Effect of RF sputtering power on the microstructure and mechanical and tribological properties of TiN-Cu coatings

This study intends to address the lack of the radio-frequency (RF) magnetron sputtering power effect and improve the mechanical performance of 316L steel. The coatings were prepared under varying RF power levels, and the resultant microstructural features, mechanical properties, and tribological behaviors were systematically analyzed. It was observed that as sputtering power increased, the coating morphology evolved from a porous cauliflower-like structure to a dense nanocrystalline structure and finally to a coarse pyramidal columnar structure. The coating deposited at 550 W exhibited the smallest grain size, highest hardness (30 GPa), and optimal H/E and H³/E²ratios. Tribological tests revealed that this coating achieved the lowest coefficient of friction (0.32) and wear rate (10.9 × 10⁻⁶mm³ N⁻¹m⁻¹). The enhanced wear resistance is attributed to the dense microstructure, high hardness, and improved deformation resistance. These results demonstrate that sputtering power plays a critical role in tailoring the performance of TiN-Cu coatings, with 550 W identified as the optimal condition for achieving high hardness and wear resistance.