Effect of Current Density on Microstructure and Frictional Properties of CoNiCrC Coatings on Cutting Tools

The CoNiCrC coating was prepared by jet electrodeposition on the cutting tool with Cr₃C₂ particles as the reinforcement.The deposition amount of Cr₃C₂ particles under different current densities was compared, and the microstructure, hardness, element content, and wear resistance of CoNiCrC coating were tested.The results show that with the increase of current density, Co content decreases, Cr₃C₂ ratio first increases and then decreases, and particle content increases to 12.1% at 40 A/dm².The coating and substrate are in good bonding state, and a compact structure is formed.At this time, Co crystal with dense hexagonal structure and Cr₃C₂ phase are formed in the coating, and the increase of current density does not affect the phase structure of the coating.With increasing current density, the hardness of CoNiCrC coating first increases and then decreases.When the current density is 40 A/dm²,the coating hardness increases to 586 HV.After increasing the current density, the wear volume of the coating first decreases and then increases.The coating reaches a minimum wear volume at a current density of 40 A/dm².The addition of Cr₃C₂ particles in the coating results in stronger dispersion enhancement and better resistance to friction.