A copper-tungsten alloy and a process for producing the same

Abstract

The application belongs to the technical field of tungsten-copper alloy materials, and particularly relates to a copper-tungsten alloy and a preparation process thereof. After tungsten powder is dried and ball milled, plasma activation treatment is performed on the surface of the tungsten powder under ultrasonic vibration. Under the ultrasonic vibration, a copper plating layer is sputtered on the surface of the activated tungsten powder by using a magnetron sputtering method, so as to obtain copper-coated tungsten composite powder. The copper-coated tungsten composite powder and copper powder are uniformly mixed, vacuum hot-press sintering is performed, and a primary copper-tungsten alloy block is prepared. The primary copper-tungsten alloy block is subjected to semi-liquid sintering, and the copper-tungsten alloy is prepared. In the application, a layer of high-purity copper with a certain thickness is coated on the surface of the tungsten powder based on the magnetron sputtering method, which can effectively modify the copper-tungsten interface, significantly reduce impurity elements in the tungsten-copper alloy, improve the uniformity of the tungsten-copper alloy, and finally obtain a tungsten-copper alloy with uniform structure and high density.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tungsten-copper alloy materials, and relates to a copper-tungsten alloy and a preparation process thereof. BACKGROUND

[0002] The tungsten-copper alloy has high density, high strength, high ablation resistance and melting welding resistance, and good heat conduction and electrical conductivity and high-temperature performance, and is thus widely applied to various high-voltage circuit breaker core component electric contact materials, electric spark machining electrode materials and large heat flow device materials. As a typical pseudo-alloy, the tungsten-copper alloy, combined with the high melting point characteristics of tungsten, determines that the tungsten-copper alloy can only be prepared through special preparation technologies such as powder metallurgy. The preparation process generally involves two key links of powder preparation and powder forming.

[0003] The powder preparation is a key technical basis for obtaining the tungsten-copper alloy. Since the melting points of tungsten and copper are quite different, it is not feasible to prepare the tungsten-copper alloy powder through traditional alloy powder preparation technologies such as atomization. At present, the composite powder used for preparing the tungsten-copper alloy can be a mixed powder of tungsten and copper. The mixed powder is generally obtained through mechanical stirring methods such as a mixer or a ball mill, and the uniformity of the obtained mixed powder is poor, and the ball milling and mixing process often introduces some unnecessary impurities, which is extremely unfavorable for the heat conduction and other properties of the tungsten-copper alloy. The tungsten-copper alloy can also use some coated powders. The uniformity of the organization of the coated powder is generally significantly better than that of the mixed powder of tungsten and copper obtained through mechanical mixing, and the interface bonding effect of tungsten and copper in the obtained composite powder is better, which is extremely favorable for preparing high-performance tungsten-copper alloys.

[0004] At present, in view of the good micro-uniformity and good surface bonding effect of the coated composite powder, people have carried out more research on the preparation of the coated composite powder, and various methods have appeared. The currently widely used coating methods include chemical vapor deposition, precipitation method, sol-gel method, chemical plating method and the like. These methods all belong to the chemical method category. Generally, the chemical method introduces more carbon, oxygen atoms and iron and other metal impurities into the precipitated metal micro-nano particles, which weakens the purity of the tungsten-copper alloy prepared through the chemical coated powder and affects the uniformity of the organization. SUMMARY

[0005] In order to solve the above technical problems, the application provides a copper-tungsten alloy and a preparation process thereof, and the tungsten powder is plated with copper by a magnetron sputtering method under vacuum conditions to obtain high-activity copper-coated tungsten composite powder with uniform structure and high purity, and further vacuum hot-pressing sintering is adopted to obtain a copper-tungsten bulk alloy. The obtained alloy has less impurity elements, uniform structure and high density; meanwhile, since the copper layer coated by the magnetron sputtering is in a metastable state, the sintering time in the hot-pressing sintering process is short and the energy consumption is low. The application solves the problems of non-uniform structure and high impurity content of the copper-tungsten alloy prepared by the traditional method, and effectively reduces the sintering energy consumption.

