Preparation method of composite silver tin oxide electric contact material based on thick wall AgSn tube

Abstract

The application provides a preparation method of a composite silver tin oxide electric contact material based on a thick-wall AgSn tube. The method for preparing the composite silver tin oxide by using the thick-wall AgSn tube guarantees the strength of the oxide skeleton, modifies the silver matrix, guarantees the uniformity of the oxidation area by the in-situ generation of the oxide, and makes the oxide particles finer. Meanwhile, the edge working layer of the rivet contact prepared by the method is an internal oxidation process organization, and has excellent arc erosion resistance, especially the arc erosion resistance to a large current. The AgSn tube composite silver tin oxide blank extrusion method can arbitrarily adjust the proportion according to the requirement, and the prepared material has better plasticity, low hardness and is easy to process.

Description

Technical Field

[0001] This invention relates to the field of electrical contact materials, and specifically to a method for preparing a composite silver-tin oxide electrical contact material based on a thick-walled AgSn tube. Background Technology

[0002] In the 21st century, AI and new energy technologies have risen and developed rapidly, and people's lives are gradually moving towards intelligence, automation, and greening. Currently, AgMeO is the most widely used electrical contact material. With the increasing awareness of environmental protection, people have begun to refuse to use silver cadmium oxide-based electrical contact materials, promoting the research and production of silver tin oxide-based environmentally friendly electrical contact materials. Silver tin oxide is widely used in many fields such as home appliances, automobiles, new energy, energy storage, 5G, and aerospace.

[0003] Silver-tin oxide materials possess excellent thermal stability; tin oxide is not easily decomposed under electric arc conditions, and tin oxide particles in the molten silver pool increase the viscosity of the molten metal, thus reducing spatter and arc erosion. However, despite its high stability, tin oxide itself is also quite hard, and after arc ablation, it tends to solidify at the contact surface, increasing contact resistance. This is a major problem with silver-tin oxide materials. Furthermore, with increasing oxide content, the forming and processing performance of silver-tin oxide electrical contact materials deteriorates sharply, even becoming unprocessable. Existing technologies have made a series of improvements to address this issue:

[0004] (1) Patent CN102268583A discloses a method for preparing silver tin oxide electrical contact material. This patent involves melting tin and additive metals in a medium-frequency melting furnace in a certain proportion, fully alloying them, and then atomizing them into tin alloy powder. The tin alloy powder is then oxidized under certain conditions to form tin oxide composite powder. This composite powder is mechanically mixed with silver powder, and then processed into silver tin oxide wires of a certain specification through ingot pressing, sintering, and extrusion. The silver tin oxide electrical contact material prepared by this method has the characteristics of more uniform distribution of trace additive components, more reasonable composition of metal oxide particles, and stable material properties.

[0005] (2) Invention patent CN105702503A discloses a method for preparing silver tin oxide indium oxide contact material. This patent improves the sintering performance of the material by doping tin-indium alloy and adding trace amounts of lithium carbonate, copper oxide, bismuth oxide, etc., thereby improving the material's density and conductivity. The prepared silver tin oxide material has advantages such as low volume resistivity, low hardness, good processing performance, and good resistance to welding.

[0006] (3) Patent CN105200262B discloses a method for preparing a silver-based sheet electrical contact material with high tin oxide content. This patent involves sintering powder ingots under a protective atmosphere, breaking them into blocks, oxidizing the blocks, pulverizing them again, molding them into ingots, and then hot-pressing, extruding, rolling, and stamping to produce silver tin oxide sheets. The silver tin oxide electrical contact material prepared by this method has the characteristics of high oxide content, large oxide particles, good processing performance, and uniform structure.

[0007] (4) The invention patent with publication number CN107598176B discloses a preparation process of silver metal oxide electrical contact material. The patent adopts the process of directly preparing alloy spheres from alloy melt and then internally oxidizing them, which eliminates the process that seriously affects the material utilization rate and production cycle, and develops a faster production method with higher material utilization rate.

[0008] However, the silver electrical contact materials with high oxide content prepared by the above-mentioned patents (1)(2)(3) using alloy atomization powder preparation, tin-indium alloy doping, crushing and molding into ingots have poor burn-off performance in actual applications, and are increasingly unable to meet the current trend of high performance development; Patent (4) uses the method of preparing alloy spheres by alloy melt and direct internal oxidation, which easily forms a depleted oxide area at the center of the sphere prepared by this method, resulting in a reduction in the proportion of normal structure and affecting the electrical life of the contact material. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a method for preparing a composite silver-tin oxide electrical contact material based on a thick-walled AgSn tube.

