Formation and characterization of aluminide coatings on alloy 800 substrate

► Pack aluminization of Fe-Ni-Cr based Alloy 800 leads multilayer formation. ► Multilayer consists of FeAl+Fe2Al5, FeAl type phases and a solid solution zone. ► Inward diffusion of Al and outward diffusion of Fe, Ni and Cr form multilayer. ► Microhardness of aluminide decreases with the decrease in Al-content. ► Scratch test indicates good adherence of aluminide coatings.