Thermal barrier coatings (TBCs) are being extensively used for improving the performance and extending the life of combustor and gas turbine components. The thermal conductivity of TBCs is usually measured by destructive methods, involving separating the ceramic coating layer from the substrate and performing laser flash measurement. Nondestructive evaluation (NDE) methods would allow for direct determination of TBC conductivity on coated components and, therefore, they can be used to inspect the quality of as-processed components and monitor TBC degradation during service. This paper presents a multilayer thermal-modeling NDE method, which analyzes data obtained from pulsed thermal imaging to determine thermal conductivity distribution over the entire surface of a TBC specimen. The significance of various TBC parameters that dictate the thermal imaging data and the measurement accuracy is investigated. Experimental results obtained from an EBPVD TBC sample are presented and discussed to demonstrate the application of this method for TBC thermal conductivity measurement.
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