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

Abstract

According to the preparation method of the composite silver tin oxide electric contact material based on the thick-wall AgSn tube, the strength of an oxide framework is guaranteed by adopting the method for preparing the composite silver tin oxide through the thick-wall AgSn tube, a silver matrix is modified and reinforced, and the uniformity of an oxidation region is guaranteed and oxide particles are finer through a mode of generating oxide in situ. And meanwhile, a working layer on the edge of the manufactured rivet contact is of an internal oxidation process structure, and the rivet contact has excellent arc erosion resistance, especially high-current arc erosion resistance. According to the extrusion method for the composite silver tin oxide blank in the AgSn tube, the proportion can be adjusted at will according to needs, the problem of difficult oxidation is avoided, and the prepared material is better in plasticity, low in hardness and easy to machine.

Description

Technical Field

[0001] The invention relates to the field of electric contact materials, and in particular to a method for preparing a composite silver tin oxide electric contact material based on a thick-walled AgSn tube. Background Art

[0002] In the 21st century, AI technology and new energy technology have emerged and developed rapidly, and people's lives are gradually moving towards intelligence, automation and greenness. At present, AgMeO is the most widely used electrical contact material. With the continuous strengthening of people's environmental awareness, people have begun to refuse to use silver cadmium oxide electrical contact materials and promote the research and production of silver tin oxide environmentally friendly electrical contact materials. Silver tin oxide is widely used in many fields such as household appliances, automobiles, new energy, energy storage, 5G, aerospace, etc.

[0003] Silver tin oxide material has good thermal stability. Tin oxide is not easy to decompose under the action of electric arc. Tin oxide particles in the silver molten pool can increase the viscosity of the molten metal, so that it is not easy to splash and reduce the amount of arc erosion. However, the highly stable tin oxide itself has a high hardness. After arc ablation, it will tend to condense on the contact surface, and the contact resistance will increase. This has become the main problem of silver tin oxide materials. And as the oxide content increases, the molding and processing performance of silver tin oxide electrical contact materials will deteriorate sharply, and even cannot be processed. A series of improvements have been made in the prior art:

[0004] (1) The invention patent with publication number CN102268583A discloses a method for preparing a silver tin oxide electrical contact material. The patent melts tin and additive metals in a medium frequency melting furnace in a certain proportion, atomizes them into tin alloy powder after complete alloying, oxidizes the tin alloy powder into tin oxide composite powder under certain conditions, mechanically mixes the composite powder with silver powder, and processes them into silver tin oxide wires of certain specifications 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 performance;

[0005] (2) The invention patent with publication number CN105702503A discloses a method for preparing a silver tin oxide indium oxide contact material. The 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 the advantages of low bulk resistance, low hardness, good processing performance, and good anti-welding performance;

[0006] (3) The invention patent with publication number CN105200262B discloses a method for preparing a silver-based sheet electrical contact material with a high tin oxide content. The patent compresses powder into ingots, sintering them in a protective atmosphere, breaking them into blocks and oxidizing the blocks. The ingots are then crushed and molded into ingots, and then processed into silver tin oxide sheets through hot pressing, sintering, extrusion, rolling and punching. The silver tin oxide electrical contact material prepared by this method has the characteristics of high oxide content, coarse oxide particles, good processing performance and uniform structure;

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

[0008] However, the high-oxide-content silver electrical contact materials prepared by the above-mentioned patents (1), (2), and (3) using methods such as alloy atomization powder making, tin-indium alloy doping, and crushing and pressing into ingots have poor burning performance during actual application, and are increasingly unable to meet the current trend of high-performance development; Patent (4) uses an alloy melt to prepare alloy spheres by direct internal oxidation. The center point of the sphere prepared by this method is prone to form an oxide-poor zone, resulting in a reduction in the proportion of normal tissue, which affects the electrical life of the contact material. Summary of the invention

[0009] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art 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 by the present invention is as follows: A method for preparing a composite silver tin oxide electrical contact material based on a thick-walled AgSn tube comprises the following steps:

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

[0012] S2: hot-extrude the ingot A prepared in step S1 into a wire, draw and punch, and obtain the ingot B after internal oxidation, cleaning and ingot pressing;

[0013] S3: melting and atomizing the silver ingot, tin ingot and additives, drying and oxidizing the powder, and then pressing and molding, and sintering to obtain an embryo;

[0014] S4: the ingot B obtained in step S2 is hot-extruded into a thick-walled tube, processed into the required specifications, and after cleaning, the embryo body prepared in step S3 is loaded into it to obtain an ingot C;

[0015] S5: hot-extrude the ingot C prepared in step S4 into a wire, and finally draw it into a finished wire of required specifications.

