Frictional Properties of M3B2 Boride Cermet Coating

Abstract The boride cermets composed of M3B2 (M: metal)-system complex borides and metals, have attained superiority over carbide cermets in various mechanical properties. However, their sintered materials have been put into only limited use due to the cost. Therefore, thermal spray coating of the boride cermets was investigated. The powders for thermal spray were prepared by low temperature sintering, and the spraying was performed by HVOF. Microstructure of the sprayed layer was finer, and its hardness was superior to that of a body sintered in vacuum having the same composition. It is clarified that these boride cermet coated layers have outstanding sliding properties. Instantly frictional stress between this boride cermet layer and glass at high temperature is extremely low compared to other materials.