A method for improving tungsten-copper connection interface based on internal oxidation and hydrogen reduction process

Abstract

The application relates to a method for improving a tungsten-copper connecting interface based on internal oxidation and hydrogen reduction process, and relates to the technical field of tungsten-copper composite material preparation. First, an oxide (Cu2O, CuO) or oxygen is added to the surface of a tungsten block for internal oxidation treatment, a nano-oxide porous structure is generated on the surface, the surface roughness is increased, then hydrogen reduction is performed to remove surface oxide impurities, the surface pores are reserved, finally, the tungsten block with the treated surface is combined with copper powder through discharge plasma sintering to realize effective combination between tungsten and copper. Through the internal oxidation process, the influence of a metal alloy layer formed by a heterogeneous element brazing filler on the tungsten-copper interface compatibility and stability under radiation can be effectively avoided, and through the reduction treatment of high-purity hydrogen, the high-purity of the matrix is maintained, and the combination performance of the porous structure reinforced connecting layer is generated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tungsten copper composite material preparation, in particular to a method for improving the interface of tungsten copper connection based on internal oxidation and hydrogen reduction process. BACKGROUND

[0002] In the nuclear fusion reactor, the plasma-facing components (PFC) are subjected to extreme thermal environment and intense neutron radiation, and need to have excellent durability and structural integrity. W is selected because of its high melting point, excellent high-temperature strength and resistance to radiation damage, and it can withstand the direct impact of high-temperature plasma. Cu and its alloy (CuCrZr) have excellent thermal conductivity, which can effectively dissipate internal heat generated at high temperature, thereby reducing thermal damage. Therefore, the composite module metal material composed of tungsten and copper and copper alloy has excellent application prospect, which poses a challenge to the bonding strength between tungsten and copper. W and Cu are not mutually soluble, and the thermal expansion coefficients are significantly different, which increases the internal stress and leads to the decrease of interface strength during service. Therefore, the development and optimization of W / Cu bonding technology is crucial for improving the performance of the diverter assembly and ensuring the reliable operation of the nuclear fusion reactor.

[0003] In order to improve the bonding strength and efficiency between W and Cu, various bonding technologies have been tried, including brazing, diffusion bonding, and explosive welding. The current intermediate layers of various brazing filler metals or alloys such as Cu-Mn, Cu-TiH2-Ni and Ni / Cu can form a metallurgical bonding layer with W or Cu to enhance the interface bonding performance. However, the use of intermediate layers affects the interface compatibility, the uniformity of the microstructure of the heterogeneous elements in the intermediate layer, the mechanical integrity of the bonding layer, and the stability under radiation conditions. In order to solve the problems caused by heterogeneous element brazing filler metal, surface treatment technology has become an effective alternative solution, which aims to change the bonding state between W and Cu through surface structure design without introducing additional interlayers or auxiliary phases at the interface. Recent studies have shown that the surface nanostructure obtained by surface treatment significantly improves the interface adhesion strength of dissimilar metal joints. Traditional mechanical surface treatment methods such as grinding and sandblasting increase the surface roughness to improve the adhesion strength of the bonding layer, but these methods may only be suitable for thick-section components and have the risk of damage. In contrast, non-mechanical methods, including plasma treatment, laser surface treatment and anodic oxidation, can provide excellent surface activity and microstructure design capabilities. However, due to high cost and operation technology reasons, they have not been widely applied.

[0004] And as a widely used oxidation process, internal oxidation can occur on the surface and near-surface of the metal at high temperature through the behavior of oxygen diffusion and penetration, and the oxides have a large volume, leading to the formation of internal pores, and then forming a porous oxide layer on the surface. As a surface treatment method, internal oxidation can control the thickness of the surface oxide layer and the density of the pores to regulate the surface roughness by changing the oxygen concentration, temperature and internal oxidation time during the internal oxidation process, which is easy to control and easy to scale up. The porous structure produced can effectively improve the surface roughness and enhance the surface free energy, effectively inhibit crack propagation, increase the bonding strength of copper and tungsten, and improve the toughness of the material connection interface. At the same time, it also avoids the influence of heterogeneous elements on the uniformity of the interface bonding and the stability under radiation conditions. Therefore, the method of using internal oxidation process to improve the bonding strength of the metal bonding layer has excellent prospects and guiding significance. SUMMARY

