Air Oxidation of AISI 310S Austenitic Stainless-Steel Superalloy between 973-1073K in Microstructured Condition and a Comparison with that of Surface Nanostructured Alloy and Same with Nanostructured Surface Oxide Layer

Oxidation of AISI 310S follows parabolic kinetics at all selected test temperatures, i.e., 973K, 1023K and 1073K. Activation energy of the oxidation reaction as calculated from the rate constant-temperature data is 209kJ/mol. Grain size increases during oxidation. Optical micrographs reveal uniform oxidized surface. No internal oxide formation as it is confirmed by optical micrographs. In low oxidation times (up to 20hours), only one scale of long-range order has been noted, i.e., chromic-ferric-manganic oxide. After a long time of oxidation (above 200hours), duplex scale has been formed with ferric oxide and ferrous ferric oxide. First inner layer is continuous one and second outer layer is spalling spinel oxide. High oxidation resistance of AISI 310S stainless steel is due to the greater alloying additions of nickel and chromium. Surface nanostructured alloy and alloy with nanostructured surface oxide layer show improved performance against oxidation