Preparation and Study on Performance for Silver Rare-Earth Alloy Electrical Contact Materials

A new type of silver rare-earth alloy contact material AgSnO₂-La₂O₃-Bi₂O₃ is obtained through using a Powder Metallurgy Process. Its preparation process is cold pressing sintering re-pressure and the mixing ratio is Ag: SnO₂: La₂O₃: Bi₂O₃ = 88.7:3.5:1.5. The parameters are chosen as follows: molding pressure is 10 ~ 40t, sintering temperature is 800 ~ 920°C, holding time is 2~8h, re-press pressure is 40t. The densitometer, conductivity meter and hardness tester are used to test the physical performance of the contact material. Through the test the AgSnO₂-La₂O₃-Bi₂O₃ contact material which is obtained at the parameters 30t forming, 920°C×8h sintering, 40t complex pressure has similar physical, mechanical properties to that of AgSnO₂(12) and AgCdO(12). Through experiments the breaking capacity, temperature rise and erosion are better than that of AgSnO₂(12) and AgCdO(12).