Cu-w-te alloy powder metallurgy electric contact material and preparation method thereof

Abstract

The application relates to a Cu-W-Te alloy powder metallurgy electric contact material and a preparation method thereof. The Cu-W-Te alloy powder metallurgy electric contact material comprises the following raw materials in parts by weight: Cu powder 30-40 parts, porous Cu-Te alloy powder 45-55 parts, W powder 8-12 parts, Ti powder 0.8-1.2 parts and boron-antimony co-doped SiC powder 0.6-0.8 parts. The application is prepared by the porous Cu-Te alloy powder, the boron-antimony co-doped SiC powder, the W powder and the Ti powder, and the raw materials are matched with each other. The porous Cu-Te alloy powder is beneficial to forming a multi-phase composite structure of the material, the SiC powder is introduced into the Cu-W-Te melt by using Ti-SiC reaction wetting, boron and antimony are doped in the SiC powder, the electric contact material with excellent mechanical properties and high conductivity is prepared, and the preparation method of the electric contact material is simple and can be industrialized.

Description

Technical Field

[0001] This invention relates to the field of electrical contact materials and their preparation technology, specifically to a Cu-W-Te alloy powder metallurgy electrical contact material and its preparation method. Background Technology

[0002] In the field of power equipment and automation instrumentation, electrical contact materials, as key components, bear the important task of contacting and disconnecting load current, and their performance directly affects the reliable operation of switching devices. With the development of high-voltage transmission and transformation networks towards larger capacity and ultra-high voltage, higher requirements are placed on the performance of electrical contact materials. Traditional electrical contact materials, such as silver-based and copper-based materials, are no longer sufficient to meet the needs of modern power systems in terms of conductivity and mechanical strength.

[0003] In recent years, powder metallurgy technology has shown great potential in improving the overall performance of materials due to its ability to prepare composite materials with two-phase or multi-phase structures. For example, copper-tungsten (Cu-W) alloy electrical contact materials prepared by powder metallurgy have been widely used in the field of high-voltage electrical appliances due to their good resistance to arc erosion, resistance to welding, and high strength. However, traditional Cu-W alloy materials still need improvement in terms of electrical conductivity, thermal conductivity, and bonding strength.

[0004] To further improve the performance of electrical contact materials, researchers have begun exploring the introduction of other elements or compounds into Cu-W alloys to form composite materials with gradient compositions or specific microstructures. For example, patent document CN202310489763.6 discloses an AgMe / AgCu electrical contact material and its preparation method, which improves the material's hardness and arc erosion resistance by introducing high-melting-point metals (such as W, Mo, etc.) into the working layer, while introducing AgCu alloy into the welding layer to improve welding performance. However, this patent mainly focuses on Ag-based composite materials, with relatively little research on Cu-based composite materials.

[0005] Based on the above background, this invention proposes a Cu-W-Te alloy powder metallurgy electrical contact material. By introducing Cu-Te alloy powder, W powder, alumina, and other raw materials, the aim is to prepare an electrical contact material with high conductivity, high bonding strength, and excellent resistance to arc burn-off and fusion welding. This provides a higher-performance and more reliable electrical contact material for the fields of power equipment and automation instrumentation. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art by providing a Cu-W-Te alloy powder metallurgy electrical contact material and its preparation method.

[0007] The objective of this invention is achieved through the following technical solution: This invention provides a Cu-W-Te alloy powder metallurgy electrical contact material, the electrical contact material comprising the following raw materials in parts by weight: 30-40 parts Cu powder, 45-55 parts porous Cu-Te alloy powder, 8-12 parts W powder, 0.8-1.2 parts Ti powder, and 0.6-0.8 parts boron-antimony co-doped SiC powder.

[0008] In this invention, the microstructure and properties of the material can be significantly improved by introducing porous Cu-Te alloy powder, boron-antimony co-doped SiC powder, W powder, and Ti powder. Te, as an element with good electrical conductivity and thermal stability, can form a Cu-Te alloy with excellent properties when introduced into a copper-based alloy, significantly improving the conductivity of the electrical contact material. The addition of W powder gives the electrical contact material good resistance to arc erosion, resistance to welding, and high strength. Meanwhile, the wettability between SiC powder and molten copper is poor; even at high temperatures, the contact angle remains high, and the density of SiC is lower than that of molten copper, making effective interfacial bonding with the copper matrix difficult. This invention utilizes Ti-SiC reactive wetting to introduce SiC powder into the Cu-W-Te melt, preparing a Cu-W-Te alloy powder metallurgy electrical contact material with both excellent mechanical properties and high conductivity. Furthermore, doping SiC powder with boron and antimony can further improve the conductivity of the electrical contact material.

[0009] Furthermore, the preparation method of the porous Cu-Te alloy composite powder includes the following steps:

[0010] (1) Add foaming agent to Cu-Te alloy powder, stir evenly and sieve, then place it in an oven for heating and foaming. The foaming temperature is 60-200℃ and the foaming time is 30-60 minutes.

