Abstract: With BN and Ni60A alloy powder as raw material and adopting the heat source of argon arc cladding,ceramic particle composite coat was in-situ synthesized on the Ti6Al4V alloy surface.Thermodynamic calculation,scanning electron microscope line scanning and X-ray diffraction analysis confirm that the ceramic particle is TiB₂-TiN.The microstructure of the coating was observed under SEM,and the formation mechanism of the TiB₂-TiN particles was investigated.The experimental results show that with appropriate alloy powder composition and cladding process parameters,TiB₂-TiN particles composite coat is liable to form.The fine and even distributed particles are combined with matrix metallurgically.The microstructure of composite coating layer is divided into coating zone,bonding zone with and heat affected zone.The shape of TiB₂ is bar and fine strip,and the TiN is granular.