Silver-based composite electrical contact material and method for producing the same

Abstract

The application discloses a silver-based composite electric contact material and a preparation method thereof, and belongs to the technical field of silver-based electric contact materials. The preparation of the silver-based composite electric contact material comprises the following steps: step 1, mixing silver powder, vanadium powder, Ti2SnC@C material and copper-plated carbon fibers to form a mixed powder; step 2, pressing the mixed powder to form a blank, and sintering the blank under an argon atmosphere, and then obtaining the silver-based composite electric contact material through extrusion or rolling. The Ti2SnC@C material is obtained by mixing a core-shell structure TiC@C material, titanium powder and tin powder and then high-temperature heat treatment. Different from traditional Ag / C materials, the Ti2SnC@C material prepared by the application can overcome the problem of poor wettability of graphite and a silver matrix, and under the condition of simultaneously adding vanadium powder, Ti2SnC@C material and copper-plated carbon fibers, a continuous conductive network can be formed, so that the silver-based composite electric contact material has high arc erosion resistance and high conductivity.

Description

Technical Field

[0001] This invention belongs to the field of silver-based electrical contact materials technology, specifically relating to a silver-based composite electrical contact material and its preparation method. Background Technology

[0002] Electrical contact materials are key structural-functional integrated materials that undertake the functions of circuit switching control, conductivity, and load bearing. Their performance directly affects the safety and stability of power systems and electrical equipment. Commonly used electrical contact materials are mainly composite materials with copper or silver as the matrix. The matrix is ​​responsible for electrical and thermal conductivity and plays a role in hardening, thereby improving the material's resistance to arc erosion. Compared with copper-based systems, silver-based electrical contact materials have advantages such as high electrical and thermal conductivity, better resistance to electrical abrasion and welding, and low and stable contact resistance, and are widely used in circuits and electrical appliances with different power load ranges.

[0003] With the rapid development of intelligentization and electrification, the operating environment of electrical equipment is becoming increasingly complex, placing higher demands on the performance of electrical contact materials. Especially under conditions of high voltage, high current, and high-frequency switching, the arc resistance of electrical contact materials is particularly important. Adding reinforcing phases to form silver-based composite electrical contact materials to actively and passively resist arc erosion has become an efficient strategy for improving the performance of silver-based electrical contact materials. However, when graphite is used as a reinforcing phase, it suffers from poor wettability with the silver matrix, which can disrupt the continuous conductive network of silver, leading to decreased conductivity and affecting the stable transmission of current. Summary of the Invention

[0004] This invention provides a silver-based composite electrical contact material and its preparation method, which can solve the problem of decreased conductivity in existing silver-based composite electrical contact materials.

[0005] The objective of this invention can be achieved through the following technical solutions: A method for preparing a silver-based composite electrical contact material includes the following steps: This invention also provides a method for preparing a silver-based composite electrical contact material, comprising the following steps: Step 1: Mix silver powder, vanadium powder, Ti2SnC@C material, and copper-plated carbon fiber to form a mixed powder; Step 2: Press the mixed powder to form a blank, sinter the blank in an argon atmosphere, and then extrude or roll it to obtain a silver-based composite electrical contact material. The Ti2SnC@C material is obtained by mixing core-shell structured TiC@C material, titanium powder, and tin powder, followed by high-temperature heat treatment.