[0010] The technical solution adopted in this invention is as follows: A method for preparing a composite silver-tin oxide electrical contact material based on a thick-walled AgSn tube, comprising the following steps:

[0011] S1: Melt silver ingots, tin ingots, and additives in a vacuum melting furnace, and continuously cast them into ingot A on a continuous casting machine;

[0012] S2: The spindle A prepared in step S1 is hot-extruded into wire, drawn and broken, and then subjected to internal oxidation, cleaning and pressing to obtain spindle B;

[0013] S3: Silver ingots, tin ingots, and additives are melted, atomized, dried, and oxidized into powder, then pressed into shape and sintered to obtain a blank.

[0014] S4: The spindle B obtained in step S2 is hot-extruded into a thick-walled tube, processed into the required specifications, cleaned, and then the blank prepared in step S3 is inserted into it to obtain spindle C.

[0015] S5: The spindle C prepared in step S4 is hot-extruded into filament and finally drawn into finished filament of the required specifications.

[0016] Preferably, in step S1, the silver content of the ingot A is 70%–85%, the tin content is 15%–30%, and the content of additives is 2%–15%.

[0017] Preferably, in step S1, the additives include at least two of indium, germanium, manganese, cobalt, and titanium.

[0018] Preferably, in step S3, the silver content of the embryo is 75%–90%, and the tin content is 10%–25%.

[0019] Preferably, the balance is an additive, specifically two or more of indium, germanium, manganese, cobalt, and titanium, in 2-10 parts by weight.

[0020] Preferably, in step S3, the embryo pressing is isostatic pressing, and the pressing pressure is 200-300 MPa.

[0021] Preferably, in step S2, the internal oxidation temperature is 680–750°C, the internal oxidation pressure is 0.6–1.5 MPa, and the internal oxidation time is 48–72 h.

[0022] Preferably, in step S3, the sintering temperature is 750–880°C and the sintering time is 2–3 hours.

[0023] Preferably, in step S5, the spindle C prepared in step S4 is kept at a temperature of 800℃~880℃ for 2~4h and then hot-extruded into wire.

[0024] Preferably, in step S5, the spindle C is hot-extruded into a shape with a diameter of [missing information]. Extruded yarn.

[0025] The beneficial effects of this invention are as follows: This invention employs a method for preparing composite silver-tin oxide using thick-walled AgSn tubes, ensuring the strength of the oxide framework and modifying and strengthening the silver matrix. By generating oxides in situ, the uniformity of the oxidation zone is guaranteed, resulting in finer oxide particles. Simultaneously, the working layer at the edge of the rivet contact point exhibits an internal oxidation process structure, possessing excellent resistance to arc erosion, especially high-current arc erosion. The AgSn tube internal composite silver-tin oxide preform extrusion method allows for arbitrary adjustment of the proportions as needed, avoiding oxidation difficulties. The resulting material has better plasticity, lower hardness, and is easier to process. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0027] Figure 1 This is a process flow diagram of the present invention;

[0028] Figure 2 This is a schematic diagram of the microstructure distribution of the silver tin oxide material obtained by the present invention;

[0029] Figure 3 This is a metallographic photograph of the silver-tin oxide material prepared according to the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] Example 1

[0032] This embodiment is performed according to the following steps:

[0033] S1. Silver ingot, tin ingot, indium, and germanium are in parts by mass of 70, 25, 4, and 1 respectively. The above silver ingot, tin ingot, and additives are melted in a vacuum melting furnace at a melting temperature of 1200℃. After melting, they are continuously cast into 30kg ingots A on a continuous casting machine.

[0034] S2. The spindle A obtained in step S1 is hot-extruded into wire, then drawn to a small size, broken, internally oxidized, post-treated, cleaned and pressed to obtain spindle B, wherein the internal oxidation temperature is 700℃, the oxidation pressure is 0.6~1.5MPa and the oxidation time is 54h.

[0035] S3. Silver ingots, tin ingots, manganese, and germanium, with a total weight of 30 kg, are melted, atomized, dried, oxidized, and sieved in a mass ratio of 75:23:1:1 to obtain a uniform powder of 300 mesh. The powder is then pressed and sintered to form a blank. The experimental parameters for atomization are set at 1150℃, powder oxidation at 650℃ for 24 h, pressing pressure at 200-300 MPa, and sintering at 880℃ for 2.5 h.

