Corrosion behavior of pure Ti under continuous NaCl solution spraying at 600 °C

Abstract

The corrosion behavior of pure Ti under continuous NaCl solution spraying at 600 °C, compared with that under solid NaCl deposit film in H2O + O2 environment, has been studied by mass gain curves, detailed microstructural investigation and phase-stability diagram. The results indicate that the oxide scale consists of three repeated multi-layered subscales composed of Na2TiO3 and TiO2. Continuous NaCl increases the volatilization of TiCl4 towards oxide/atmosphere interface as well as introduces pores and cracks. Pores and cracks allow the oxidizing atmosphere to enter and rapidly spread and resulting in a repeat multi-layered oxide scale. Relatively dense repeat TiO2 delayed active oxidation process, which will decrease the corrosion rate of the pure Ti under NaCl spraying.