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通过高温固相合成方法制备了烧绿石结构Gd2Zr2O7陶瓷材料,研究了其高温相稳定性和热物理性能。采用电子束物理气相沉积方法制备了Gd2Zr2O7-8YSZ(8%Y2O3-ZrO2)双陶瓷层结构热障涂层,分析了涂层顶层的晶体结构和原子数量比。结果表明,Gd2Zr2O7在室温至1500℃范围内具有良好的相稳定性,比第一代热障涂层8YSZ的高温相稳定区间提高250℃以上。Gd2Zr2O7块材的热膨胀系数在100~1500℃范围内介于8.8×10-6~11.0×10-6 K-1之间,与8YSZ接近;在1000~1400℃高温区间,热导率约为1.0W(m·K)-1,比8YSZ降低一半左右。沉积制得的Gd2Zr2O7涂层化学成分符合化学计量比,为烧绿石结构,涂层呈现典型的柱状晶结构。
The pyrochlore structure Gd2Zr2O7 ceramic was prepared by high-temperature solid-phase synthesis. The phase stability and thermophysical properties were studied. The thermal barrier coatings of Gd2Zr2O7-8YSZ (8% Y2O3-ZrO2) dual ceramic layer structure were prepared by electron beam physical vapor deposition. The crystal structure and atomic ratio of the top layer were analyzed. The results show that Gd2Zr2O7 has good phase stability from room temperature to 1500 ℃, which is more than 250 ℃ higher than the high temperature phase stability of the first generation thermal barrier coating 8YSZ. The thermal expansion coefficient of Gd2Zr2O7 block is between 8.8 × 10-6 ~ 11.0 × 10-6 K-1 in the range of 100 ~ 1500 ℃, which is close to 8YSZ. At 1000 ~ 1400 ℃, the thermal conductivity is about 1.0 W (m · K) -1, lower than 8YSZ by about half. The chemical composition of the deposited Gd2Zr2O7 coating is in the stoichiometric ratio and is a pyrochlore structure with a typical columnar crystal structure.