Materials Performance of Oxyfuel Turbine Alloys

Oxyfuel combustion efforts to burn fossil fuels with oxygen, for easier post-combustion CO₂ capture, include schemes to use flue gas to drive turbines for power generation. The environment examined here is 10% CO₂ and 0.2% O₂, with the balance being steam, with temperatures ranging from 630 to 821 °C. The relatively high C and O₂ activities of this environment, as compared to pure steam, may lead to changes in oxidation behavior and mechanical properties. Oxidation coupons of Ni- and Co-base superalloys, in both bare metal and TBC coated conditions, were exposed to this environment for up to 1000 hours. The results of these exposures, in terms of mass gain and scale morphology, are presented.