THE EFFECT OF STATIC AND DYNAMIC LOADING ON THE CORROSION RATE OF SURGICAL IMPLANT METALS

ABSTRACT There is increasing interest in identifying factors which affect corrosion of implant metals. Reasons for this are both fundamental (regarding biological effects of released ions) and practical (increasing use of porous metals with larger corrosion currents.) Previously we presented evidence showing that static stresses can significantly change corrosion behavior of certain implant metals. The objectives of the present study were 1) to more thoroughly investigate this effect quantitatively using various electrochemical tests which measure corrosion current density i c and 2) to examine this effect over a broader range of stresses to more accurately approximate in vivo conditions. The results indicate that different alloys behave differently when stressed. With 316 L there is a lowering of breakdown potential in stressed material. For Ti-6Al-4V ELI, i c under stressed conditions can be much increased. Corrosion of Co-Cr-Mo is basically unaffected by stress.