High Temperature Nanostructured MoAlSi Coatings on Alloys For Ultra Supercritical Coal-Fired Boilers

Steam oxidation at high temperatures is a critical limitation of candidate boiler materials under consideration for applications in ultrasupercritical coal-fired power plants. This project will develop innovative nanostructured MoAlSi coatings to provide enhanced oxidation resistance for alloys at temperatures up to 1300°C. Phase I will (1) demonstrate the ability to process and deposit suitable nanostructured MoAlSi coatings on ferritic steel T92, austenitic steel 304H or Super304H, and Ni-base alloy IN617 or CCA617; (2) investigate the ability of these coatings to provide enhanced resistance to steam oxidation at temperatures up to 750°C; (3) characterize the oxide scale, kinetics of scale growth, microstructure evolution, and mechanism associated with scale development; and (4) demonstrate that the coatings can be applied to the internal surfaces of tubes fabricated from the respective alloys. Commercial Applications and other Benefits as described by the awardee: The enhanced coatings should find applicability not only for the boiler market but also for other high temperatures markets such as turbines for energy conversion. The use of these coatings should lead to improvements in energy use, life improvement, and productivity improvements, and also should have a positive environmental impact from less material waste.