Alloy Layer Formation on SUS316 Stainless Steel by Hot-Dip Aluminum Coating

The structure of the alloy layers formed by hot-dip aluminum coatings on SUS316 stainless steel has been studied. The fundamental construction of the coating layer was found to be the SUS316-substrate/FeAl3/FeAl6/adhered-aluminum-layer. The formation of FeAl6 has not been reported so far. The thickness of the alloy layer was found to increase logarithmically with dipping time up to about 3 min in the case of coating at 700°C and thereafter to decrease gradually. The effect of coating temperature on the formation of the alloy layer was a little up to about 760°C, but at higher temperatures the thickness of the alloy layer decreased gradually. Diffusion heating treatment after coating resulted in the disappearance of the adhered aluminum layer and FeAl6, and in the formation of a mixture alloy layer of FeAl3 and Fe2Al5.