MICROSTRUCTURE AND PROPERTIES OF LASER REMELTED NI-BASED ALLOY SELFLUBRICATING HVOF SPRAYED COATING

摘要

A process of HVOF spraying and laser remelting of a Ni-based alloy nana h-BN powder to form a coating on AISI1045 steel was carried out. Microstructure and frictional properties of HVOF spraying and laser remelted coating were studied. Lamellar structure was obtained in HVOF spraying process, high porosities and lower bonding strength. During the laser remelting process, a reaction between h-BN and Ni occurred, and generated hard phase CrB, Ni3B. Moreover some carbide was deposited in the laser remelted layer. Results show that laser remelting can greatly improve the microstructure of HVOF sprayed nickel/h-BN composite coatings. The remelted coatings with hard phases and lubricant have uniform and dense microstructure, firm interface and higher wear resistance.