Synergistic Effects of Corrosion and Tribocorrosion Behavior in AISI 316Ti Stainless Steel for Engineering and Biomedical Applications

The corrosion behavior of AISI 316Ti stainless steel was examined in NaCl solutions (0.9%, 3.5%, and 5%), whereas tribocorrosion tests were performed in both chloride-containing solutions and distilled water as a reference environment. Potentiodynamic polarization tests were performed to evaluate passive film stability, while tribocorrosion experiments were conducted under a 10 N normal load using a ball-on-flat configuration with continuous monitoring of open circuit potential (OCP) and coefficient of friction (COF). Surface degradation was quantified using optical 3D profilometry and scanning electron microscopy. Electrochemical results confirmed passive behavior in all environments; however, increasing chloride concentration shifted corrosion and pitting potentials toward more negative values and reduced passive stability. During sliding, a pronounced cathodic OCP shift indicated mechanical depassivation, with the magnitude of the shift increasing in chloride-rich solutions. Repassivation after sliding was progressively hindered as NaCl concentration increased. Wear analysis revealed a clear dependence on chloride content, with the wear area in 5% NaCl (0.0020 mm2) exceeding that in distilled water (0.0009 mm2) by approximately 122%. Abrasive wear was identified as the dominant mechanism, accompanied by delamination wear in highly aggressive environments. The results demonstrate a strong synergistic interaction between wear and corrosion, with chloride concentration significantly intensifying tribocorrosion-induced material degradation.