[0016] Preferably, in step S1, the silver content of the ingot A is 70% to 85%, the tin content is 15% to 30%, and the content of the additive is 2% to 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 body is 75% to 90%, and the tin content is 10% to 25%.

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

[0020] Preferably, in step S3, the embryo body is pressed by 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 ingot C prepared in step S4 is kept at a temperature of 800° C. to 880° C. for 2 to 4 hours and then hot-extruded into a wire.

[0024] Preferably, in step S5, the ingot C is hot extruded into a diameter of of extruded wire.

[0025] The beneficial effects of the present invention are as follows: The present invention adopts a method for preparing composite silver tin oxide by using a thick-walled AgSn tube, which ensures the strength of the oxide skeleton, modifies and strengthens the silver matrix, and generates oxides in situ to ensure the uniformity of the oxidation zone, and the oxide particles are finer. At the same time, the edge working layer of the manufactured rivet contact is an internal oxidation process organization, which has excellent arc erosion resistance, especially high current arc erosion resistance. The AgSn tube composite silver tin oxide embryo extrusion method can arbitrarily adjust the proportion according to needs, and there will be no problem of oxidation difficulty. The obtained material has better plasticity, low hardness, and is easy to process. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still belong to the scope of the present invention.

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

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

[0029] Figure 3 The metallographic photograph of the silver tin oxide material prepared by the present invention. DETAILED DESCRIPTION

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

[0031] Example 1

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

[0033] S1. Silver ingot, tin ingot, indium, germanium are 70, 25, 4, 1 parts by mass respectively, the silver ingot, tin ingot, additives are melted in a vacuum melting furnace, wherein the melting temperature is 1200 ° C, after the melting is completed, the ingot A of 30 kg is continuously cast on a continuous casting machine;

[0034] S2. The ingot A obtained in step S1 is hot extruded into a wire, then drawn into a small size, punched, internally oxidized, post-processed, cleaned and pressed to obtain an ingot B, wherein the internal oxidation temperature is 700°C, the oxidation pressure is 0.6-1.5MPa, and the oxidation time is 54h;

[0035] S3. A total weight of 30 kg of silver ingots, tin ingots, manganese and germanium were melted and atomized in a mass ratio of 75:23:1:1, dried, oxidized and sieved to obtain a 300 mesh uniform powder, which was then pressed and sintered to obtain an embryo body, wherein the experimental parameters of atomization were set at 1150°C, powder oxidation was oxidized at 650°C for 24h, pressing pressure was 200-300MPa, and sintering conditions were sintering at 880°C for 2.5h;

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

[0037] S5. The ingot C obtained in step S4 is kept in a heating furnace at 850°C for 4 hours and then hot extruded into a diameter of extruded wire; finally drawn into the finished wire of required specifications and processed into contacts of required shape and specifications.

[0038] Example 2

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

[0040] S1. Silver ingot, tin ingot, indium, germanium are 80, 15, 4, 1 parts by mass respectively, the silver ingot, tin ingot, additives are melted in a vacuum melting furnace, wherein the melting temperature is 1200 ° C, after the melting is completed, the ingot A of 30 kg is continuously cast on a continuous casting machine;

[0041] S2. The ingot A obtained in step S1 is hot extruded into a wire, then drawn into a small size, punched, internally oxidized, post-processed, cleaned and pressed to obtain an ingot B, wherein the internal oxidation temperature is 700°C, the oxidation pressure is 0.6-1.5MPa, and the oxidation time is 54h;

[0042] S3. A total weight of 30 kg of silver ingots, tin ingots, manganese and germanium are melted and atomized in a mass ratio of 85:12:2:1, dried, oxidized with special powders, and sieved to obtain a 300 mesh uniform powder, which is then pressed and sintered to obtain an embryo body, wherein the experimental parameters for atomization are set at 1150°C, the powder oxidation is oxidized at 650°C for 24h, the pressing pressure is 200-300MPa, and the sintering conditions are sintering at 880°C for 2.5h;

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

[0044] S5. The ingot C obtained in step S4 is kept in a heating furnace at 850°C for 4 hours and then hot extruded into a diameter of extruded wire; finally drawn into the finished wire of required specifications and processed into contacts of required shape and specifications.

