CN-122013094-A - Method for preparing dispersion strengthening silver-tin-indium alloy electric contact material by using water vapor internal oxidation method

Abstract

The invention provides a method for preparing a dispersion-strengthened silver-tin-indium alloy electric contact material by a steam internal oxidation method, and belongs to the technical field of preparation of electrical alloy materials. And (3) placing the silver-tin-indium alloy workpiece in a tubular oxidation furnace, introducing argon with certain relative humidity, and carrying out internal oxidation treatment at high temperature and normal pressure. The invention utilizes high-temperature steam decomposition to provide oxygen atoms, so that the oxygen atoms are diffused into a silver matrix and selectively oxidized to react with Sn, in and Te which are In solid solution, and SnO 2 、In 2 O 3 and TeO 2 dispersion strengthening phases are generated In situ In the alloy. The method avoids the problem of silver enrichment area caused by precipitation and aggregation of indium and tin elements in an oxidized workpiece caused by high-pressure pure oxygen in the traditional internal oxidation process, has simple process and environment friendliness, and the obtained material has uniform internal oxide dispersion and excellent hardness, and is suitable for electric contact elements under low-pressure, medium-high-current loads.

Inventors

• TAN XIAOYUE
• QU YINGHAO
• WU YUCHENG
• LUO LAIMA
• Xie Siyao
• PAN YAFEI

Assignees

• 合肥工业大学

Dates

Publication Date

20260512

Application Date

20260214

Claims (8)

1. 1. A method for preparing a dispersion strengthening silver-tin-indium alloy electric contact material by a water vapor internal oxidation method is characterized In that the internal oxidation of the silver-tin-indium alloy is realized at high temperature and normal pressure by utilizing water vapor under a protective atmosphere, the water vapor is decomposed at high temperature to generate low oxygen partial pressure, oxygen atoms are diffused into a silver matrix to perform selective oxidation reaction with solid-solution Sn, in and Te, and nano SnO 2 、In 2 O 3 and TeO 2 dispersion strengthening phases are generated In situ, so that an obtained oxidized workpiece does not exist or has less silver enrichment area caused by oxide precipitation aggregation, and has excellent physical properties.
2. 2. The method of claim 1, wherein the protective atmosphere is argon, and a mixed gas of the argon and steam is continuously and synchronously introduced, and the argon with the relative humidity of 35% -45% at the temperature of 16-20 ℃ is regulated to participate in the internal oxidation reaction of the silver-tin-indium alloy.
3. 3. The method of claim 1, wherein the silver-tin-indium alloy has an internal oxidation reaction temperature of 750-850 ℃ and a reaction time of 25-30 hours.
4. 4. The method of claim 1, comprising the steps of: (1) Preparing a sample, namely providing a silver-tin-indium alloy workpiece to be treated, wherein the silver-tin-indium alloy workpiece comprises 6-7wt% of Sn, 3-4wt% of In, less than or equal to 0.5 wt wt% of Te and the balance of Ag, wherein the silver-tin-indium alloy is a single-phase solid solution obtained by dissolving Sn, in and Te elements In an Ag matrix; (2) Placing the silver-tin-indium alloy workpiece in a tubular oxidation reaction furnace, exhausting air in the furnace in the processes of vacuumizing and argon filling, then filling inert gas argon, wherein the system is in a flowing atmosphere, and the pressure in the furnace is normal pressure; (3) Oxidizing, namely heating the system In the tubular oxidation reaction furnace to 750-850 ℃, and then filling a mixed atmosphere which takes inert gas argon as carrier gas and carries water vapor, wherein the mixed atmosphere is subjected to thermal insulation oxidation treatment for 25-30 hours, so that oxygen atoms diffuse through a silver matrix and are subjected to selective internal oxidation reaction with Sn, in and Te In the mixed atmosphere; (4) And (3) after the heat preservation is finished, cooling to 200 ℃ along with the furnace under the argon atmosphere, then continuing to air-cool to room temperature, and taking out the workpiece.
5. 5. The method of claim 4, wherein argon with a relative humidity of 35% -45% at a temperature of 16-20 ℃ is regulated in the step (3) to participate in the internal oxidation reaction of the silver-tin-indium alloy.
6. 6. The method of claim 4, wherein the flow rate of the mixed atmosphere of argon-carrying water vapor in step (3) into the tubular oxidation reactor is 16 sccm.
7. 7. The dispersion-strengthened silver-tin-indium alloy electrical contact material prepared by the method according to any one of claims 1-6, wherein SnO 2 、In 2 O 3 and TeO 2 particles are uniformly dispersed in the silver matrix, a complete inner oxide layer is formed from the outside to the inside, the thickness of the inner oxide layer penetrates through the whole thickness of the workpiece, and no or few silver enrichment areas exist.
8. 8. A silver tin oxide indium oxide workpiece prepared by the method of any one of claims 1 to 6.

