Improvement of Oxidation and Hot Corrosion Resistance of Austenitic. Stainless Steel 316L alloy by Chromium-Silicon

      Аннотация: Diffusion coating is carried by simultaneous chromizing-siliconizing process to deposite chromium and silicon on the surface of austenitic stainless steel 316L alloy, using a pack mixture containing (67 wt. % Cr, 8 wt. % Si, 2 wt. % NH4Cl, 23 wt. % Al2O3). It was found that diffusion coating time of 6hrs at 950oC produce coating thickness of 80-100µm and consisted mainly of CrSi2 and Cr3Si phases. Cyclic oxidation tests are conducted on the coated and uncoated austenitic stainless steel 316L alloy at a temperature range between 700-900oC for 52hrs at 4hrs cycle in air. The cyclic hot corrosion tests of coated and uncoated austenitic stainless steel 316L alloy austenitic stainless steel 316L alloy deposited with 2 mg / cm2 NaCl : Na2SO4 (100:0, 50:50 and 0:100 wt. %) are conducted at 850oC for 52hrs at 4hrs cycle and with 5 mg / cm2 (67 wt. % V2O5 + 33 wt. %Na2SO4) deposits at test temperatures (550, 650, 750, 850 and 950oC) for 4hrs at each temperature. The oxidation kinetics for uncoated austenitic stainless steel 316L alloy is found to be parabolic. The oxidation rate constant (kP) values obtained at 700, 800 and 900oC in air are:(1.77x10-10, 2.25 x 10-10, 3.36x 10-10 (mg2.c

Ключевые слова: Hot Corrosion, Oxidation, austenitic stainless steel, 316L., Chromium-Silicon