Thermal Property Measurement for Thermal Barrier Coatings Using Pulsed Thermal Imaging - Multilayer Analysis Method

Thermal barrier coatings (TBCs) are extensively used on hot gas-path components in gas turbines to improve engine performance and extend component life. TBC thermal properties, specifically the thermal conductivity and heat capacity (the product of density and specific heat), are important parameters in these applications. These TBC properties are usually measured by destructive methods with specially prepared TBC samples. Nondestructive evaluation (NDE) methods have been developed in recently years that can measure TBC properties on natural TBC samples. However, many have limitations when examining TBCs on engine components. One exception is the pulsed thermal imaging multilayer analysis (PTI-MLA) method, which can be applied to essentially any TBC samples with one or more coating layers and can determine TBC property distributions over the entire TBC surface. This paper describes its basic theories and implementations and discusses its potential applications to all areas of TBC studies.