Corrosion, Wear, and Fretting Corrosion Properties of Cr/CrN and Mo/MoN Multilayer Coatings with Biomedical Potential

In this study, Cr/CrN and Mo/MoN alternating multilayer coatings with pure metal interlayers were deposited on 316 L stainless steel substrates via physical vapor deposition to systematically investigate the corrosion resistance, wear resistance, and tribocorrosion behavior of the multilayer coating systems in physiological saline environments. Microstructural characterization revealed that the CrN layer consists of mixed CrN and Cr₂N phases, whereas the MoN layer exhibits a highly densified microstructure along with the presence of MoO₂ phase, which collectively contribute to the superior corrosion resistance of the Mo/MoN coating. Furthermore, compared to the CrN layer, the MoN layer demonstrates enhanced nanomechanical properties and improved resistance to crack initiation, due to the greater hardness and higher H/E and H³/E² values. Consequently, the Mo/MoN coating exhibits significantly better wear and tribocorrosion performance than its CrN counterpart. This work provides a theoretical foundation for the design of tribocorrosion-resistant hard coatings for artificial joint materials.