A model of splats deposition state and wear resistance of WC-10Co4Cr coating

In this research both low temperature high velocity oxygen-fuel flame (LT-HVOF) and high velocity oxygen-fuel flame (HVOF) techniques were employed to prepare WC-10Co4Cr splats and coatings. In situ cutting of WC-10Co-4Cr splats was carried out with focused ion beam (FIB), and a model was proposed to describe how the wear resistance of WC-10Co4Cr coatings was correlated with its residual stress state and the splats deposition state. It was observed that in LT-HVOF spraying process, WC-10Co4Cr splats were slightly melted showing "hill" shape, while in HVOF spraying process, the splats were half melted having the appearance of "concavity". The residual stress of WC-10Co4Cr coatings is determined by the size, melting state, flight speed and temperature gradient of splats. In this paper, the quantitative function formula involving heating temperature and the flight speed of the powder is put forward for the first time to predict the wear resistance of the WC-10Co4Cr coatings. This will provide a theoretical basis for engineering practice and an effective way to save costs.