Indentation method for fracture resistance determination of metal/ceramic interfaces in thick TBCs

The indentation technique has been used to measure the adhesion of plasma-sprayed ceramic coatings on metals intended for thick thermal barrier coating (TTBC) applications. This approach provides the adhesion value as the critical strain energy release rate of the interface, which also takes into account any residual stresses. The theoretical background of the method is outlined, and specific examples are reported with respect to the effect of substrate temperature on the metal/ceramic adhesion of TTBCs.