[0011] (2) Solid-state sintering of Cu-Te alloy powder after foaming in step (1) at a temperature of 400-600℃ for 30-120 minutes in a reducing or vacuum atmosphere. Fixed pores are formed inside the powder. The sintered powder is crushed and sieved to obtain porous Cu-Te alloy powder.

[0012] Furthermore, in step (1), the Cu-Te alloy powder contains 90-95 wt% Cu and the balance is Te.

[0013] Furthermore, in step (1), the powder wetted by the foaming agent is sieved through a 200-400 mesh screen; in step (2), the crushed powder after solid-phase sintering is sieved through a 150-350 mesh screen.

[0014] Furthermore, the foaming agent is at least one selected from ammonium bicarbonate, ammonium carbonate, ammonium bioxate, and ammonium oxalate.

[0015] Furthermore, the amount of foaming agent added is in a mass ratio of 1:300-700 to the Cu-Te alloy powder.

[0016] Furthermore, the preparation method of the Cu-Te alloy powder includes the following steps:

[0017] C1. Weigh out CuTe master alloy and electrolytic copper by weight. Under nitrogen protection, first place the electrolytic copper in a medium-frequency melting furnace and heat it to 1150-1200℃ to completely melt the electrolytic copper. Then add CuTe master alloy and heat it to 1300-1350℃ to completely melt the CuTe master alloy. Hold the temperature for 5-10 minutes.

[0018] C2. The molten metal obtained in step C1 is injected into an atomizing device and powdered by high-pressure water atomization. The water pressure is 4-8 MPa. Finally, the alloy powder is collected, dried, and screened to obtain Cu-Te alloy powder.

[0019] In this invention, Cu-Te alloy powder with low oxygen content, uniform particle size distribution, and good pressing performance can be obtained by high-pressure water atomization.

[0020] Furthermore, the preparation method of the boron-antimony co-doped SiC powder includes the following steps:

[0021] A1. Take B4C, SiO2, SiO2@Sb, C and PVA adhesive, mix them evenly, and press them into a cylindrical blank with a pressure of 3-8MPa;

[0022] A2. Place the cylindrical blank in a vacuum hot pressing sintering furnace and evacuate to 10°C. -5 -10 -3 Pa, then heat to 2000-2200℃ and hold for 1.5-2.5h to obtain boron-antimony co-doped SiC powder.

[0023] Furthermore, in step A1, the mass ratio of SiO2, C, B4C and SiO2@Sb is 110:108:120-130:45-55.

[0024] Furthermore, the PVA adhesive accounts for 6-10% of the total mass.

[0025] Furthermore, the preparation method of SiO2@Sb includes the following steps:

[0026] B1. Soak Sb powder in 3-8% dilute hydrochloric acid for 25-35 minutes, stir to remove the oxide layer on the surface of Sb powder, filter, rinse with deionized water until neutral, then ultrasonically clean with anhydrous ethanol for 8-12 minutes, and vacuum dry at 55-65℃ for 1-2 hours.

[0027] B2. Etch the Sb powder obtained in step B1 with hydrofluoric acid with a mass fraction of 0.1-0.5% at room temperature for 5-10 minutes. Immediately after etching, rinse with deionized water 6-10 times and vacuum dry at 75-85℃ for 1-2 hours to obtain activated Sb powder.

[0028] B3. Mix tetraethyl orthosilicate, anhydrous ethanol, and deionized water in a volume ratio of 2.8-3.2:5:1, and add a trace amount of nitric acid with a pH of 3-4 to catalyze hydrolysis to obtain silica sol.

[0029] B4. Add the activated Sb powder obtained in step B2 to the silica sol obtained in step B3, and ultrasonically stir for 25-35 minutes to make the silica sol uniformly coat the Sb surface. After filtration, calcine in an inert atmosphere at a temperature of 900-1100℃ for 1-3 hours to obtain SiO2@Sb.

[0030] In this invention, by slightly corroding the Sb surface with hydrofluoric acid in step B2, a micro-rough structure is formed on the Sb surface, and -OH is also introduced on the Sb surface, thereby improving the compatibility and bonding force between Sb powder and silica sol.

[0031] Furthermore, in step B1, the Sb powder particle size is 0.6-1.5 mm.

[0032] Furthermore, the thickness of the SiO2 coating layer is 200-400 nm.

[0033] In this invention, by modifying the surface of Sb powder to construct a SiO2 coating layer, the contact between Sb and oxygen is blocked, thus preventing Sb from volatilizing violently due to oxidation to form low-boiling-point oxides under ultra-high temperature conditions. At the same time, it can also improve its compatibility with SiO2, C and B4C.

[0034] Another objective of this invention is achieved through the following technical solution: the preparation method of the Cu-W-Te alloy powder metallurgy electrical contact material includes the following steps:

[0035] Step S1: Press the porous Cu-Te alloy composite powder into a Cu-Te skeleton, and spray Al-Zn-Si alloy powder onto the Cu-Te skeleton to obtain a pre-fabricated Cu-Te skeleton.

