High-temperature oxidation behavior of 9Cr ferritic-steel in carbon dioxide

Abstract

Commercial STBA26, 9Cr-1Mo ferritic steel, was exposed to CO2 gas and air at 700°C in order to understand the oxidation behavior of a 9Cr-steel in CO2 atmosphere. Oxidation of STBA26 was significantly accelerated in CO2 compared to that in air. In CO2 thick iron rich oxide nodules were formed on the steel and chromium rich carbides were found to form below the oxide scale. The carbon activity at the scale/alloy interface was sufficiently high to maintain parabolic internal continuous carbon supply to the interface is considered to be a reason to cause a breakaway of protective oxide scale. © 2014 ISIJ.