A simple method for measurement of shear delamination toughness in environmental barrier coatings

A simple technique for measurement of delamination toughness in environmental barrier coatings (EBCs) under shear loading has been developed. The technique overcomes micro damage accumulation properties of CMC substrate and a delamination toughness with a phase angle of ~ 80° could be obtained using a simple fixture. Demonstration of the present procedure is carried out using a BSAS/mullite + BSAS/Si standard EBC layer on a three-dimensional woven fabric SiC/SiC composite substrate. The delamination path suggests that it is possible to apply the method to wavy EBC coatings and also to thermal barrier coatings.