Maintainable Solution-Derived Nanocoatings for Advanced Boiler Systems

78188S Ultra-Supercritical (USC) coal-fired power plants are being designed to meet the Vision 21 goals of fuel efficiency and environmental emission standards. The material systems for these plants will be required to limit degradation occuring from corrosion at elevated temperatures. Due to higher operational temperatures in USC plants (up to 750 C), the environments encountered in these plants are chemically complex, dynamic, and challenging, requiring not only advanced alloys and but also protective coatings. The protective coatings need to be robust, low-cost, and able to be applied easily and inexpensively. Metallurgical overlay coatings are being investigated by a number of groups, and while they may provide adequate protection, they are not suitable for some of the environments, are prohibitively expensive, and are not amenable to on-site application. This project will investigate the use of solution-derived thin glassy films that are easy-to-apply, inexpensive, and can enable maintenance and repair which is critically important for successful deployment and can also serve as prime-relaint films for certain selected USC components. Phase I will determine the effectiveness of the proposed coating on selected ferritic, austenitic, and Inconel substrates under corrosive environments that include steam side oxidation, sulfidation, fire side corrosion, and air oxidation. The coated materials will be tested in simulated environments at short-term exposures (up to 1000h). In Phase II, one specific application of interest will be selected and a suitable coating process will be developed for large-scale integration with USC components. Commercial Applications and other Benefits as described by the awardee: The proposed nanocoating technology should be suitable for use in a number of industrial, automotive, and aerospace systems and may provide key material savings benefits both from extended durability and use of lower grade advanced alloys. In addition, these nanocoatings should reduce downtimes and shutdowns, further boosting production efficiencies and lower costs for the end user. The nanocoating innovation also should have direct relevance to turbine engines, solid oxide fuel cells, hydrogen processing and infrastructure, and other energy generating systems.