Effects of micro-arc oxidation on the corrosion behaviors of magnesium alloy Mg-8.0Al-1.0Zn-1.0La

Abstract-Magnesium alloys attract more and more attentions in the field of biomaterials because of their favorable biocompatibility and biodegradable properties. Presently, the bottleneck of application of magnesium alloys as biomaterials is that their corrosion speed is too rapid. The magnesium alloy will seriously erode before the tissue or organ recovers. Moreover, the excessive hydrogen gas that cannot be processed by human body will generate in the corrosion process. Therefore, improving the corrosion resistance is the key to successfully apply magnesium alloys in the field of biomaterials. In present, magnesium alloy Mg-8.0Al-1.0Zn-1.0La fabricated by authors in prior research was processed by micro-arc oxidation technology for improving the corrosion resistance. Results showed that the anodic polarization behavior transferred from the active dissolution to the self-passivation after micro-arc oxidation. The self corrosion current density decreased 3-5 order of magnitude. The micro-arc oxidation film generated in-situ on the surface of Mg-8.0Al-1.0Zn-1.0La alloy constitutes of ceramic materials, such as MgO, MgSiO₃, Mg₂SiO₄ and Al₂O₃. The ceramic film can protected the magnesium matrix from eroding.