Abstract
The strength of thermal barrier coating (TBC) is usually evaluated from a free-standing coating because it is difficult to detect the damage from a TBC system which consists of a TBC, a bond coat and a substrate. In this study, evaluation method of the damage stress in TBC using change in the stress share of substrate was developed. Four point bending was applied to a TBC system specimen. The applied force and the substrate strain were measured. The substrate stress of a TBC system specimen became high when the TBC was damaged, because apparent Young's modulus of the TBC decreased. Therefore, the stress of TBC damage can be detected by comparing the substrate strain of a TBC system specimen with that of a bare substrate specimen. It was found that the evaluated damage stress agreed with that of a free standing TBC.
