等离子喷涂ZrO2—NiCoCrAlY梯度热障涂层的抗热震性及失效机理

研究了ZrO2-NiCoCrAlY热障涂层的抗热震性和热震失效机理。实验结果表明，梯度热隙涂层能明显延缓热震裂纹的形成和扩展，具有较高的抗热震性。热震裂纹形成与扩展主要在粘结层与基体的界面处。随热循环次数的增加，热震裂纹可在表面陶瓷层内和陶瓷层与过渡层的界面处形成。实验表明热障涂层热震失效的过程主要是裂纹形成、扩展及涂层剥落，粘结层的氧化是导致涂层剥落失效的重要原因。

Thermal Shock Resistance Property and Failure Mechanism of Plasma Sprayed ZrO_2-NiCoCrAlY Thermal Barrier Graded Coating

Thermal shock resistance property and failure mechanism of plasma sprayed ZrO 2 NiCoCrAlY thermal barrier coatings were studied in this paper. The test results show that retardation of thermal shock crack initiation and propagation and higher thermal shock resistance property were displayed in graded thermal barrier coating. The thermal shock crack initiation and propagation take place mainly at the interface between the NiCoCrAlY bond layer and substrate. However, with the increase of thermal cycles, the thermal shock crack will be formed inside top ceramic layer and at the interface between top ceramic layer and graded layer. The experiment results demonstrate that the failure process of thermal barrier coating mainly goes through crack formation, propagation and spallation of coating, whereas, the oxidation of bond coat is the main cause of coating spallation.