[0006] The application is implemented by the following technical solutions.

[0007] The application provides a preparation process of a copper-tungsten alloy, which comprises the following steps:

[0008] After the tungsten powder is dried and ball milled, the surface of the tungsten powder is subjected to plasma activation treatment under ultrasonic vibration. Not only the residual impurities on the surface of the tungsten powder can be removed, but also the surface energy of the tungsten powder can be increased, so that the tungsten powder can be better combined with the plated metal and the combination is stronger.

[0009] Under ultrasonic vibration, a copper plating layer is sputtered on the surface of the activated tungsten powder particles by a magnetron sputtering method until the thickness of the copper plating layer is 0.2-20 μm, and copper-coated tungsten composite powder is obtained. After the tungsten powder particles are activated, the increase of the surface energy enables the tungsten powder to form a firm chemical bond with copper; the tungsten powder is in a continuous vibration state during the plating process, and the plating rate is controlled, so that a uniform plating layer is formed on each surface of the particles, which lays an important foundation for the uniformity of the tungsten-copper bulk alloy; since the target materials used in the magnetron sputtering are all high-purity (99.99%), and the sputtering process is completely completed under high vacuum conditions, the copper-coated tungsten composite powder obtained has high purity, and the existence of impurities in the particles is avoided.

[0010] The copper-coated tungsten composite powder and pure copper powder are uniformly mixed and subjected to vacuum hot-pressing sintering to prepare a primary copper-tungsten alloy bulk.

[0011] The primary copper-tungsten alloy bulk is subjected to semi-liquid sintering, and during the semi-liquid sintering process, part of the pure copper is melted, and the molten liquid copper is filled into the micro-nano holes existing in the primary copper-tungsten alloy bulk to prepare a copper-tungsten alloy. During the hot-pressing process, there are some small gaps in the copper-coated tungsten powder particles, and the existence of these gaps leads to the existence of part of the holes in the hot-pressing sintered bulk, which is an inevitable phenomenon of the traditional sintering technologies including vacuum hot-pressing sintering, plasma rapid sintering and high-pressure sintering. On the basis of the hot-pressing sintering, the molten liquid copper effectively fills the micro-nano holes existing in the hot-pressing sintered primary blank through semi-liquid sintering (i.e. partial melting of pure copper under sintering temperature conditions), which is beneficial to improving the combination effect and the density of the sintered structure.

[0012] In the preferred embodiment of the present application, the plasma activation treatment is carried out by using a continuous magnetron sputtering coating device, and the platform is vibrated during the treatment, and the specific parameters are as follows: the protective atmosphere is Ar, the working pressure is 0.5 Pa to 1.0 Pa, the treatment time is 5 min to 30 min, the temperature is room temperature, the power is 200 W to 600 W, and the bias voltage is 80 V to 200 V.

[0013] In the preferred embodiment of the present application, the magnetron sputtering is carried out by using a continuous magnetron sputtering coating device, and the platform is vibrated during the deposition, and the parameters are as follows: the working atmosphere is Ar, the working pressure is 0.2 Pa to 0.6 Pa, the magnetron sputtering power is 800 W to 1200 W, the sputtering time is 50 min to 120 min, and the vacuum chamber heating temperature is 40 DEG C to 80 DEG C.

[0014] In the preferred embodiment of the present application, the mass ratio of the copper-coated tungsten composite powder and the pure copper powder is 0.26 to 0.75:1.

[0015] In the preferred embodiment of the present application, when the vacuum hot-pressing sintering is carried out, the vacuum degree is 1*10 -3 Pa, the sintering pressure is 20 MPa to 60 MPa, the temperature is 850 DEG C to 950 DEG C, the holding time is 20 min to 60 min, and the cooling mode is furnace cooling.