[0005] The present application provides a method for improving the tungsten-copper connection interface based on internal oxidation and hydrogen reduction process, which mainly solves the problem that the significant difference in thermal expansion coefficient and the inherent immiscibility between W and Cu lead to the problem that W and Cu are difficult to effectively bond. The internal oxidation process can effectively avoid the influence of the metal alloy layer formed by the introduction of heterogeneous filler material in traditional brazing on the compatibility of the tungsten-copper interface and the stability under radiation conditions, and the reduction treatment of high-purity hydrogen gas can maintain the high purity of the substrate while producing a nano-porous structure to strengthen the bonding performance of the connection layer. The prepared tungsten-copper connection material can be applied to the field of nuclear fusion reactor divertor.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] A method for improving the tungsten-copper connection interface based on internal oxidation and hydrogen reduction process, the tungsten block is placed in a tube furnace, and an oxide is added to the surface or an oxygen atmosphere is used for internal oxidation treatment at high temperature, a nano-oxide porous structure is generated on the surface, the surface roughness is increased, then the surface oxide impurities are removed by hydrogen atmosphere reduction, the surface pores are retained, and finally the tungsten block treated by the surface is combined with the copper powder prepared by mechanical alloying and treated by hydrogen atmosphere reduction to realize the effective combination between tungsten and copper by discharge plasma sintering.

[0008] As a preferred technical scheme of the present application, the preparation method specifically comprises the following steps:

[0009] Step one, internal oxidation of tungsten block:

[0010] The surface of the tungsten block is treated, the tungsten block is placed in a tube furnace, an oxide is added to the surface or an oxygen atmosphere is used, after heating and holding for a period of time, the surface added oxide is removed, and a tungsten block after surface oxidation is obtained;

[0011] Step two, mechanical alloying preparation of copper powder:

[0012] Put the copper powder into the planetary ball mill, set the parameters for mechanical alloying for a period of time, and then take it out;

[0013] Step three, hydrogen atmosphere reduction:

[0014] Put the obtained surface tungsten oxide block and the copper powder obtained by mechanical alloying into a tube furnace and separate them from each other, adjust the parameters, pass hydrogen to heat, and take it out after heat preservation for a period of time, to obtain reduced copper powder and reduced tungsten block with rough surface and no impurity oxide;

[0015] Step four, sintering densification of tungsten-copper connecting material:

[0016] Discharge plasma sintering the surface rough reduced tungsten block and reduced copper powder obtained in step three, and finally obtain the tungsten-copper connecting material with improved tungsten-copper interface bonding state by internal oxidation reduction process.

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

[0018] The oxide used in step one is Cu2O or CuO. The temperature in the tube furnace is 650-800℃, the heat preservation time is 12h, and the mass ratio of the added oxide to the tungsten block is 4:1.

[0019] The parameters of the planetary ball mill in step two are 500r / min, the ball milling time is 24h, and the ball-to-material ratio is 7:3.

[0020] The calcination and reduction parameters of the tube furnace in step three are: the atmosphere used is 10% H2-containing Ar-H2 mixed gas, the heating rate is 5℃ / min, the calcination temperature is 600℃, and the heat preservation time is 8h.

[0021] The specific steps of sintering densification in step four are: put the internal oxidation reduced tungsten block into a sintering mold, add the mechanical alloying copper powder treated by hydrogen atmosphere reduction on the surface of the tungsten block with rough porous structure, use carbon paper to isolate the mold wall and the powder, and place it in a discharge plasma sintering furnace, and vacuumize the sintering furnace; set the initial pressure to 10MPa, start sintering, heat from room temperature to 600℃ and keep for 5min; then heat to 900℃ and keep for 5min, manually pressurize to a sintering pressure of 50MPa during the heating process, and the heating rate is 100℃ / min; after heat preservation, cool down with the furnace, take out the product, polish the surface carbon paper with a grinding machine, and finally obtain the tungsten-copper connecting material with improved tungsten-copper interface bonding state.

