Electric Contact Strengthening to Improve the Bonding Between WC-Co Coating and 45# Steel Substrate

Adhesion between thermally sprayed coating and the substrate is a type of mechanical bonding. In many cases, the adhesion strength is relatively low. In this study, an electric contact surface strengthening method was used to improve the bonding between thermally sprayed WC/Co coating and 45# steel substrate. Electric contact strengthening equipment was made for this research. Localization of resistive heating was obtained by passing 12-18 kA current through the contact between the electrode and the workpiece, the small size of the contact imposed a severe constriction on the current causing intense resistive heating the contact. In this way, the bonding way between the WC/Co coating and the 45# steel substrate would be changed from mechanical bonding to metallurgical bonding. Orthogonal array design was applied to select the optimum conditions. The effects of different factors and levels have been studied using a statistic method.