[0045] Example 3

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

[0047] S1. Silver ingot, tin ingot, indium, germanium are 85, 12, 2, 1 parts by mass respectively, and the above silver ingot, tin ingot, additive are melted in a vacuum melting furnace, wherein the melting temperature is 1200 ° C, and after the melting is completed, the ingot A of 30 kg is continuously cast on a continuous casting machine;

[0048] S2. The ingot A obtained in step S1 is hot extruded into a wire, then drawn into a small size, punched, internally oxidized, post-processed, cleaned and pressed to obtain an ingot B, wherein the internal oxidation temperature is 700°C, 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 and atomized in a mass ratio of 88:10:1:1, dried, oxidized with special powders, and sieved to obtain a 300-mesh uniform powder, which was then pressed and sintered to obtain an embryo body, wherein the experimental parameters for atomization were set at 1150°C, the powder oxidation was oxidized at 650°C for 24h, the pressing pressure was 200-300MPa, and the sintering conditions were sintering at 880°C for 2.5h;

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

[0051] S5. The ingot C obtained in step S4 is kept in a heating furnace at 850°C for 4 hours and then hot extruded into a diameter of extruded wire; finally drawn into the finished wire of required specifications and processed into contacts of required shape and specifications.

[0052] Comparative Example

[0053] S1. The silver ingot, tin ingot, manganese and germanium with a total weight of 30 kg are melted and atomized, dried, oxidized with special powders, and sieved according to the mass ratio of 85:12:2:1 to obtain a 300-mesh uniform powder, which is then pressed and sintered to obtain ingot A, wherein the experimental parameters for melting are 1200°C, the experimental parameters for atomization are set at 1150°C, the powder oxidation is oxidized at 650°C for 24h, the pressing pressure is 200-300MPa, and the sintering conditions are sintering at 880°C for 2.5h;

[0054] S2. The ingot A obtained in step S1 is kept in a heating furnace at 850°C for 4 hours and then hot extruded into a diameter of extruded wire; finally drawn into the finished wire of required specifications and processed into contacts of required shape and specifications.

[0055] The extruded wires prepared in the above-mentioned embodiments 1-3 did not break during the drawing process, and the minimum specification reached It has excellent processing performance and basically meets all current wire material needs.

[0056] The products of the above-mentioned embodiments 1-3 were made into rivet contacts, and no rivet cracking problem occurred during the making process, which shows that the processing performance meets the requirements of rivet making. Finally, the rivet contacts were assembled into relay products, and electrical performance tests were carried out under the conditions of 250V, 50A, lamp load, 1s on and 9s off, and sealing test. The specific results are shown in Table 1. It can be seen that the arcing time and electrical life times of embodiments 1-3 are better than those of the comparative example, wherein the arcing time is reduced by about 10ms, the Weibull distribution 95% confidence interval, and the electrical life times are increased by more than 102,000 times.

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

[0058]

[0059] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to 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: The following steps are involved: S1: melt the silver ingot, tin ingot and additives in a vacuum melting furnace and continuously cast them into ingot A on a continuous casting machine; S2: hot-extrude the ingot A prepared in step S1 into a wire, draw and punch, and obtain the ingot B after internal oxidation, cleaning and ingot pressing; S3: The silver ingot, tin ingot and additives are melted, atomized, dried, and the powder is oxidized, then pressed into a shape, and then sintered to obtain an embryo; S4: the ingot B obtained in step S2 is hot-extruded into a thick-walled tube, processed into the required specifications, and after cleaning, the embryo body prepared in step S3 is loaded into it to obtain an ingot C; S5: hot-extrude the ingot C prepared in step S4 into a wire, and finally draw it into a finished wire of 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% to 85%, the tin content is 15% to 30%, and the content of the additive is 2% to 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 body is 75% to 90%, and the tin content is 10% to 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: The balance is additives, specifically two or more of indium, germanium, manganese, cobalt, and titanium, in an amount of 2 to 10 parts by mass.

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 S3, the embryo body is pressed by isostatic pressing, and the pressing pressure is 200-300 MPa.

7. 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°C, the internal oxidation pressure is 0.6-1.5 MPa, and the internal oxidation time is 48-72 hours.

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 to 7, characterized in that: In step S3, the sintering temperature is 750-880° C., and the sintering time is 2-3 hours.

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 to 7, characterized in that: In step S5, the ingot C prepared in step S4 is kept at a temperature of 800° C. to 880° C. for 2 to 4 hours and then hot-extruded into a wire.

10. 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 to 7, characterized in that: In step S5, the spindle C is hot extruded into an extruded wire with a diameter of φ5 mm to φ8 mm.

Images