Corrosion of metallic biomaterials

Corrosion of metallic biomaterials leads to a loss of their structural integrity and surface function. Because some dissolved metal ions cause allergic response and carcinogenesis, such dissolution must be within acceptable levels. Moreover, corrosion accelerates the fatigue, fretting fatigue, and wear, which may give rise to the deformation or the fracture of metals. In the case of biodegradable metals, corrosion products may delay the cure of affected part and cause inflammation. Therefore, the understanding and accurate evaluation of corrosion behavior are important to secure the reliability of metallic biomaterials. Corrosion behavior depends on the sort of metals, the design of devices, and the chemical and mechanical environment inside the body. Then, the condition and method of corrosion tests should be decided, depending on the sort of metals, the environment inside the body, and the purpose of the test. This chapter therefore describes the methods for corrosion testing and their electrochemical background. Additionally, the characteristic corrosion factors inside the living body are discussed.