintering to prepare a tungsten skeleton with a certain surface roughness and high porosity, and then performing spark plasma sintering and infiltration with high-sphericity copper powder prepared by gas atomization to obtain a tungsten-copper composite material with high density and high thermal conductivity, thereby achieving effective bonding between tungsten and copper.

[0035] The present invention is further described in detail below in conjunction with embodiments and drawings.

[0036] Example 1

[0037] The steps of the method for preparing the tungsten-copper composite material in this embodiment are as follows:

[0038] Step 1: Calcium thermal reduction of tungsten oxide powder:

[0039] Tungsten oxide powder (WO 3 ) and calcium powder are mixed with a mixer, and calcium powder and tungsten oxide powder (WO 3 ) with a mass ratio of 6:1, and then the mixed powder is placed in a tubular furnace, the temperature is raised to 900°C, and kept warm for 5 hours, the powder is taken out, and placed in a screening machine for sieving to obtain tungsten powder after calcium thermal reduction.

[0040] Step 2: Preparation of porous tungsten skeleton:

[0041] The tungsten powder after the calcium thermal reduction in step 1 was pressed into a green body with a certain diameter using a hydraulic press at a pressure of 50 MPa, the initial density was maintained at 60%, and then the green body was sintered at 1400° C. in a hydrogen atmosphere for 4 hours. After cooling in a furnace, a porous tungsten skeleton was obtained.

[0042] Step 3: Spark plasma sintering and infiltration:

[0043] The porous tungsten skeleton obtained in step 2 is subjected to spark plasma sintering with the gas atomized copper powder to finally obtain a tungsten-copper composite material prepared by calcium thermal reduction and infiltration process. The specific steps of sintering densification are:

[0044] A porous tungsten skeleton was loaded into a sintering mold, and atomized copper powder was added to the surface of the tungsten skeleton with a rough porous structure. The mold wall and the powder were isolated by carbon paper, and the mold was placed in a discharge plasma sintering furnace, and the sintering furnace was vacuumed. The initial pressure was set to 10 MPa, and sintering began. The temperature was raised from room temperature to 600°C and kept warm for 5 minutes; the temperature was then raised to 1000°C and kept warm for 5 minutes, and the sintering pressure was manually increased to 50 MPa during the heating process. After the insulation was completed, the furnace was cooled, the product was taken out, and the carbon paper on the surface was polished with a grinder, and finally a tungsten-copper composite material prepared by calcium thermal reduction and melt infiltration process was obtained.

[0045] Example 2

[0046] The steps of the method for preparing the tungsten-copper composite material in this embodiment are as follows:

[0047] Step 1: Calcium thermal reduction of tungsten oxide powder:

[0048] Tungsten oxide powder (WO 2.9 ) and calcium powder are mixed with a mixer, and calcium powder and tungsten oxide powder (WO 2.9 ) with a mass ratio of 6:1, and then the mixed powder is placed in a tubular furnace, the temperature is raised to 900°C, and kept warm for 5 hours, the powder is taken out, and placed in a screening machine for sieving to obtain tungsten powder after calcium thermal reduction.

[0049] Step 2: Preparation of porous tungsten skeleton:

[0050] The tungsten powder after the calcium thermal reduction in step 1 was pressed into a green body with a certain diameter using a hydraulic press at a pressure of 50 MPa, the initial density was maintained at 60%, and then the green body was sintered at 1400° C. in a hydrogen atmosphere for 4 hours. After cooling in a furnace, a porous tungsten skeleton was obtained.

[0051] Step 3: Spark plasma sintering and infiltration:

[0052] The porous tungsten skeleton obtained in step 2 is subjected to spark plasma sintering with the gas atomized copper powder to finally obtain a tungsten-copper composite material prepared by calcium thermal reduction and infiltration process. The specific steps of sintering densification are:

[0053] A porous tungsten skeleton was loaded into a sintering mold, and atomized copper powder was added to the surface of the tungsten skeleton with a rough porous structure. The mold wall and the powder were isolated by carbon paper, and the mold was placed in a discharge plasma sintering furnace, and the sintering furnace was vacuumed. The initial pressure was set to 10 MPa, and sintering began. The temperature was raised from room temperature to 600°C and kept warm for 5 minutes; the temperature was then raised to 1000°C and kept warm for 5 minutes, and the sintering pressure was manually increased to 50 MPa during the heating process. After the insulation was completed, the furnace was cooled, the product was taken out, and the carbon paper on the surface was polished with a grinder, and finally a tungsten-copper composite material prepared by calcium thermal reduction and melt infiltration process was obtained.

