Mechanical Properties and Fracture Mechanism of WC-10Co4Cr Coating Sprayed by High Velocity Oxygen Fuel

WC-10Co4Cr coating was prepared on the substrate of stainless steel by high velocity oxygen fuel (HVOF) spraying. The micro-hardness and bond strength of the coating were investigated; phase composition, section and surface morphology was studied; and the fracture mode and mechanism were analyzed as well. The results show that the average micro-hardness of the WC-10Co4Cr coating reached to 1 147.6 HV and the bond strength was 70 MPa. The tensile fracture was with typical characteristics of brittle fracture and there was no significant plastic deformation. The fracture cracks were formed under the external stress due to the pores and microcracks among particles in the coating. These cracks propagated along the interface between particle and particle and were accompanied by deflections of crack paths, then caused the fracture of the coating.