Production of Aluminide Layers on AISI 304 Stainless Steel at Low Temperatures Using the Slurry Process

Intermetallic compounds, such as iron aluminides exhibit excellent oxidation and corrosion resistance, as well as metallurgical bonding with excellent adhesion to the substrate. In this work, aluminizing treatments were carried out using the dipping into slurry process to produce iron aluminide coatings on stainless steel substrates. In this process, AISI 304 stainless steel samples were immersed in a slurry consisting of polyvinyl butyral, ethyl alcohol and a powder composed of Al, AlCl3 and Al2O3, dried and then placed in sealed crucibles without further protection. These samples were treated at temperatures of 500 and 650 °C for 2, 4, 6 and 8 h and then air-cooled. Flat and homogeneous layers were obtained over the substrate with increased thickness observed with increasing temperature and treatment time. Considering that the traditional treatments of aluminization by the pack process are carried out at temperatures close to 900 °C and use larger amounts of material, the low temperature treatments used in this work offer potential cost savings.