OXIDATION BEHAVIOR OF SENSITIZED AISI 310 STEEL IN KNO_3 AND K_2CO_3 AT 1123 K

摘要

Sometimes the operating temperature is such that the stainless steel can become sensitized, i.e. chromium carbide can precipitate at grain boundaries. The behavior of sensitized stainless steel is quite different from that of the solution-treated stainless steels in corrosive environments. The oxidation behavior of sensitized austenitic AISI 310 stainless steel were carried out in KNO_3 and K_2CO_3 at 1123 K. The oxidation rate was appreciably higher as well as the alloy severely attacked by nitrate & carbonate salts due to evolution of nitrogenous and CO_2 gases respectively. The decomposition of nitrate and carbonate takes place leading to passivity break down, resulting evolution of gases. The microstructural evolution and chemical analysis of the oxide films grown by oxidation were performed by SEM and EDX.