Compact Instrumentation for Thermal Barrier Coating Integrity Monitoring

In this SBIR Phase II proposal, we outline a plan to develop a novel optical tool for quantitative Thermal Barrier Coating (TBC) integrity monitoring. Its operation uniquely combines three independent optical techniques based on measurement of fluorescence and thermal signals generated within the Thermally Grown Oxide (TGO) layer. These signals are used to quantify the compressive stress inside the TGO, the TGO layer thickness, and the fraction of delaminated interface areas. A technical advantage of this approach is that it provides inherent subsurface selectivity at the location where TBC structures are most prone to fail. During Phase I, we successfully demonstrated the feasibility of these techniques by performing a blind test evaluation. The thrust of Phase II is to develop these techniques into an imaging mode, with the additional advantage of more rapid mapping of complex surfaces such as turbine engine components. The design includes a compact optical probe for inspection of components in areas with difficult access.