[0054] Example 3

[0055] The steps of the method for preparing the tungsten-copper composite material in this embodiment are as follows:

[0056] Step 1: Calcium thermal reduction of tungsten oxide powder:

[0057] Tungsten oxide powder (WO 2 ) and calcium powder are mixed with a mixer, and calcium powder and tungsten oxide powder (WO 2 ) with a mass ratio of 6:1, and then the mixed powder is placed in a tubular furnace, the temperature is raised to 900°C, and kept warm for 5 hours, the powder is taken out, and placed in a screening machine for sieving to obtain tungsten powder after calcium thermal reduction.

[0058] Step 2: Preparation of porous tungsten skeleton:

[0059] The tungsten powder after the calcium thermal reduction in step 1 was pressed into a green body with a certain diameter using a hydraulic press at a pressure of 50 MPa, the initial density was maintained at 60%, and then the green body was sintered at 1400° C. in a hydrogen atmosphere for 4 hours. After cooling in a furnace, a porous tungsten skeleton was obtained.

[0060] Step 3: Spark plasma sintering and infiltration:

[0061] The porous tungsten skeleton obtained in step 2 is subjected to spark plasma sintering with the gas atomized copper powder to finally obtain a tungsten-copper composite material prepared by calcium thermal reduction and infiltration process. The specific steps of sintering densification are:

[0062] A porous tungsten skeleton was loaded into a sintering mold, and atomized copper powder was added to the surface of the tungsten skeleton with a rough porous structure. The mold wall and the powder were isolated by carbon paper, and the mold was placed in a discharge plasma sintering furnace, and the sintering furnace was vacuumed. The initial pressure was set to 10 MPa, and sintering began. The temperature was raised from room temperature to 600°C and kept warm for 5 minutes; the temperature was then raised to 1000°C and kept warm for 5 minutes, and the sintering pressure was manually increased to 50 MPa during the heating process. After the insulation was completed, the furnace was cooled, the product was taken out, and the carbon paper on the surface was polished with a grinder, and finally a tungsten-copper composite material prepared by calcium thermal reduction and melt infiltration process was obtained.

[0063] Comparative Example 1

[0064] The steps of preparing the tungsten-copper composite material in this comparative example are as follows:

[0065] Step 1: Hydrogen reduction of tungsten oxide powder:

[0066] Tungsten oxide powder (WO 3 ) is placed in a tubular furnace, heated to 900°C in a hydrogen atmosphere, and kept warm for 5 hours. The powder is taken out and placed in a screening machine for screening to obtain tungsten powder after hydrogen reduction.

[0067] Step 2: Preparation of tungsten skeleton:

[0068] The tungsten powder after hydrogen reduction in step 1 was pressed into a green body with a certain diameter using a hydraulic press at a pressure of 50 MPa, the initial density was maintained at 60%, and then the green body was sintered at 1400° C. in a hydrogen atmosphere for 4 hours. After cooling in a furnace, a porous tungsten skeleton was obtained.

[0069] Step 3: Spark plasma sintering and infiltration:

[0070] The porous tungsten skeleton obtained in step 2 is subjected to spark plasma sintering with the gas atomized copper powder to finally obtain a tungsten-copper composite material prepared by hydrogen reduction and infiltration process. The specific steps of sintering densification are:

[0071] A tungsten skeleton was placed in a sintering mold, and atomized copper powder was added to the surface of the tungsten skeleton with a rough porous structure. The mold wall and the powder were isolated by carbon paper, and the mold was placed in a discharge plasma sintering furnace, and the sintering furnace was vacuumed. The initial pressure was set to 10 MPa, and sintering began. The temperature was raised from room temperature to 600°C and kept warm for 5 minutes; the temperature was then raised to 1000°C and kept warm for 5 minutes, and the sintering pressure was manually increased to 50 MPa during the heating process. After the insulation was completed, the furnace was cooled, the product was taken out, and the carbon paper on the surface was polished with a grinder, and finally a tungsten-copper composite material prepared by hydrogen reduction and infiltration process was obtained.

[0072] Table 1. Relevant properties of tungsten-copper composite materials prepared in the embodiments of the present invention and comparative examples

[0073] Density(%) Hardness(Hv) Conductivity (%) Example 1 85.83％ 188 48.7％ Example 2 88.69％ 175 48.3％ Example 3 90.12％ 191 51.6％ Comparative Example 1 83.92％ 164 38.4％

[0074] It can be seen from Table 1 that the degree of reduction by calcium thermal reduction is good, resulting in higher conductivity, reduced impurities, improved performance and density. 2 The higher degree of reduction of (prepared in Example 3) resulted in the best performance.

