Corrosion, Corrosion Fatigue, and Protection of Magnesium Alloys: Mechanisms, Measurements, and Mitigation

Magnesium (Mg) alloys are non-toxic, biodegradable, and biocompatible special metallic biomaterials for biomedical applications, but less corrosion-resistant in physiological and chloride-containing environments. This often limits their use as potential biomedical implants due to loss of their mechanical integrity. This can be addressed by adopting several approaches such as surface modifications and coatings as well as pretreatments including anodization, microarc oxidation, and electrodeposition. To further provide insights into better ways to improve the corrosion resistance of Mg alloys in saline and physiological environments, the present work provides a comprehensive overview of the electrochemical properties of Mg alloys as a biodegradable material. More importantly, the corrosion and corrosion fatigue mechanisms in surface-modified Mg alloys are explicitly reviewed. The significant influence of alloying on the corrosion resistance behaviors of biodegradable Mg alloys is also reviewed and discussed explicitly. The different methods of measuring the corrosion rates of Mg and its alloys are reviewed and summarized. As potential implant materials, the recent progress and developments on Mg alloys in the biomedical fields and their resulting corrosion properties are discussed and the research trends for future works are highlighted.