Advanced Thermal Barrier Coating Materials

Desire to operate gas-turbine engines at higher gas temperatures, beyond melting points of metal airfoil components, for improved engine efficiency and performance, drives demand for more durable, less conductive ceramic thermal barrier coatings (TBCs) that insulate metals from hot gas streams. Particularly for aircraft, TBCs must withstand the most demanding temperature gradient and stress from thermal-expansion mismatch, under dynamic conditions, without changing composition, microstructure, or interfacial morphology. Military and commercial gas turbine engines require more durable and more reliable hot-section components to achieve their “design” service life, and avoid unscheduled inspections, costly outages, repairs, and major overhauls. Inspections, repairs and overhauls result in reduced operational readiness and negatively impact flight safety. The structure of ceramic coated metals is a complex, multilayered interface to mitigate different thermomechanical properties, stresses, and metal oxidation. This project will develop custom liquid-based coating methods to manipulate microstructure, for lower conductivity and better oxidation resistance, without sacrificing thermomechanical robustness. Thor Technologies has teamed with Southwest Research Institute to develop advanced composite TBCs and with a turbine engine OEM to validate their use on actual hot-section turbine components. Novel chemical precursors will be combined with simple solution-based coating methods to produce new robust microstructures with low thermal conductivity.