横向梯度温度场下热障涂层的失效分析

Failure Analysis of Thermal Barrier Coating Being Subjected to Lateral Thermal Gradient on Surface

采用热障涂层服役环境性能实验模拟器,利用电化学阻抗谱针对横向梯度温度场条件下的热障涂层结构变化开展研究,并结合有限元方法对热力耦合作用下热障涂层的失效机理进行了分析,发现当管状试样处于两端约束受力状态下,加热区边缘为涂层易发生开裂部位。

Due to the combustion chamber usually provide flam with a non-uniform temperature field, therefore, a lateral temperature gradient should exist on the surface of nozzle guide-vanes for a gas turbine. In the present article, the structure evolution of thermal barrier coatings on nozzle guide-vanes was examined under the action of the above mentioned lateral temperature gradient by means of a home madeinfrared thermal shock testing system combined with impedance spectrosco- py measurement. Meanwhile, the failure analysis of thermal barrier coatings being subjected to thermo-mechanical loading was also studied using fmite element analysis. It＇s found that with constrain at both ends of a tube, cracks are apt to initiate at the edge of a heated area.