Photoluminescence Piezospectroscopy: A Multi‐Purpose Quality Control and NDI Technique for Thermal Barrier Coatings

Many thermal barrier coating (TBC) applications have been hampered by the lack of accurate quality control, nondestructive inspection, remaining life assessment, and lifetime prediction tools for TBCs. Photoluminescence piezospectroscopy (PLPS) has the potential to provide these capabilities. The PLPS technique provides for the measurement of stress in the thermally grown oxide (TGO) and for the determination of TGO type (α, θ, γ alumina) and distribution. The capability of PLPS for these various applications will be described based on specimen and engine component measurements.