[0036] Step S2: Mix Cu powder, W powder, Ti powder and boron-antimony co-doped SiC powder according to the formula ratio;

[0037] Step S3: The mixed powder obtained in step S2 is loaded into a polyurethane soft sleeve, and the powder is pressed into an ingot using a cold isostatic press with a pressing pressure of 180-220 MPa.

[0038] Step S4: Place the ingot obtained in step S3 on the prefabricated Cu-Te skeleton obtained in step S1, and perform melting infiltration in a vacuum melting furnace. The melting infiltration temperature is 1200-1500℃ and the melting infiltration time is 100-140 minutes to obtain a composite metal material.

[0039] Step S5: Use a horizontal extruder to extrude the composite metal material obtained in step S3 into a strip for processing moving contacts, or into a round bar for processing stationary contacts. The extrusion temperature is 860~880 ℃, the extrusion force of the extruder is 0.8-1.2MN, and the extrusion speed is 5-10mm / s.

[0040] Step S6: Roll the extruded strip using a rolling mill, or draw the extruded bar using a straight drawing machine, and anneal it to obtain Cu-W-Te alloy powder metallurgy electrical contact material.

[0041] Furthermore, in step S1, the pressing pressure is 50 MPa, taking into account both the skeleton strength and the melting efficiency.

[0042] Furthermore, in step S1, Al-Zn-Si alloy powder is sprayed onto the Cu-Te skeleton using plasma spraying under an inert atmosphere. The thickness of the sprayed powder is 80-120 μm. The inert gas pressure in the spraying chamber is 0.105-0.11 MPa, and the inert gas is Ar. The plasma gas is pure Ar with a flow rate of 40-60 L / min. The plasma arc power is 18-32 kW. The powder feeding gas is pure Ar with a flow rate of 5-10 L / min. The powder feeding rate is 8-15 g / min, and the powder carrier gas pressure is 0.2-0.3 MPa.

[0043] In this invention, plasma spraying under an inert atmosphere can reduce the oxidation of Al, Zn, and Si, and low-power plasma spraying can avoid excessive temperature causing oxidation or deformation of the Cu-Te skeleton surface.

[0044] Furthermore, in step S1, the Al-Zn-Si alloy powder comprises 25-35 wt% Zn, 40-50 wt% Al-12Si master alloy, and the balance Al.

[0045] Furthermore, the preparation method of the Al-Zn-Si alloy powder includes the following steps:

[0046] D1. According to the formula ratio, take Zn, Al-12Si master alloy and Al, and melt them in an electric resistance furnace at a melting temperature of 750-850℃. First, add pure aluminum. After the pure aluminum is completely melted, skim off the surface oxide scale, then add pure zinc, followed by Al-12Si master alloy, and press the pure zinc completely into the alloy solution. After the alloy is completely melted, cool down, remove slag, hold at 660-760℃ for 10-20 minutes, and pour into a trapezoidal mold at room temperature to obtain the Al-Zn-Si alloy.

[0047] D2. The Al-Zn-Si alloy obtained in step B1 is crushed and sieved to obtain 80-120 mesh Al-Zn-Si alloy powder.

[0048] In this invention, the preparation process of the Cu-W-Te alloy powder metallurgy electrical contact material is simple, simplifying the production process. This method also boasts high production yield, a clean process, and is easily scalable. At high temperatures, Cu powder in the ingot melts and, under capillary force, penetrates into the pores of the Cu-Te skeleton formed by pressing porous Cu-Te alloy powder. Simultaneously, high-temperature phases such as W, Ti, and SiC are uniformly distributed in the Cu matrix, forming a multiphase composite structure. This structure integrates the advantages of each phase, thereby improving the overall performance of the electrical contact material. Spraying Al-Zn-Si alloy powder onto the Cu-Te skeleton allows Zn to act as a bridge between the Cu-Te skeleton and the ingot during the melting and infiltration process, due to the high solid solubility of Zn in Al and Cu. At the same time, Al enhances the mechanical properties of the electrical contact material, and Si improves its conductivity. This approach enhances the mechanical properties of the electrical contact material while minimizing its impact on conductivity, achieving a balance between enhanced mechanical properties and maintained conductivity, resulting in strong functionality.

[0049] Furthermore, in step S6, the annealing treatment specifically involves heating to 700-900℃ for annealing for 1-1.5 hours, cooling it, placing it in a phosphoric acid solution for ultrasonic treatment, and then cleaning and drying it to obtain the Cu-W-Te alloy powder metallurgy electrical contact material.

[0050] The beneficial effects of this invention are as follows:

[0051] (1) This invention introduces porous Cu-Te alloy powder, boron-antimony co-doped SiC powder, W powder and Ti powder. The raw materials are combined with each other. As an element with good electrical conductivity and thermal stability, the introduction of an appropriate amount of Te into the copper-based alloy can form a Cu-Te alloy with excellent performance, which can significantly improve the electrical conductivity of the electrical contact material. The addition of W powder can make the electrical contact material have good resistance to arc erosion, resistance to welding and high strength. At the same time, the SiC powder is introduced into the Cu-W-Te melt by Ti-SiC reaction wetting to prepare Cu-W-Te alloy powder metallurgy electrical contact material with both excellent mechanical properties and high electrical conductivity.

