Effect Of Texture On Bonding Strength Of High Velocity Oxyfuel Spraying Coatings

HVOF(high velocity oxyfuel spraying)WC-Co coating has excellent comprehensive performance.The coating material achieved by HVOF have low porosity,high bonding strength,high microhardness and high wear resistance.In recent years,The HVOF research obtained rapid development.also have made great achievement.Similarly,the surface texture can change the contact characteristics of the substrate surface,such as wear resistance,noise reduction and so on,It has peculiar surface modification ability.Research on the effect of coating bonding strength of texture,It is of great theoretical significance and practical value to improve the interfacial bonding strength,strengthen the protective performance of coating and prolong the service life of the coating.The main research content was as follows:1.The regular micro-textured on the surface of 304 stainless steel were processed by the method of single point diamond scratch.The surface morphology of scratch was observed by using the ultra deep field microscope,and the difference of the scratch depth and the scratch distance was observed.2.Compared with the untexured coating,The influence of different parameters on the tensile stress distribution at the interface between the coating and the substrate was simulated by the finite element method.the stress concentration of crack tip were analysed by finite element analysis,It will help the evaluation of bond strength of high-strength coatings.3.High velocity oxyfuel spraying WC-Co coating on the surface of the processed groove.symmetrical U cuts were cut along the interface of the coating/substrate exactly by wire cutting,the same size of the block bonding which were parallel to interface between the coating and the substrate were adhered.Then,the tensile strength of different parameters of the texture on the tensile testing machine was studied.The average fracture stress of the coating and substrate and the crack propagation path of the coating were obtained.The research results show that under tensile stress,crack tip stress concentration obviously promoted the brittle fracture of high strength coating/substrate interface,The bonding strength of the coating can be improved in a relatively reasonable range of texture parameters.