Preparation method of CuW contact with high electric-erosion resistance

Abstract

The application relates to the technical field of copper-tungsten contact, in particular to a preparation method of a CuW contact with high electric-erosion-resistance performance; the preparation method comprises the following steps: preparing a tungsten framework with a honeycomb structure unit, preparing a copper-tungsten composite base body through a post-sintering infiltration method, preparing a W-25Cu end cap, and preparing the CuW contact; the CuW contact is prepared through the composite W-25Cu end cap, a CuCr adhesive layer and the copper-tungsten composite base body; under large-current sintering, the CuCr adhesive layer can effectively improve the bonding strength of the W-25Cu end cap and the copper-tungsten composite base body, so that the contact end of the CuW contact not only has high conductivity and hardness, but also can make the position of the breakdown current change from the copper-rich area to the copper-tungsten interface, thereby improving the electric-erosion-resistance performance of the CuW contact.

Description

Technical Field

[0001] This invention relates to the field of copper-tungsten contact manufacturing technology, specifically to a method for manufacturing CuW contacts with high resistance to electro-ablation. Background Technology

[0002] Copper-tungsten alloys, which combine the high electrical and thermal conductivity of copper with the wear resistance and refractory properties of tungsten, are widely used in the fields of power and nuclear engineering, such as contact materials for high-voltage circuit breakers, arc-resistant electrodes, and divertors in nuclear reactors.

[0003] Traditional processes for manufacturing copper-tungsten contacts often result in a one-piece structure. Due to the difficulty in controlling this structure, the contact's hardness, conductivity, and resistance to electro-ablation cannot be simultaneously satisfied. To improve the conductivity of the copper-tungsten contact, the proportion of copper phase in the contact needs to be increased, but this leads to insufficient contact hardness. If the hardness is increased by increasing the proportion of tungsten phase in the copper-tungsten contact, the conductivity will be insufficient. If a one-piece contact with a uniform structure is prepared using a copper-tungsten composite alloy, the molten copper is difficult to prevent splashing out by the tungsten phase during electrical breakdown, thus reducing the contact's service life as the copper phase decreases. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for preparing CuW contacts with high resistance to electro-ablation. The CuW contacts are prepared by combining a W-25Cu end cap, a CuCr adhesive layer, and a copper-tungsten composite matrix. This method not only ensures high conductivity and hardness at the contact end of the CuW contacts but also shifts the location of the breakdown current from the copper-rich region to the copper-tungsten interface, thereby improving the resistance to electro-ablation of the CuW contacts.

[0005] The technical solution of the present invention is as follows:

[0006] S1. Prepare a tungsten framework with honeycomb structure units;

[0007] S1-1. Place pure tungsten spherical powder with a particle size range of 15-50μm in the feeding zone of the laser selective melting equipment;

[0008] S1-2. Input the laser selective melting parameters and preheat the substrate under a vacuum inert atmosphere;

[0009] The laser selective melting parameters are as follows: slice thickness: 25 μm, laser spot diameter: 90–100 μm, scanning power: 280–300 W, scanning speed: 430–450 mm / s, scanning interval: 55–60 μm, and inert gas flow rate: 3 m³ / s. 3 / h;

[0010] Note: Because laser selective melting technology can precisely control the irradiation position of the laser beam layer by layer, it allows for highly free shape design. Therefore, in this invention, it is possible to design a tungsten skeleton with honeycomb structure units. When the external force is perpendicular to the hexagonal surface of the honeycomb structure, the deformation of the tungsten skeleton is very small and the compressive strength is high. This makes the tungsten skeleton based on honeycomb structure units able to resist external impact when the contact is struck along the central axis.

[0011] S1-3. Laser printing of tungsten skeletons with honeycomb structure units according to the slice thickness. The tungsten skeletons are then ultrasonically acid-washed, alcohol-washed, and water-washed for later use.

[0012] S2. A copper-tungsten composite matrix was prepared by sintering and melting infiltration.

[0013] S3. Prepare W-25Cu end caps;

[0014] S3-1. W-25Cu composite microspheres with a particle size of 5-20 μm were prepared by in-situ synthesis. The W-25Cu composite microspheres were pressed into a second green body with a relative density of 45-78% by isobaric pressure of 200-550 MPa in a mold.

