Silver tin oxide indium oxide electrical contact material and method of making same

Abstract

The application relates to the field of electric contact material preparation, and particularly discloses a silver-tin oxide-indium oxide electric contact material and a preparation method thereof. The method comprises the following steps: mixing Ag, Sn, In and AgMe, performing vacuum induction smelting to obtain an alloy solution; performing casting on the alloy solution, and then performing cooling and solidification to obtain alloy particles; preheating the alloy particles, and then performing an isobaric differential temperature rapid internal oxidation process to obtain an electric contact material crude product; and performing a post-processing step on the electric contact material crude product to obtain the electric contact material. Through one-step granulation and the isobaric differential temperature rapid internal oxidation process, the production cycle is greatly shortened, the oxidation speed is significantly improved, the uniformity and compactness of the oxidation film are improved, and the prepared electric contact material has good electrical and mechanical properties.

Description

Technical Field

[0001] This application relates to the field of electrical contact material preparation technology, and more specifically, it relates to a silver oxide-tin oxide-indium oxide electrical contact material and its preparation method. Background Technology

[0002] Silver oxide, tin oxide, and indium oxide electrical contact materials are crucial components in the field of electrical switches, attracting widespread attention due to their excellent conductivity, wear resistance, and resistance to arc erosion. With the rapid development of electrical equipment, the demand for high-performance electrical contact materials is increasing daily. While traditional manufacturing processes can meet basic performance requirements, their shortcomings are gradually becoming apparent under the demands of high efficiency, energy saving, and stability. Therefore, there is an urgent need to develop more advanced manufacturing technologies to meet the needs of modern industry.

[0003] In existing technologies, a combination of methods is typically employed to prepare silver-tin-indium oxide electrical contact materials. For example, different metal components are thoroughly mixed through high-temperature melting, followed by pressing to impart a specific geometry to the material, and then internal oxidation treatment to create the desired oxide distribution within the material. In addition, other processes such as extrusion and wire drawing are used to further optimize the material's microstructure and macroscopic properties. These methods collectively constitute the most common preparation process in the industry today.

[0004] However, the aforementioned conventional methods have significant drawbacks in practical applications. Particularly in the internal oxidation stage, the differences in diffusion rates of different elements often lead to uneven distribution of the material's internal structure, thus affecting the consistency of the final product's performance. Furthermore, the complex process not only prolongs the production cycle but also significantly increases energy costs. These problems severely restrict the large-scale industrial production of silver-tin-indium oxide electrical contact materials. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a silver oxide-tin oxide-indium oxide electrical contact material and its preparation method.

[0006] The technical solution adopted in this application is as follows: In a first aspect, this application provides a method for preparing a silver oxide-tin oxide-indium oxide electrical contact material, comprising: Prepare the materials according to the following weight proportions: Ag 86-90 parts, Sn 5.0-6.0 parts, In 3.0-4.0 parts, AgMe 1.0-2.0 parts; The Ag, Sn, In and AgMe are mixed and subjected to vacuum induction melting to obtain an alloy solution; After casting the alloy solution, it is cooled and solidified to obtain alloy particles; After preheating the alloy particles, a rapid internal oxidation process with isobaric differential temperature is performed to obtain crude electrical contact material. The crude electrical contact material is subjected to a post-processing step to obtain the electrical contact material.

[0007] By adopting the above technical solution, the preparation of materials according to specific weight proportions ensures the basic properties and stability of the material; vacuum induction melting fully fuses the raw materials to form a homogeneous alloy solution; casting and cooling solidification to obtain alloy pellets is beneficial for subsequent internal oxidation reactions; the preheating of the alloy pellets followed by an isobaric differential temperature rapid internal oxidation process significantly improves the oxidation rate, shortens the preparation cycle, effectively reduces energy consumption, and makes the oxide distribution of the obtained material more uniform, improving the material's resistance to welding and electrical contact stability. Post-processing steps can further improve the material properties, meeting the requirements of resistivity ≤ 2.80 μΩ•cm and density ≥ 9.5 g / cm³. 3 The standard requires that the annealing step eliminates internal stress in the material, cold pressing makes the material denser, and finishing ensures the shape and dimensional accuracy of the material, resulting in a material hardness HV≥80 kgf / mm². 2 Tensile strength ≥ 240 N / mm 2 This improves the quality and stability of silver oxide, tin oxide, and indium oxide electrical contact materials, making them suitable for practical applications.

