Influence of Normal Loads on Corrosion Behaviour of Ti-6Al-4V Alloy during Fretting in Artificial Saliva

Résumé

The fretting corrosion behaviour of untreated Ti-6Al-4V alloy in artificial saliva solution was evaluated based on the change in open circuit potential (OCP) measured as a function of time. Fretting corrosion experiments were performed using a unidirectional reciprocating fretting experimental set-up which was mechanically and electrochemically instrumented, under various solicitation conditions. The effect of applied normal force on corrosion-wear of the tested material was determined. Before the onset of fretting a large increase of the OCP in the noble direction for the Ti-6Al-4V alloy was observed. With the onset of fretting it was observed a cathodic shift in OCP, shift which decreases linearly with increasing normal load. The restoration ability of Ti-6Al-4V alloy after the passive films damaged during fretting was observed after the fretting motion ceased. It was confirmed a decrease in friction coefficient with gradually increasing load. The morphological features of the fretted zone and the wear mechanism were assessed using scanning electron microscopy and non-contact optical profilometer.