Corrosion Behavior of Pure Ti under a Solid NaCl Deposit in a Wet Oxygen Flow at 600 C

The corrosion behavior of pure Ti under a solid NaCl deposit in a wet O2 flow at 600 ̋C has been studied. The results showed that the corrosion rate was greatly accelerated by solid NaCl, which destroyed the compact and protective TiO2 scale to yield non-protective N4Ti5O12 and other products. Detailed scanning electron microscopy (SEM) equipped with an energy dispersive spectrometer (EDX), and X-ray diffraction (XRD) analysis showed that, during the corrosion process, the metal (Ti) diffused outward rapidly and reacted with the wet O2 to form a thick and porous corrosion products scale. The electrochemical reaction was also observed during the whole corrosion process at 600 ̋C, which further accelerated the corrosion rate. A possible mechanism has been proposed for pure Ti covered with a solid NaCl deposit in wet O2 at 600 ̋C, based on the experimental results.