Engineered Composites for USC Applications

Ultrasupercritical (USC) steam boilers will operate at higher temperature/pressure than subcritical and supercritical steam boilers in service today. However, the majority of current high-temperature materials do not posses the desired characteristics for the operating conditions of a USC unit (760 C/35MPa). This project will develop innovative composite powders and composites that will surpass the properties of currently identified materials for USC steam turbine applications. Phase I will demonstrate a powder metallurgy technique for fabricating high-temperature, steam-oxidation-resistant composite powders. Once consolidated, the resulting composite will possess high creep and thermal fatigue strength, high conductivity, and a low coefficient of thermal expansion. Commercial Applications and other Benefits as described by the awardee: The new composites should increase the life expectancy and performance of current steam turbine components, such as rotor/disc, blade, bolt, superheater tubing, and thick sections. The composite powders also should find application in thermal-sprayed or cold-sprayed steam oxidation, corrosion-resistant high-temperature coatings for retrofitting existing fossil-fired power plant equipment, and laser additives manufacturing for turbine engine/blade repairing or refurbishing.