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

High temperature self-lubricating composites Ni3Al–BaF2–CaF2–Ag–Cr 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 0.24–0.37 and a wear rate of 0.52–2.32×10−4 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.

► Ni3Al matrix composite with 20 wt% Cr exhibited favorable tribological behavior from RT to 1000 °C.
► Especially at 800 °C it showed low friction coefficient and wear rate.
► Its excellent tribological behavior could be due to the balance between strength and lubricity.