铈锆酸镧涂层高温时效行为和热震性能研究

Aging Behavior and Thermal Shock Property of Ce-modified La_2Zr_2O_7 TBCs at High Temperature

采用等离子喷涂制备了铈锆酸镧涂层,采用扫描电子显微镜(SEM)、X射线衍射分析(XRD)、图像分析法等研究了喷涂功率对沉积态涂层表面和截面微观结构、孔隙率等的影响规律,研究了涂层在1200℃、1300℃高温100h时效下相稳定性、微观结构、孔隙率的变化,比较了不同喷涂功率涂层的抗热震性能。研究结果表明:随着等离子喷涂功率的增加,喷涂过程中半熔融颗粒比例减小,涂层的孔隙率减小。涂层经1200℃、1300℃高温保温100 h后仍然具有单一的烧绿石结构,随着热处理温度升高,涂层孔隙率减小。研究了不同功率喷涂的涂层从1250℃到冷水中的热震行为,失效机制分析表明:陶瓷层与粘结层热应力不匹配造成陶瓷层底部产生裂纹是导致涂层失效的主要方式。

The Ce-modified La2Zr2O7 （ CLZ ） thermal barrier coatings were prepared by atmospheric plasma spraying. The effects of spraying power on the surface and cross-sectional microstructure, porosity of the deposited coatings were studied using scanning electron microscopy （SEM）, X-ray diffraction analysis （ XRD ） , and image analysis method. The phase stability, microstructure, porosity of the coating after aging at 1200, 1300 ℃ for 100h were also studied. The thermal shock resistance of the coating with different spraying powers were compared. The experimental results show that： as the plasma spraying power increased, the proportion of semi-molten particles reduced during the spraying process and the porosity of the coating increased. The coating still showed a single pyrochlore structure after heat treatment at 1200℃, 1300℃ for 100h. The porosity of the coating reduced after heat treatment at higher temperature. The thermal shock behavior of the coating with different spraying powers from 1250 ℃ to cold water were studied. The failure mechanism analysis showed that： the cracks formed at the bottom of the ceramic layer due to the thermal stress mismatch between the ceramic layer and the adhesive layer, which is the main way that caused coating failure.