Silver tin oxide material is a common contact material used in low-voltage electrical appliances. Due to its good resistance to fusion welding and corrosion resistance, it successfully replaces silver cadmium oxide material and is widely used in relays and circuit breakers.At present, there are three main methods of preparing silver-tin oxide electrocontact materials at home and abroad: powder mixing, internal oxidation and chemical method
Blending method is to put the silver and tin oxide powder in a mixed powder machine through mechanical mixing, and the preparation of silver tin oxide wire by the method of powder metallurgy or sheet, this method is simple in process, but the demand of raw materials of powder particle size is very small to get uniform organization, existing mixing equipment is difficult to the preparation of superfine powder, powder led to the law can not meet the requirements of uniformity.
Method, chemical method, the preparation of tin oxide powder first and then tin oxide powder dispersed in aqueous solution and adding reducing agent, adding complexing of silver ions to make silver deposit on the surface of oxide powder, thereby the silver tin oxide powder and composite is prepared by powder metallurgy method of preparation of silver tin oxide wire or sheet, but this method in order to guarantee the morphology of metal silver precipitation reduction, and ensure uniformity requirements, of silver ions to join ammonia complexation, reduction process need to use toxic hydrazine hydrate at the same time, to meet the environmental requirements of subsequent water treatment brings a lot of pressure