[0016] In the preferred embodiment of the present application, when the semi-liquid sintering is carried out, the vacuum degree is 1*10 -3 Pa, the sintering pressure is 20 MPa to 60 MPa, the temperature is 1085 DEG C to 1200 DEG C, the holding time is 20 min to 60 min, and the cooling mode is furnace cooling.

[0017] In the preferred embodiment of the present application, after the semi-liquid sintering, the mass ratio of the copper-tungsten powder to the pure copper in the copper-tungsten alloy is 0.16 to 0.55:1.

[0018] In the preferred embodiment of the present application, the particle size of the tungsten powder is 1 to 8 microns, and the tungsten powder is dried and ball-milled for 0.5 h. The purity of the copper target and the copper powder used for the magnetron sputtering is all greater than or equal to 99.99%.

[0019] The present application also provides a copper-tungsten alloy prepared by the above preparation process.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] In the present application, the tungsten powder is coated with copper by the magnetron sputtering method under vacuum conditions, and a high-activity copper-coated tungsten composite powder with uniform structure and high purity is obtained, and then vacuum hot-pressing sintering and semi-liquid sintering are carried out to obtain a copper-tungsten alloy. The copper-tungsten alloy prepared by the present application has high purity and uniform structure, and the specific mechanism is that:

[0022] The tungsten powder particles are subjected to plasma activation treatment before coating, which not only removes the residual impurities on the surface of the tungsten powder, but also increases the surface energy of the tungsten powder, so that the tungsten powder can be better combined with the plated metal, and the combination is stronger; in the environment of ultrasonic vibration, copper is plated by using a magnetron sputtering method, which is different from the mechanical paste of the metal layer on the surface of the tungsten powder obtained by electroplating; after the tungsten powder particles are activated, the increase of the surface energy makes the tungsten powder and copper form a firm chemical bond; the tungsten powder is in a continuous vibration state during the plating process, and the plating rate is controlled, so that the plating layer is uniform on each surface of the particle, which lays an important foundation for the uniformity of the tungsten-copper bulk alloy; since the target material used in the magnetron sputtering is high-purity (99.99%), and the sputtering process is completely completed under high vacuum conditions, the purity of the copper-coated tungsten composite powder is high, and the existence of impurities in the particle is avoided.

[0023] During the hot pressing process of the copper-coated tungsten powder particles, some small gaps inevitably exist, which leads to the existence of some pores in the hot-pressed sintered block, which is an unavoidable phenomenon in traditional sintering technologies including vacuum hot pressing sintering, plasma rapid sintering, high-pressure sintering, etc. On the basis of hot pressing sintering, the present application is sintered in a semi-liquid state (i.e. partial melting of pure copper under sintering temperature conditions), and the micro-nano pores existing in the hot-pressed sintered primary blank are effectively filled with molten liquid copper, which is beneficial to improve the bonding effect and density of the sintered structure. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 In the figure, (a) is a cross-sectional picture of the copper-coated tungsten composite powder obtained in step 1 of Example 1, (b) and (c) are EDS energy spectrum element distribution maps of the copper-coated tungsten composite powder, wherein (b) is the tungsten element, and (c) is the copper element.

[0025] Figure 2 The SEM picture of the initial copper-tungsten alloy block obtained in step 2 of Example 1.

[0026] Figure 3 The SEM picture of the copper-tungsten alloy obtained in step 3 of Example 1.

[0027] Figure 4 The SEM picture of the copper-tungsten alloy obtained in Comparative Example 1.

[0028] Figure 5 The metallographic picture of the copper-tungsten alloy obtained in Comparative Example 1.

[0029] Figure 6 The metallographic picture of the copper-tungsten alloy obtained in step 3 of Example 1.

[0030] Figure 7 The grain size picture of the copper-tungsten alloy obtained in step 3 of Example 1.

[0031] Figure 8 Copper-tungsten alloy grain size map obtained for Comparative Example 1. DETAILED DESCRIPTION

[0032] In order for those skilled in the art to better understand the technical solutions of the present application and implement them, the present application will be further described below in conjunction with specific examples and drawings, but the examples are not intended to limit the present application. The experimental methods and detection methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials described are all commercially available unless otherwise specified.

