Nanostructured Coatings by Pulsed Plasma Processing for Alloys used in Coal-Fired Environments

79811 Coal-fired power plants are a significant part of the nation¿s power generating capacity, currently accounting for more than 55 percent of the country¿s total electricity production. Efficient and profitable operation of coal-fired power plants requires higher steam temperatures, necessitating the use of advanced alloys such as ferritic and austenitic alloys. A major concern in using these advanced materials is their poor corrosion and oxidation resistance in fossil energy environments. The high temperatures and the presence of sulfur and water vapor can lead to severe oxidation, sulfidization, and carburizing problems in tubing, piping, and valves in fossil fuel-fired boilers. This project will develop protective coatings for these ferritic and austenitic steels used in coal-fired environments. In particular, an innovative pulsed-plasma fused coating technology will be developed, which uses slurry precursors in the preparation of durable nanostructured coatings of titanium aluminide coatings on Fe- and Ni-based alloys. In Phase I, a prototype of the pulsed plasma coating system will be constructed. Coated samples will be fabricated and then characterized by chemical, physical, structural, and microscopical techniques. The performance of the pulsed plasma-coated samples will be compared with uncoated samples in simulated furnace environment. Commercial Applications and other Benefits as described by the awardee: The new coating technology should have a significant impact on the electrical utility industry by saving the materials costs involved in replacing corroded tubes. Other benefits include reduced downtime, increased efficiency in power generation, and a reduced probability of catastrophic failure. The technology is versatile and could be extended to materials or components used in other industrial applications.