Chiang Mai Journal of Science

           The hot-dip aluminizing process was performed on AISI 304 austenitic stainless steel at different temperatures and durations. Characterizations of intermetallic layers, e.g., thickness, species and cross-sectional microstructures were performed. Growth kinetics of the intermetallic layer was analyzed by diffusion theory and the Arrhenius equation. It was found that an aluminium and iron aluminide layer, Fe₂Al₅ phase, were mainly detected for all investigated hot-dip aluminizing processes. The thickness of the iron aluminide layer increased with increasing temperature and time, according to the diffusion theory. The activation energy of 86.51 kJ/mol was determined. Finally, a simulation diagram of the predicted layer thickness as a function of aluminizing temperature and time was constructed. Moreover, to observe and illustrate the phase transformation of the iron aluminide layer, the selected hot-dip aluminized condition was annealed at a temperature of 800 °C for 12 h.

Keywords: Aluminizing; Stainless steel; Kinetics; Diffusion