A novel electrochemical deposited Fe Ni coating designed by laser-induced periodic current density: Effect of microstructure on microhardness and wear resistance improvement

A novel FeNi coating with refined grain size and alternated distribution of element content was designed via laser-assisted electrochemical deposition. The formation of this microstructure is attributed to a specific laser scanning strategy, forming the periodic current waveform. This novel coating is expected to enhance the microhardness and wear performance within the grain size range of the inverse Hall–Petch (HP) relationship. The critical size of the HP relationship was estimated at 13 nm based on the relationship between different grain sizes and microhardness. Compared to the coating prepared by electrochemical deposition, the average grain sizes decrease from 8.4 ± 1.4 nm to 4.5 ± 1.6 nm. In addition, the microhardness was enhanced by approximately 28 %; the wear rate was decreased by approximately 58 %. The main mechanisms include abrasive, fatigue, and slight oxidation wear. This unique structure may enhance the resistance to grain boundaries mediated plastic deformation.