[0052] (2) In this invention, boron and antimony are doped into SiC powder, which can further improve the conductivity of electrical contact materials. Moreover, by modifying the surface of Sb powder to construct a SiO2 coating layer, the contact between Sb and oxygen is blocked, avoiding the violent volatilization of Sb due to oxidation to form low-boiling-point oxides under ultra-high temperature environment. At the same time, it can also improve its compatibility with SiO2, C and B4C.

[0053] (3) The preparation process of Cu-W-Te alloy powder metallurgy electrical contact material provided by the present invention is simple, the production process is simplified, and the production yield of this method is high, the process is clean, and it is easy to achieve large-scale production. Attached Figure Description

[0054] Figure 1 This is a SEM image of the Cu-W-Te alloy powder metallurgy electrical contact material from Example 2. Figure 2 The image shows a SEM image of the Cu-W-Te alloy powder metallurgy electrical contact material prepared in Example 2, with a pixel size of 10 μm. Figure 3 The image shows a SEM image of the Cu-W-Te alloy powder metallurgy electrical contact material prepared in Example 2, with a pixel size of 1 μm. Figure 4 The image shows a SEM image of the Cu-W-Te alloy powder metallurgy electrical contact material prepared in Example 2, with a pixel size of 2 μm. Figure 5 The Cu-W-Te alloy powder metallurgy electrical contact material prepared in Example 2 is different from... Figure 2 The SEM image at another location has a pixel size of 10 μm. Figure 6 The Cu-W-Te alloy powder metallurgy electrical contact material prepared in Example 2 is different from... Figure 2 The SEM image at another location has a pixel size of 1 μm. Figure 7 The image shown is the EDS surface scan analysis image corresponding to Comparative Example 2. Detailed Implementation

[0055] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention.

[0056] Example 1

[0057] This embodiment provides a Cu-W-Te alloy powder metallurgy electrical contact material, which comprises the following raw materials in parts by weight: 30 parts Cu powder, 45 parts porous Cu-Te alloy powder, 8 parts W powder, 0.8 parts Ti powder, and 0.6 parts boron-antimony co-doped SiC powder.

[0058] Furthermore, the preparation method of the porous Cu-Te alloy composite powder includes the following steps:

[0059] (1) Add foaming agent to Cu-Te alloy powder, stir evenly and sieve, then place it in an oven for heating and foaming. The foaming temperature is 150℃ and the foaming time is 40 minutes.

[0060] (2) The Cu-Te alloy powder foamed in step (1) is solid-state sintered at a temperature of 450°C for 60 minutes in a vacuum atmosphere. Fixed pores are formed inside the powder. The sintered powder is crushed and sieved to obtain porous Cu-Te alloy powder.

[0061] Furthermore, in step (1), the Cu-Te alloy powder contains 93 wt% Cu and the remainder is Te.

[0062] Furthermore, in step (1), the powder wetted by the foaming agent is sieved through a 400-mesh sieve; in step (2), the powder crushed after solid-phase sintering is sieved through a 300-mesh sieve.

[0063] Furthermore, the foaming agent is ammonium bicarbonate.

[0064] Furthermore, the amount of foaming agent added is in a mass ratio of 1:500 to the Cu-Te alloy powder.

[0065] Furthermore, the preparation method of the Cu-Te alloy powder includes the following steps:

[0066] C1. Weigh out CuTe master alloy and electrolytic copper by weight. Under the protection of nitrogen, first place the electrolytic copper in a medium-frequency melting furnace and heat it to 1180℃ to completely melt the electrolytic copper. Then add CuTe master alloy and heat it to 1325℃ to completely melt the CuTe master alloy. Hold the temperature for 8 minutes.

[0067] C2. The molten metal obtained in step C1 is injected into an atomizing device and powdered by high-pressure water atomization. The water pressure is 6 MPa. Finally, the alloy powder is collected, dried, and screened to obtain Cu-Te alloy powder.

[0068] Furthermore, the preparation method of the boron-antimony co-doped SiC powder includes the following steps:

[0069] A1. Take B4C, SiO2, SiO2@Sb, C and PVA adhesive, mix them evenly, and press them into a cylindrical blank with a pressure of 5MPa;

[0070] A2. Place the cylindrical blank in a vacuum hot pressing sintering furnace and evacuate to 10°C. -4 Pa, then heat to 2100℃ and hold for 2 hours to obtain boron-antimony co-doped SiC powder.

[0071] Furthermore, in step A1, the mass ratio of SiO2, C, B4C and SiO2@Sb is 110:108:125:50.

[0072] Furthermore, in the SiO2@Sb, the SiO2 coating layer has a thickness of 200 nm.

[0073] Furthermore, the PVA adhesive accounts for 8% of the total mass.