[0006] To address the issue of reduced conductivity in Ag-C electrical contact materials due to poor wettability between carbon phase materials and Ag, this invention first forms a TiC layer in situ on the graphite surface to obtain a core-shell structured TiC@C material. Then, the core-shell structured TiC@C material, titanium powder, and tin powder are mixed and sintered to form a Ti2SnC@C material. The Ti2SnC layer exhibits good wettability with silver, and the Ti2SnC on the graphite surface acts as a transition layer, improving the interfacial bonding between the carbon phase material and silver. Ti2SnC combines the unique properties of ceramics and metals, possessing high strength, good thermal conductivity, and electrical conductivity. This endows the electrical contact material with better thermal and electrical conductivity, allowing the electric arc on the material surface to move rapidly and quickly dissipate heat, avoiding internal thermal stress caused by localized heat accumulation and subsequent deformation and crack propagation. Simultaneously, under excessive current, carbon will burn to generate CO gas, helping to reduce the erosion of the material by the electric arc energy. Adding Ti2SnC@C material to silver-based electrical contact materials imparts excellent resistance to arc ablation. However, during material preparation, Sn easily escapes from Ti2SnC and diffuses continuously into the Ag group under high temperature induction. During arc discharge, Ti2SnC gradually decomposes into TiCx and Sn. As the temperature rises, Ti2SnC is easily oxidized into titanium oxide and tin oxide. This decomposition process helps absorb arc energy, but the accumulation of titanium oxide will cause cracks and gaps on the surface of the contact interface, leading to the degradation of material performance. This invention simultaneously adds vanadium powder and copper-plated carbon fiber to the silver-based electrical contact material. Under sintering or arc action, V preferentially reacts with possible residual oxygen to generate vanadium oxide, or reacts with C to generate VC, inhibiting the formation of titanium oxide. Furthermore, the generated fine dispersed phase pins the grain boundaries, inhibiting the growth of Ag grains under high-temperature arc, and improving arc erosion resistance. Copper-plated carbon fiber improves the interfacial bonding effect of the fiber in the silver matrix through the surface copper layer, enabling the carbon fiber and Ag matrix to form a metallurgical bond, maintaining the overall conductive network. Moreover, the copper plating layer melts at high temperature to form molten Cu, which has a strong affinity for Sn, preventing the Sn diffusion from Ti2SnC into the matrix from accumulating. This avoids the increase in contact resistance caused by oxide accumulation and alleviates the resistance increase caused by Ti2SnC decomposition and tin diffusion. The silver-based composite electrical contact material of the present invention has both high resistance to arc erosion and high conductivity.

[0007] Furthermore, the vanadium powder is 0.1-0.5% of the mass of the silver powder.

[0008] Furthermore, the copper-plated carbon fiber comprises 0.3-0.8% of the silver powder by mass.

[0009] Furthermore, the Ti2SnC@C material comprises 1-3% of the mass of silver powder.

[0010] Furthermore, the sintering temperature is 900-1150℃, and the sintering time is 2-4 hours.

[0011] Furthermore, the preparation steps of the core-shell structured TiC@C material are as follows: S1. Mix titanium powder, graphite, sodium chloride and potassium chloride, add ethanol and stir to mix, filter and vacuum dry to form a mixed powder; S2. Under an argon atmosphere, the mixed powder is heated to 900-1000℃ and held for 2-3 hours; S3. After cooling, add water and stir to dissolve. Centrifuge to remove the supernatant and dry the precipitate to obtain the core-shell structured TiC@C material.

[0012] A molten salt synthesis method is used to react titanium powder with graphite, which forms a uniform and continuous TiC shell on the graphite surface, resulting in a core-shell structured TiC@C material.

[0013] Furthermore, the mass ratio of the titanium powder, sodium chloride, and potassium chloride is (0.4-0.8):4:3.

[0014] Furthermore, the mass ratio of titanium powder to graphite is 0.8-1.2:1. With low titanium powder content, some graphite surface remains exposed. As the titanium content gradually increases, the TiC shell on the carbon core surface gradually evolves from tiny nanocrystals to a large grain structure with higher crystallinity. However, the large grain structure of TiC formed by excessive titanium powder is prone to detachment, resulting in the inability to form a complete encapsulating shell.

[0015] Furthermore, the preparation steps of the Ti2SnC@C material are as follows: The core-shell structured TiC@C material, titanium powder, and tin powder were added to ethanol and ultrasonically dispersed, filtered, and vacuum dried to obtain a powder mixture. The powder mixture was cold-pressed to form a green body, heated to 950-1250℃ under vacuum conditions, held for 10-20 minutes, cooled to room temperature, and pulverized to obtain Ti2SnC@C material.

[0016] Furthermore, the mass ratio of the core-shell structure TiC@C material, titanium powder, and tin powder is (1.7-2.2):1:(2.0-2.5).

