Abstract
The paper presents the experimental investigation on the fracture of thermal barrier ceramic coating (TBC) at high temperature. The fracture was induced by temperature gradient along TBC system thickness direction and oxidation between TBC and bond coat. Laser heating method was used to simulate the operating state of TBC system. Both micro-observation and acoustic emission (AE) detection revealed that fatigue crack was in two forms: surface crack and interface delamination. One can understand the failure mechanism from the plane of TBC surface temperature and substrate surface temperature. It was found that the life of thermal fatigue was reduced by the formation of alumina at interface. On the other hand, it was found that the temperature gradient between inner and outer surface of specimen accelerated the growth of alumina layer.
