Influence of seawater depth and electrode potential on the tribocorrosion of Ti6Al4V alloy under the simulated deep-sea environment by in-situ electrochemical technique

The Tribocorrosion Behaviour of Ti-6Al-4 V Alloy: The Role of Both Normal Force and Electrochemical Potential

“…The influence of hydrogen embrittlement seems not to predominate the interface for the tests included in this study since the material losses became comparatively greater while moving towards less cathodic potentials. This has been also reported by Ren et al [13] where under a cathodic potential of − 1 V/V Ref , the immersion of Ti-6Al-4 V into deionised water entailed nearly equal material losses with those observed in seawater. Hence, the negative drop in the cathodic currents may be more controlled by the oxygen absorption at the interface, as reported by Ren et al [13].…”

“…Under the cathodic potential of − 1.2 V/V Ref , the current remained in the negative domain and dropped to more negative currents once the rubbing was started. This negative drop may be due to the oxygen reduction process due to the solution motions and subsequent oxygen absorption at the interface, as discussed by Ren et al [13] for Ti-6Al-4 V at a potential of − 1 V/V Ag/AgCl . Another possible reason for this drop is hydrogen segregation at the interface [13,41,51] which can subsequently reduce the ductility of the interface and induce hydrogen embrittlement.…”

“…This negative drop may be due to the oxygen reduction process due to the solution motions and subsequent oxygen absorption at the interface, as discussed by Ren et al [13] for Ti-6Al-4 V at a potential of − 1 V/V Ag/AgCl . Another possible reason for this drop is hydrogen segregation at the interface [13,41,51] which can subsequently reduce the ductility of the interface and induce hydrogen embrittlement. Under the cathodic potential of − 0.6 V/V Ref and by starting the rubbing, the current moved to the anodic domain with small magnitudes.…”

“…In addition, there is a controversy in the literature that under certain circumstances, the total loss in the cathodic domain cannot be assumed as purely mechanical since the wear characteristics of the interface are altered by hydrogen segregation and interface embrittlement [41]. However, it is still common to assume this total loss as being mechanical, as detailed and used by other researchers in the literature [10, 13,29,35,42]. Therefore, taking into account this concept, this study assumed the total loss in the cathodic domain as mechanical.…”

“…Through the cyclic actions of these two mechanisms and their interrelations, the material surface in contact is damaged/tribocorroded. The positive/negative synergy between these mechanisms depends on various parameters such as normal force [5][6][7], sliding distance and its frequency [8][9][10][11], electrochemical potential [12,13], solution type and its pH [4,14], and also the material couple in contact [15][16][17].…”