[0015] S3-2, The second green body prepared in S3-1 is fired into a W-25Cu end cap using the SPS method;

[0016] At a vacuum degree of 10 -3 Under the conditions of Pa, output voltage of 8-12V, output current of 9000-16000A, the temperature is increased to 1480℃ at a rate of 280-300℃ / s, held for 5-10 minutes, and then cooled to room temperature with the furnace.

[0017] Description: Rapid sintering (SPS) is a powder metallurgy process used for the efficient and rapid sintering of powder materials. This process achieves sintering by applying an electric current under high temperature and pressure. In the SPS process, the powder sample is placed between two electrodes, and a direct current or pulsed current is applied. The current passing through the sample generates a strong localized heating effect, causing the powder particles to rapidly sinter together, forming a dense, bulk material.

[0018] Compared to traditional sintering methods, SPS can complete the sintering process at relatively lower temperatures, thus reducing energy consumption and the risk of thermal corrosion of materials. Secondly, the SPS sintering process is very fast, typically taking only minutes to hours, while traditional sintering methods take much longer. Furthermore, SPS achieves a highly uniform temperature and stress distribution, helping to maintain the homogeneity and density of the material.

[0019] S4. The W-25Cu end cap, CuCr0.1 powder and copper-tungsten composite matrix are sintered into CuW contacts by high-temperature sintering.

[0020] Furthermore, the step in S2 to prepare the copper-tungsten composite matrix by sintering and melting is as follows:

[0021] S2-1. Measure the porosity of the tungsten framework in S1-3, and record it as... The mass M of copper powder is calculated using the following formula. Cu :

[0022]

[0023] In the formula, ρ Cu The density of Cu;

[0024] S2-2. The Cu powder weighed in S2-1 is pressurized at 180-200 MPa to obtain the first green body;

[0025] S2-3. The first green body in S2-2 is melt-infiltrated into the tungsten framework in S1-5 using the sintering melt-infiltration method to obtain a copper-tungsten composite matrix.

[0026] Explanation: Copper has excellent thermal conductivity. Infiltrating copper into a tungsten skeleton can effectively improve the overall thermal conductivity of the composite material. Copper infiltration can fill the pores of the tungsten skeleton, thus retaining the high strength of tungsten while introducing the high electrical conductivity and high thermal conductivity of copper, thereby increasing the overall strength, electrical conductivity, and high thermal conductivity of the material. Copper infiltration can fill and fix the structure of the tungsten skeleton, thereby improving the stability and durability of the contacts. In addition to the above advantages, infiltration is also a highly adaptable preparation method, especially suitable for the preparation of materials with complex skeleton structures.

[0027] Furthermore, the heating gradient of the sintering and melting infiltration method in S2-3 is as follows: under a reducing atmosphere and a pressure of 40 MPa, the temperature is increased to 1300℃ at a rate of 7-10℃ / min and held for 70-90 min; then the temperature is decreased to 1100℃ at a rate of 3-5℃ / min and held for 30-40 min; after the holding period, the temperature is cooled to room temperature with the furnace.

[0028] Note: By controlling the heating rate and holding time, the strength, conductivity, and thermal performance of the contacts can be controlled to meet different design requirements.

[0029] Furthermore, the steps for preparing W-25Cu composite microspheres by in-situ synthesis in S3-1 are as follows:

[0030] S3-1-1. Take 0.6 mol / L sodium tungstate solution and 0.6 mol / L copper nitrate solution;

[0031] S3-1-2. Add 25% ammonia and sodium tungstate dropwise to the copper nitrate solution until the pH of the mixed solution is 5.5; stir at 60-80 r / min for 1.5-2 h at room temperature.

[0032] S3-1-3. Place the mixed solution from S3-1-2 in a reaction vessel and heat it to 180°C at a heating rate of 16-20°C / min. Hold the temperature for 20-24 hours. After the holding period, cool the solution to room temperature with the furnace.

[0033] S3-1-4. Separate the precipitate from the solution in S3-1-3 and wash the precipitate until the pH of the mother liquor is 7. The obtained precipitate is dried at 100-120℃ for 8-10 hours, ground and sieved to obtain W-25Cu composite microspheres with a particle size of 5-20μm.

