表面陶瓷层厚度对Sm2Zr2O7/8YSZ热障涂层热冲击性能的影响

稀土锆酸盐与8YSZ所组成的双陶瓷层涂层是目前热障涂层领域研究的热点,而陶瓷层厚度对其热冲击性能有着显著影响。采用有限元软件ANSYS研究了表层厚度对Sm2Zr2O7/8YSZ热障涂层淬冲击热应力的影响,并与单一Sm2Zr2O7涂层进行了比较。结果表明,在Sm2Zr2O7/8YSZ涂层的表面处具有最大的径向热冲击应力,最大轴向应力则存在于陶瓷层/金属粘结层界面处,涂层各处剪应力基本相当。涂层表面及两陶瓷层界面处的径向热应力随表层厚度的增加而减小,陶瓷层/粘结层界面处径向应力则随表层厚度增加而增大。每个界面处的轴向应力随表层厚度增加而降低,而剪应力绝对值则随表层厚度增加而增大。与单一Sm2Zr2O7涂层相比,Sm2Zr2O7/8YSZ涂层的热应力明显偏小,说明增加涂层的层数有利益改善涂层的抗热冲击性能。

Influence of Surfacelayer Thickness on Thermalshocking Property of Sm2Zr2O7/8YSZ Thermal Barrier Coatings

Double-ceramic-layer thermal barrier coatings (TBCs) of rare earth zirconates and 8% yttria stabilized zirconia are the focal point. Thickness of surface-layer has an important impact on the thermal-shocking property of TBCs. The influence of surface-layer thickness on water-quenching thermal stress in Sm₂Zr₂O₇/8YSZ thermal barrier coating was investigated by ANSYS, compared with that in single Sm₂Zr₂O₇ coating. The results indicate that the highest radial thermal stress exists on the surface of Sm₂Zr₂O₇/8YSZ TBCs, and the highest axial thermal stress exists at ceramic-layer/bonding coat interface, however, shear stresses at different locations in TBCs are in the same order. Radial stress at top-surface and interface between two ceramic-layers reduces gradually with increasing surface-layer thickness, however, the radial stress at the ceramic-layer/bonding coat interface is proportional to the surface-layer thickness. Axial stress at each interface is inverse-proportional to the thickness of the surface-layer, however, the absolute value of shear thermal stress increases with increasing thickness of the surface-layer. Thermal stress in double-ceramic-layer TBCs is lower than that in single-cerami-clayer TBCs. Increasing number of the layer can improve the thermalshocking property of thermal barrier coatings.