A Survey of Materials and Corrosion Issues for Metal Implant Materials

While the materials available to the medical device designer are widely varied, most permanent implant materials are either completely metallic or supported by a metallic structure. This discussion provides a survey of common medical materials in wire form through a comparative study following the ASTM F2129 cyclic potentiodynamic polarization methodology. Additionally, a detailed examination of corrosion issues surrounding the shape memory metal Nitinol are reviewed. The newest development in medical materials focuses on bioabsorbable materials, primarily the nutrient metals magnesium, iron and zinc, that serve their intended purpose, and are then gradually absorbed by the body. These materials present an exceptionally difficult challenge to evaluate as the F2129 techniques are not applicable. Data on recent studies in various media are reviewed.