[0034] Note: The in-situ synthesis of W-25Cu composite microspheres mainly involves solid-phase diffusion and chemical vapor migration. Through the vapor migration of the volatile phase WO2(OH)2, the tungsten phase adheres to the surface of copper particles during reduction, resulting in heterogeneous nucleation and growth. This inhibits the aggregation and growth of the copper phase and improves the bonding interface between the tungsten and copper particles.

[0035] Furthermore, the step in S4 to prepare the CuW contact via high-temperature sintering is as follows:

[0036] S4-1, W-25Cu end cap from S3-2, CuCr0.1 powder and copper-tungsten composite matrix from S2-3 are sequentially pressed in a mold under isobaric pressure of 230-250MPa to obtain the third green compact;

[0037] S4-2. The third green blank in S4-1 is sintered at high temperature under a gradient temperature, and then aged under a protective atmosphere to obtain CuW contacts.

[0038] Explanation: Gradient sintering can effectively reduce thermal stress caused by temperature differences, help alleviate the thermal stress differences between different components, and improve adhesion; temperature gradient melting can cause the CuCr0.1 liquid to gradually increase in temperature during melting, and impregnate the W-25Cu end cap and copper-tungsten composite matrix in the form of CuCr adhesive layer, thereby improving the bonding strength between the two.

[0039] Solid-state aging can promote grain recrystallization and grain growth while inhibiting excessive grain growth. This results in more uniform grain size and finer grain boundaries in copper-tungsten alloys, thereby improving the material's strength and toughness.

[0040] Furthermore, the temperature gradient for high-temperature sintering described in S4-2 is: 6 × 10⁻⁶. -1Under a vacuum of Pa, the temperature is first raised from room temperature to 600℃ within 3–6 minutes and held for 10–15 minutes; then raised from 600℃ to 1000℃ within 10–15 minutes and held for 20–25 minutes; finally raised from 1000℃ to 1400℃ within 25–30 minutes and held for 3.5–4 hours.

[0041] The temperature gradient for aging treatment is as follows: first, hold at 1000℃ for 1 to 1.2 hours, then cool down to 500℃ and hold for 4 to 5 hours.

[0042] Note: By controlling the heating / cooling rate and holding time, the strength, conductivity, and thermal performance of the contacts can be controlled to meet different design requirements.

[0043] Compared with existing methods for preparing CuW contacts, the advantages of this invention are:

[0044] (1) The tungsten skeleton with honeycomb structure unit is designed in this invention. When the direction of external force is perpendicular to the hexagonal surface of the honeycomb structure, the deformation of the tungsten skeleton is very small, that is, the compressive strength is high. This makes the tungsten skeleton based on honeycomb structure unit able to effectively resist the external impact applied to the contact along the central axis.

[0045] (2) The CuW contact prepared by the present invention is composed of W-25Cu end cap, CuCr adhesive layer and copper-tungsten composite matrix. Under SPS high current sintering, CuCr adhesive layer can effectively improve the bonding strength between W-25Cu end cap and copper-tungsten composite matrix, so that the contact end of CuW contact not only has high conductivity and hardness, but also changes the location of breakdown current from copper-rich area to copper-tungsten interface, thereby improving the anti-electro-ablation performance of CuW contact. Attached Figure Description

[0046] Figure 1 This is a morphology image of the CuW contact prepared in Example 1 at 100x magnification;

[0047] Figure 2 This is a morphology image of the CuW contact prepared in Example 1 at 200x magnification;

[0048] Figure 3 This is a morphology image of the CuW contact prepared in Example 1 at 500x magnification. Detailed Implementation

[0049] To further illustrate the methods adopted and the effects achieved by the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0050] Example 1

[0051] Example 1 mainly illustrates the design of the present invention under specific parameters.

[0052] S1. Prepare a tungsten framework with honeycomb structure units;

[0053] S1-1. Place pure tungsten spherical powder with a particle size range of 15-50μm in the feeding zone of the laser selective melting equipment;

[0054] S1-2. Input the laser selective melting parameters and preheat the substrate under a vacuum inert atmosphere;

[0055] The parameters for laser selective melting are: slice thickness: 25 μm, laser spot diameter: 90 μm, scanning power: 280 W, scanning speed: 430 mm / s, scanning interval: 55 μm, and inert gas flow rate: 3 m³ / s. 3 / h;

[0056] S1-3. Laser printing of tungsten skeletons with honeycomb structure units according to the slice thickness. The tungsten skeletons are then ultrasonically acid-washed, alcohol-washed, and water-washed for later use.

