Effects of PEO and BN-PVD coatings on the wear, corrosion, and surface properties of AZ31 magnesium alloy

This study investigates the effects of Plasma Electrolytic Oxidation (PEO) and subsequent Boron Nitride (BN) coatings applied via Physical Vapor Deposition (PVD) on the wear, corrosion, and surface properties of AZ31 magnesium alloy. The AZ31 alloy samples were first coated using the PEO process, forming a ceramic-like layer that enhances surface properties. However, inherent microcracks and pores in PEO coatings can compromise corrosion resistance. To mitigate these issues, a BN layer was applied over the some of PEO coating using RF-PVD, significantly improving wear resistance, corrosion protection, and surface integrity. The coatings were characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and electrochemical testing. The results indicate that the PEO-BN coatings provide the highest wear resistance, lowest friction coefficient, and most effective barrier against corrosion among the samples tested. These findings highlight the potential of PEO-BN coatings to enhance the durability and performance of magnesium alloys, making them suitable for demanding applications.