Overview

The practice of using metals and alloys to repair or replace human body parts is now well established. Two of the most important parameters in determining a material s suitability for biomedical applications are its biocompatibility and corrosion resistance. This chapter will give a basic introduction to the thermodynamic and electrochemical aspects behind corrosion, focusing on the various forms of localized corrosion that are responsible for most of the in vivo failures. This will be followed by a brief review of the successes and, in reality, the remarkably few failures of the traditional materials which are mainly titanium alloys, cobalt-chromium alloys, amalgams, and stainless steels. The desire to utilize a few advanced materials such as memory-shape alloys, porous materials, and rare earth magnets will then be discussed. Unfortunately nearly all of these materials have inadequate corrosion resistances, such that they cannot be used directly in vivo without some form of protection. The chapter ends with some case histories of surgical implant failure.