[0017] Furthermore, the preparation steps of the copper-plated carbon fiber are as follows: Step 1: Soak carbon fiber in acetone for degumming. After degumming, soak the carbon fiber in an ammonium superphosphate aqueous solution for roughening treatment. After roughening, wash the fiber with water until neutral and then dry it. Soak the washed carbon fiber in an activation solution for activation. After activation, soak the carbon fiber in a degumming solution and a reducing solution in sequence. After washing and drying, the pre-plating treatment is completed. Step 2: Place the pre-treated carbon fiber in the copper plating solution, heat and stir to perform copper plating. After copper plating is completed, remove it, wash it, and dry it to obtain copper-plated carbon fiber.

[0018] Furthermore, the copper plating solution comprises the following components: 5-15 g / L copper sulfate, 5-25 mL / L formaldehyde, 50 g / L potassium sodium tartrate, and sodium hydroxide to adjust the pH to 12.5-13.5.

[0019] The present invention also provides a silver-based composite electrical contact material, which is prepared by the preparation method described above.

[0020] The beneficial effects of this invention are: (1) Unlike traditional Ag-C electrical contact materials, the present invention incorporates copper-plated carbon fiber and Ti2SnC@C material, which exhibit far superior conductivity compared to graphite and can form a more continuous conductive network with lower interfacial resistance. Compared to the significant increase in resistance caused by graphite in traditional Ag / C materials, the conductivity of the material in the present invention decreases only slightly and imparts excellent resistance to arc erosion.

[0021] (2) This invention does not directly add Ti2SnC material, but only uses Ti2SnC as the shell of graphite. The designed and prepared Ti2SnC@C material overcomes the problem of poor wettability between graphite and silver matrix, and at the same time enables the electrical contact material to have the gasification arc extinguishing mechanism of graphite burning CO gas, the solid phase change arc extinguishing mechanism of Ti2SnC decomposing and absorbing energy, and the passive anti-arc mechanism of carbon material and Ti2SnC itself, thereby improving the anti-arc erosion ability of electrical contact material.

[0022] (3) In this invention, vanadium powder, Ti2SnC@C material, and copper-plated carbon fiber are simultaneously added to the silver matrix. Vanadium can stabilize the contact resistance and prevent the formation of a rough oxide layer after repeated interruptions of silver. At the same time, it can form stable VC bonds with carbon, improving the interfacial bonding force between the silver matrix and the reinforcing phase. The generated fine dispersed phase refines the silver grains. The copper plating layer of the copper-plated carbon fiber melts at high temperature to form molten Cu, which has a strong affinity for Sn. This can prevent the Sn diffusion from Ti2SnC into the matrix from accumulating, thereby avoiding the increase in contact resistance caused by oxide accumulation and alleviating the resistance increase caused by Ti2SnC decomposition and tin diffusion. By utilizing the interaction of the three, a continuous overall conductive network in the electrical contact material can be maintained, so that the silver-based composite electrical contact material of this invention has both high resistance to arc erosion and high conductivity, improving the stability and reliability of the electrical contact material and extending its service life. Attached Figure Description

[0023] Figure 1 This is a flowchart of the preparation process of the present invention. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1 Preparation of core-shell structured TiC@C materials: S1. Weigh titanium powder, sodium chloride, and potassium chloride in a mass ratio of 0.6:4:3. Weigh graphite in a mass ratio of titanium powder to graphite of 1.0:1. Mix the titanium powder, graphite, sodium chloride, and potassium chloride. Add ethanol with a solid content of 20% and stir until homogeneous. After filtration, vacuum dry at 70°C for 12 hours to form a mixed powder.

[0026] S2. Under an argon atmosphere, the mixed powder is heated to 950℃ and held at that temperature for 2.5 hours.

[0027] S3. After cooling, add water and stir to dissolve. Centrifuge to remove the supernatant. Repeat 5 times to remove residual chloride salts. The precipitate is vacuum dried at 70℃ for 12h to obtain core-shell structured TiC@C material.

[0028] Preparation of Ti2SnC@C materials: Weigh the core-shell structured TiC@C material, titanium powder, and tin powder prepared in this embodiment according to a mass ratio of 2.0:1:2.3. Add 5% solid content to ethanol and ultrasonically disperse for 20 min. After filtration, transfer to a vacuum drying oven and dry at 80°C for 8 h to obtain a powder mixture. Transfer the powder mixture to a mold and cold press it under 20 MPa pressure to form a green body. Heat to 1050°C under vacuum conditions, hold for 15 min, cool to room temperature, and pulverize to obtain Ti2SnC@C material.

