Tribological Behavior of VN-MoS2/Ag Composites over a Wide Temperature Range.

As a type of thermal structure ceramic, vanadium nitride (VN) ceramics are widely used in harsh conditions, such as high temperatures, variable temperatures, or oxidizing atmospheres. However, high friction coefficients and wear rates under wide temperature ranges limit the application of VN in moving parts. In this article, VN-based composites with different contents of MoS₂/Ag lubricants are prepared by vacuum hot-press sintering technology, and the microstructure and tribological behavior of VN-MoS₂/Ag composites over a wide temperature range are studied. The results show that sintered VN-based composites are composed of the VN phase and corresponding MoS₂/Ag lubricants, where MoS₂ and Ag are uniformly distributed in the VN matrix. The tribological behavior of VN-based composites confirms that the addition of MoS₂ lubricant significantly improves the friction coefficient of the VN ceramic at room temperature and 300 °C, whereas the MoS₂/Ag lubricants obviously decrease the friction coefficient of the VN ceramic at room temperature to 700 °C; in particular, the friction coefficient of the VN-MoS₂/Ag composites at 700 °C is lower than 0.17. Furthermore, the synergistic effect between MoS₂ and Ag lubricants is the key factor for the excellent friction coefficient and wear performance of VN-based composites over a wide temperature range. [ABSTRACT FROM AUTHOR]