Localized corrosion and repassivation behaviors of additively manufactured titanium alloys in simulated biomedical solutions

Abstract

The localized corrosion behavior of additively manufactured (AM) titanium alloys is studied based on the relation between pitting potentials, the flux of oxygen vacancies in a passive film, and the repassivation rate using potentiodynamic polarization, Mott–Schottky, and an abrading electrode techniques. The relationship between the localized corrosion resistance and the repassivation behaviors of AM titanium alloys was explained by the survival probability constant based upon the point defect model which describe the generated oxygen vacancies and accumulated cation vacancies affect the occurrence of the localized corrosion. Localized corrosion can be initiated by survival pits under sufficient conditions of the breakdown passive films. Survival probability is constant means a quantitative probability value of the transition from metastable pit to stable pit to occur localized corrosion. The higher the survival probability constant of AM titanium alloys, the more difficult repassivation and the easier occurrence of localized corrosion.