Ni3Al matrix high temperature self-lubricating composites

A Ni3Al matrix high temperature self-lubricating composite Ni3Al–BaF2–CaF2–Ag–Cr was fabricated by the powder metallurgy technique, and tribological behavior at a wide temperature range from room temperature to 800 °C was investigated. The results indicated that the composite exhibited low friction coefficients (0.30–0.36) and wear rates (0.65–2.45×10−4 mm3 N−1 m−1). It was found that the low friction coefficient was attributed to the synergistic effects of Ag, fluorides and chromates formed in the tribo-chemical reaction at high temperatures. The low wear rate of the composite was due to the high strength and the excellent lubricating properties.

Research highlights
► A high temperature self-lubricating composite Ni3Al–BaF2–CaF2–Ag–Cr synthesized by the powder metallurgy technique showed good tribological property at a wide temperature range from room temperature to 800 °C.
► The low friction coefficient was attributed to the favorable mechanical strength and the synergistic effects of Ag, fluorides and chromates formed in the tribo-chemical reaction at high temperatures.
► The low wear rate was attributed to the high strength and the excellent lubricating properties of the composite.