[0029] Preparation of copper-plated carbon fiber: Step 1: Soak carbon fiber in acetone for 90 minutes to degumme. After degumming, soak the carbon fiber in 200 g / L ammonium superphosphate aqueous solution for 30 minutes to complete the roughening treatment. After roughening, wash the fiber with water until neutral and then air dry. Soak the washed carbon fiber in an activation solution (0.5 g / L palladium chloride, 50 g / L stannous chloride, and 30% hydrochloric acid solution) for 15 minutes to activate. After activation, soak the carbon fiber in a degumming solution (150 mL / L 98% concentrated sulfuric acid and 25 mL / L 37% concentrated hydrochloric acid) for 2 minutes, and then soak it in a reducing solution (10% hypochlorous acid solution) for 1 minute. After washing with water until neutral, vacuum dry at 80℃ for 24 hours to complete the pre-plating treatment.

[0030] Step 2: Place the pre-treated carbon fiber in a copper plating solution (10g / L copper sulfate, 15mL / L formaldehyde, 50g / L potassium sodium tartrate, and sodium hydroxide to adjust the pH to 12.5-13.5), heat to 50℃ and stir to perform copper plating for 7 minutes. After copper plating, remove the carbon fiber, wash it with water, and vacuum dry it at 80℃ for 24 hours to obtain copper-plated carbon fiber.

[0031] Preparation of silver-based composite electrical contact materials: Step 1: Weigh silver powder, vanadium powder, the Ti2SnC@C material prepared in this embodiment, and copper-plated carbon fiber, wherein the vanadium powder is 0.3% of the mass of the silver powder, the Ti2SnC@C material is 2% of the mass of the silver powder, and the copper-plated carbon fiber is 0.5% of the mass of the silver powder, and mix them all to form a mixed powder.

[0032] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0033] Example 2 The only difference from Example 1 is that the mass ratio of titanium powder to graphite was adjusted to 0.8:1 when preparing the core-shell structured TiC@C material.

[0034] Preparation of core-shell structured TiC@C materials: S1. Weigh titanium powder, sodium chloride, and potassium chloride in a mass ratio of 0.6:4:3. Weigh graphite in a mass ratio of titanium powder to graphite of 0.8:1. Mix the titanium powder, graphite, sodium chloride, and potassium chloride. Add ethanol with a solid content of 20% and stir evenly. After filtration, vacuum dry at 70°C for 12 hours to form a mixed powder.

[0035] S2. Under an argon atmosphere, the mixed powder is heated to 950℃ and held at that temperature for 2.5 hours.

[0036] S3. After cooling, add water and stir to dissolve. Centrifuge to remove the supernatant. Repeat 5 times to remove residual chloride salts. The precipitate is vacuum dried at 70℃ for 12h to obtain core-shell structured TiC@C material.

[0037] Preparation of Ti2SnC@C materials: Weigh the core-shell structured TiC@C material, titanium powder, and tin powder prepared in this embodiment according to a mass ratio of 2.0:1:2.3. Add 5% solid content to ethanol and ultrasonically disperse for 20 min. After filtration, transfer to a vacuum drying oven and dry at 80°C for 8 h to obtain a powder mixture. Transfer the powder mixture to a mold and cold press it under 20 MPa pressure to form a green body. Heat to 1050°C under vacuum conditions, hold for 15 min, cool to room temperature, and pulverize to obtain Ti2SnC@C material.

[0038] The conditions and steps for preparing copper-plated carbon fibers are the same as in Example 1.

[0039] Preparation of silver-based composite electrical contact materials: Step 1: Weigh silver powder, vanadium powder, the Ti2SnC@C material prepared in this embodiment, and copper-plated carbon fiber, wherein the vanadium powder is 0.3% of the mass of the silver powder, the Ti2SnC@C material is 2% of the mass of the silver powder, and the copper-plated carbon fiber is 0.5% of the mass of the silver powder, and mix them all to form a mixed powder.

