Effects of sliding speed and testing temperature on the tribological behavior of a nickel-alloy based solid-lubricating composite

High temperature solid lubricating materials show important demands in applications for moving machine assemblies under extreme operating conditions. In this study, the tribological behavior of a nickel-alloy based self-lubricating composite (82.5%nickel-alloy–12.5%Ag–5%BaF₂/CaF₂) against Si₃N₄ ball was evaluated under various temperatures and sliding speeds. Results showed that the friction coefficient and wear rate of the composite were greatly dependent on testing temperature and sliding speed. The composite exhibited favorable lubricity in the wide temperature range from 25 °C to 800 °C. The friction and wear mechanisms were explored by observing and analyzing the worn surfaces.