[0036] S4. The spindle B obtained in step S2 is hot-extruded into a thick-walled tube, machined to the required specifications, and after post-treatment and cleaning, it is loaded into the blank obtained in step S3 to obtain spindle C. The wall thickness of the thick-walled tube is controlled at 40-50mm and the length is controlled at 300-400mm.

[0037] S5. The spindle C obtained in step S4 is kept at 850°C in a furnace for 4 hours, and then hot-extruded into a shape with a diameter of [missing information]. The extruded wire is drawn into finished wire of the required specifications and then processed into contacts of the required shape and specifications.

[0038] Example 2

[0039] This embodiment is performed according to the following steps:

[0040] S1. Silver ingot, tin ingot, indium, and germanium are in parts by mass of 80, 15, 4, and 1 respectively. The above silver ingot, tin ingot, and additives are melted in a vacuum melting furnace at a melting temperature of 1200℃. After melting, they are continuously cast into 30kg ingots A on a continuous casting machine.

[0041] S2. The spindle A obtained in step S1 is hot-extruded into wire, then drawn to a small size, broken, internally oxidized, post-treated, cleaned and pressed to obtain spindle B, wherein the internal oxidation temperature is 700℃, the oxidation pressure is 0.6~1.5MPa and the oxidation time is 54h.

[0042] S3. A total of 30 kg of silver ingots, tin ingots, manganese, and germanium are melted, atomized, dried, oxidized with special powder, and sieved to obtain a 300-mesh uniform powder in a mass ratio of 85:12:2:1. The powder is then pressed and sintered to form a blank. The experimental parameters for atomization are set at 1150℃, powder oxidation is carried out at 650℃ for 24 hours, pressing pressure is 200-300 MPa, and sintering conditions are sintering at 880℃ for 2.5 hours.

[0043] S4. The spindle B obtained in step S2 is hot-extruded into a thick-walled tube, machined to the required specifications, and after post-treatment and cleaning, it is loaded into the blank obtained in step S3 to obtain spindle C. The wall thickness of the thick-walled tube is controlled at 40-50mm and the length is controlled at 300-400mm.

[0044] S5. The spindle C obtained in step S4 is kept at 850°C in a furnace for 4 hours, and then hot-extruded into a shape with a diameter of [missing information]. The extruded wire is drawn into finished wire of the required specifications and then processed into contacts of the required shape and specifications.

[0045] Example 3

[0046] This embodiment is performed according to the following steps:

[0047] S1. Silver ingots, tin ingots, indium, and germanium are in parts by mass of 85, 12, 2, and 1 respectively. The above silver ingots, tin ingots, and additives are melted in a vacuum melting furnace at a melting temperature of 1200°C. After melting, the ingots are continuously cast into 30kg ingots A on a continuous casting machine.

[0048] S2. The spindle A obtained in step S1 is hot-extruded into wire, then drawn to a small size, broken, internally oxidized, post-treated, cleaned and pressed to obtain spindle B, wherein the internal oxidation temperature is 700℃, the oxidation pressure is 0.6~1.5MPa and the oxidation time is 54h.

[0049] S3. A total weight of 30 kg of silver ingots, tin ingots, manganese, and germanium were melted, atomized, dried, oxidized with special powder, and sieved to obtain a 300-mesh uniform powder in a mass ratio of 88:10:1:1. The powder was then pressed and sintered to form a blank. The atomization experimental parameters were set at 1150℃, the powder oxidation was carried out at 650℃ for 24 hours, the pressing pressure was 200-300 MPa, and the sintering conditions were sintering at 880℃ for 2.5 hours.

[0050] S4. The spindle B obtained in step S2 is hot-extruded into a thick-walled tube, machined to the required specifications, and after post-treatment and cleaning, it is loaded into the blank obtained in step S3 to obtain spindle C. The wall thickness of the thick-walled tube is controlled at 40-50mm and the length is controlled at 300-400mm.

[0051] S5. The spindle C obtained in step S4 is kept at 850°C in a furnace for 4 hours, and then hot-extruded into a shape with a diameter of [missing information]. The extruded wire is drawn into finished wire of the required specifications and then processed into contacts of the required shape and specifications.

