Microstructure and wear resistance of in-situ synthesis TiB₂-TiN particulates of composite coating reinforced titanium alloy surface by argon arc cladding

The composite coating reinforced by in-situ synthesized TiB₂ and TiN particulates was prepared on the surface of TC4 alloy by means of argon arc cladding using BN and Ni60A powders as raw materials. The microstructure of TiB₂-TiN composite coating were characterized by means of X-ray diffraction(XRD) and scanning electron microscopy(SEM). The wear properties of coating were examined using friction and wear tester. Experimental results show that three regions with different microstructures existed in the coating, the cladding zone, the binding zone and the heat-affected zone along the depth profile. There is a good metallurgical bonding between the composite coating and the substrate, the TiB₂ and TiN particulates are dispersively distributed in the coating. The composite coating exhibits high microhardness and excellent wear resistance under dry sliding wear test condition. The wear mechanism of the coating is micro-cutting wear and adhesive wear.