Low Conductivity for Thermal Barrier Coatings (TBCs)

Higher inlet operational temperatures for turbine engines is expected to provide significant benefits in fuel efficiency and performance for both military and commercial air vehicles. To accomplish this goal, new generation of thermal barrier coatingswith superior reliability and durability will be needed. While the currently-used zirconia-based thermal barrier coatings provide excellent thermal protection, they suffer from thermomechanical degradation during exposure at elevated temperatures. In thisPhase I effort, a crystal chemistry approach is being explored to examine a new family of layered perovskites. Key properties of these highly anisotropic materials include low thermal conductivity (0.7 W/M.K @ 13000C), tailorable CTE to match substrate,and inherent toughness/compliance primarily imparted through weak bonding between interbasal planes. In Phase I, coatings will be developed by plasma spray techniques with subsequent characterization of microstructure, texture, and thermal conductivity.The objective is to induce microstructurally designed features via texture and porosity to further lower thermal conductivity and to improve mechanical properties. The multifunctional nature of these materials will allow for their use in a broad range ofapplications.Potential commercial applications include TBC coatings for helicopter engines, diesel engine components for low wear and friction, and coatings for MEMS and microturbines.