[0033] Example 1

[0034] A preparation process of a copper-tungsten alloy, comprising the following steps:

[0035] Step 1, preparation of copper-coated tungsten composite powder

[0036] 1) Disperse tungsten powder into the cavity of an oven device, the particle size of the tungsten powder is 1 μm-8 μm, dry the tungsten powder at 100 °C for 0.5 h and then ball mill for 0.5 h before copper plating by magnetron sputtering, so as to fully disperse the agglomerated tungsten powder.

[0037] 2) Use a continuous magnetron sputtering film deposition device to evenly lay the tungsten powder particles obtained in step 1) on a heating platform and then place the platform on a conveyor belt, keep the platform vibrating during the deposition process, and adjust the parameters to perform plasma activation treatment on the tungsten powder particles; the specific parameters are: room temperature, Ar as the working atmosphere, 0.8 Pa as the working gas pressure, 10 min as the cleaning time, 400 W as the power, and 100 V as the bias voltage.

[0038] 3) Use the same device and adjust the magnetron sputtering parameters to sputter a copper layer on the surface of the activated tungsten powder; the specific magnetron sputtering parameters are: Ar as the working atmosphere, 0.6 Pa as the working gas pressure, 1000 W as the magnetron sputtering power, 50 min as the sputtering time, and 50 °C as the heating temperature of the vacuum chamber, to obtain copper-coated tungsten composite powder. The thickness of the copper plating layer is distributed in the range of 0.2 μm-1.1 μm. The post-treatment process after magnetron sputtering plating is: vacuum drying-vacuum packaging.

[0039] Step 2, vacuum hot-pressing sintering

[0040] Pour the copper-coated tungsten composite powder and high-purity copper powder into a Φ30 graphite mold, and the ratio of the two powders is about 0.75:1. Then place it into a vacuum hot-pressing sintering furnace, vacuumize and pressurize, start sintering when the vacuum degree is lower than 10 Pa, the sintering pressure is 50 MPa, the temperature is 850 °C, the holding time is 20 min, the vacuum degree is 1×10 -3 Pa, and the cooling mode is furnace cooling, to obtain a primary copper-tungsten alloy block.

[0041] Step 3, semi-liquid sintering

[0042] 5) Put the initial copper-tungsten alloy block into a Φ50 graphite mold, start sintering when the vacuum degree is lower than 10 Pa, the sintering pressure is 50 MPa, the temperature is 1085°C, the holding time is 20 min, the vacuum degree is 1x10 -3 Pa, the cooling mode is furnace cooling, and the copper-tungsten alloy is prepared.

[0043] Example 2

[0044] A preparation process of a copper-tungsten alloy, comprising the following steps:

[0045] Step 1, preparation of copper-coated tungsten composite powder

[0046] 1) Disperse tungsten powder into the cavity of an oven device, the particle size of the tungsten powder is 1-8 μm, dry the tungsten powder at 100°C for 0.5 h and then ball mill for 0.5 h before copper plating by magnetron sputtering, so that the agglomerated tungsten powder is fully dispersed.

[0047] 2) Use a continuous magnetron sputtering film deposition device to evenly lay the tungsten powder particles obtained in step 1) on a heating platform, then place the platform on a conveyor belt, keep the platform vibrating during the deposition process, and adjust the parameters to perform plasma activation treatment on the tungsten powder particles; the specific parameters are: room temperature, Ar as the working atmosphere, 0.8 Pa as the working pressure, 10 min as the cleaning time, 400 W as the power, and 100 V as the bias voltage.

[0048] 3) Use the same device and adjust the magnetron sputtering parameters to sputter a copper layer on the surface of the activated tungsten powder; the specific magnetron sputtering parameters are: Ar as the working atmosphere, 0.6 Pa as the working pressure, 1000 W as the magnetron sputtering power, 80 min as the sputtering time, and 50°C as the vacuum chamber heating temperature, to obtain copper-coated tungsten composite powder. The thickness of the copper plating layer is distributed in the range of 7-8 μm. The post-treatment process after magnetron sputtering plating is vacuum drying-vacuum packaging.

