High-temperature corrosion of Fe3Al in chlorine-containing environments

The corrosion of Fe3Al in Cl-2-Ar gas mixtures has been investigated at the temperature range of 600-800 degrees C using thermogravimetric analysis, SEM, XRD, and EDS. Weight gain was observed during the corrosion of Fe(3)A1 at 600 degrees C in 0.25% Cl-2-Ar, which is due to the formation of Fe2O3, while continuous weight loss of the specimen in 5% Cl-2-Ar at 800 degrees C was observed because of the formation of volatile metal chlorides, FeCl2, FeCl3, and AlCl3. Meanwhile, three distinct stages of weight change during the corrosion of Fe3Al at 700 degrees C in 1% Cl-2-Ar were observed, (1) weight gain, (2) linear weight loss, and (3) gradual decrease of weight loss. Initial weight gain is due to the formation of Fe2O3, and the weight loss in the subsequent two stages is in consequence of the formation of volatile metal chlorides, FeCl2, FeCl3 and AlCl3. (C) 1999 Elsevier Science S.A. All rights reserved.