Stress variation with thermal cycling in the thermally grown oxide of an EB-PVD thermal barrier coating

A measurement approach for detecting thermal barrier coating (TBC) damage and assessing remaining life is described in this study. This is based on an experimental study of the oxide stress evolution as a function of thermal cycling. Residual stress in the thermally grown oxide (TGO) has been measured using photo-stimulated luminescence piezo spectroscopy (PLPS) for electron beam physical vapor deposited TBCs that were thermally cycled at 1100, 1121 and 1151 °C using 1-h and 24-h cycling periods. The observed monotonic change in the oxide stress level with life fraction is systematic with cycle time and nearly independent of exposure temperatures. The temperature independence of the measured stress with life fraction greatly simplifies the use of this technology for non-destructive evaluation of this TBC coating.