Semiconducting properties assessment of passive oxide films forming on pure tungsten in 1.0 M H3PO4 solution

Abstract

The current study is mainly to discuss the observed semiconducting characteristics of oxide passive films formed on pure tungsten (W) in H3PO4 solution (1.0 M). Potentiodynamic polarization (PDP) curve reveals that pure tungsten shows passive behavior in the given solution. Also, impedance spectroscopy shows that pure tungsten displays passive behavior at open-circuit potential condition in the solution. Mott–Schottky (M–S) analysis indicates that mentioned films which are formed on pure tungsten in phosphoric acid solution (1.0 M) display the semiconductors behavior of type n. The conduction of these passive films are not affected by anodic passive potential. In addition, according to M–S results, fewer defects are found in the passive film at higher anodic passive potentials. The obtained results show that corrosion resistance of pure tungsten in 1.0 M H3PO4 solution improves at higher passivation potentials due to the formation of passive films that are less defective.