Gd_2O_3-Yb_2O_3-Y_2O_3-ZrO_2热障涂层材料的热物理性能

Thermophysical Properties of Gd_2O_3-Yb_2O_3-Y_2O_3-ZrO_2 Thermal Barrier Coating Material

目的通过多元稀土氧化物掺杂改性YSZ,提高传统热障涂层的性能。方法使用化学共沉淀法制备不同掺杂量的Gd2O3-Yb2O3-Y2O3-Zr O2（GYYZO）材料,并分别使用冷等静压-烧结和等离子喷涂工艺制备块材和涂层。通过测试块材的热导率和热膨胀系数,分析评价材料的热物理性能。对高温退火处理后的涂层进行X射线衍射分析,评价不同成分涂层的高温相稳定性。结果氧化锆基材料的热导率和热膨胀系数随总掺杂量升高而降低。氧化锆中稀土氧化物总掺杂量为5.5%~9.84%（摩尔分数）时,在1000℃下的热导率为1.25~1.56 W/（m·K）,相对8YSZ材料下降了22%~37.5%;在200~1300℃的热膨胀系数为（10~11.1）×10-6/K,与传统8YSZ材料相当。在1400℃长时间退火处理后,低掺杂量GYYZO涂层中的单斜相含量明显低于8YSZ涂层。结论多元稀土氧化物掺杂改性氧化锆材料具有良好的高温相稳定性、低热导率和适当的热膨胀系数,可以作为高性能热障涂层的备选材料。

Objective To improve the performance of traditional ceramic thermal barrier coatings by rare earth oxides doping yttria stabilized zirconia（ YSZ）. Methods The Gd2O3-Yb2O3-Y2O3-Zr O2（ GYYZO） materials with various doped contents were prepared by co-precipitation,and the GYYZO bulk materials and coatings were prepared by cold isostatic pressing（ CIP） and plasma spraying（ PS）,respectively. The thermal conductivity and thermal expansion coefficient tests of materials with different compositions were taken to analyze and evaluate the thermophysical properties of GYYZO materials. X-ray diffraction（ XRD） analysis of the coatings was conducted after high-temperature annealing treatment to evaluate the high temperature stability of coatings with different compositions. Results The thermal conductivities and coefficient of thermal expansion（ CTEs） of zirconia based bulk materials decreased with the increasing doped content. The thermal conductivity of bulk GYYZO doped with 5. 5% ~ 9. 84% mole fraction of rare earth oxides at 1000 ℃ was 1. 25 ~ 1. 56 W /（ m·K）,which was reduced by 22% ~ 37. 5% as compared with that of bulk 8YSZ,and the CTEs was（ 10 ~ 11. 1） × 10- 6/ K,which was closed to that of the tradition 8YSZ materials. After long-term heat treatment at 1400 ℃,the content of monoclinic phase for GYYZO coating with low doped content was obviously lower than that of 8YSZ coating. Conclusion The multiple rare earth oxides doped YSZ has good high temperature phase stability,low thermal conductivity and suitable thermal expansion coefficient,and can be used as candidate ceramic materials for high-performance thermal barrier coatings.