Activated Ti surface breaking the galvanic immunity to Zn

Purpose Hybridization of dissimilar bio-metals overcomes limitations of monolithic metals, satisfying diverse clinical requirements for implants. However, galvanic corrosion remains the central challenge. This study aims to investigate the effect of Ti on the galvanic corrosion of Zn. Design/methodology/approach In this study, pure Zn was individually coupled with pure Mg, Fe or Ti and co-immersed in 3.5 Wt.% NaCl. By comparing the corrosion rate, surface morphology and electrochemical response of each galvanic couple, this study specifically quantified the influence of Ti on Zn corrosion. Findings Zn/Ti galvanic corrosion is negligible under oxidizing conditions. After 56 days of co-immersion in 3.5 Wt.% NaCl, the corrosion rate of Ti-coupled Zn (0.31 mm/y) is similar to that of bare Zn (0.30 mm/y). A dense passive film restricts the average galvanic current density (Iga) between Ti and Zn to 0.02 µA·cm−2. After this film is removed with hydrofluoric acid, Iga rises to 2.27 µA·cm−2. Originality/value This study is expected to provide experimental evidence for the reliable design of Zn/Ti hybrid biomedical devices.