[0022] The raw materials used in the application are tungsten blocks, Cu2O and CuO, which are respectively subjected to hydrogen reduction after internal oxidation treatment and mechanical alloying of copper powder, and then subjected to discharge plasma sintering densification to obtain tungsten-copper connecting materials with improved tungsten-copper interface bonding state. The prepared tungsten-copper connecting materials can be applied in nuclear fusion reactors as composite modules. Compared with the prior art, the application has the beneficial effects of:

[0023] 1. The internal oxidation process can effectively form a high-activity nano-porous structure on the metal surface, improve the surface roughness and enhance the surface free energy, effectively inhibit crack propagation, change the tensile fracture mode from brittle fracture to ductile fracture, and improve the toughness of the material connection interface. At the same time, the influence of the solder and metal alloy layer introduced by the traditional brazing and chemical vapor deposition method on the interface compatibility of tungsten-copper, the uniformity of heterogeneous elements and the stability under radiation conditions can be effectively avoided. The internal oxidation process is simple and easy to produce, avoids the high cost and low efficiency of traditional anodic oxidation and laser surface treatment, and can quickly obtain a porous structure.

[0024] 2. As an effective surface modification technology, the internal oxidation process can control the thickness of the surface oxide layer and the density of the pores by changing the oxygen concentration, temperature and internal oxidation time during the internal oxidation process to regulate the surface roughness, which is easy to control and suitable for large-scale production and has economic value.

[0025] 3. Surface treatment technology has become an effective solution by designing the surface structure to change the bonding state between W and Cu without introducing additional interlayers or auxiliary phases at the interface, which is suitable for different sizes of thick and thin parts. At the same time, internal oxidation surface treatment avoids the damage risk caused by the influence of heterogeneous elements in the intermediate layer on the uniformity of the microstructure in traditional mechanical surface treatment methods such as grinding and sandblasting.

[0026] 4. The hydrogen reduction process can avoid the influence of impurity phases during the tungsten-copper connection process, does not introduce other impurity elements, maintains the high purity of the matrix, and as much as possible reduces the influence on the performance of the matrix.

[0027] 5. The discharge plasma sintering significantly shortens the processing time, the precise control of sintering parameters allows fine-tuning of the microstructure at the interface, optimization of mechanical and thermal properties, rapid heating and cooling cycles can allow the processing temperature to be reduced, reduce the risk of thermal damage and maintain the integrity of the microstructure, and the use of single-axis pressure and pulse direct current induced rapid heating to improve the bonding quality, resulting in dense and uniform bonding with minimal porosity and defects, thereby obtaining excellent bonding strength. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The process flow chart of the tungsten-copper connecting material with improved interface bonding state.

[0029] Figure 2 SEM image of the surface of the tungsten copper connecting material for improving the interface bonding state of Example 1 of the present application.

[0030] Figure 3 SEM image of the surface of the tungsten copper connecting material for improving the interface bonding state of Example 1 of the present application.

[0031] Figure 4 EDS spectrum of the connecting interface of the tungsten copper connecting material for improving the interface bonding state of Example 1 of the present application.

[0032] Figure 5 SEM image of the fracture of the connecting interface of the tungsten copper connecting material for improving the interface bonding state of Example 1 of the present application.

[0033] Figure 6 Comparison chart of mechanical properties of the tungsten copper connecting material for improving the interface bonding state of Example 1 and Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0034] Reference should be made to Figure 1 As shown in the drawings, the present application proposes a method for improving the tungsten copper connecting interface based on internal oxidation and hydrogen reduction process, the tungsten block is put into a tube furnace, an oxide (Cu2O or CuO) is added on the surface or an oxygen atmosphere is used for internal oxidation treatment at high temperature, a nano-oxide porous structure is generated on the surface, the surface roughness is increased; then hydrogen atmosphere is used for reduction to remove the surface oxide impurities, the surface pores are reserved, finally the tungsten block after surface treatment is combined with the mechanical alloying prepared copper powder after hydrogen atmosphere reduction treatment to realize the effective combination between tungsten and copper by discharge plasma sintering.

[0035] The present application will be further described in detail below in combination with the embodiments and the drawings.

[0036] Example 1

[0037] The method for preparing the tungsten copper connecting material in this embodiment is as follows:

[0038] Step one, internal oxidation of the tungsten block:

[0039] The surface of the tungsten block is treated, the tungsten block is put into a tube furnace, Cu2O is added on the surface, the mass ratio of the added Cu2O to the tungsten block is 4:1. The temperature is gradually increased to 700℃, and the temperature is kept for 12h, then the surface added oxide is removed after taking out, and the surface oxidized tungsten block is obtained.

