Study On The Preparation Of Silver Tin Oxide Electrical Contact Material By Internal Oxidation

AgCdO is an excellent kind of electrical contact material,because of its good resistance to arc erosion and welding resistance,and low contact resistance.So it is called"universal contact".However,during the using of it the"cadmium poison"which is harm to human health will be released,therefore people set out to develop its alternatives.AgSnO₂ is a new type of environmentally friendly electrical contact material with its excellent electrical arc resistance and good welding resistance,thus it is most likely to replace AgCdO.When the content of Sn exceeds 6%in Ag-Sn alloy,the internal oxidation is difficult to complete,so it is difficult to prepare the AgSnO₂ electrical contact material by the conventional internal oxidation process.In this paper,according to the theory of diffusion and metallurgical,the internal oxidation process of Ag-9.5Sn binary alloy is explored and studied,the importance of pre-oxygen degreasing was emphasized,and the internal oxidation technology of alloy pre-oxygen annealing and low-temperature oxidation of putting into cold furnace was put forward,so as to realize the alloy be oxidized completely;The AgSnO₂ material prepared by internal oxidation process with high hardness,So its processing performance is very poor.In this paper,With the application of the property which the SnO₂ particles in AgSnO₂material have a small-scale aggregation under high temperature,The high temperature heat treatment can improve the processing performance of AgSnO₂ material by reducing the hardness.Based on the above technology,the paper has proposed a preparation of“internal oxidation-press-sintering extrusion”,by which the AgSnO₂?12?electrical contact material was prepared successfully.Compared with the powder metallurgy technology which is widely used currently,The mechanical properties and electrical performances of the AgSnO₂?12?electrical contact material prepared by the former process are superior.So far,It is a new breakthrough that the preparation of AgSnO₂ material by internal oxidation of the Ag-Sn binary alloy in China.It will make a positive contribution to the development of the electrical contact materials in China.