[0057] S2. A copper-tungsten composite matrix was prepared by sintering and melting infiltration.

[0058] S2-1. Measure the porosity of the tungsten framework in S1-3, and record it as... The mass M of copper powder is calculated using the following formula. Cu : In the formula, ρ Cu The density of Cu;

[0059] S2-2. The Cu powder weighed in S2-1 is pressurized at 180MPa to obtain the first green body;

[0060] S2-3. The first green body in S2-2 is melt-infiltrated into the tungsten framework in S1-5 by sintering and melting infiltration method to obtain a copper-tungsten composite matrix.

[0061] The temperature gradient for the sintering and melting process is as follows: under a reducing atmosphere and a pressure of 40 MPa, the temperature is increased to 1300℃ at a rate of 7℃ / min and held for 70 min; then the temperature is decreased to 1100℃ at a rate of 3℃ / min and held for 30 min; after the holding period, the temperature is cooled to room temperature with the furnace.

[0062] S3. Prepare W-25Cu end caps;

[0063] S3-1. W-25Cu composite microspheres with a particle size of 5-20 μm were prepared by in-situ synthesis. The W-25Cu composite microspheres were then pressed into a second green body with a relative density of 45% by isobaric pressure at 200 MPa in a mold.

[0064] S3-1-1. Take 0.6 mol / L sodium tungstate solution and 0.6 mol / L copper nitrate solution;

[0065] S3-1-2. Add 25% ammonia and sodium tungstate dropwise to the copper nitrate solution until the pH of the mixed solution is 5.5; stir at 60 r / min for 2 h at room temperature.

[0066] S3-1-3. Place the mixed solution from S3-1-2 in a reactor and heat it to 180°C at a heating rate of 16°C / min. Hold the temperature for 20 hours. After the holding period, cool the solution to room temperature with the reactor.

[0067] S3-1-4. Separate the precipitate from the solution in S3-1-3 and wash the precipitate until the pH of the mother liquor is 7; dry the obtained precipitate at 100℃ for 8 hours, grind and sieve to obtain W-25Cu composite microspheres with a particle size of 5-20μm;

[0068] S3-2, The second green body prepared in S3-1 is fired into a W-25Cu end cap using the SPS method;

[0069] At a vacuum degree of 10 -3 Under the conditions of Pa, output voltage of 8V, and output current of 9000A, the temperature is increased to 1480℃ at a rate of 280℃ / s, held for 5 minutes, and then cooled to room temperature with the furnace.

[0070] S4. The W-25Cu end cap, CuCr0.1 powder and copper-tungsten composite matrix are sintered into CuW contacts by high-temperature sintering.

[0071] S4-1, W-25Cu end cap from S3-2, CuCr0.1 powder and copper-tungsten composite matrix from S2-3 are pressed in a mold under isobaric pressure of 230MPa to obtain the third green blank;

[0072] S4-2. The third green compact in S4-1 is sintered at high temperature under a gradient temperature, and then aged under a protective atmosphere to obtain CuW contacts. See [link to relevant documentation]. Figures 1-3 ;

[0073] The temperature gradient for the high-temperature sintering method is: 6 × 10⁻⁶ -1 Under a vacuum of Pa, the temperature was first raised from room temperature to 600°C within 3 minutes and held for 10 minutes; then raised from 600°C to 1000°C within 10 minutes and held for 20 minutes; finally, raised from 1000°C to 1400°C within 25 minutes and held for 3.5 hours.

[0074] The temperature gradient for aging treatment is as follows: first, hold at 1000℃ for 1 hour, then cool down to 500℃ and hold for 4 hours.

[0075] Example 2

[0076] The description of Example 2 is based on the scheme described in Example 1, and aims to illustrate the scheme design under another parameter.

[0077] S1. Prepare a tungsten framework with honeycomb structure units;

[0078] S1-1. Place pure tungsten spherical powder with a particle size range of 15-50μm in the feeding zone of the laser selective melting equipment;

[0079] S1-2. Input the laser selective melting parameters and preheat the substrate under a vacuum inert atmosphere;

[0080] The parameters for laser selective melting are: slice thickness: 25 μm, laser spot diameter: 100 μm, scanning power: 300 W, scanning speed: 450 mm / s, scanning interval: 60 μm, and inert gas flow rate: 3 m³ / s. 3 / h;

[0081] S1-3. Laser printing of tungsten skeletons with honeycomb structure units according to the slice thickness. The tungsten skeletons are then ultrasonically acid-washed, alcohol-washed, and water-washed for later use.

