The impact of process changes on the physical properties and formability of silver metal oxide contact materials

The physical characteristics of electrical contact materials are influenced by the method and process parameters used in their manufacture. This study examines internally oxidized silver metal oxide contact materials manufactured using two casting methods (vertical, semi-continuous casting and horizontal, continuous casting), grain refining additives, and variations to the internal oxidation temperature. The impact of these changes on the physical characteristics (oxide particle size and distribution, grain structure, and mechanical properties) and the effect on formability was evaluated in order to understand the consequences of these changes on the ability to fabricate finished electrical contacts. The results indicate that additives and oxidation temperature influence formability by altering the oxide particle size, geometry, and distribution. However, the method of casting had little or no influence on the formability of the material.