TRIBOLOGICAL CHARACTERISTICS OF MOSI2 SIC NANOCOMPOSITES/

The tribological behavior of surfaces depends on a number of factors i ncluding hardness, elasticity, fracture toughness, adhesion and oxidat ion rate. Many of these are determined unambiguously by the compositio n and microstructure. The ultimate way to modify the microstructure is a refinement of the grain size down to the nanometric scale. This res ults in an increase in hardness and fracture toughness, among other ch anges. The microstructure and mechanical properties of MoSi2/SiC nanoc omposites have been reported elsewhere. The wide variety of microstruc tures of this system with a constant nominal composition provides an e xcellent opportunity to examine the effect of ultimate microstructure modifications on tribological behavior In this work we used a pin-on-d isc test in a controlled humidity of 50% and a steel pin as a counterf ace to investigate the dry sliding properties of MoSi2/SiC nanocomposi tes with two different microstructures. For comparison, single layers of MoSi2 and SiC were examined. The results are discussed in terms of the hardness and elasticity.