Self-healing performance and wear resistance of electro-spark deposition TiVCrNiSi0.1 coating on Ti6Al4V alloy at high temperature

Heat accumulation and rapid cooling during the electro-spark deposition (ESD) process led to the inevitable occurrence of cracks. In this paper, TiVCrNiSi0.1 ESD coatings were prepared on the surface of Ti6Al4V. The TiVCrNiSi0.1 ESD coatings presented excellent resistance to oxidation and possessed a self-healing ability for crack inside of coating at high temperatures. The oxidation kinetics of TiVCrNiSi0.1 coatings at 700 degrees C conform to the parabolic law, the oxidation rate of TiVCrNiSi0.1 coating at 700 degrees C compared with Ti6Al4V decreased by 15 %. During the oxidation process at 700 degrees C, the initial cracks in the TiVCrNiSi0.1 coating self-healed due to the formation of oxides. During the formation of oxides at high temperature, a Laves phase with amorphous SiO2 on the surface is formed at the interface between the coating and the oxide layer. The existence of amorphous phase can effectively prevent the external diffusion of alloying elements and the internal diffusion of O. The TiVCrNiSi0.1-oxide composite coating has excellent wear resistance. The hardness of TiVCrNiSi0.1 coatings after self-healing at high temperature was 3.9 times that of the Ti6Al4V substrate, and the wear rate is reduced by about 80 % compared to Ti6Al4Vsubstrate.