[0040] Step two, mechanical alloying for preparing copper powder:

[0041] The copper powder is put into a planetary ball mill, the parameters of the ball mill are set as 500r / min, the ball milling time is 24h, and the ball to material ratio is 7:3, and the mechanical alloying is taken out after the treatment.

[0042] Step three, hydrogen atmosphere reduction:

[0043] The obtained surface oxidized tungsten block and the copper powder prepared by mechanical alloying are placed in a tube furnace separately, the heating rate is adjusted to 5℃ / min, the calcination temperature is 600℃, the holding time is 8h, the hydrogen is passed to heat, and the reduced copper powder and the reduced tungsten block with rough surface and no impurity oxide are obtained after being taken out after a period of holding.

[0044] Step four, sintering densification of tungsten-copper connecting material:

[0045] The surface roughened reduced tungsten block and the reduced copper powder obtained in step three are subjected to spark plasma sintering, the inner-oxidized reduced tungsten block is loaded into a sintering mold, the mechanical alloying copper powder treated by hydrogen atmosphere reduction is added on the surface of the tungsten block with rough porous structure, the carbon paper is used to insulate the mold wall and the powder, and the spark plasma sintering furnace is used to place the above-mentioned materials, the sintering furnace is subjected to vacuum treatment, the initial pressure is set to 10MPa, the sintering is started, the temperature is increased from room temperature to 600℃ and is kept for 5min, then the temperature is increased to 900℃ and is kept for 5min, the pressure is manually increased to 50MPa during the temperature increasing process, and the temperature increasing rate is 100℃ / min; after the holding is finished, the product is taken out, the carbon paper on the surface is polished by a grinding machine, and finally the tungsten-copper connecting material with improved tungsten-copper interface bonding state prepared by the inner-oxidized reduction process is obtained.

[0046] Example 2

[0047] The method for preparing the tungsten-copper connecting material in this example is as follows:

[0048] Step one, inner oxidation of tungsten block:

[0049] The tungsten block is subjected to surface treatment, the tungsten block is placed in a tube furnace, CuO is added on the surface, the mass ratio of CuO to tungsten block is 4:1, the temperature is gradually increased to 700℃, the holding time is 12h, and the oxide added on the surface is removed after being taken out, thereby obtaining the surface oxidized tungsten block.

[0050] Step two, preparation of copper powder by mechanical alloying:

[0051] The copper powder is placed in a planetary ball mill, the parameters of the ball mill are set to 500r / min, the ball milling time is 24h, and the ball-to-material ratio is 7:3, and the copper powder is taken out after being subjected to mechanical alloying.

[0052] Step three, hydrogen atmosphere reduction:

[0053] The surface oxidized tungsten block obtained in step one and the copper powder obtained by mechanical alloying are placed in a tube furnace separately, the temperature increasing rate is adjusted to 5℃ / min, the calcination temperature is 600℃, the holding time is 8h, hydrogen is passed to increase the temperature, and the product is taken out after a holding time, to obtain reduced copper powder and reduced tungsten block with rough surface and no impurity oxide.

[0054] Step four, sintering densification of tungsten-copper connecting material:

[0055] The surface roughened reduced tungsten block obtained in step three and the reduced copper powder are subjected to spark plasma sintering, the inner-oxidized reduced tungsten block is placed in a sintering mold, mechanical alloying copper powder treated by reduction in hydrogen atmosphere is added on the surface of the tungsten block with rough porous structure, carbon paper is used to insulate the mold wall and the powder, and the product is placed in a spark plasma sintering furnace, which is vacuumized; the initial pressure is set to 10MPa, sintering is started, the temperature is increased from room temperature to 600℃ and held for 5min, then the temperature is increased to 900℃ and held for 5min, the pressure is manually increased to 50MPa during the temperature increasing process, and the temperature increasing rate is 100℃ / min; after the holding is finished, the product is taken out, the carbon paper on the surface is polished by a grinding machine, and finally the tungsten-copper connecting material with improved tungsten-copper interface bonding state by inner-oxidized reduction process is obtained.