[0049] Step 2, vacuum hot-pressing sintering

[0050] Pour the copper-coated tungsten composite powder and high-purity copper powder into a Φ30 graphite mold, and the ratio of the two powders is about 0.7:1. Then put it into a vacuum hot-pressing sintering furnace to vacuumize and pressurize, start sintering when the vacuum degree is lower than 10 Pa, the sintering pressure is 60 MPa, the temperature is 950°C, the holding time is 30 min, the vacuum degree is 1x10 -3 Pa, and the cooling mode is furnace cooling, to prepare an initial copper-tungsten alloy block.

[0051] Step 3, semi-liquid sintering

[0052] 5) Put the initial copper-tungsten alloy block into a Φ50 graphite mold, start sintering when the vacuum degree is lower than 10 Pa, the sintering pressure is 50 MPa, the temperature is 1085°C, the holding time is 20 min, the vacuum degree is 1*10 -3 Pa, the cooling mode is furnace cooling, and the copper-tungsten alloy is prepared.

[0053] Example 3

[0054] A preparation process of a copper-tungsten alloy, comprising the following steps:

[0055] Step 1, preparation of copper-coated tungsten composite powder

[0056] 1) Disperse tungsten powder into the cavity of an oven device, the particle size of the tungsten powder is 1-8 μm, dry the tungsten powder at 100°C for 0.5 h and then ball mill for 0.5 h before copper plating by magnetron sputtering, so that the agglomerated tungsten powder is fully dispersed.

[0057] 2) Use a continuous magnetron sputtering film deposition device, evenly lay the tungsten powder particles obtained in step 1) on a heating platform and then place the platform on a conveyor belt, keep the platform vibrating during the deposition process, and adjust the parameters to perform plasma activation treatment on the tungsten powder particles; the specific parameters are: room temperature, Ar as the working atmosphere, 0.8 Pa as the working pressure, 10 min as the cleaning time, 400 W as the power, and 100 V as the bias voltage.

[0058] 3) Use the same device, adjust the magnetron sputtering parameters, and sputter a copper layer on the surface of the activated tungsten powder; the specific magnetron sputtering parameters are: Ar as the working atmosphere, 0.6 Pa as the working pressure, 1000 W as the magnetron sputtering power, 110 min as the sputtering time, and 50°C as the vacuum chamber heating temperature, to obtain copper-coated tungsten composite powder. The thickness of the copper plating layer is distributed in the range of 18-19 μm. The post-treatment process after magnetron sputtering plating is vacuum drying-vacuum packaging.

[0059] Step 2, vacuum hot pressing sintering

[0060] Pour the copper-coated tungsten composite powder and high-purity copper powder into a Φ30 graphite mold, and the ratio of the two kinds of powders is about 0.7:1. Then put it into a vacuum hot pressing sintering furnace, vacuumize and pressurize, start sintering when the vacuum degree is lower than 10 Pa, the sintering pressure is 20 MPa, the temperature is 900°C, the holding time is 60 min, the vacuum degree is 1*10 -3 Pa, and the cooling mode is furnace cooling, to prepare an initial copper-tungsten alloy block.

[0061] Step 3, semi-liquid sintering

[0062] 5) Put the initial copper-tungsten alloy block into a Φ50 graphite mold, start sintering when the vacuum degree is lower than 10 Pa, the sintering pressure is 20 MPa, the temperature is 1200°C, the holding time is 20 min, the vacuum degree is 1x10 -3 Pa, and the cooling mode is furnace cooling to obtain the copper-tungsten alloy.

