Improvement of Delamination Resistant properties for Thermal Barrier Coatings by Formation Wedge-like Thermally Grown Oxide

摘要

It is necessary to improve the delamination resistance of thermal barrier coatings (TBC). In our previous studies, it has reported that, by using Ce containing bond coatings, wedge-like thermally grown oxide (TGO) was formed at the interface, resulting in improved delamination resistance of the TBC. However, wedge-like TGO is formed at temperatures greater than 1100℃, which is higher than the operating temperatures of real plants. Therefore, in this study, in order to obtain wedge-like TGO, pre-oxidation was carried out for 20 h at 1100℃ and then high temperature exposure tests were conducted for 1000 h at 1000℃. As a result, the growth of a wedge-like TGO was confirmed below 1000℃, and an isolated Ce oxide was sufficiently formed in the bond coating by preoxidation. Furthermore, the interface strength between the top coating and the bond coating was evaluated by four point bending tests. As a result, the TBC with a wedge-like TGO had a higher interface strength than did the TBC without a wedge-like TGO.