Pre-oxidation Effect on Oxidation Behavior of F91 in Carbon Dioxide at 550 °C

Upon exposure to CO2 at 550 °C, F91 tends to form rapidly growing scales consisting of an outer Fe oxide and an inner Fe–Cr spinel oxide. A comparative study has been carried out between the pre-oxidized and non-pre-oxidized F91, to determine the influence of pre-oxidation upon the oxidation behavior of F91 in CO2. Formation of a rapidly growing scale and carburization could be inhibited by a pre-oxidation treatment in air prior to oxidation in CO2. Although during exposure to CO2, a fast growing scale still would form locally, pre-oxidation changed its structure. Effects of pre-oxidation time on the oxidation resistance in CO2 are investigated.