Durable thermal barrier coatings with high thermal insulation performance are of significance for the development of advanced gas turbines. However, the complicated stress following the rapid growth of thermally grown oxide (TGO) on bond coat leads to the cracking and delamination failure. In this talk, we will demonstrate the coating delamination mechanism resulting from localized oxide nodulation and homogeneously grown oxide. For the homogeneously grown TGO, there is a critical thickness to result in cracking at the interface between ceramic top coat and bond coat. Therefore, reducing the growth rate of TGO can improve the durability of thermal barrier coatings. We will also discuss the design and deposition of bond coat aiming at reducing TGO growth rate. Based on these efforts, durable thermal barrier coatings are achieved to protect hot section parts in advanced F-class and G/H-class gas turbines.
 

Thermal barrier coatings; Durability; TGO; Oxidation resistance