[0040] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0041] Example 3 The only difference from Example 1 is that the mass ratio of titanium powder to graphite was adjusted to 1.2:1 when preparing the core-shell structured TiC@C material.

[0042] Preparation of core-shell structured TiC@C materials: S1. Weigh titanium powder, sodium chloride, and potassium chloride in a mass ratio of 0.6:4:3. Weigh graphite in a mass ratio of titanium powder to graphite of 1.2:1. Mix the titanium powder, graphite, sodium chloride, and potassium chloride. Add ethanol with a solid content of 20% and stir until homogeneous. After filtration, vacuum dry at 70°C for 12 hours to form a mixed powder.

[0043] S2. Under an argon atmosphere, the mixed powder is heated to 950℃ and held at that temperature for 2.5 hours.

[0044] S3. After cooling, add water and stir to dissolve. Centrifuge to remove the supernatant. Repeat 5 times to remove residual chloride salts. The precipitate is vacuum dried at 70℃ for 12h to obtain core-shell structured TiC@C material.

[0045] Preparation of Ti2SnC@C materials: Weigh the core-shell structured TiC@C material, titanium powder, and tin powder prepared in this embodiment according to a mass ratio of 2.0:1:2.3. Add 5% solid content to ethanol and ultrasonically disperse for 20 min. After filtration, transfer to a vacuum drying oven and dry at 80°C for 8 h to obtain a powder mixture. Transfer the powder mixture to a mold and cold press it under 20 MPa pressure to form a green body. Heat to 1050°C under vacuum conditions, hold for 15 min, cool to room temperature, and pulverize to obtain Ti2SnC@C material.

[0046] The conditions and steps for preparing copper-plated carbon fibers are the same as in Example 1.

[0047] Preparation of silver-based composite electrical contact materials: Step 1: Weigh silver powder, vanadium powder, the Ti2SnC@C material prepared in this embodiment, and copper-plated carbon fiber, wherein the vanadium powder is 0.3% of the mass of the silver powder, the Ti2SnC@C material is 2% of the mass of the silver powder, and the copper-plated carbon fiber is 0.5% of the mass of the silver powder, and mix them all to form a mixed powder.

[0048] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0049] Example 4 The only difference from Example 1 is that the mass ratio of the core-shell structure TiC@C material, titanium powder, and tin powder is adjusted to 1.7:1:2.0.

[0050] The conditions and steps for preparing core-shell structured TiC@C materials are the same as in Example 1.

[0051] Preparation of Ti2SnC@C materials: Weigh the core-shell structured TiC@C material, titanium powder, and tin powder prepared in this embodiment according to a mass ratio of 1.7:1:2.0. Add 5% solid content to ethanol and ultrasonically disperse for 20 min. After filtration, transfer to a vacuum drying oven and dry at 80°C for 8 h to obtain a powder mixture. Transfer the powder mixture to a mold and cold press it under 20 MPa pressure to form a blank. Heat to 1050°C under vacuum conditions, hold for 15 min, cool to room temperature, and pulverize to obtain Ti2SnC@C material.

[0052] The conditions and steps for preparing copper-plated carbon fibers are the same as in Example 1.

[0053] Preparation of silver-based composite electrical contact materials: Step 1: Weigh silver powder, vanadium powder, the Ti2SnC@C material prepared in this embodiment, and copper-plated carbon fiber, wherein the vanadium powder is 0.3% of the mass of the silver powder, the Ti2SnC@C material is 2% of the mass of the silver powder, and the copper-plated carbon fiber is 0.5% of the mass of the silver powder, and mix them all to form a mixed powder.

[0054] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0055] Example 5 The only difference from Example 1 is that the mass ratio of the core-shell structure TiC@C material, titanium powder, and tin powder is adjusted to 2.2:1:2.5.

[0056] The conditions and steps for preparing core-shell structured TiC@C materials are the same as in Example 1.

[0057] Preparation of Ti2SnC@C materials: Weigh the core-shell structured TiC@C material, titanium powder, and tin powder prepared in this embodiment according to a mass ratio of 2.2:1:2.5. Add 5% solid content to ethanol and ultrasonically disperse for 20 min. After filtration, transfer to a vacuum drying oven and dry at 80°C for 8 h to obtain a powder mixture. Transfer the powder mixture to a mold and cold press it under 20 MPa pressure to form a blank. Heat to 1050°C under vacuum conditions, hold for 15 min, cool to room temperature, and pulverize to obtain Ti2SnC@C material.

