Aluminizing and oxidation treatment of 1Cr18Ni9 stainless steel

The process of hot dipping pure aluminum on a stainless steel (1Cr18Ni9) followed by oxidation was studied to form a surface oxide layer. The thickness of the top aluminum on the steel substrate increases with increasing aluminizing time, while the thickness of the aluminum layer in the steel decreases as the increase in dipping temperature. Lower temperature and longer time favor a thicker layer of the aluminum on the substrate. The thickness of the intermetallic layer in the steel substrate increases with dipping temperature and time. However, the higher aluminizing temperature does not appear to have a significant effect on the thickness of the intermetallic layer. The oxidation treatment of the aluminized steel at 800°C results the formation of a top oxide layer on the steel surface, composed of α-alumina, Al4Cr and Al17Cr9. The aluminizing and oxidation treatment of the stainless steel creates about 120μm thickness of top oxide layer which has an extremely sound adherency to the steel substrate and a greatly improved properties of thermal shock withstanding, high temperature oxidation resistance and anti-liquid aluminum corrosion.