[0008] Furthermore, the isobaric differential temperature rapid internal oxidation process includes: First, the alloy particles are preheated at 480-520℃ and then placed in a furnace with an oxygen pressure of 0.1-0.3MPa. After the gas is vented, the oxygen pressure is increased to 0.35-0.45MPa and the temperature is maintained for 0.5-1.5 hours. The temperature is then raised to 630-670℃, the oxygen pressure is increased to 0.55-0.65MPa, and the temperature is maintained for 0.5-1.5 hours. Finally, raise the temperature to 740-760℃, maintain the oxygen pressure at 0.55-0.65 MPa, and hold for 10-14 hours.

[0009] By employing the aforementioned isobaric differential temperature internal oxidation process, the alloy particles are first preheated at a relatively low temperature of 480-520℃ with an oxygen pressure of 0.1-0.3 MPa. This allows each part of the alloy particles to initially adapt to the oxidation environment. Subsequently, the original gas is discharged, and a higher oxygen pressure of 0.35-0.45 MPa is introduced and held at this temperature. During this stage, the oxidation reaction is slowly initiated under relatively mild conditions, which helps oxygen molecules gradually penetrate into the interior of the alloy and avoids excessively rapid local oxidation. Next, the temperature is raised to 630-670℃, while the oxygen pressure is increased to 0.55-0.65 MPa and held at this temperature to further accelerate the oxidation process. Finally, the oxidation process is held at 740-760℃ with an oxygen pressure of 0.55-0.65 MPa for an extended period, ensuring that the oxidation reaction proceeds fully under high temperature and high pressure. This phased, gradient-based control of temperature and oxygen pressure allows oxygen molecules to diffuse evenly and fully into all parts of the alloy grains, significantly increasing the oxidation rate, shortening the preparation cycle, and effectively reducing energy consumption. At the same time, it makes the oxide distribution of the resulting material more uniform, thereby improving the material's resistance to welding and electrical contact stability.

[0010] Furthermore, the above-mentioned AgMe is a silver-based alloy, wherein the Me element includes at least one of Cu, Pd, Cd, Sn, Bi or Te.

[0011] By adopting the above technical solution, in the preparation of silver oxide tin oxide indium oxide electrical contact material, the silver-based alloy AgMe containing a specific Me element is selected as one of the raw materials, which helps to improve the uniformity and density of the oxide film, enhance the anti-welding performance and electrical contact stability of the material, and make the final prepared material more in line with the requirements of high efficiency and stable use.

[0012] Furthermore, the temperature of the above-mentioned vacuum induction melting is 1200-1400℃, and the time is 20-30 minutes.

[0013] By adopting the above technical solution, vacuum induction melting at this specific temperature and time can ensure that the alloy solution is fully formed and has stable properties, which is beneficial to obtaining high-quality alloy particles in subsequent steps, thereby further ensuring the performance stability of the prepared silver oxide-tin oxide-indium oxide electrical contact material.

[0014] Furthermore, the particle size of the aforementioned alloy particles is 1.5-2.5 mm.

[0015] By adopting the above technical solution, the particle size of the alloy particles is kept within a suitable range, which is conducive to the subsequent isobaric differential temperature rapid internal oxidation process being carried out more efficiently, further improving the oxidation rate, shortening the preparation cycle and reducing energy consumption. At the same time, it helps to ensure a more uniform distribution of oxides in the material, and improves the material's resistance to welding and electrical contact stability.

[0016] Furthermore, the above post-processing steps include annealing, cold pressing, and finishing.

[0017] Furthermore, the annealing temperature is 300-400℃, and the time is 1-2 hours.

[0018] Furthermore, the aforementioned finishing processes include slicing and pressing, sintering, and extrusion.

[0019] Secondly, this application provides a silver-tin-indium oxide electrical contact material prepared by the above-described method, wherein the resistivity of the electrical contact material is ≤2.80 μΩ•cm and the density is ≥9.5 g / cm³. 3 .

[0020] Furthermore, the hardness HV of the aforementioned electrical contact material is ≥80 kgf / mm. 2 Tensile strength ≥ 240 N / mm 2 .

[0021] In summary, this application has the following beneficial effects: 1. This application simplifies the original complex processes such as melting, peeling, extrusion, and wire drawing in the preparation method of silver-tin-indium oxide electrical contact materials into a one-step granulation method. The raw materials are directly melted under vacuum induction, cooled, and solidified into granules, which are then processed into silver-tin-indium oxide materials through an isobaric differential temperature internal oxidation process. This process improvement not only significantly shortens the overall production cycle of the material but also reduces energy consumption, thereby achieving the manufacturing industry's goals of high efficiency, energy saving, and low cost.

[0022] 2. In the internal oxidation process, by precisely controlling the process parameters such as oxygen pressure, temperature, time, and atmosphere, and optimizing the material formulation, the oxidation rate is significantly improved, the uniformity and density of the oxide film are enhanced, and the anti-welding performance and electrical contact stability of the material are improved.