[0058] The conditions and steps for preparing copper-plated carbon fibers are the same as in Example 1.

[0059] Preparation of silver-based composite electrical contact materials: Step 1: Weigh silver powder, vanadium powder, the Ti2SnC@C material prepared in this embodiment, and copper-plated carbon fiber, wherein the vanadium powder is 0.3% of the mass of the silver powder, the Ti2SnC@C material is 2% of the mass of the silver powder, and the copper-plated carbon fiber is 0.5% of the mass of the silver powder, and mix them all to form a mixed powder.

[0060] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0061] Example 6 The only difference from Example 1 is that the Ti2SnC@C material in the electrical contact material is 1% of the mass of the silver powder.

[0062] The conditions and steps for preparing core-shell structured TiC@C materials, preparing Ti2SnC@C materials, and preparing copper-plated carbon fibers are the same as in Example 1.

[0063] Preparation of silver-based composite electrical contact materials: Step 1: Weigh silver powder, vanadium powder, the Ti2SnC@C material prepared in this embodiment, and copper-plated carbon fiber, wherein the vanadium powder is 0.3% of the mass of the silver powder, the Ti2SnC@C material is 1% of the mass of the silver powder, and the copper-plated carbon fiber is 0.5% of the mass of the silver powder, and mix them all to form a mixed powder.

[0064] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0065] Compared with Example 7 The only difference from Example 1 is that the Ti2SnC@C material in the electrical contact material is 3% of the mass of the silver powder.

[0066] The conditions and steps for preparing core-shell structured TiC@C materials, preparing Ti2SnC@C materials, and preparing copper-plated carbon fibers are the same as in Example 1.

[0067] Preparation of silver-based composite electrical contact materials: Step 1: Weigh silver powder, vanadium powder, the Ti2SnC@C material prepared in this embodiment, and copper-plated carbon fiber, wherein the vanadium powder is 0.3% of the mass of the silver powder, the Ti2SnC@C material is 3% of the mass of the silver powder, and the copper-plated carbon fiber is 0.5% of the mass of the silver powder, and mix them all to form a mixed powder.

[0068] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0069] Example 8 The only difference from Example 1 is that the copper-plated carbon fiber in the electrical contact material is 0.3% of the mass of silver powder.

[0070] The conditions and steps for preparing core-shell structured TiC@C materials, preparing Ti2SnC@C materials, and preparing copper-plated carbon fibers are the same as in Example 1.

[0071] Preparation of silver-based composite electrical contact materials: Step 1: Weigh silver powder, vanadium powder, the Ti2SnC@C material prepared in this embodiment, and copper-plated carbon fiber, wherein the vanadium powder is 0.3% of the mass of the silver powder, the Ti2SnC@C material is 2% of the mass of the silver powder, and the copper-plated carbon fiber is 0.3% of the mass of the silver powder, and mix them all to form a mixed powder.

[0072] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0073] Example 9 The only difference from Example 1 is that the copper-plated carbon fiber in the electrical contact material is 0.8% of the mass of silver powder.

[0074] The conditions and steps for preparing core-shell structured TiC@C materials, preparing Ti2SnC@C materials, and preparing copper-plated carbon fibers are the same as in Example 1.

[0075] Preparation of silver-based composite electrical contact materials: Step 1: Weigh silver powder, vanadium powder, the Ti2SnC@C material prepared in this embodiment, and copper-plated carbon fiber, wherein the vanadium powder is 0.3% of the mass of silver powder, the Ti2SnC@C material is 2% of the mass of silver powder, and the copper-plated carbon fiber is 0.8% of the mass of silver powder, and mix them all to form a mixed powder.

[0076] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0077] Example 10 The only difference from Example 1 is that the vanadium powder in the electrical contact material is 0.1% of the mass of the silver powder.

[0078] The conditions and steps for preparing core-shell structured TiC@C materials, preparing Ti2SnC@C materials, and preparing copper-plated carbon fibers are the same as in Example 1.

