Evaluation of delamination on thermal barrier coatings by stress measurement and addition of strengthening mechanism

热障涂层系统被广泛应用于提高燃气轮机、叶片和叶片热段部件的工作温度。热障涂层通常由外层氧化物陶瓷涂层(TC)和内层金属间化合物涂层(BC)组成，以保护镍基高温合金免受高温和氧化。在使用过程中，会形成TGO，这种形成会增加涂层的残余应力。TGO/BC界面的分层是由于TGO/BC界面的残余应力增加，最终TC层从热障涂层上剥落而成。在本研究中，局部应力分量的评估采用Wilkinson方法，其中应力由EBSD模式的变形决定。此外，由于热处理后的屈服应力较低，利用BC层的应力消散作用形成了高韧性的热障涂层。

Thermal barrier coating systems (TBCs) have been widely used to increase the operating temperature of hot section components in gas turbines blades and vanes. TBCs usually consists of outer oxide ceramics top coat (TC) layer and inner intermetallic bond coat (BC) layer in order to protect the Ni-base superalloy from high temperature and oxidation. During the service, TGO forms and this formation increases the residual stress of the coating. Delamination of TGO/BC interface occurs because of the increasing residual stress and finally TC layer spall off from the TBCs. In this research, local stress components were evaluated by Wilkinson method where the stresses were decided by the distortion of the EBSD pattern. Further, high toughened TBCs were formed by using the stress dissipation of the BC layer due to the low yield stress by heat treatment.