Piezospectroscopic Analysis of Interface Debonding in Thermal Barrier Coatings

Abstract

One of the principal modes by which electron‐beam‐evaporated thermal barrier coatings fail is via the nucleation of local regions of debonding, which grow and link together until reaching a critically sized flaw for spontaneous buckling and spalling. This progressive‐failure mode is used as a basis for analyzing the changes that can occur in photostimulated luminescence spectra that have been recorded from the thermally grown oxide. This process also provides a basis for the quantitative determination of the extent of local damage prior to spalling from an analysis of the shape of the luminescence spectra.