Description

Method for preparing dispersion strengthening silver-tin-indium alloy electric contact material by using water vapor internal oxidation method Technical Field The invention belongs to the technical field of electrical alloy material preparation, relates to a method for performing controllable internal oxidation on silver-tin-indium alloy by using water vapor as an oxygen source, and in particular relates to a method for preparing a dispersion strengthening type silver-tin-indium alloy electric contact material by using a water vapor internal oxidation method. Background Silver is an irreplaceable base material in the field of electrical contact materials due to its excellent electrical conductivity, thermal conductivity and excellent processability. The application of the silver-based oxide composite material in the field of electric contact improves the defects of soft texture, poor arc erosion resistance, easiness in material migration and the like of a pure silver material. By introducing high-melting-point and high-stability oxide particles (such as SnO 2, cuO, znO and the like) which are dispersed and distributed into a silver matrix, wherein AgSnO 2 gradually replaces the traditional AgCdO due to the advantage of environmental protection, the hardness, the wear resistance, the fusion welding resistance and the arc erosion inhibition capability of the material can be obviously improved, so that the electric life and the mechanical life of an electric appliance are greatly prolonged on the premise of ensuring good conductive contact. Currently, the preparation and performance core bottlenecks of silver-based oxide composites are the uniformity of distribution of the second phase oxide, the particle size and its interfacial bonding state with the silver matrix (silver enrichment due to oxide precipitation). The internal oxidation technology is a key method for preparing the high-performance dispersion strengthening silver-based electric contact material. The principle is that oxygen reacts with alloy elements (such as Sn, in, cd and the like) In solid solution by utilizing high diffusion rate of oxygen In silver and low diffusion rate of oxygen In alloy elements, so that uniform and fine oxide particles are generated In the silver, and an oxide film is not formed on the surface, so that the strength, the hardness and the arc resistance of the material are greatly improved on the premise of not obviously damaging the conductivity. The traditional internal oxidation method is mainly divided into two types, namely, an alloy piece is placed in a high-pressure pure oxygen atmosphere, a compact oxidation layer is easily formed on the surface of the alloy piece by the method, oxygen is prevented from further diffusing to the inside to cause incomplete oxidation, and oxygen is provided by powder decomposition by adopting a metal oxide powder (such as Cu 2 O, pbO) embedding method, but the process is complex, the workpiece is easy to pollute, and the oxygen partial pressure is difficult to control. Therefore, the internal oxidation process of the alloy commonly adopted in the current industry is difficult to thoroughly avoid the phenomenon of silver enrichment caused by macroscopic segregation of oxide particles and uneven oxide distribution, and the uneven microstructure directly causes uneven current distribution, aggravated local temperature rise and concentrated arc erosion of the material during working, so that contact resistance fluctuation is increased, temperature rise exceeds standard and even contact failure is caused, and is a key commonality problem for restricting product performance consistency and stability. Particularly, if the silver-tin-indium alloy in the field of electric contact materials is internally oxidized in high-pressure pure oxygen atmosphere, a silver enrichment area exists in the oxidized workpiece, so that the conductivity, arc resistance and hardness of the material are reduced, and the service life of the material is not facilitated. Therefore, finding a new method with controllable oxygen partial pressure, clean process and uniform internal oxidation is always a research difficulty in the field. The water vapor can be decomposed at a certain temperature to provide controllable oxygen atoms, a potential new oxygen source is provided for internal oxidation, the internal oxidation of the silver-tin-indium alloy can be realized at high temperature and normal pressure, the process is simple and environment-friendly, the obtained material has uniform internal oxide dispersion, and the material has excellent hardness and is suitable for electric contact elements under low load. The method is applied to silver-tin-indium alloy with specific components, and the influence of oxidation time on the material structure and the electrical contact performance is systematically researched, and has not been reported. In view of this, the invention provides a method for preparing a dispersion-str