[0023] 3. The prepared electrical contact material has good electrical and mechanical properties, and its resistivity, density, hardness and tensile strength all meet the standards, making it suitable for large-scale industrial production. Attached Figure Description

[0024] Figure 1 This is a metallographic diagram of the silver oxide-tin oxide-indium oxide electrical contact material provided in Example 1 of this application. Detailed Implementation

[0025] The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Specific conditions not specified in the examples shall be carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0026] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention. Example

[0027] This embodiment provides a silver-tin-indium oxide electrical contact material, the preparation method of which includes the following steps: (1) Prepare materials according to Table 1: Table 1. Ag 88 Sn 6.0 In 4.0 AgMe (Me stands for Sn) 2.0 (2) Mix Ag, Sn, In and AgMe in the raw materials and perform vacuum induction melting in an automated equipment. The melting temperature is 1250℃ and the time is 25min to obtain an alloy solution. After casting, cool and solidify the particles to obtain alloy particles with a particle size of 1.5-2.5mm. (3) Internal oxidation treatment: After preheating the alloy particles at 500℃, they are put into the furnace and the oxygen pressure is 0.2MPa. After the gas is vented, the oxygen pressure is 0.4MPa and the temperature is held for 1h. Then the temperature is raised to 650℃ and the oxygen pressure is raised to 0.6MPa and held for 1h. Finally, the temperature is raised to 750℃ and the oxygen pressure is maintained at 0.6MPa for 12h to obtain the crude product of electrical contact material. (4) Annealing, cold pressing and finishing of the crude electrical contact material to obtain the electrical contact material. Example

[0028] The difference between this embodiment and Embodiment 1 lies in the raw materials and composition, as detailed in Table 2: Table 2. Ag 90 Sn 5.0 In 3.0 AgMe (Me stands for Pd) 2.0 Example

[0029] The difference between this embodiment and Embodiment 1 lies in the raw materials and composition, as detailed in Table 3: Table 3. Ag 88 Sn 6.0 In 4.0 AgMe (Me is Cu:Bi = 1:1) 2.0 Example

[0030] The difference between this embodiment and Embodiment 1 lies in the process parameters of vacuum induction melting: the melting temperature is 1400℃ and the time is 20min. Example

[0031] The difference between this embodiment and Embodiment 1 lies in the process parameters of the internal oxidation treatment: the alloy particles are preheated at 520°C and then placed in a furnace with an oxygen pressure of 0.1 MPa. After the gas is vented, the oxygen pressure is increased to 0.45 MPa and the temperature is maintained for 0.5 hours. The temperature is then increased to 670°C, the oxygen pressure is increased to 0.65 MPa, and the temperature is maintained for 0.5 hours. Finally, the temperature is increased to 760°C, the oxygen pressure is maintained at 0.55 MPa, and the temperature is maintained for 14 hours to obtain the crude electrical contact material. Example

[0032] The difference between this embodiment and Embodiment 1 lies in the process parameters of the internal oxidation treatment: Internal oxidation treatment: After preheating the alloy particles at 480°C, they are placed in a furnace with an oxygen pressure of 0.3 MPa. After venting the gas, the oxygen pressure is increased to 0.35 MPa and held for 1.5 hours. Then, the temperature is raised to 630°C, the oxygen pressure is increased to 0.55 MPa, and the temperature is held for 1.5 hours. Finally, the temperature is raised to 740°C, the oxygen pressure is maintained at 0.65 MPa, and the temperature is held for 10 hours to obtain the crude electrical contact material.

[0033] Comparative Example 1 The difference between this comparative example and Example 1 is that the particle size of the alloy particles is 3.0-4.0 mm.

[0034] Comparative Example 2 The difference between this comparative example and Example 1 is that the temperature at which the alloy particles are preheated before the isobaric differential temperature rapid internal oxidation treatment is 200°C.

[0035] Comparative Example 3 The difference between this comparative example and Example 1 is that the internal oxidation treatment process is a conventional process, specifically: After preheating the alloy particles at 650℃, they were placed in a furnace and subjected to an oxygen pressure of 0.4MPa. After the gas was vented, the furnace was filled with oxygen at a pressure of 0.4MPa and held for 1 hour. The temperature was then raised to 750℃ and held for 36 hours to obtain the crude electrical contact material.

[0036] Comparative Example 4 The difference between this comparative example and Example 1 lies in the composition of the raw materials, as shown in Table 4: Table 4. Ag 88 Sn 6.0 In 4.0 AgMe (Me stands for Al) 2.0 Comparative Example 5 The difference between this comparative example and Example 1 is that the vacuum induction melting and granulation step is not performed, and the traditional process is used: melting—peeling—extrusion—fiber drawing and annealing—internal oxidation—annealing, cold pressing and finishing. The melting process involves melting at approximately 1250°C until fully melted, refining at approximately 1150°C for 30 minutes, and casting at approximately 1000°C. The wire drawing annealing process involves holding at 650°C for 30 minutes. The internal oxidation process is the same as in Example 1.

