Effects of composition and age hardening on precious metal electrical contacts

A pin-on-plate experimental configuration was used to evaluate two different palladium-alloy pins (ASTM B540 and ASTM B563) sliding on a gold-alloy plate (ASTM B541) age-hardened at two temperatures. For all combinations of test conditions except the higher-palladium-content alloy (ASTM B563), two stages of wear were observed: (1) a prow of Au alloy was formed on the palladium-alloy pin, and (2) work hardening and roughening of the wear track occurred with transfer and backtransfer of Au-alloy material. With the higher-palladium-alloy pin, a friction polymer was formed for laboratory air testing. Results of pin-on-plate tests for air, low partial pressures of O/sub 2/, and atmospheric pressure He are reported.<>