[0074] Furthermore, the preparation method of SiO2@Sb includes the following steps:

[0075] B1. Soak Sb powder in 5% dilute hydrochloric acid for 30 minutes, stir to remove the oxide layer on the surface of Sb powder, filter, rinse with deionized water until neutral, then ultrasonically clean with anhydrous ethanol for 10 minutes, and vacuum dry at 60℃ for 1.5 hours.

[0076] B2. Etch the Sb powder obtained in step B1 with 0.3% hydrofluoric acid at room temperature for 7 minutes. While forming a micro-rough structure on the Sb surface through slight etching, -OH is also introduced on the Sb surface. Immediately after etching, rinse with deionized water 8 times and vacuum dry at 80°C for 1.5 hours to obtain activated Sb powder.

[0077] B3. Mix tetraethyl orthosilicate, anhydrous ethanol, and deionized water in a volume ratio of 3:5:1, and add a trace amount of nitric acid with a pH of 3-4 to catalyze hydrolysis to obtain silica sol.

[0078] B4. Add the activated Sb powder obtained in step B2 to the silica sol obtained in step B3, and ultrasonically stir for 30 minutes to make the silica sol uniformly coat the Sb surface. After filtration, calcine at 1000℃ for 2 hours in an inert atmosphere to obtain SiO2@Sb.

[0079] Furthermore, in step B1, the Sb powder particle size is 1 mm.

[0080] This embodiment also provides a method for preparing the above-mentioned Cu-W-Te alloy powder metallurgy electrical contact material, including the following steps:

[0081] Step S1: Press the porous Cu-Te alloy composite powder into a Cu-Te skeleton, and spray Al-Zn-Si alloy powder onto the Cu-Te skeleton to obtain a pre-fabricated Cu-Te skeleton.

[0082] Step S2: Mix Cu powder, W powder, Ti powder and boron-antimony co-doped SiC powder according to the formula ratio;

[0083] Step S3: The mixed powder obtained in step S2 is loaded into a polyurethane soft sleeve, and the powder is pressed into an ingot using a cold isostatic press at a pressure of 200 MPa.

[0084] Step S4: Place the ingot obtained in step S3 on the prefabricated Cu-Te skeleton obtained in step S1, and perform melting infiltration in a vacuum melting furnace at a melting temperature of 1350℃ for 120 minutes to obtain a composite metal material.

[0085] Step S5: Use a horizontal extruder to extrude the composite metal material obtained in step S3 into a strip for processing moving contacts, or into a round bar for processing stationary contacts, wherein the extrusion temperature is 870 ℃, the extrusion force of the extruder is 1 MN, and the extrusion speed is 8 mm / s.

[0086] Step S6: Roll the extruded strip using a rolling mill, or draw the extruded bar using a straight drawing machine, and anneal it to obtain Cu-W-Te alloy powder metallurgy electrical contact material.

[0087] Furthermore, in step S1, the pressing pressure is 50 MPa.

[0088] Furthermore, in step S1, Al-Zn-Si alloy powder is sprayed onto the Cu-Te skeleton using plasma spraying under an inert atmosphere. The thickness of the spray is 100 μm. The inert gas pressure in the spraying chamber is 0.1 MPa, and the inert gas is Ar. The plasma gas is pure Ar with a flow rate of 50 L / min. The plasma arc power is 25 kW. The powder feeding gas is pure Ar with a flow rate of 8 L / min. The powder feeding rate is 12 g / min, and the powder carrier gas pressure is 0.2 MPa.

[0089] Furthermore, in step S1, the Al-Zn-Si alloy powder comprises 30 wt% Zn, 45 wt% Al-12Si master alloy, and the balance Al.

[0090] Furthermore, the preparation method of the Al-Zn-Si alloy powder includes the following steps:

[0091] D1. According to the formula ratio, take Zn, Al-12Si master alloy and Al, and melt them in an electric resistance furnace at a melting temperature of 760℃. First, add pure aluminum. After the pure aluminum is completely melted, skim off the surface oxide scale, then add pure zinc, followed by Al-12Si master alloy, and press the pure zinc completely into the alloy solution. After the alloy is completely melted, cool down, remove slag, hold at 750℃ for 15 minutes, and pour into a trapezoidal mold at room temperature to obtain the Al-Zn-Si alloy.

[0092] D2. The Al-Zn-Si alloy obtained in step B1 is crushed and sieved to obtain 100-mesh Al-Zn-Si alloy powder.

[0093] Furthermore, in step S6, the annealing process specifically involves heating to 800°C for annealing for 1 hour, cooling it, placing it in a phosphoric acid solution for ultrasonic treatment, and then cleaning and drying it to obtain the Cu-W-Te alloy powder metallurgy electrical contact material.

[0094] Example 2

[0095] Unlike Example 1, this example provides a Cu-W-Te alloy powder metallurgy electrical contact material, which comprises the following raw materials in parts by weight: 35 parts Cu powder, 50 parts porous Cu-Te alloy powder, 10 parts W powder, 1 part Ti powder, and 0.7 parts boron-antimony co-doped SiC powder.

