Atomic-scale investigations of passive film formation on Ti-Nb alloys

This study extensively investigates the passive film formation mechanisms on Ti-xNb alloys by using several electrochemical techniques, including electrochemical impedance spectroscopy (EIS) before and after potentiostatic polarization at the passive zone, and Mott-Schottky (MS) measurements in 9 g/l NaCl electrolyte at 37 degrees C, together with X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis. Overall, the Ti40Nb presented lower corrosion resistance due to a thinner passive film as compared to commercial pure Ti (grade 2) and Ti12Nb. The passive film formed on Ti12Nb and Ti40Nb alloys at a steadystate condition (+0.5 VAg/AgCl for 60 min) is composed of amorphous phases of TiO, Ti2O3, TiO2, Nb2O5, and crystalline phases of TiO2 (anatase) and Nb2O5.

Automated summary

This study extensively investigated the passive film formation mechanisms on Ti-xNb alloys using electrochemical techniques such as EIS and MS measurements, as well as XPS and TEM analysis. It was found that Ti40Nb had lower corrosion resistance due to a thinner passive film compared to commercial pure Ti and Ti12Nb. The passive film formed on Ti12Nb and Ti40Nb alloys under steady-state conditions consisted of amorphous phases of TiO, Ti2O3, TiO2, Nb2O5, and crystalline phases of TiO2 (anatase) and Nb2O5.