NSF Award
9961056
This Small Business Innovation Research project will develop highly engineered, oxidation resistant and durable NZP-based TBCs for components in advanced aerospace and gas turbine engine systems. Next generation aerospace propulsion and power generation systems have to meet requirements of higher efficiencies, greater fuel economy, and longer lifetimes. Higher firing temperatures and better insulation are required to improve engine efficiency and lifetimes of components in such systems. State-of-the art thermal barrier coatings (TBCs) based on yttria partially-stabilized zirconia (YPSZ) are inadequate to meet these temperature and lifetime requirements because of:(1) oxidation problems, (2) low thermo-chemical stability, (3) in-service microstructural changes, and (4) low strain tolerance. At least, two compositions viz. Ba1.25Zr4P5.5Si0.5O24 (BS-25) and Ca0.5Sr0.5Zr4P6O24 (CS-50,) belonging to the NZP ceramics family, are ideally suited for advanced TBCs. Attractive properties of these compositions include high melting temperature (> 1800C), high thermal cycling stability, very low thermal conductivity (~1.0 W/mK), excellent thermal shock resistance, and low oxygen ion conductivity. In addition, their thermal expansion coefficients are very low. Functionally Graded (FG) design approach will be used to minimize thermal expansion mismatches and introduce beneficial surface compressive stresses. When successfully developed, this technology will also be beneficial to automotive and metallurgical industries.<br/><br/>Specific commercial applications that could be immediately realized for NZP ceramics-based TBCs are: for turbine blades, combustor liners, stator vanes, etc., in jet and gas turbine engines; and pistons, valve heads, exhaust port, and cylinders in diesel engines. Other commercial applications are in: (1) Heat Exchangers, (2) Burner Nozzles, (3) Hot Gas Fans and Filters, and (4) Pump and Valve Linings in Corrosive Environments.<br/><br/>NZP-Based TBCs, Thermal Spray, Functionally Gradient, Advanced Gas Turbines, Low Thermal Conductivity, Oxidation Resistance
