Research on microstructure and properties of reactive plasma spraying TiN composite coatings
TiN composite coatings were successfully fabricated on 45 steel surface using commercial pure titanium powders by means of reactive plasma spraying technology. The phase composition of the coating was analyzed with XRD. The microstructure,indentation,fracture and worn morphologies of TiN coating were observed through SEM. The indentation composition was analyzed by EDS. The micro-hardness and the wear resistance were also determined as well. Results indicate that the coating is mainly consisted of TiN,TiN0.3 and Ti3O. The coating has typical layer structure,and the layers between coatings or substrates are in good adhesive condition. The micro-hardness of the coating is 983-1 254 HV0.1. The indentation is clear and there is no crack around. The fracture morphology shows that the coating has better toughness and the fracture mechanism is a mixture of ceram-ic and ductile materials. The coating has the best wear resistance when the load is low.