High temperature tribological behaviors of MoAlB ceramic from 800 to 1200°C

Abstract

The tribological behaviors of MoAlB ceramic were studied using different counterpart materials under 800–1200 °C, and the influences of the counterpart material and temperature are intensively discussed. The results indicate that MoAlB shows outstanding wear resistance (the wear rate is within 10−6 mm3·N−1·m−1) under 800–1200 °C and excellent lubricating performance at 1200 °C (the friction coefficient is as low as 0.3), which is almost the best performance reported for ceramics at high temperature so far. Besides, the counterpart ball with higher hardness always causes higher wear rate of MoAlB. However, the effect of the temperature is closely related to the hardness and the oxidation degree of MoAlB disc. At 800–1000 °C, the wear mechanism is mainly the abrasive wear because of the uncompact Al2O3 product. At 1200 °C, the low-shear plastic deformation of the nanocrystalline Al2O3 layer and the discontinuous MoO3 film together result in the excellent tribological behaviors of MoAlB.