Tribocorrosion behaviour of plasma oxidized titanium in an artificial saliva solution

Titanium is used for dental implant applications because of its attractive properties such as low modulus, good fatigue strength, excellent corrosion resistance and biocompatibility. However, the poor wear resistance of titanium and titanium alloys still limits their application [1]. In fact, when used as implants cyclic micro-movements at the implant/bone interface or implant/porcelain interface occur inducing wear. In fact, most failures result from a combined action of mechanical solicitations (sliding or abrasive wear, erosion, impact, fretting or fatigue processes) and chemical solicitations on contact with saliva, cells or bacteria. Consequently, dental implants are part of a tribocorrosion system [2]. Recent work has shown that wear resistance of titanium might be improved by an appropriate surface treatment, such as plasma oxidation, which is also often used to enhance the oseo-integration process [3, 4]. The aim of this work is to study the effect of the characteristics of oxide layers obtained by plasma oxidation on the tribocorrosion behavior of c.p. Ti used for the fabrication of dental implants. Plasma oxidation treatments were performed at 300, 450 and 530 ºC. A detailed study of surface topography, thickness, structure and chemical composition of the oxidized layers was performed. Tribocorrosion experiments were performed in a reciprocating motion pin-on-plate tribometer with an alumina pin as a counterface material in a Fusayama solution. Electrochemical impedance spectroscopy was performed before and after sliding to evaluate the protective character of the oxide film. Results clearly showed that plasma oxidation treatments have a strong influence on the tribocorrosion behavior of titanium. Corrosion and wear performance of the samples improve at higher processing temperature.Abstract (Oral communication)status: publishe