Surface modification of CP-TI to improve the fretting corrosion resistance: Thermal oxidation vs. anodizing

Fretting corrosion is one of the important reasons for the failure of prosthesis made of titanium and titanium alloys under in vivo condition. The fretting corrosion behaviour of untreated, anodized and thermally oxidized commercially pure titanium (CP-Ti) in Ringer's solution was evaluated based on the change in free corrosion potential (FCP) measured as a function of time. A comparison of the performance of untreated, anodized and thermally oxidized CP-Ti under fretting corrosion conditions is reported for the first time in this paper. The study reveals that surface modification of CP-Ti by both anodizing and thermal oxidation improved the fretting corrosion resistance of CP-Ti and among them the performance of thermally oxidized CP-Ti is superior to that of the anodized one. Adhesive galling is the predominant wear mechanism for untreated CP-Ti, adhesive wear and delamination are found to be operative for anodized CP-Ti whereas an abrasive wear mechanism is operative for thermally oxidized CP-Ti when they are fretted against the alumina ball.