[0063] Example 4

[0064] A preparation process of a copper-tungsten alloy, comprising the following steps:

[0065] Step 1, preparation of copper-coated tungsten composite powder

[0066] 1) Disperse tungsten powder with a particle size of 1 μm~8 μm into the cavity of an oven device, dry the tungsten powder at 100°C for 0.5 h and then ball mill for 0.5 h before copper plating by magnetron sputtering, so that the agglomerated tungsten powder is fully dispersed.

[0067] 2) Use a continuous magnetron sputtering film deposition device to evenly lay the tungsten powder particles obtained in step 1) on a heating platform and then place the platform on a conveyor belt, keep the platform vibrating during the deposition process, and adjust the parameters to perform plasma activation treatment on the tungsten powder particles; the specific parameters are: room temperature, Ar as the working atmosphere, 0.5 Pa as the working pressure, 30 min as the cleaning time, 600 W as the power, and 80 V as the bias voltage.

[0068] 3) Use the same device and adjust the magnetron sputtering parameters to sputter a copper layer on the surface of the activated tungsten powder; the specific magnetron sputtering parameters are: Ar as the working atmosphere, 0.2 Pa as the working pressure, 800 W as the magnetron sputtering power, 110 min as the sputtering time, and 50°C as the vacuum chamber heating temperature to obtain the copper-coated tungsten composite powder. The thickness of the copper plating layer is distributed in the range of 19 μm~20 μm. The post-treatment process after magnetron sputtering plating is vacuum drying-vacuum packaging.

[0069] Step 2, vacuum hot-pressing sintering

[0070] Pour the copper-coated tungsten composite powder and high-purity copper powder into a Φ30 graphite mold, and the ratio of the two kinds of powders is about 0.7:1. Then put it into a vacuum hot-pressing sintering furnace to vacuumize and pressurize, start sintering when the vacuum degree is lower than 10 Pa, the sintering pressure is 50 MPa, the temperature is 850°C, the holding time is 20 min, the vacuum degree is 1x10 -3 Pa, and the cooling mode is furnace cooling to obtain the initial copper-tungsten alloy block.

[0071] Step 3, semi-liquid sintering

[0072] 5) Put the initial copper-tungsten alloy block into a Φ50 graphite mold, start sintering when the vacuum degree is lower than 10 Pa, the sintering pressure is 50 MPa, the temperature is 1100°C, the holding time is 20 min, the vacuum degree is 1*10 -3 Pa, the cooling mode is furnace cooling, and the copper-tungsten alloy is prepared.

[0073] Example 5

[0074] A preparation process of a copper-tungsten alloy, comprising the following steps:

[0075] Step 1, preparation of copper-coated tungsten composite powder

[0076] 1) Disperse tungsten powder with a particle size of 1 μm~8 μm into the cavity of an oven device, dry the tungsten powder at 100°C for 0.5 h, and then ball mill for 0.5 h before copper plating by magnetron sputtering, so that the agglomerated tungsten powder is fully dispersed.

[0077] 2) Use a continuous magnetron sputtering film deposition device to evenly lay the tungsten powder particles obtained in step 1) on a heating platform, then place the platform on a conveyor belt, keep the platform vibrating during the deposition process, and adjust the parameters to perform plasma activation treatment on the tungsten powder particles; the specific parameters are: room temperature, Ar as the working atmosphere, 1 Pa as the working gas pressure, 5 min as the cleaning time, 200 W as the power, and 200 V as the bias voltage.

[0078] 3) Use the same device and adjust the magnetron sputtering parameters to sputter a copper layer on the surface of the activated tungsten powder; the specific magnetron sputtering parameters are: Ar as the working atmosphere, 0.2 Pa as the working gas pressure, 1200 W as the magnetron sputtering power, 120 min as the sputtering time, and 50°C as the vacuum chamber heating temperature, to obtain copper-coated tungsten composite powder. The thickness of the copper plating layer is distributed in the range of 19 μm~20 μm. The post-treatment process after magnetron sputtering plating is vacuum drying-vacuum packaging.

