Potential bioactivity of coatings formed on AZ91D magnesium alloy by plasma electrolytic anodizing.

Magnesium is a potential candidate as biodegradable orthopedic implant thanks to its remarkable mechanical properties closed to those of natural bone. But its low corrosion resistance in the body fluid is a limiting factor. By using electrolytic plasma (or microarc) anodizing process, 10-20 μm protective coatings were formed on AZ91D magnesium alloys at a constant current density of 20 mA cm(-2).