Al2O3 含量对 YSZ 热障涂层性能的影响

Al_2O_3等氧化物对YSZ热障涂层的高温使用性能有一定的影响。本文用HVOF喷涂Ni Co Cr Al Y合金粘结层,APS喷涂YSZ陶瓷面层,制备了Al_2O_3含量为0.01~0.64wt%的YSZ涂层。比较了不同Al_2O_3含量的YSZ涂层在1100℃下的热震性能和抗烧结性能,并探讨Al_2O_3对涂层的影响机理。结果表明相较于高纯YSZ涂层,随着涂层中Al_2O_3含量升高,涂层的抗热震性能降低,且Al_2O_3促进YSZ涂层的烧结。Al_2O_3含量在小于0.01wt%-0.12wt%区间内时,对涂层抗热震和抗烧结性能有显著影响,含量继续增加至0.64%时,对性能影响减缓。显微组织观察与EDS检测结果表明涂层中Al_2O_3并未在熔融颗粒界面处偏聚,但在颗粒内部有局部偏析。由此推测,含Al_2O_3的YSZ涂层热震失效的原因可能是Al_2O_3在YSZ颗粒内部偏析,并影响涂层的烧结性能,导致裂纹容易萌生和扩展。

Effects of Al2O3 content on properties of YSZ thermal barrier coatings

Oxide impurities such as Al2O3 have certain effects on the high temperature performance of YSZ thermal barrier coatings. In this paper, YSZ coatings with Al2O3 content of 0.01-0.64wt% were prepared with APS. The anti-sintering performance and thermal shock resistance of the coating with different Al2O3 contents were compared to explore the mechanism of Al2O3 on the coating. The results show that compared with the highpurity YSZ coating, the thermal shock resistance of the coating decreases with the increase of Al2O3 content, and Al2O3 promotes the sintering of the YSZ coating. When the content of Al2O3 is in the range of less than 0.01wt%-0.12wt%, the thermal shock resistance and anti-sintering performance of the coating are significantly affected. When the content is further increased to 0.64%, the effect on the performance is slowed down. Microstructure observation and EDS results showed that Al2O3 did not segregate at the interface of the melted particles, but there was local segregation within the particles. Therefore, it is speculated that the thermal shock failure of YSZ coatings containing Al2O3 may be due to the segregation of Al2O3 inside the YSZ particles and affect the sinterability of the coating, leading to crack initiation and propagation.