Passivation evolution of Ti -Ta-Nb medium-entropy sputtered thin films in sulfuric acid solution

摘要

The microstructure and passivation behavior of the Ti-Ta-Nb medium-entropy alloy (MEA) films prepared by sputtering were investigated. The Ti-Ta-Nb MEA films show significantly improved corrosion resistance compared to pure Ti in 0.5 M H2SO4. The mechanisms of the passivation behavior and stability of the passive films were extensively explored and discussed. The passivation evolution phenomenon consisting of two passive regions is due to the variation of chemical compositions of passive films. The excellent corrosion resistance can be ascribed to the stable passive films consisting of the mixture of TiO2/Ti2O3, Ta2O5 and Nb2O5, particularly Ta2O5.

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