Thermal Cycling Damage and Thermal Barrier Property of TBC

Two kinds of thermal cycle tests with short (10 min) and long (23h) holding times were carried out to investigate thermal cycling damage characteristics and thermal barrier property of thermal barrier coatings (TBCs). Surface cracks vertical to the coating surface were nucleated due to thermal stress during both the thermal cycle tests. Holding time had no significant influence on the surface cracking behavior. On the other hand, holding time had a significant influence on the thermal barrier property, which was degraded with increasing total holding time. The degradation of thermal barrier property was caused by the decrease in porosity and hence by the increase in density of ceramic layer.