High temperature thermo-physical properties of and preparation of a novel thermal barrier coating Gd2Zr2O7-8YSE
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摘要: 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1.0 W(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。Abstract: Gd2Zr2O7 was prepared by solid state synthesis and its phase stability and thermo-physical properties were investigated. The Gd2Zr2O7-8YSZ(8%Y2O3-ZrO2) double-ceramic-layer thermal barrier coatings was prepared by electron beam physical vapour deposition. The crystal structure and atomic number ratio of the top coating were analysed. Results reveal that Gd2Zr2O7 powders show excellent phase stability up to 1500℃, 250℃ higher as compared to the conventional 8YSZ.The coefficients of thermal expansion of the Gd2Zr2O7 bulk ranges from 8.8×10-6-11.0×10-6 K-1 at the temperature from 100 to 1500℃, which are comparable to that of the 8YSZ bulk.The thermal conductivities of the Gd2Zr2O7 bulk are in a level of 1.0 W(m·K)-1 at 1000-1400℃ and about 50% lower than that of the conventional 8YSZ. The as-deposited Gd2Zr2O7 coating with pyrochlore structure has a stoichiometrical composition and exhibits a typical columnar grain structure.
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