NaCl-induced accelerated oxidation of 304 stainless steel and Fe-Mn-Al alloy at 900°C

The high-temperature corrosion behavior of cold-rolled and annealed 304 stainless steel (304SS) and Fe-29Mn-8Al-2.5Si-2Cr-0.74C alloy coated with 0.002 g cm(-2) NaCl initially were studied at 900degreesC in air. The corrosion kinetics of the two alloys follow the parabolic rate law. The initial NaCl coating accelerates oxidation of these alloys by oxychlorination and chlorination/oxidation cyclic reactions, and catalytic actions of chloride or chlorine are thought to be the principal causes. A bulky, layered scale as well as some intergranular attack is noted on the annealed 304SS, and intergranular attack distributes over the alloy substrate of the cold-rolled 304SS during a 144 h exposure. With the formation of a compact Al2O3 scale to decrease further chlorine attack, the corrosion resistance of Fe-Mn-Al alloy is superior to that of 304SS in this study. (C) 2003 Kluwer Academic Publishers.