[0056] Example 3

[0057] The method for preparing tungsten-copper connecting material in this example is as follows:

[0058] Step one, inner oxidation of tungsten block:

[0059] The tungsten block is subjected to surface treatment, and is placed in a tube furnace for inner oxidation treatment at high temperature in oxygen atmosphere. The temperature is gradually increased to 700℃ and held for 12h, and then the product is taken out and the surface added oxide is removed, to obtain the tungsten block after surface oxidation.

[0060] Step two, preparation of copper powder by mechanical alloying:

[0061] The copper powder is placed in a planetary ball mill, the parameters of the ball mill are set to 500r / min, the ball milling time is 24h, and the ball-to-material ratio is 7:3, and the product is taken out after mechanical alloying.

[0062] Step three, reduction in hydrogen atmosphere:

[0063] The surface oxidized tungsten block obtained and the copper powder obtained by mechanical alloying are placed in a tube furnace separately, the temperature increasing rate is adjusted to 5℃ / min, the calcination temperature is 600℃, the holding time is 8h, hydrogen is passed to increase the temperature, and the product is taken out after a holding time, to obtain reduced copper powder and reduced tungsten block with rough surface and no impurity oxide.

[0064] Step four, sintering densification of tungsten-copper connecting material:

[0065] The surface roughened reduced tungsten block and the reduced copper powder of step three are subjected to discharge plasma sintering, the tungsten block subjected to internal oxidation reduction is loaded into a sintering mold, the mechanically alloyed copper powder subjected to reduction treatment in a hydrogen atmosphere is added on the surface of the tungsten block where the rough porous structure exists, the mold wall is insulated from the powder by carbon paper, and the sintering furnace is placed in a discharge plasma sintering furnace and subjected to vacuum treatment; the initial pressure is set to 10 MPa, sintering is started, and the temperature is raised from room temperature to 600°C and kept for 5 min; the temperature is raised to 900°C and kept for 5 min, and the pressure is manually increased to 50 MPa during the temperature raising process, and the temperature raising rate is 100°C / min; after the temperature keeping is finished, the furnace is cooled down, the product is taken out, the carbon paper on the surface is polished by a grinding machine, and finally the tungsten-copper connecting material with improved interface bonding state by internal oxidation reduction process is obtained.

[0066] Comparative Example 1

[0067] The tungsten-copper connecting material prepared in the comparative example is prepared by taking a tungsten block as a raw material, and combining the copper powder subjected to mechanical alloying by discharge plasma sintering to realize the combination between tungsten and copper.

[0068] The method for preparing the tungsten-copper connecting material in the comparative example is as follows:

[0069] Step one, preparation of copper powder by mechanical alloying:

[0070] The copper powder is put into a planetary ball mill, the parameters of the ball mill are set to 500 r / min, the ball milling time is 24 h, and the ball-to-material ratio is 7:3, and the mechanically alloyed copper powder is taken out after the mechanical alloying.

[0071] Step two, reduction in a hydrogen atmosphere:

[0072] The copper powder obtained by mechanical alloying in step one is put into a tube furnace and separated from each other, the temperature raising rate is adjusted to 5°C / min, the calcination temperature is 600°C, the temperature keeping time is 8 h, hydrogen is passed to raise the temperature, and the reduced mechanically alloyed copper powder without impurities is taken out after a period of temperature keeping.

[0073] Step three, sintering and densification of the tungsten-copper connecting material:

[0074] Untreated tungsten blocks and mechanically alloyed copper powder reduced in step two were subjected to spark plasma sintering. The tungsten blocks were placed in a sintering mold, and mechanically alloyed copper powder that had been reduced in a hydrogen atmosphere was added to the surface of the tungsten blocks. The mold wall and the powder were isolated with carbon paper, and the mold was placed in a spark plasma sintering furnace. The sintering furnace was evacuated. The initial pressure was set to 10 MPa, and sintering was started. The temperature was increased from room temperature to 600°C and held for 5 minutes. The temperature was then increased to 900°C and held for 5 minutes. During the heating process, the pressure was manually increased to 50 MPa, and the heating rate was 100°C / min. After the holding period, the furnace was cooled, the product was removed, and the carbon paper on the surface was polished with a grinding wheel to finally obtain the untreated tungsten-copper bonding material.

[0075] Table 1. Relevant performance of tungsten-copper connecting materials prepared in the embodiments and comparative examples of the present invention.

