Galvanic corrosion behavior and protection of 921A/Ti80 couple in NaCl solution

Abstract

The Present work is devoted to investigating the complex galvanic corrosion behavior of 921A/Ti80 couple in NaCl solution. The galvanic corrosion law of 921A/Ti80 couple under different influencing factors (cathode/anode area ratio, pH, Cl⁻, temperature) was explored by electrochemical test method in detail, and the corrosion morphology was characterized. Furthermore, the protective effect of Al₂O₃ coating on galvanic corrosion of 921A/Ti80 couple under various factors was innovatively discussed. Results indicate that 921A steel and Ti80 are prone to galvanic corrosion when coupled in NaCl solution. The galvanic corrosion effect of Ti80 on 921A steel significantly intensifies with the increase of cathode/anode area ratio and the decline of pH. Noteworthy, the galvanic battery effect of 921A/Ti80 couple increased first and then decreased with the increment of Cl⁻ as well as the rise of temperature. Al₂O₃ coating provides an excellent anti-galvanic corrosion effect between 921A and Ti80, and significantly weakens the sensitive difference of cathode/anode area ratio, pH, Cl⁻ concentration and temperature to galvanic corrosion of 921A/Ti80 couple.