Effect of Adding Y₂O₃ on Microstructure of TiB₂ and TiC Reinforced Ni-Based Composite Coating In-Situ Synthesized by Laser Cladding

TiB2 and TiC particles reinforced Ni-based composite coatings were in-situ synthesized by laser cladding on Ti6Al4V alloy surface. The effect of adding 2wt% Y2O3 content on microstructure of the coating was studied by X-ray diffraction, optical microscopy, scanning electron microscopy and energy dispersive spectroscopy. The results show that the coating without Y2O3 consisted of reinforcement phases, a small quantity of CrB and the substrate. After adding Y2O3, the size of reinforcement phase TiB2 was refined greatly and and a new phase Ni3Y was found, and the number of CrB compound decreased. A metallurgical bonding was formed between the coating and substrate and the interface became smoother and more compact. The composition transition zone was reduced to a certain extent tecame.