Compact Instrumentation for Thermal Barrier Coating Integrity Monitoring

In this proposal, we outline a plan to develop compact non-destructive inspection instrumentation for Thermal Barrier Coating (TBC) integrity monitoring on fielded turbine engine components. Its operation is based on a unique combination of two optical techniques. Using a compact laser, fluorescence and thermal signals are generated simultaneously within the Thermally Grown Oxide (TGO) layer. These signals are used to quantify the residual stress inside this layer, as well as the fraction of delaminated interface areas, thus providing a means to assess the remaining lifetime of the coating. The instrumentation can be used in two modes: a global monitoring mode to appraise the integrity of the entire engine components, and a local monitoring mode to look at specific surface areas of these components. In this proposal, we outline the operational principles of the proposed system and the anticipated performance envelope. For Phase I, we propose to develop a breadboard system for analysis of critical performance and design parameters, determine the suitability for practical use on fielded engine components, and deliver a conceptual prototype design to be produced in Phase II.