Microstructure and high temperature sliding wear behaviour of laser remelted NiCrBSi/35(WC-12Ni) composite coating

摘要

Plasma sprayed NiCrBSi/WC-Ni composite coating and corresponding laser remelted coating were prepared on 1Cr18Ni9Ti stainless steel substrate. The microstructures of coatings were characterised by means of scanning electron microscopy equipped with energy dispersive spectrometry (SEM/EDS). The friction and wear properties for both coatings were comparatively investigated from room temperature to 800°C. Results revealed that the as remelted coating possessed a denser microstructure with pore and crack free and a higher microhardness than the as sprayed coating. At the same time, fiction and wear tests indicated the laser remelted coating exhibited a better wear resistance than the plasma sprayed coating from room temperature to 600°C, while the wear resistance of the former was inferior to that of the latter at elevated temperature of above 600°C. Their detailed wear mechanisms were also discussed in terms of microstructures, mechanical properties and worn surfaces of coatings as well as corresponding worn surfaces of Si_3N_4 ball.