Novel Surface Modification Method for Ultrasupercritical Coal-Fired Boilers

The efficiency of conventional pulverized coal power plant cycles is strongly related to operating temperature and pressure. Ultrasupercritical (USC) coal-fired boilers are being developed to operate with higher steam temperatures and steam pressures. However, the increasing temperatures and corrosive environment cause more severe oxidation and corrosion in USC boiler components. New surface modification technology is needed to solve the corrosion problem. This project will develop an innovative process for forming an ultrafine-grained alloy coating at a competitive cost and will optimize coating materials and structures for high-temperature corrosion and erosion resistance. Phase I demonstrated a process that is capable of producing a superior coating with nanometer grains, high adherence, and full density. Extensive experimental tests were performed to evaluate coating performance under corrosion and erosion conditions, and promising coating systems were identified. Phase II will demonstrate an improved, optimized manufacturing process, evaluate coating characteristics, and determine long-term exposure properties in simulated boiler environments and in field testing. Commercial Applications and Other Benefits as described by the awardeee: Potential applications include supercritical and ultrasupercritical boiler components, coal gasification systems, solid oxide fuel cell systems, hot-section components of steam turbines, land-based gas turbine engines and aerocraft engines, and other industry components involved in oxidation and corrosion at elevated temperatures.