Influence of Cr content on tribological properties of Ni₃Al matrix high temperature self-lubricating composites

High temperature self-lubricating composites Ni₃AlBaF ₂CaF₂AgCr were fabricated by powder metallurgy technique. In this paper the effect of Cr content on tribological properties at a wide temperature range starting from room temperature to 1000 °C was investigated. It was found that Ni₃Al matrix composite with 20 wt% Cr exhibited low friction coefficient of 0.240.37 and a wear rate of 0.522.32×10^-4 mm³ N^-1 m^-1. Especially at 800 °C it showed the lowest friction coefficient of 0.24 and a favorable wear rate of 0.71×10^-4 mm³ N^-1 m^-1. This implied that 20 wt% Cr was the optimal Cr content and its excellent tribological performance could be attributed to the balance between strength and lubricity.