[0076]

[0077] The performance differences between the examples and comparative examples in Table 1 show that the internal oxidation-reduction process can significantly increase the roughness of the bonding surface, improve the density of the bonding material, and improve the thermal properties to a certain extent. Furthermore, the comparison between the examples shows that different oxygen sources in the internal oxidation process bring different enhancement effects; overall, the Cu2O oxygen source used in Example 1 shows the best effect.

[0078] Depend on Figure 2 It can be seen that the inner oxide-reduction tungsten surface has a large roughness and porosity, providing good bonding pores.

[0079] Depend on Figure 3 It can be seen that the surface porous structure covers a depth of about 20μm, providing good space for copper infiltration.

[0080] Depend on Figure 4 It can be seen that the tungsten-copper interface has a clean interface and interdiffusion layers that are twisted together, which can provide good bonding strength.

[0081] Depend on Figure 5 It can be seen that the connection interface has dimples and pores where tungsten and copper permeate each other, indicating a certain degree of connectivity.

[0082] Depend on Figure 6 It can be seen that the internal oxidation-reduction process is different from the process that can significantly improve the bonding strength of the tungsten-copper interface.

[0083] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for improving tungsten copper joint interface based on internal oxidation and hydrogen reduction process, characterized in that, The tungsten block is placed in a tube furnace, and oxides are added to the surface for internal oxidation treatment at high temperature to generate a nano-oxide porous structure on the surface, increase the surface roughness, and then remove the surface oxide impurities by reduction in a hydrogen atmosphere to retain the surface pores, and finally the tungsten block after surface treatment is combined with copper powder prepared by mechanical alloying and reduction treatment in a hydrogen atmosphere through spark plasma sintering to realize effective combination between tungsten and copper; the method comprises the following steps: Step one, internal oxidation of the tungsten block: The tungsten block is placed in a tube furnace, and oxides are added to the surface, the oxides being Cu2O or CuO, the mass ratio of the added oxides to the tungsten block being 4:1; the temperature is raised to 650-800 ℃ and kept for 12 h, and then the surface-added oxides are removed to obtain the tungsten block after surface oxidation; Step two, preparation of copper powder by mechanical alloying: The copper powder is placed in a planetary ball mill, and mechanical alloying is performed for a period of time, and then the copper powder is taken out; Step three, reduction in a hydrogen atmosphere: The tungsten block after surface oxidation and the copper powder prepared by mechanical alloying are placed in a tube furnace and separated from each other, and calcination reduction is performed to obtain reduced copper powder and reduced tungsten block with rough surface and no impurity oxides; The calcination reduction parameters in the tube furnace are as follows: the atmosphere used is Ar-H2 mixed gas with H2 content of 10 %, the temperature rising rate is 5 ℃ / min, the calcination temperature is 600 ℃, and the holding time is 8 h; Step four, sintering densification of the tungsten-copper connecting material: The reduced tungsten block is loaded into a sintering mold, and reduced copper powder is added to the surface of the rough porous structure of the reduced tungsten block, and then spark plasma sintering is performed to finally obtain the tungsten-copper connecting material with improved tungsten-copper interface bonding state by internal oxidation and reduction process.

2. The method of claim 1, wherein, The parameters of the planetary ball mill in step two are as follows: the speed is 500 r / min, the ball milling time is 24 h, and the ball-to-material ratio is 7:

3.

3. The method of claim 1, wherein, The specific steps of sintering densification in step four are as follows: The reduced tungsten block is loaded into a sintering mold, and reduced copper powder is added to the surface of the rough porous structure of the reduced tungsten block, and then carbon paper is used to isolate the mold wall from the powder, and the assembly is placed in a spark plasma sintering furnace, and the furnace is vacuumized; the initial pressure is set to 10 MPa, and sintering is started, and the temperature is raised from room temperature to 600 ℃ and kept for 5 min; then the temperature is raised to 900 ℃ and kept for 5 min, and the pressure is manually increased to 50 MPa during the temperature rising process, and the temperature rising rate is 100 ℃ / min; after the holding time ends, the assembly is cooled in the furnace, and the product is taken out, and the carbon paper on the surface is polished by a grinding machine, and finally the tungsten-copper connecting material with improved tungsten-copper interface bonding state is obtained.

4. Application of the tungsten-copper connecting material prepared by the method of any one of claims 1-3 to a composite module in a nuclear fusion reactor.

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