[0037] The electrical contact materials prepared in the above embodiments and comparative examples were subjected to performance testing, and the testing methods are as follows: Resistivity: Tested according to JB / T7780.3 standard; Hardness: Tested according to JB / T7780.2 standard; Density: Tested according to JB / T7780.1 standard; Tensile strength: Tested according to JB / T7780.4 standard.

[0038] The results are shown in Table 5: Table 5. Example 1 2.56 125.1 9.78 385.19 Example 2 2.41 123.6 9.62 386.24 Example 3 2.43 124.2 9.74 385.73 Example 4 2.59 123.7 9.66 384.98 Example 5 2.55 125.6 9.73 386.21 Example 6 2.43 124.7 9.66 386.78 Comparative Example 1 2.87 122.1 9.67 380.43 Comparative Example 2 2.78 120.8 9.52 372.44 Comparative Example 3 2.94 118.2 9.43 376.65 Comparative Example 4 2.83 121.0 9.27 374.51 Comparative Example 5 2.69 122.5 9.59 380.20 As can be seen from Table 5: The resistivity, hardness, density, and tensile strength of the electrical contact materials provided in Examples 1-6 of this application all meet the standard requirements, and their tensile strength and resistivity are even better.

[0039] As can be seen from the comparison between Example 1 and Comparative Examples 1-4, the particle size of the alloy particles, the preheating treatment, the relevant parameters of the internal oxidation process, and the composition and formulation of the raw materials all have a significant impact on the performance of the electrical contact material.

[0040] As can be seen from the comparison between Example 1 and Comparative Example 5, the present application adopts a one-step granulation method + rapid internal oxidation process. Compared with the traditional process of melting - peeling - extrusion - wire drawing annealing followed by internal oxidation, it not only significantly shortens the material production cycle and reduces energy consumption, but also produces electrical contact materials with superior performance.

[0041] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a silver-tin-indium oxide electrical contact material, characterized in that, It includes: Prepare the following materials by weight: 86-90 parts Ag, 5.0-6.0 parts Sn, 3.0-4.0 parts In, and 1.0-2.0 parts AgMe; mix the Ag, Sn, In, and AgMe and perform vacuum induction melting to obtain an alloy solution; cast the alloy solution and then cool and solidify it to obtain alloy pellets; preheat the alloy pellets and then perform an isobaric differential temperature rapid internal oxidation process to obtain a crude electrical contact material; perform post-processing steps on the crude electrical contact material to obtain the electrical contact material. The isobaric differential temperature rapid internal oxidation process after preheating the alloy particles includes: first, preheating the alloy particles at 480-520℃ and then placing them in a furnace with an oxygen pressure of 0.1-0.3 MPa. After venting the gas, the oxygen pressure is increased to 0.35-0.45 MPa and held for 0.5-1.5 hours; then the temperature is increased to 630-670℃, the oxygen pressure is increased to 0.55-0.65 MPa, and held for 0.5-1.5 hours; finally, the temperature is increased to 740-760℃, the oxygen pressure is maintained at 0.55-0.65 MPa, and held for 10-14 hours. The AgMe is a silver-based alloy, wherein the Me element includes at least one of Cu, Pd, Cd, Sn, Bi, or Te; The vacuum induction melting temperature is 1200-1400℃, and the time is 20-30 minutes; The particle size of the alloy particles is 1.5-2.5 mm.

2. The method for preparing the silver oxide-tin oxide-indium oxide electrical contact material according to claim 1, characterized in that, The post-processing steps include annealing, cold pressing, and finishing.

3. The method for preparing the silver oxide-tin oxide-indium oxide electrical contact material according to claim 2, characterized in that, The annealing temperature is 300-400℃, and the time is 1-2 hours.

4. The method for preparing the silver oxide-tin oxide-indium oxide electrical contact material according to claim 2, characterized in that, The finishing process includes slicing and pressing, sintering, and extrusion.

5. A silver-tin-indium oxide electrical contact material prepared by the preparation method according to any one of claims 1-4, characterized in that, The resistivity of the electrical contact material is ≤2.80 μΩ•cm, and the density is ≥9.5 g / cm³. 3 .

6. The silver oxide-tin oxide-indium oxide electrical contact material according to claim 5, characterized in that, The hardness of the electrical contact material is HV≥80 kgf / mm². 2 Tensile strength ≥ 240 N / mm 2 .

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