[0096] Furthermore, the preparation method of the boron-antimony co-doped SiC powder includes the following steps:

[0097] A1. Take B4C, SiO2, SiO2@Sb, C and PVA adhesive, mix them evenly, and press them into a cylindrical blank with a pressure of 5MPa;

[0098] A2. Place the cylindrical blank in a vacuum hot pressing sintering furnace and evacuate to 10°C. -4 Pa, then heat to 2100℃ and hold for 2 hours to obtain boron-antimony co-doped SiC powder.

[0099] This embodiment also provides a method for preparing the above-mentioned Cu-W-Te alloy powder metallurgy electrical contact material, including the following steps:

[0100] Step S1: Press the porous Cu-Te alloy composite powder into a Cu-Te skeleton, and spray Al-Zn-Si alloy powder onto the Cu-Te skeleton to obtain a pre-fabricated Cu-Te skeleton.

[0101] Step S2: Mix Cu powder, W powder, Ti powder and boron-antimony co-doped SiC powder according to the formula ratio;

[0102] Step S3: The mixed powder obtained in step S2 is loaded into a polyurethane soft sleeve, and the powder is pressed into an ingot using a cold isostatic press at a pressure of 200 MPa.

[0103] Step S4: Place the ingot obtained in step S3 on the prefabricated Cu-Te skeleton obtained in step S1, and perform melting infiltration in a vacuum melting furnace at a melting temperature of 1350℃ for 120 minutes to obtain a composite metal material.

[0104] Step S5: Use a horizontal extruder to extrude the composite metal material obtained in step S3 into a strip for processing moving contacts, or into a round bar for processing stationary contacts, wherein the extrusion temperature is 870 ℃, the extrusion force of the extruder is 1 MN, and the extrusion speed is 8 mm / s.

[0105] Step S6: Roll the extruded strip using a rolling mill, or draw the extruded bar using a straight drawing machine, and anneal it to obtain Cu-W-Te alloy powder metallurgy electrical contact material.

[0106] Example 3

[0107] Unlike Example 1, this example provides a Cu-W-Te alloy powder metallurgy electrical contact material, which comprises the following raw materials in parts by weight: 40 parts Cu powder, 55 parts porous Cu-Te alloy powder, 12 parts W powder, 1.2 parts Ti powder, and 0.8 parts boron-antimony co-doped SiC powder.

[0108] Furthermore, the preparation method of the boron-antimony co-doped SiC powder includes the following steps:

[0109] A1. Take B4C, SiO2, SiO2@Sb, C and PVA adhesive, mix them evenly, and press them into a cylindrical blank with a pressure of 5MPa;

[0110] A2. Place the cylindrical blank in a vacuum hot pressing sintering furnace and evacuate to 10°C. -4 Pa, then heat to 2100℃ and hold for 2 hours to obtain boron-antimony co-doped SiC powder.

[0111] This embodiment also provides a method for preparing the above-mentioned Cu-W-Te alloy powder metallurgy electrical contact material, including the following steps:

[0112] Step S1: Press the porous Cu-Te alloy composite powder into a Cu-Te skeleton, and spray Al-Zn-Si alloy powder onto the Cu-Te skeleton to obtain a pre-fabricated Cu-Te skeleton.

[0113] Step S2: Mix Cu powder, W powder, Ti powder and boron-antimony co-doped SiC powder according to the formula ratio;

[0114] Step S3: The mixed powder obtained in step S2 is loaded into a polyurethane soft sleeve, and the powder is pressed into an ingot using a cold isostatic press at a pressure of 200 MPa.

[0115] Step S4: Place the ingot obtained in step S3 on the prefabricated Cu-Te skeleton obtained in step S1, and perform melting infiltration in a vacuum melting furnace at a melting temperature of 1350℃ for 120 minutes to obtain a composite metal material.

[0116] Step S5: Use a horizontal extruder to extrude the composite metal material obtained in step S3 into a strip for processing moving contacts, or into a round bar for processing stationary contacts, wherein the extrusion temperature is 870 ℃, the extrusion force of the extruder is 1 MN, and the extrusion speed is 8 mm / s.

[0117] Step S6: Roll the extruded strip using a rolling mill, or draw the extruded bar using a straight drawing machine, and anneal it to obtain Cu-W-Te alloy powder metallurgy electrical contact material.

[0118] Comparative Example 1

[0119] The difference between this comparative example and Example 2 is that Cu-Te alloy powder is used instead of porous Cu-Te alloy powder. That is, this comparative example provides a Cu-W-Te alloy powder metallurgy electrical contact material core, which includes the following raw materials in parts by weight: 35 parts Cu powder, 50 parts Cu-Te alloy powder, 10 parts W powder, 1 part Ti powder, and 0.7 parts boron-antimony co-doped SiC powder.

