Performance of chromia- and alumina-forming Fe- and Ni-base alloys exposed to metal dusting environments: The effect of water vapor and temperature

Abstract

Fe- and Ni-base alloys including an alumina-forming austenitic alloy were exposed for 500h under metal dusting environments with varying temperature, gas composition and total pressure. For one H2–CO–CO2–H2O environment, the increase in temperature from 550 to 750°C generally decreased metal dusting. When H2O was added to a H2–CO–CO2 environment at 650°C, the metal dusting attack was reduced. Even after 5000h at a total pressure of 9.1atm with 20%H2O, the higher alloyed specimens retained a thin protective oxide. For gas mixtures containing little or no H2O, the Fe-base alloys were less resistant to metal dusting than Ni-base alloys.