Deposition of WC-Co Coatings Using a Novel High Pressure HVOF

WC-Co coating is primarily deposited by the high velocity oxy-fuel (HVOF) spray process. However, the decomposition and decarburization of tungsten carbide during spraying process will degrade the wear resistance of the coating. In this paper, a novel high pressure HOVF with a characteristic of lower flame temperature and higher velocity, operated at a combustion pressure up to 3.0MPa was used to deposit WC-Co coating. The microstructure and the microhardness of the coatings, as well as the deposition efficiency deposited under different spray conditions were investigated. The comparison to the conventional HVOF sprayed WC-Co coating is carried out. The results reveal that the stoichiometric ratios of oxygen/fuel gives significant influence on the morphology of WC particles and the binder phase in the coatings. The microhardness of the coatings are comparable or higher than that of the conventional HVOF sprayed coating at higher stoichiometric ratios of oxygen/fuel.