[0079] Step 2, vacuum hot pressing sintering

[0080] Pour the copper-coated tungsten composite powder and high-purity copper powder into a Φ30 graphite mold, and the ratio of the two powders is about 0.7:1. Then put it into a vacuum hot pressing sintering furnace to vacuumize and pressurize, start sintering when the vacuum degree is lower than 10 Pa, the sintering pressure is 50 MPa, the temperature is 850°C, the holding time is 20 min, the vacuum degree is 1*10 -3 Pa, and the cooling mode is furnace cooling, to prepare an initial copper-tungsten alloy block.

[0081] Step 3, semi-liquid sintering

[0082] 5) Put the initial copper-tungsten alloy block into a Φ50 graphite mold, start sintering when the vacuum degree is lower than 10 Pa, the sintering pressure is 50 MPa, the temperature is 1085°C, the holding time is 20 min, the vacuum degree is 1x10 -3 Pa, the cooling mode is furnace cooling, and the copper-tungsten alloy is prepared.

[0083] Comparative Example 1

[0084] Compared with Example 1, one-step sintering is adopted, which specifically includes the following steps:

[0085] Step 1, preparation of copper-coated tungsten composite powder

[0086] 1) Disperse tungsten powder with a particle size of 1 μm to 8 μm into the cavity of an oven device, dry the tungsten powder at 100°C for 0.5 h, and then ball mill for 0.5 h before copper plating by magnetron sputtering, so that the agglomerated tungsten powder is fully dispersed.

[0087] 2) Use a continuous magnetron sputtering coating device to evenly lay the tungsten powder particles obtained in step 1) on a heating platform, then place the platform on a conveyor belt, keep the platform vibrating during the deposition process, and adjust the parameters to perform plasma activation treatment on the tungsten powder particles; the specific parameters are: temperature is room temperature, working atmosphere is Ar, working pressure is 0.8 Pa, cleaning time is 10 min, power is 400 W, and bias voltage is 100 V.

[0088] 3) Use the same device and adjust the magnetron sputtering parameters to sputter a copper layer on the surface of the activated tungsten powder; the magnetron sputtering parameters are as follows: working atmosphere is Ar, working pressure is 0.6 Pa, magnetron sputtering power is 1000 W, sputtering time is 50 min, and vacuum chamber heating temperature is 50°C, to obtain copper-coated tungsten composite powder. The thickness of the copper coating layer is distributed in the range of 0.2 μm to 1.1 μm. The post-treatment process after magnetron sputtering plating is vacuum drying-vacuum packaging.

[0089] Step 2, vacuum hot-pressing sintering

[0090] Pour the copper-coated tungsten composite powder and high-purity copper powder into a Φ30 graphite mold, and the ratio of the two powders is about 0.75:1. Then put it into a vacuum hot-pressing sintering furnace, vacuumize and pressurize, start sintering when the vacuum degree is lower than 10 Pa, the sintering pressure is 50 MPa, the temperature is 1085°C, the holding time is 20 min, the vacuum degree is 1x10 -3 Pa, and the cooling mode is furnace cooling, to prepare an initial copper-tungsten alloy block.

[0091] Figure 1In the figure, (a) is a cross-section picture of the copper-coated tungsten composite powder obtained in step 1 of Example 1, (b) and (c) are EDS energy spectrum element distribution pictures of the copper-coated tungsten composite powder, wherein (b) is tungsten element and (c) is copper element. It can be seen that the copper coating is uniformly plated on the surface of the tungsten powder, and only the composite powder with large particle size has part of tungsten exposed after grinding.

[0092] Figure 2 The SEM picture of the initial copper-tungsten alloy block obtained in step 2 of Example 1. It can be seen that the density is low, only some small particle powders and large particle powders form sintering necks, and the large particles are not completely fused.

[0093] Figure 3 The SEM picture of the copper-tungsten alloy obtained in step 3 of Example 1. Figure 4 The SEM picture of the copper-tungsten alloy obtained in Comparative Example 1. In Comparative Example 1, the alloy is rough and uneven, and the alloy organization in Example 1 is uniform.

