Anticorrosion behaviour and tribological properties of AZ31 magnesium alloy coated with NbO/NbO-Mg/Mg layer by magnetron sputtering.

Magnesium alloys are attracting increasing attention for the fabrication of temporary implants because of their superior biodegradability and biocompatibility. However, their high degradation rate under physiological conditions limits their clinical applications. In this work, a NbO/NbO-Mg/Mg multilayer coating was prepared on the surface of AZ31 magnesium alloy by magnetron sputtering in order to improve its corrosion resistance. The microstructure and performance of the layers were studied by SEM, AFM, EDS, and XPS, and a scratch tester, nanoindenter, friction tester, and electrochemical workstation, using NbO monolayer coating as a control. The results show that these two coatings significantly improved the mechanical, tribological, and anticorrosion performance of AZ31 magnesium alloy. Compared with a NbO monolayer coating, the multilayer coating exhibits an increased adhesion by about 10.6 times, and a decreased wear rate and corrosion current density by one order of magnitude, meaning higher damage resistance. This study provides a feasible strategy for enhancing the properties of ceramic layers on magnesium alloys for medical applications.