[0120] This comparative example also provides a method for preparing the above-mentioned Cu-W-Te alloy powder metallurgy electrical contact material, including the following steps:

[0121] Step S1: Press Cu-Te alloy powder into Cu-Te blocks, and spray Al-Zn-Si alloy powder onto the Cu-Te blocks to obtain prefabricated Cu-Te blocks;

[0122] Step S2: Mix Cu powder, W powder, Ti powder and boron-antimony co-doped SiC powder according to the formula ratio;

[0123] Step S3: The mixed powder obtained in step S2 is loaded into a polyurethane soft sleeve, and the powder is pressed into an ingot using a cold isostatic press at a pressure of 200 MPa.

[0124] Step S4: Place a pre-made Cu-Te block on the pre-made Cu-Te skeleton obtained in step S1, and perform melting infiltration in a vacuum melting furnace at a melting temperature of 1350℃ for 120 minutes to obtain a composite metal material.

[0125] Step S5: Use a horizontal extruder to extrude the composite metal material obtained in step S3 into a strip for processing moving contacts, or into a round bar for processing stationary contacts, wherein the extrusion temperature is 870 ℃, the extrusion force of the extruder is 1 MN, and the extrusion speed is 8 mm / s.

[0126] Step S6: Roll the extruded strip using a rolling mill, or draw the extruded bar using a straight drawing machine, and anneal it to obtain Cu-W-Te alloy powder metallurgy electrical contact material.

[0127] The rest of the contents of this comparative example are the same as those of Example 2, and will not be repeated here.

[0128] Comparative Example 2

[0129] The difference between this comparative example and Example 2 is that this comparative example provides a Cu-W-Te alloy powder metallurgy electrical contact material, which includes the following raw materials in parts by weight: 52 parts Cu powder, 45 parts Cu-Te alloy powder, 8 parts W powder, 1.2 parts alumina, 1 part Ti powder, and 0.7 parts SiC powder; wherein, the SiC powder is boron-antimony co-doped SiC powder, and the antimony surface is not coated with a SiO2 coating layer.

[0130] Furthermore, the preparation method of the boron-antimony co-doped SiC powder includes the following steps:

[0131] A1. Take B4C, SiO2, Sb, C and PVA adhesive, mix them evenly, and press them into a cylindrical blank with a pressure of 5MPa;

[0132] A2. Place the cylindrical blank in a vacuum hot pressing sintering furnace and evacuate to 10°C. -4 Pa, then heat to 2100℃ and hold for 2 hours to obtain boron-antimony co-doped SiC powder.

[0133] Furthermore, in step A1, the mass ratio of SiO2, C, B4C and Sb is 110:108:125:50.

[0134] Furthermore, the PVA adhesive accounts for 8% of the total mass.

[0135] The rest of the contents of this comparative example are the same as those of Example 2, and will not be repeated here.

[0136] Comparative Example 3

[0137] The difference between this comparative example and Example 2 is that Al powder is used instead of Al-Zn-Si alloy powder. This comparative example provides a method for preparing Cu-W-Te alloy powder metallurgy electrical contact material, comprising the following steps:

[0138] Step S1: Press the porous Cu-Te alloy composite powder into a Cu-Te skeleton, and spray Al powder onto the Cu-Te skeleton to obtain a prefabricated Cu-Te skeleton;

[0139] Step S2: Mix Cu powder, W powder, Ti powder and boron-antimony co-doped SiC powder according to the formula ratio;

[0140] Step S3: The mixed powder obtained in step S2 is loaded into a polyurethane soft sleeve, and the powder is pressed into an ingot using a cold isostatic press at a pressure of 200 MPa.

[0141] Step S4: Place the ingot obtained in step S3 on the prefabricated Cu-Te skeleton obtained in step S1, and perform melting infiltration in a vacuum melting furnace at a melting temperature of 1350℃ for 120 minutes to obtain a composite metal material.

[0142] Step S5: Use a horizontal extruder to extrude the composite metal material obtained in step S3 into a strip for processing moving contacts, or into a round bar for processing stationary contacts, wherein the extrusion temperature is 870 ℃, the extrusion force of the extruder is 1 MN, and the extrusion speed is 8 mm / s.

[0143] Step S6: Roll the extruded strip using a rolling mill, or draw the extruded bar using a straight drawing machine, and anneal it to obtain Cu-W-Te alloy powder metallurgy electrical contact material.

[0144] The rest of the contents of this comparative example are the same as those of Example 2, and will not be repeated here.

[0145] Performance testing

[0146] The performance of the Cu-W-Te alloy powder metallurgy electrical contact materials prepared in Examples 1-3 and Comparative Examples 1-3 was tested. Vickers hardness was tested using an HVS-1000 digital display microhardness tester, with a load of 9.8 N and a holding time of 15 seconds. The conductivity of the samples was tested using an MP30 digital portable eddy current conductivity meter. The tensile strength of the high-strength conductive copper alloy was tested at room temperature using a WDW3200 micro-controlled electronic universal testing machine, with a tensile speed set to 1 mm / min.