[0052] Comparative Example

[0053] S1. Silver ingots, tin ingots, manganese, and germanium, with a total weight of 30 kg, are melted, atomized, dried, oxidized with special powder, and sieved to obtain a 300-mesh uniform powder in a mass ratio of 85:12:2:1. The powder is then pressed and sintered to obtain ingot A. The experimental parameters for melting are 1200℃, the experimental parameters for atomization are 1150℃, the powder oxidation is carried out at 650℃ for 24 hours, the pressing pressure is 200-300 MPa, and the sintering conditions are sintering at 880℃ for 2.5 hours.

[0054] S2. The spindle A obtained in step S1 is kept at 850°C in a furnace for 4 hours, and then hot-extruded into a shape with a diameter of [missing information]. The extruded wire is drawn into finished wire of the required specifications and then processed into contacts of the required shape and specifications.

[0055] The extruded wires obtained in Examples 1-3 above did not exhibit any drawing breakage during the drawing process, and the minimum specification reached... It has excellent processing performance and basically meets the needs of all current wire materials.

[0056] The products from Examples 1-3 were fabricated into rivet contacts. No rivet cracking occurred during the fabrication process, indicating that the processing performance met the requirements for rivet fabrication. Finally, the rivet contacts were assembled into relay products, and electrical performance tests were conducted under the conditions of 250V, 50A, lamp load, 1s on / 9s off, and sealing. The specific results are shown in Table 1 below. It can be seen that the arcing time and electrical life cycles of Examples 1-3 are superior to the comparative examples, with the arcing time reduced by approximately 10ms, a Weibull distribution 95% confidence interval, and an electrical life cycle increase of over 102,000 cycles.

[0057] Table 1. Comparison of different implementation cases and electrical performance.

[0058]

[0059] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for preparing a composite silver-tin oxide electrical contact material based on a thick-walled AgSn tube, characterized in that, Includes the following steps: S1: Melt silver ingots, tin ingots, and additives in a vacuum melting furnace, and continuously cast them into ingot A on a continuous casting machine; S2: The spindle A prepared in step S1 is hot-extruded into wire, drawn and broken, and then subjected to internal oxidation, cleaning and pressing to obtain spindle B; S3: Silver ingots, tin ingots, and additives are melted, atomized, dried, and oxidized into powder, then pressed into shape and sintered to obtain a blank. S4: The spindle B obtained in step S2 is hot-extruded into a thick-walled tube, processed into the required specifications, cleaned, and then the blank prepared in step S3 is inserted into it to obtain spindle C. S5: The spindle C prepared in step S4 is hot-extruded into filament and finally drawn into finished filament of the required specifications.

2. The method for preparing a composite silver-tin oxide electrical contact material based on a thick-walled AgSn tube according to claim 1, characterized in that: In step S1, the silver content of the ingot A is 70%~85%, the tin content is 15%~30%, and the content of additives is 2%~15%.

3. The method for preparing a composite silver-tin oxide electrical contact material based on a thick-walled AgSn tube according to claim 1, characterized in that: In step S1, the additives include at least two of indium, germanium, manganese, cobalt, and titanium.

4. The method for preparing a composite silver-tin oxide electrical contact material based on a thick-walled AgSn tube according to claim 1, characterized in that: In step S3, the silver content of the embryo is 75%~90%, and the tin content is 10%~25%.

5. The method for preparing a composite silver-tin oxide electrical contact material based on a thick-walled AgSn tube according to claim 1, characterized in that: In step S3, the embryo is pressed by isostatic pressing, and the pressing pressure is 200~300MPa.

6. The method for preparing a composite silver-tin oxide electrical contact material based on a thick-walled AgSn tube according to claim 1, characterized in that: In step S2, the internal oxidation temperature is 680~750℃, the internal oxidation pressure is 0.6~1.5Mpa, and the internal oxidation time is 48~72h.

7. A method for preparing a composite silver-tin oxide electrical contact material based on a thick-walled AgSn tube according to any one of claims 1-6, characterized in that: In step S3, the sintering temperature is 750~880℃ and the sintering time is 2~3h.

8. A method for preparing a composite silver-tin oxide electrical contact material based on a thick-walled AgSn tube according to any one of claims 1-6, characterized in that: In step S5, the spindle C prepared in step S4 is kept at 800℃~880℃ for 2~4 hours and then hot-extruded into wire.

9. A method for preparing a composite silver-tin oxide electrical contact material based on a thick-walled AgSn tube according to any one of claims 1-6, characterized in that: In step S5, the spindle C is hot-extruded into extruded wires with a diameter of φ5mm~φ8mm.

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