[0075] Depend on Figure 2 It can be seen that the tungsten particles of the porous tungsten skeleton reduced by calcium heat are nearly spherical and have a large roughness, which can provide effective binding sites for the subsequent infiltration of copper liquid.

[0076] Depend on Figure 3 It can be seen that on the surface of the calcium thermal reduced tungsten copper material, tungsten and copper are tightly combined and effectively dispersed, and have a good bonding effect.

[0077] Depend on Figure 4 It can be seen that the copper at the fracture wraps the tungsten particles with a rough surface, has good dispersibility, has a certain number of dimples, and has a certain plasticity.

[0078] Depend on Figure 5 It can be seen that the tungsten copper material has obvious diffraction peaks of tungsten and copper, and no strong impurity peaks, indicating that the material is relatively pure and the degree of calcium thermal reduction is high.

[0079] Depend on Figure 6 It can be seen that the mechanical properties of Example 1 of calcium thermal reduction are better than those of Comparative Example 1 of hydrogen reduction, indicating that the product raw materials obtained by calcium thermal reduction have better bonding properties, which in turn leads to better mechanical properties.

[0080] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a tungsten-copper composite material based on calcium thermal reduction and infiltration process, characterized in that: Tungsten oxide is mixed with calcium powder and subjected to calcium thermal reduction treatment, and then sieved to remove the impurity phase CaO with a larger particle size to obtain a tungsten powder raw material with more pores. The tungsten powder is pressed into a billet, and a tungsten skeleton is prepared by pre-sintering to obtain a tungsten skeleton with a certain surface roughness and high porosity. The billet is then subjected to spark plasma sintering and infiltration with high-sphericity copper powder prepared by gas atomization to obtain a tungsten-copper composite material with high density and high thermal conductivity, thereby achieving an effective combination of tungsten and copper.

2. The method according to claim 1, characterized in that The specific steps include: Step 1: Calcium thermal reduction of tungsten oxide powder: The tungsten oxide powder and calcium powder are mixed in a mixer, and then the mixed powder is placed in a tube furnace, and the temperature is increased and kept for a period of time. After the powder is taken out, it is placed in a sieving machine for sieving to obtain tungsten powder after calcium thermal reduction; Step 2: Preparation of porous tungsten skeleton: The tungsten powder after the calcium thermal reduction in step 1 is pressed into a green body with a certain diameter by using a hydraulic press, and then the green body is pre-sintered in a hydrogen atmosphere, and after cooling in a furnace, a porous tungsten skeleton is obtained; Step 3: Spark plasma sintering and infiltration: The porous tungsten skeleton obtained in step 2 is subjected to spark plasma sintering with gas atomized copper powder to finally obtain a tungsten-copper composite material prepared by calcium thermal reduction and infiltration process.

3. The method according to claim 2, characterized in that In the step 1, the holding temperature in the tubular furnace is 800-1000° C., the holding time is 3-5 hours, and the mass ratio of calcium powder to tungsten oxide powder is 4-8:

1.

4. The method according to claim 2, characterized in that In the step 2, the pressure for pressing the embryo is 30-50 MPa, and the initial density of the embryo is controlled to be 50%-60%.

5. The method according to claim 2, characterized in that In the step 2, the pre-sintering temperature is 1300-1500° C., and the sintering time is 3-4 hours.

6. The method according to claim 2, characterized in that The specific steps of sintering densification in step 3 are: A porous tungsten skeleton was loaded into a sintering mold, and atomized copper powder was added to the surface of the tungsten skeleton with a rough porous structure. The mold wall and the powder were isolated by carbon paper, and the mold was placed in a discharge plasma sintering furnace, and the sintering furnace was vacuumed. The initial pressure was set to 10 MPa, and sintering began. The temperature was raised from room temperature to 600°C and kept warm for 5 minutes; the temperature was then raised to 1000°C and kept warm for 5 minutes, and the sintering pressure was manually increased to 50 MPa during the heating process. After the insulation was completed, the furnace was cooled, the product was taken out, and the carbon paper on the surface was polished with a grinder, and finally a tungsten-copper composite material prepared by calcium thermal reduction and melt infiltration process was obtained.

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