Evaluation for the Corrosion Behavior of Magnesium Coated with Biomaterials in Pseudo-Body Fluid

Biomaterial is a material that is embedded in human body and the most of that are used metals because of its high mechanical property. In some of the biomaterials, surgery is required to remove after complete recovery so that it imposes high surgery cost and physical and mental pains to patients. The development of a magnesium based bioabsorbable material that is not required surgery and safely vanish in human body has attracted attention. On the other hand, a practical use of Mg has some problems and one of them is low corrosion resistance. Since Cl- ion contained in body fluid causes corrosion under biological environmental, Mg has greatly low corrosion potential in metals and easily corroded in human body. It is also concerned about secondary damage such as refracture of bone by keeping it in the body, and it is required to vanish immediately after recovery, so we controlled corrosion behavior of Mg with coating Ti and PLA. Mg and Ti have a large potential difference so that corrosion proceeds immediately by galvanic corrosion and Mg coated with Ti (Mg/Ti) dissolved for a day. PLA is a bioabsorbable polymeric material and it is already practical use as a bioabsorbable material. PLA dissolves gradually by hydrolysis so that it can suppress corrosion until hydrolysis. We resulted that Mg/Ti coated with PLA remained for 20 days, so PLA could suppress corrosion of Mg/Ti.