[0082] S2. A copper-tungsten composite matrix was prepared by sintering and melting infiltration.

[0083] S2-1. Measure the porosity of the tungsten framework in S1-3, and record it as... The mass M of copper powder is calculated using the following formula. Cu : In the formula, ρ Cu The density of Cu;

[0084] S2-2. The Cu powder weighed in S2-1 is pressurized at 200MPa to obtain the first green body;

[0085] S2-3. The first green body in S2-2 is melt-infiltrated into the tungsten framework in S1-5 by sintering and melting infiltration method to obtain a copper-tungsten composite matrix.

[0086] The temperature gradient for the sintering and melting process is as follows: under a reducing atmosphere and a pressure of 40 MPa, the temperature is increased to 1300℃ at a rate of 10℃ / min and held for 90 min; then the temperature is decreased to 1100℃ at a rate of 5℃ / min and held for 40 min; after the holding period, the temperature is cooled to room temperature with the furnace.

[0087] S3. Prepare W-25Cu end caps;

[0088] S3-1. W-25Cu composite microspheres with a particle size of 5-20 μm were prepared by in-situ synthesis. The W-25Cu composite microspheres were then pressed into a second green body with a relative density of 78% by isobaric pressure at 550 MPa in a mold.

[0089] S3-1-1. Take 0.6 mol / L sodium tungstate solution and 0.6 mol / L copper nitrate solution;

[0090] S3-1-2. Add 25% ammonia and sodium tungstate solution dropwise to copper nitrate solution until the pH of the mixed solution is 5.5; stir at 80 r / min for 1.5 h at room temperature.

[0091] S3-1-3. Place the mixed solution from S3-1-2 in a reaction vessel and heat it to 180°C at a heating rate of 20°C / min. Hold the temperature for 24 hours. After the holding period, cool the solution to room temperature with the furnace.

[0092] S3-1-4. Separate the precipitate from the solution in S3-1-3 and wash the precipitate until the pH of the mother liquor is 7; dry the obtained precipitate at 120℃ for 10h, grind and sieve to obtain W-25Cu composite microspheres with a particle size of 5-20μm;

[0093] S3-2, The second green body prepared in S3-1 is fired into a W-25Cu end cap using the SPS method;

[0094] At a vacuum degree of 10 -3 Under the conditions of Pa, output voltage of 12V, and output current of 16000A, the temperature is increased to 1480℃ at a rate of 300℃ / s, held for 10min, and then cooled to room temperature with the furnace.

[0095] S4. The W-25Cu end cap, CuCr0.1 powder and copper-tungsten composite matrix are sintered into CuW contacts by high-temperature sintering.

[0096] S4-1, W-25Cu end cap from S3-2, CuCr0.1 powder and copper-tungsten composite matrix from S2-3 are pressed in a mold under isobaric pressure of 250MPa to obtain the third green blank;

[0097] S4-2. The third green blank in S4-1 is sintered at high temperature under gradient temperature, and then aged under protective atmosphere to obtain CuW contact.

[0098] The temperature gradient for high-temperature sintering is: 6 × 10 -1 Under a vacuum of Pa, the temperature was first raised from room temperature to 600°C within 6 minutes and held for 15 minutes; then raised from 600°C to 1000°C within 15 minutes and held for 25 minutes; finally, raised from 1000°C to 1400°C within 30 minutes and held for 4 hours.

[0099] The temperature gradient for aging treatment is as follows: first, hold at 1000℃ for 1.2h, then cool down to 500℃ and hold for 5h.

[0100] Experimental Example

[0101] The description of this experimental example is based on the scheme described in Example 1, and aims to illustrate the practical application effect of the present invention.

