A novel strategy for designing Fe-Ni gradient multilayer coatings using laser-assisted electrodeposition and regulation mechanism

Abstract

This study proposed a new process strategy to obtain Fe-Ni multilayer gradient structure. Laser irradiation was introduced into the electrochemical deposition (ECD) process. Based on activation and diffusion control steps, the regulation of element content is realized by adjusting laser parameters. In addition, the surface quality, internal structure, and performance of the coating prepared by laser-assisted ECD were evaluated. The results show that laser irradiation can reduce surface defects and roughness without changing the internal structure. Laser irradiation improves the uniformity of element content distribution and reduces the Fe content. In the same deposition time, the coating's thickness increased by approximately 91.2 %. The element content delamination was successfully achieved by changing the laser parameters without changing the electrochemical parameters. The main mechanism is that laser irradiation increases the limiting current density and inhibits diffusion control. Compared with monolithic ECD coatings, the mechanical properties and corrosion resistance are improved. According to the control mechanism, the preparation of gradient structures along the horizontal direction of the substrate is verified.