Interface strengthening for thermal sprayed WC-10Co4Cr coating subjected to pulsed magnetic treatment

The reliability of the coated industry components demands ideal fatigue properties of the coating, and it is mainly determined by the performance of the interfaces. In this study, pulsed magnetic treatment (PMT) was applied to the thermal sprayed WC-10Co4Cr coating, and the fatigue lifetime of the coated bolt increased by 219.82% under an imitation of the operating mode condition. Scratch tests further proved that both the adhesion and cohesion strength were improved after PMT, and they benefit from the interface strengthening effects. The formation of coherent WC/Co interfaces was characterized by in-situ transmission electron microscopy (TEM), and the molecular dynamic simulations indicate that the work of separation of these interfaces is much higher than the original disordered ones. Residual stress was relaxed and distributed more homogeneously after PMT, and it mainly contributes to the coating/substrate strengthening. This work provides a new post-treatment method focusing on the interfaces in the WC-based coating and gives insight into its mechanism so that it is hopeful to be applied to other kinds of coatings.