(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 采用化学沉淀法制备了La2Zr2O7(LZ)和CeO2-La2O3-ZrO2(LCZ)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及霍尔流速计等分析方法，对粉末的化学组成、不同CeO2掺杂量LCZ的相组成、不同煅烧温度下的相组成、高温相稳定性和流动性能进行了研究。结果表明：所制备粉末的组成与锆酸镧烧绿石相的组成相近；热处理温度600 ℃时粉末为无定形的混合氧化物，900 ℃时转化为复合氧化物，1 150 ℃时转变为单一的锆酸镧烧绿石相；高温下LCZ无明显相变；温度高于1 400 ℃煅烧后，LCZ的流动性显著改善，可用于等离子喷涂。
关键字: 锆酸镧；复合陶瓷；热障涂层；化学沉淀法
powder by chemical precipitation method
（School of Materials Science and Engineering, Central South University,
Changsha 410083, China）
Abstract:Lanthanum zirconate (La2Zr2O7, LZ) and CeO2-La2O3-ZrO2 (LCZ) composite ceramic powders were prepared by the chemical precipitation. The chemical composition of the powders was analyzed by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The crystallogrphic phases of LZ and LCZ with different CeO2 doped concentrations were determined by X-ray diffractometry. Differential scanning calorimetry (DSC) and TG were used to analyze the phase stability of LCZ sintered at different temperatures. The Hall flow meter was performed to determine the flowability of LCZ powder. The results show that the compositions of all prepared ceramic powders are similar to that of La2Zr2O7 with pyrochlore structure, the ceramic powders are amorphous mixed oxide at 600 ℃, the amorphous mixed oxide is converted to composite oxide when temperature rises to 900 ℃, and the composite oxide is converted to single La2Zr2O7 with pyrochlore structure at 1 150 ℃. The LCZ powders keep pyrochlore structure and no phase transformations occur for LCZ at high temperatures (1 350 ℃). The flowability of LCZ powder sintered at 1 400 ℃ is improved clearly, and which could be used in plasma spray coatings.
Key words: lanthanum zirconate; composite ceramics; thermal barrier coatings; chemical precipitation
