Influence of hydrostatic pressure on the passive film of titanium alloy

The effect of hydrostatic pressure on the corrosion behavior and failure mechanism of Ti-6Al-4V in simulated deep-sea environments has been investigated through microstructure analysis and in-situ electrochemical measurements. Hydrostatic pressure does not change the nucleation mechanism of passive film of Ti-6Al-4V. Charge transfer resistance ( R ct ) decreases by 53.0% and 69.9% at 10 MPa and 30 MPa respectively, compared to 0.1 MPa, suggesting that the corrosion resistance of passive film degrades with increasing hydrostatic pressure. Oxygen vacancies act as the primary donors within the passive film of Ti-6Al-4V. At the etching depth of 10 nm, the TiO 2 content in the passive film decreases from 47.75% (0.1 MPa) to 33.23% (30 MPa). The average valence state of Ti in the inner layer of the passive film decreases with the increase in hydrostatic pressure, indicating that the stability of the passive film decreases.