[0094] Figure 5 The metallographic picture of the copper-tungsten alloy obtained in Comparative Example 1. Figure 6 The metallographic picture of the copper-tungsten alloy obtained in step 3 of Example 1. Compared with Comparative Example 1, Figure 6 the alloy is more dense. It is illustrated that the present application is firstly vacuum hot-pressed and sintered, and then semi-liquid sintered, which is beneficial to improve the density of the alloy.

[0095] Figure 7 The grain size picture of the copper-tungsten alloy obtained in step 3 of Example 1. Figure 8 The grain size picture of the copper-tungsten alloy obtained in Comparative Example 1. It can be seen that, compared with Comparative Example 1, the grain size distribution of the copper-tungsten alloy in Example 1 is more uniform, and the grain size is smaller, the grain size of the copper-tungsten alloy in Comparative Example 1 is dispersed, and the grain size is larger. It is illustrated that the alloy prepared by one-step sintering method is not beneficial to the refinement of the alloy grain. The remaining examples are similar to Example 1, and will not be repeated.

[0096] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application belong to the scope of the claims of the present application and their equivalent technologies, these modifications and variations are also intended to be included in the present application.

Claims

1. A process for the production of a copper-tungsten alloy, characterized in that, The method comprises the following steps: After the tungsten powder is dry-milled, the surface of the tungsten powder is subjected to plasma activation treatment under ultrasonic vibration; Under ultrasonic vibration, a copper coating is sputtered on the surface of the activated tungsten powder by using a magnetron sputtering method to obtain a copper-coated tungsten composite powder; the thickness of the copper coating sputtered by the magnetron sputtering method is 0.2 μm to 20 μm; The copper-coated tungsten composite powder and copper powder are uniformly mixed, vacuum hot-press sintering is performed, and a primary copper-tungsten alloy block is prepared; the mass ratio of the copper-coated tungsten composite powder to the copper powder is 0.26 to 0.75:1; The primary copper-tungsten alloy block is subjected to semi-liquid sintering, during which part of the copper is melted, and the molten liquid copper is filled into the micro-nano holes present in the primary copper-tungsten alloy block to obtain a copper-tungsten alloy; during the semi-liquid sintering, the sintering pressure is 20 MPa to 60 MPa, the temperature is 1085℃ to 1200℃, and the holding time is 20 min to 60 min under vacuum conditions.

2. The process for the production of a copper-tungsten alloy according to claim 1, characterized in that, The plasma activation treatment is performed by using a continuous magnetron sputtering coating equipment, and the platform is vibrated during the treatment; the specific parameters are as follows: the working atmosphere is Ar, the working pressure is 0.5 Pa to 1.0 Pa, the treatment time is 5 min to 30 min, the temperature is room temperature, the power is 200 W to 600 W, and the bias voltage is 80 V to 200 V.

3. The process for preparing a copper-tungsten alloy according to claim 1, characterized in that, The magnetron sputtering is performed by using a continuous magnetron sputtering coating equipment, and the platform is vibrated during the deposition; the parameters are as follows: the working atmosphere is Ar, the working pressure is 0.2 Pa to 0.6 Pa, the magnetron sputtering power is 800 W to 1200 W, the sputtering time is 50 min to 120 min, and the heating temperature of the vacuum chamber is 40℃ to 80℃.

4. The process for preparing a copper-tungsten alloy according to claim 1, characterized in that, During the vacuum hot-press sintering, the sintering pressure is 20 MPa to 60 MPa, the temperature is 850℃ to 950℃, and the holding time is 20 min to 60 min under vacuum conditions.

5. The process for preparing a copper-tungsten alloy according to claim 1, characterized in that, The particle size of the raw tungsten powder is 1 μm to 8 μm, the purity of the copper target used for the magnetron sputtering is ≥99.99%, and the purity of the copper powder is ≥99.99%.

6. A copper-tungsten alloy prepared by the preparation process according to any one of claims 1 to 5.

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