[0079] Preparation of silver-based composite electrical contact materials: Step 1: Weigh silver powder, vanadium powder, the Ti2SnC@C material prepared in this embodiment, and copper-plated carbon fiber, wherein the vanadium powder is 0.1% of the mass of the silver powder, the Ti2SnC@C material is 2% of the mass of the silver powder, and the copper-plated carbon fiber is 0.5% of the mass of the silver powder, and mix them all to form a mixed powder.

[0080] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0081] Example 11 The only difference from Example 1 is that the vanadium powder in the electrical contact material is 0.5% of the mass of the silver powder.

[0082] The conditions and steps for preparing core-shell structured TiC@C materials, preparing Ti2SnC@C materials, and preparing copper-plated carbon fibers are the same as in Example 1.

[0083] Preparation of silver-based composite electrical contact materials: Step 1: Weigh silver powder, vanadium powder, the Ti2SnC@C material prepared in this embodiment, and copper-plated carbon fiber, wherein the vanadium powder is 0.5% of the mass of the silver powder, the Ti2SnC@C material is 2% of the mass of the silver powder, and the copper-plated carbon fiber is 0.5% of the mass of the silver powder, and mix them all to form a mixed powder.

[0084] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0085] Comparative Example 1 The only difference from Example 1 is that vanadium powder is not added to the electrical contact material.

[0086] The conditions and steps for preparing core-shell structured TiC@C materials, preparing Ti2SnC@C materials, and preparing copper-plated carbon fibers are the same as in Example 1.

[0087] Preparation of silver-based composite electrical contact materials: Step 1: Weigh silver powder, the Ti2SnC@C material prepared in this embodiment, and copper-plated carbon fiber, wherein the Ti2SnC@C material is 1% of the mass of silver powder and the copper-plated carbon fiber is 0.5% of the mass of silver powder, and mix them all to form a mixed powder.

[0088] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0089] Comparative Example 2 The only difference from Example 1 is that copper-plated carbon fiber is not added to the electrical contact material.

[0090] The conditions and steps for preparing core-shell structured TiC@C materials, preparing Ti2SnC@C materials, and preparing copper-plated carbon fibers are the same as in Example 1.

[0091] Preparation of silver-based composite electrical contact materials: Step 1: Weigh silver powder, vanadium powder, and the Ti2SnC@C material prepared in this embodiment, wherein the vanadium powder is 0.3% of the mass of the silver powder and the Ti2SnC@C material is 1% of the mass of the silver powder, and mix them all to form a mixed powder.

[0092] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0093] Comparative Example 3 The only difference from Example 1 is that the Ti2SnC@C material is replaced with graphite or similar materials in the electrical contact material.

[0094] The conditions and steps for preparing copper-plated carbon fibers are the same as in Example 1.

[0095] Preparation of silver-based composite electrical contact materials: Step 1: Weigh out silver powder, vanadium powder, graphite, and copper-plated carbon fiber, wherein the vanadium powder is 0.3% of the mass of the silver powder, the graphite is 1% of the mass of the silver powder, and the copper-plated carbon fiber is 0.5% of the mass of the silver powder. Mix all of them to form a mixed powder.

[0096] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0097] Comparative Example 4 The only difference from Example 1 is that the Ti2SnC@C material is replaced by conventional Ti2SnC powder of equal mass in the electrical contact material.

[0098] The conditions and steps for preparing copper-plated carbon fibers are the same as in Example 1.

[0099] Preparation of silver-based composite electrical contact materials: Step 1: Weigh out silver powder, vanadium powder, Ti2SnC powder, and copper-plated carbon fiber, wherein the vanadium powder accounts for 0.3% of the mass of the silver powder, the Ti2SnC powder accounts for 2% of the mass of the silver powder, and the copper-plated carbon fiber accounts for 0.5% of the mass of the silver powder. Mix all of them to form a mixed powder.

[0100] Step 2: The mixed powder is pressed into a blank at 600 MPa. The blank is heated to 950°C at a heating rate of 5°C / min under an argon atmosphere and held at that temperature for 2.5 hours for sintering. After sintering, the silver-based composite electrical contact material is obtained by extrusion.

