Improvement of Oxidation Resistance of Austenitic Stainless Steel by Chromizing-Siliconizing


The application of a pack cementation of chromium and silicon coatings on austenitic stainless steel 316L alloy yields a significant improvement in the oxidation and hot corrosion resistance over a wide temperature range (300-900oC). In this work, austenitic stainless steel 316L alloy is coated with chromizing-siliconizing diffusions coatings. Chromium and silicon were simultaneously deposited by diffusion into austenitic stainless steel by the pack-cementation process using a pack mixtures containing (67 wt. % Cr, 8wt. %Si, 2wt. %NH4Cl and 23wt. %Al2O3) when required. It was found that diffusion coating time of six hours at 950oC produces coating thickness of 80-100μm and consist mainly of CrSi2 and Cr3Si phase.