Oxidation Behavior of Nanostructured TiAlN and AlCrN Thin Coatings on ASTM-SA213-T-22 Boiler Steel

Abstract

Metals and alloys gets oxidized when exposed to elevated temperatures in air or highly oxidizing environments, such as combustion gas with excess of air or oxygen. They often rely on the oxidation reaction to develop a protective oxide scale to resist corrosion attack. In the present study, nanostructured TiAlN and AlCrN thin films were deposited by physical vapour deposition process on T-22 boiler steel (ASTM-SA213-T-22). Cyclic oxidation studies in air were conducted at 900°C temperature in the laboratory using silicon carbide furnace. The weight gain was measured after each cycle and visually examined the surface morphology of the oxidized samples was studied using FE-SEM with EDAX attachment and XRD analysis. The results obtained showed the better performance of AlCrN coated T-22 boiler steels then the TiAlN coated and uncoated T-22 boiler steel.