采用化学沉淀法制备了热障涂层用Nd2Zr2O7(NZ)以及CeO2-Nd2O3-ZrO2(NCZ)陶瓷粉末. 通过电感耦合等离子体原子发射光谱(ICP-AES)、X射线衍射、DSC及霍尔流速计对粉末化学组成、相组成、高温相稳定性和流动性能进行了研究. 通过高温膨胀仪、DSC和激光热导仪分别测定其热膨胀系数和导热系数. 结果表明, 掺杂的NCZ粉末保持了NZ的烧绿石相结构, 120℃时粉末为无定形的混合氧化物, 900℃时转化为复合氧化物, 1200℃时转变为单一的锆酸钕烧绿石相; 高温下NCZ无明显相变; 在高于1400℃的温度下煅烧后, NCZ的流动性得到显著改善; 添加CeO2可提高锆酸钕的热膨胀系数, 而对其导热系数和比热系数的影响不大.
Neodymium zirconate (Nd2Zr2O7, NZ) and CeO2-Nd2O3-ZrO2 (NCZ) ceramics were synthesized by the chemical precipitation method. The chemical compositions of the powders were nalyzed by means of Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). Differential Scanning Calorimetry (DSC), TG and XRD were used to analyze the crystallogrphic phase and the phase stability of NCZ. The Hall flowmeter was performed to determine the flowability of NCZ powder. High-temperature dilatometer, DSC and laser thermal diffusivity methods were used to analyze its thermal expansion coefficient (TEC), thermal conductivity. The results show that the compositions of all prepared ceramic powders are in the range of the synthesis of Nd2 ZrO7 with pyrochlore structure, the ceramic powders are amorphous mixed oxide at 120℃, composite oxide at 900℃, Nd2 ZrO7 with pyrochlore structure at 1200℃. The NCZ powders keep the pyrochlore structure and there is no phase transformations for NCZ at high temperatures (～1300℃). The flowability of NCZ powder sintered at 1400℃ is improved clearly. TEC of the NCZ ceramic is slightly higher than that of conventional Y2O3 8wt ZrO2 (YSZ) and the thermal conductivity of the ceramic is much lower than that of YSZ, which indicates that NCZ may be an excellent material for preparing thermal barrier coatings.
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