Microstructures and tribological properties of vacuum plasma sprayed B4C–Ni composite coatings

A promising wear resistant coating has been fabricated via vacuum plasma spray (VPS) technique by using electroless plating composite powders comprised of B4C and different amounts of Ni (10 and 20 vol.%). Tribological evaluation from the ball-on-disk test showed that the wear resistance of the composite coatings was superior to that of the pure B4C coating, and the composite deposit containing 10 vol.% Ni demonstrated the optimum tribological properties. This mainly attributed to the more uniform microstructures of the composite coatings, and the higher thermal conductivity of the composite coating also contributed to its distinguished wear behaviors. For the coatings investigated, the dominant wear mechanism was determined to be oxidation and the formation of a transfer layer on the worn surface.