[0102] 1. Experimental Design

[0103] To clarify the specific properties of the AgWC contact blank grease prepared in this invention, the following experimental group was designed:

[0104] Blank group: The existing CuW60 contacts are used as the blank group;

[0105] Control group 1: Except for the following, all other parts are the same as those in Example 1: CuCr0.1 material is used to replace the tungsten framework and copper phase to prepare the matrix;

[0106] Control group 2: Except for the following, the rest is the same as in Example 1: When preparing the third green body, no CuCr0.1 powder is added to the W-25Cu end cap and copper-tungsten composite matrix;

[0107] Control group 3: Except for the following, all other parts are the same as those in Example 1: the thickness of CuCr0.1 powder between the W-25Cu end cap and the copper-tungsten composite matrix is ​​0.3 mm;

[0108] Control group 4: Except for the following, all other parts are the same as those in Example 1: the thickness of CuCr0.1 powder between the W-25Cu end cap and the copper-tungsten composite matrix is ​​0.6 mm;

[0109] Control group 5: Except for the following, the rest is the same as in Example 1: the thickness of CuCr0.1 powder between the W-25Cu end cap and the copper-tungsten composite matrix is ​​0.9 mm.

[0110] 2. Relevant performance experiments

[0111] The effects of different experimental conditions on the performance of the contact were investigated, and the data are shown in Table 1.

[0112] Table 1 Experimental Data

[0113]

[0114] As can be seen from the data in Table 1, compared with the CuW60 contact in the blank group, the hardness of the contacts prepared in the control groups 3 to 5 of this invention is close to that of the CuW60 contact. Only the contact in control group 4 has a higher hardness than the CuW60 contact, but the conductivity of all of them is higher than that of the CuW60 contact. This is because the CuW60 contact is made of a uniform CuW60 alloy as a whole, with a high W content, which increases the hardness of the contact but results in a low conductivity.

[0115] Regarding resistance to electro-ablation, the initial current breakdown location of the contacts in the blank group and control groups 1-3 was in the copper-rich region, indicating that the copper phase melts and copper droplets splash during the electro-ablation process. This would greatly affect the service life of the contacts. In contrast, in control groups 3-5, because W-25Cu end caps were provided at the contact ends of the contacts, the current breakdown location occurred at the copper-tungsten interface. In this way, even if the copper phase melts, it will be blocked by the tungsten phase during the sputtering process, thereby reducing the amount of copper phase loss and improving the service life of the contacts.

[0116] Comparing control group 1 and blank group, it can be seen that the conductivity of the contacts prepared by W powder using the 3DP method is higher than that of CuW80 contacts, but the hardness is significantly reduced. This is because the binder content used in the powder metallurgy method is high, which leaves pores in the subsequent binder removal process, reducing the overall hardness of the contacts.

[0117] Comparing control group 2 and control group 1, it can be seen that using CuCr0.1 material to replace the tungsten skeleton and copper phase to prepare the matrix, although the overall conductivity of the contact is improved, the lack of tungsten skeleton support results in the contact hardness not meeting the standard.

[0118] Comparing control group 3 and control group 2, it can be seen that control group 3, due to the design of the CuCr adhesive layer, effectively improves the bonding strength between the W-25Cu end cap and the copper-tungsten composite substrate, thus improving the hardness and conductivity of the contact.

[0119] Comparing control groups 3, 4, and 5, it can be seen that as the thickness of the CuCr adhesive layer increases, the conductivity of the contact increases, while the hardness of the contact first increases and then decreases. It is speculated that this is because the excessively thick CuCr adhesive layer cannot fully penetrate into the W-25Cu end cap and copper-tungsten composite matrix during the subsequent melting and infiltration process, resulting in a decrease in the hardness of the contact.

Claims

1. A method for preparing a CuW contact with high resistance to electro-ablation, characterized in that, Including the following steps: S1. Prepare a tungsten framework with honeycomb structure units; S1-1. Place pure tungsten spherical powder with a particle size range of 15~50 μm in the feeding zone of the laser selective melting equipment; S1-2. Input the laser selective melting parameters and preheat the substrate under a vacuum inert atmosphere; The laser selective melting parameters are as follows: slice thickness: 25 μm, laser spot diameter: 90~100 μm, scanning power: 280~300 W, scanning speed: 430~450 mm / s, scanning interval: 55~60 μm, and inert gas flow rate: ; S1-3. A tungsten skeleton with honeycomb structure units is printed by laser according to the thickness of the slice. The tungsten skeleton is then ultrasonically acid-washed, alcohol-washed and water-washed for later use. S2. A copper-tungsten composite matrix was prepared by sintering and melting infiltration. S3. Prepare W-25Cu end caps; S3-1. W-25Cu composite microspheres with a particle size of 5~20 μm were prepared by in-situ synthesis. The W-25Cu composite microspheres were pressed into a second green body with a relative density of 45~78% by isobaric pressure of 200~550 MPa in a mold. S3-2, The second green body prepared in S3-1 is fired into a W-25Cu end cap using the SPS method; At a vacuum degree of Under the conditions of output voltage of 8~12 V and output current of 9000~16000 A, the temperature is raised to 1480 ℃ at a rate of 280~300℃ / s, held for 5~10 min, and then cooled to room temperature with the furnace. S4. The W-25Cu end cap, CuCr0.1 powder and copper-tungsten composite matrix are sintered into CuW contacts by high-temperature sintering.