[0147] Group Hardness (HV) Electrical conductivity (%IACS) Tensile strength (MPa) Example 1 95 59.5 645.2 Example 2 101 57.1 660.8 Example 3 109 53.9 678.9 Comparative Example 1 102 49.3 667.7 Comparative Example 2 100 54.2 658.3 Comparative Example 3 104 57.8 644.6

[0148] This invention utilizes the interaction of Cu powder, porous Cu-Te alloy powder, W powder, Ti powder, and boron-antimony co-doped SiC powder to prepare Cu-W-Te alloy powder metallurgy electrical contact materials that possess both excellent mechanical properties and high electrical conductivity.

[0149] The specific embodiments described above are further illustrations of the technical solution and beneficial effects of the present invention, and are not intended to limit the implementation methods. For those skilled in the art, any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A Cu-W-Te alloy powder metallurgy electrical contact material, characterized in that: The electrical contact material comprises the following raw materials in parts by weight: 30-40 parts Cu powder, 45-55 parts porous Cu-Te alloy powder, 8-12 parts W powder, 0.8-1.2 parts Ti powder, and 0.6-0.8 parts boron-antimony co-doped SiC powder.

2. The Cu-W-Te alloy powder metallurgy electrical contact material according to claim 1, characterized in that: The preparation method of the porous Cu-Te alloy composite powder includes the following steps: (1) Add foaming agent to Cu-Te alloy powder, stir evenly and sieve, then place it in an oven for heating and foaming. The foaming temperature is 60-200℃ and the foaming time is 30-60 minutes. (2) Solid-state sintering of Cu-Te alloy powder after foaming in step (1) at a temperature of 400-600℃ for 30-120 minutes in a reducing or vacuum atmosphere. Fixed pores are formed inside the powder. The sintered powder is crushed and sieved to obtain porous Cu-Te alloy powder.

3. The Cu-W-Te alloy powder metallurgy electrical contact material according to claim 2, characterized in that: In step (1), the Cu-Te alloy powder contains 90-95 wt% Cu and the balance is Te.

4. The Cu-W-Te alloy powder metallurgy electrical contact material according to claim 1, characterized in that: The foaming agent is at least one of ammonium bicarbonate, ammonium carbonate, ammonium bioxate, and ammonium oxalate.

5. The Cu-W-Te alloy powder metallurgy electrical contact material according to claim 4, characterized in that: In step (1), the powder wetted by the foaming agent is sieved through a 200-400 mesh screen; in step (2), the crushed powder after solid-phase sintering is sieved through a 150-350 mesh screen.

6. The Cu-W-Te alloy powder metallurgy electrical contact material according to claim 3, characterized in that: The preparation method of the boron-antimony co-doped SiC powder includes the following steps: A1. Take B4C, SiO2, SiO2@Sb, C and PVA adhesive, mix them evenly, and press them into a cylindrical blank with a pressure of 3-8MPa; A2. Place the cylindrical blank in a vacuum hot pressing sintering furnace and evacuate to 10°C. -5 -10 -3 Pa, then heat to 2000-2200℃ and hold for 1.5-2.5h to obtain boron-antimony co-doped SiC powder.

7. The Cu-W-Te alloy powder metallurgy electrical contact material according to claim 6, characterized in that: In step A1, the mass ratio of SiO2, C, B4C and SiO2@Sb is 110:108:120-130:45-55.

8. The Cu-W-Te alloy powder metallurgy electrical contact material according to claim 6, characterized in that: In SiO2@Sb, the SiO2 coating layer has a thickness of 200-400 nm.

9. The preparation method of Cu-W-Te alloy powder metallurgy electrical contact material as described in claim 1, characterized in that: Includes the following steps: Step S1: Press the porous Cu-Te alloy composite powder into a Cu-Te skeleton, and spray Al-Zn-Si alloy powder onto the Cu-Te skeleton to obtain a pre-fabricated Cu-Te skeleton. Step S2: Mix Cu powder, W powder, Ti powder and boron-antimony co-doped SiC powder according to the formula ratio; Step S3: The mixed powder obtained in step S2 is loaded into a polyurethane soft sleeve, and the powder is pressed into an ingot using a cold isostatic press with a pressing pressure of 180-220 MPa. Step S4: Place the ingot obtained in step S3 on the prefabricated Cu-Te skeleton obtained in step S1, and perform melting infiltration in a vacuum melting furnace. The melting infiltration temperature is 1200-1500℃ and the melting infiltration time is 100-140 minutes to obtain a composite metal material. Step S5: Use a horizontal extruder to extrude the composite metal material obtained in step S3 into a strip for processing moving contacts, or into a round bar for processing stationary contacts. The extrusion temperature is 860~880 ℃, the extrusion force of the extruder is 0.8-1.2MN, and the extrusion speed is 5-10mm / s. Step S6: Roll the extruded strip using a rolling mill, or draw the extruded bar using a straight drawing machine, and anneal it to obtain Cu-W-Te alloy powder metallurgy electrical contact material.

10. The method for preparing Cu-W-Te alloy powder metallurgy electrical contact material according to claim 9, characterized in that: In step S1, the Al-Zn-Si alloy powder comprises 25-35 wt% Zn, 40-50 wt% Al-12Si master alloy, and the balance Al.

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