Tribological behaviors of SiC/h-BN composite coating at elevated temperatures

In this paper, the tribological behaviors of SiC/hexagonal boron nitride (SiC/h-BN) composite coating prepared by pack cementation on carbon/carbon (C/C) composites were investigated, comparing with those of SiC coating. The worn surfaces and wear debris of these coatings were analyzed by means of scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that the h-BN addition can stabilize the friction coefficient of SiC coating at room temperature. At 600 °C the tribological behaviors of both coatings showed similar feature with high friction coefficient and negligible wear rate. At 800 °C the SiC coating underwent severe wear, while the SiC/h-BN composite coating exhibited self lubricity and possessed lower friction coefficient and smaller wear rate than SiC coating.