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

The corrosion behavior of pure Ti under a solid NaCl deposit in a wet O-2 flow at 600 degrees 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 O-2 to form a thick and porous corrosion products scale. The electrochemical reaction was also observed during the whole corrosion process at 600 degrees C, which further accelerated the corrosion rate. A possible mechanism has been proposed for pure Ti covered with a solid NaCl deposit in wet O-2 at 600 degrees C, based on the experimental results.