STTR Phase I: EBC/TBC coating system for Si-based ceramic components for improved gas turbine performance and lifetimes

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). This Small Business Technology Transfer Phase I project between Plasma Technology Incorporated and Boston University will develop a functionally graded thermal barrier/environmental barrier coating (TBC/EBC) system for aerospace and power generation gas turbines. Introducing ceramic components (such as SiC/SiC composites) into gas turbines increases their operating temperatures, leading to increased efficiency and reduced environmental impact. However, these silicon-based ceramics are susceptible to hot-corrosion and recession in the presence of hot corrosive gases, particulates, and water vapor. The innovation in this project involves developing an integrated TBC/EBC system on SiC/SiC composite components in gas turbines, where the multifunctional mullite-based chemically vapor deposited EBC layer prevents recession and hot-corrosion and reduces thermal stresses by being functionally graded, dense, and crack-free. This coating layer is also substantially thinner than EBCs currently being used, leading to weight savings, which is of critical importance in aerospace applications. Subsequently, a plasma sprayed YSZ topcoat with engineered crack microstructure will be deposited over the EBC layer which will further increase the operating temperature and/or reduce the temperatures the components are exposed to, thereby enhancing sustainability of the gas turbine components. This innovative coating system will reduce costs by increasing the coating lifetime and reducing the need for refurbishment and repair. It will also lead to fuel savings due to increased efficiency and reduce emissions that adversely affect the global climate, thereby increasing environmental sustainability. This project will also provide a Materials Science and Engineering graduate student with commercially relevant research experience in this very critical area of gas turbine technology. The major customers who will be benefited are Solar Turbines, GE, Siemens and Pratt & Whitney. The world turbine industry is roughly a $90 billion industry, and there is a high market potential for the developed technology. For example, the projected supply and demand for turbine engines alone in the United States is about $10 billion by year 2012. Successfully capturing just 0.1 % of this potential market translates into a $10 million business. Therefore, the large market potential provides justification for the development of EBC coating techniques and PTI will work closely with industry partners to commercialize the technology.