[0101] The performance of the silver-based composite electrical contact materials obtained in Examples 1-11 and Comparative Examples 1-4 was tested. The silver-based composite electrical contact materials were welded onto copper sheets. Using a JF04D electrical contact testing system, under AC power conditions of 250V, 25A, ON 1s, OFF 1s, with copper as the moving contact (anode) and the silver-based composite electrical contact material as the stationary contact (cathode), with a 2mm distance between the two contacts, an arc erosion resistance test was conducted in air. The results are shown in Table 1. Table 1

[0102] As can be seen from Table 1, under the synergistic effect of the reinforcing vanadium powder, Ti2SnC@C material and copper-plated carbon fiber, the silver-based composite electrical contact material prepared in the embodiments of the present invention has both high resistance to arc erosion and high conductivity.

[0103] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0104] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a silver-based composite electrical contact material, characterized in that, Includes the following steps: Step 1: Mix silver powder, vanadium powder, Ti2SnC@C material, and copper-plated carbon fiber to form a mixed powder; Step 2: Press the mixed powder to form a blank, sinter the blank in an argon atmosphere, and then extrude or roll it to obtain a silver-based composite electrical contact material. The Ti2SnC@C material is obtained by mixing core-shell structured TiC@C material, titanium powder, and tin powder, followed by high-temperature heat treatment.

2. The method for preparing a silver-based composite electrical contact material according to claim 1, characterized in that, The vanadium powder is 0.1-0.5% of the mass of the silver powder.

3. The method for preparing a silver-based composite electrical contact material according to claim 1, characterized in that, The copper-plated carbon fiber contains 0.3-0.8% of the silver powder by weight.

4. The method for preparing a silver-based composite electrical contact material according to claim 1, characterized in that, The Ti2SnC@C material is 1-3% of the mass of silver powder.

5. The method for preparing a silver-based composite electrical contact material according to claim 1, characterized in that, The preparation steps of the core-shell structured TiC@C material are as follows: S1. Mix titanium powder, graphite, sodium chloride and potassium chloride, add ethanol and stir to mix, filter and vacuum dry to form a mixed powder; S2. Under an argon atmosphere, the mixed powder is heated to 900-1000℃ and held for 2-3 hours; S3. After cooling, add water and stir to dissolve. Centrifuge to remove the supernatant and dry the precipitate to obtain the core-shell structured TiC@C material.

6. The method for preparing a silver-based composite electrical contact material according to claim 5, characterized in that, The mass ratio of titanium powder, sodium chloride, and potassium chloride is (0.4-0.8):4:3; The mass ratio of titanium powder to graphite is 0.8-1.2:

1.

7. The method for preparing a silver-based composite electrical contact material according to claim 1, characterized in that, The preparation steps of the Ti2SnC@C material are as follows: The core-shell structured TiC@C material, titanium powder, and tin powder were added to ethanol and ultrasonically dispersed, filtered, and vacuum dried to obtain a powder mixture. The powder mixture was cold-pressed to form a green body, heated to 950-1250℃ under vacuum conditions, held for 10-20 minutes, cooled to room temperature, and pulverized to obtain Ti2SnC@C material.

8. A method of producing a silver-based composite electrical contact material according to claim 7, characterized in that, The mass ratio of the core-shell structured TiC@C material, titanium powder, and tin powder is (1.7-2.2):1:(2.0-2.5).

9. The method for preparing a silver-based composite electrical contact material according to claim 1, characterized in that, The preparation steps of the copper-plated carbon fiber are as follows: Step 1: Soak carbon fiber in acetone for degumming. After degumming, soak the carbon fiber in an ammonium superphosphate aqueous solution for roughening treatment. After roughening, wash the fiber with water until neutral and then dry it. Soak the washed carbon fiber in an activation solution for activation. After activation, soak the carbon fiber in a degumming solution and a reducing solution in sequence. After washing and drying, the pre-plating treatment is completed. Step 2: Place the pre-treated carbon fiber in the copper plating solution, heat and stir to perform copper plating. After copper plating is completed, remove it, wash it, and dry it to obtain copper-plated carbon fiber.

10. A silver-based composite electrical contact material, characterized in that, It is prepared by the preparation method described in any one of claims 1-9.

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