Durable Thermal Barrier Coating with Low Thermal Conductivity Composition and Unique Microstructure

The Navy seeks to develop an innovative thermal barrier coating (TBC) system that will exhibit twice the durability and half the thermal conductivity (TC) compared with that of today's EB-PVD TBC systems. This Phase I program will demonstrate the feasibility of exploiting a novel TBC with unique fabrication process, composition and microstructure for lower TC, better durability and high sintering resistance. The uniqueness of this new TBC, compared to EB-PVD TBCs, is the use of a multi-component rare earth oxide doped zirconia (lower TC) ceramic topcoat, generated by a novel solution precursor plasma spray ("SPPS") technique. The unique SPPS TBC microstructure, consisting of vertical microcracks, uniform nanometer and micrometer sized pores, and ultrafine splats, will increase thermal cycle resistance through enhanced strain tolerance to thermal stresses. A 7YSZ thin inner layer, or primer, and a robust LPPS CoNiCrAlY bond coat will be applied to improve interfacial bond strength / toughness, and oxidation resistance, respectively. Inframat Corporation has assembled a strong team with the University of Connecticut, industrial partners Pratt & Whitney and Rolls Royce, Indianapolis, plus consultant NASA-Glenn Research. With this team and in-house experience, the new SPPS TBC should readily meet the program goals.