The pitting corrosion of titanium in aggressive environments: A review

This study presents an overview of a number of factors influencing the pitting corrosion of Ti in aggressive environments. Firstly, the effects of temperature and metal cations on the pitting corrosion of Ti are summarized based on previous research. The pitting corrosion of Ti in chloride solutions is strongly temperature-dependent; the breakdown potential £& decreases as the operating temperature increases. The presence of oxidizing metal cations can cause severe pitting on Ti in chloride solutions. Secondly, the inhibition effects of different oxygen-containing anions, such as C1O₄^2-, HPO₄^2-, SO₄^2-, Se04^2- and S^2-O₃^2-, on the pitting corrosion of Ti in CI" solutions at 150°C are explored. SO₄^2-, > SeC>₄^2-, Cr0₄^2- and HP0₄^2- anions all retards the pitting corrosion of Ti in CI" solutions. The inhibition effect decreases in the order: Cr0₄^2-; > SO₄^2- = Se0₄² > HPO₄². On the other hand, S^2-O3^2- and CI^- ions have a synergistic effect in inducing localized corrosion on Ti.