2. The method for preparing a CuW contact with high resistance to electro-ablation as described in claim 1, characterized in that, The step in S2 to prepare the copper-tungsten composite matrix by sintering and melting infiltration is as follows: S2-1. Measure the porosity of the tungsten framework in S1-3, and record it as... The mass of copper powder weighed is calculated using the following formula. : in, Porosity is dimensionless; V is the volume of the tungsten framework. The density of Cu For the quality of copper powder; S2-2. The Cu powder weighed in S2-1 is pressurized at 180~200 MPa to obtain the first green body; S2-3. The first green body in S2-2 is melt-infiltrated into the tungsten framework in S1-3 using the sintering melt-infiltration method to obtain a copper-tungsten composite matrix.

3. The method for preparing a CuW contact with high resistance to electro-ablation as described in claim 2, characterized in that, The heating gradient of the sintering and melting infiltration method described in S2-3 is as follows: under a reducing atmosphere and a pressure of 40 MPa, the temperature is increased to 1300℃ at a rate of 7~10℃ / min and held for 70~90 min; then the temperature is decreased to 1100℃ at a rate of 3~5℃ / min and held for 30~40 min; after the holding period, the temperature is cooled to room temperature with the furnace.

4. The method for preparing a CuW contact with high resistance to electro-ablation as described in claim 1, characterized in that, The steps for preparing W-25Cu composite microspheres by in-situ synthesis in S3-1 are as follows: S3-1-1, Take a 0.6 mol / L sodium tungstate solution and a 0.6 mol / L copper nitrate solution; S3-1-2. Add 25% ammonia and sodium tungstate solution dropwise to copper nitrate solution until the pH of the mixed solution is 5.5; stir at 60-80 r / min for 1.5-2 h at room temperature. S3-1-3. Place the mixed solution from S3-1-2 in a reactor and heat it to 180°C at a heating rate of 16~20 ℃ / min. Hold the temperature for 20~24 h and then cool it to room temperature with the reactor after the holding period. S3-1-4: Separate the precipitate from the solution in S3-1-3 and wash the precipitate until the pH of the mother liquor is 7; dry the obtained precipitate at 100~120℃ for 8~10 h, grind and sieve to obtain W-25Cu composite microspheres with a particle size of 5~20 μm.

5. The method for preparing a CuW contact with high resistance to electro-ablation as described in claim 1, characterized in that, The step in S4 to prepare the CuW contact by high-temperature sintering is as follows: S4-1, W-25Cu end cap from S3-2, CuCr0.1 powder and copper-tungsten composite matrix from S2-3 are sequentially pressed in a mold under isobaric pressure of 230~250 MPa to obtain the third green blank; S4-2. The third green blank in S4-1 is sintered at high temperature under a gradient temperature, and then aged under a protective atmosphere to obtain CuW contacts.

6. The method for preparing a CuW contact with high resistance to electro-ablation as described in claim 5, characterized in that, The temperature gradient for high-temperature sintering described in S4-2 is: Under vacuum, the temperature is first raised from room temperature to 600℃ within 3-6 minutes and held for 10-15 minutes; then raised from 600℃ to 1000℃ within 10-15 minutes and held for 20-25 minutes; finally raised from 1000℃ to 1400℃ within 25-30 minutes and held for 3.5-4 hours. The temperature gradient of the aging treatment is as follows: first, it is kept at 1000℃ for 1~1.2 h, and then cooled to 500℃ and kept at 500℃ for 4~5 h.

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