Effect of TiB₂ on microstructure and properties of Ni-based alloy coating by laser cladding

Ni-base alloy and TiB₂/Ni-based alloy metal-ceramics coatings were obtained on low carbon steel surface by 5 kW CO₂ laser.Microstructure, phases, microhardness and sliding wear resistance of the coatings were studied.The results shown that Nibased alloy coating consists of γ-(Ni, Fe), Cr₂₃C₆ etc and TiB₂ Nibased alloy composite coating consists of γ-(Ni, Fe), Ni₃B, TiB₂ and TiC and so on.The Ni-based alloy coating is made up of flourishing γ-(Ni, Fe)dendrite and eutectic structure.Equiaxed solid solution and fine eutectic structure are observed in the TiB₂/Ni-based alloy composite coating.The influence of TiB₂ ceramics on microstructure of coating is prominent that the microstructure of coating is finer and the dendrite crystal gradually becomes equiaxed grain.The microhardness and wear resistance of Ni-based alloy can be improved remarkablely by adding TiB₂.