| Abstract Scope |
Electrical contacts are manufactured with powder metallurgy technique, typically by Press, Sinter, and Repress process. Contacts physical properties like, density, porosity and metallurgical characteristics are very important for their Switching Duty Performance. After Contacts are subjected to Switching Duty, the surfaces change mainly as a result of reactions between the contact surface and the electrical arc. As a result of arcing, silver metal oxide contacts build up a surface layer, which contains a mixture of metal and slag, fused metal oxide aggregates. Like erosion characteristics, the microstructure of this layer will vary as a result of many factors including contact chemical composition, contact metallurgical characteristics, and switching load. The characteristics of this layer will determine many performance aspects of the contact and in particular both contact resistance and welding resistance. The present investigation is a metallurgical study of electrical contacts and high pole resistance. |