Preparation of CeO2-La2O3-ZrO2 ceramic powder by chemical precipitation method

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°C, the amorphous mixed oxide is converted to composite oxide when temperature rises to 900°C, and the composite oxide is converted to single La2Zr2 O7 with pyrochlore structure at 1150°C. The LCZ powders keep pyrochlore structure and no phase transformations occur for LCZ at high temperatures (1350°C). The flowability of LCZ powder sintered at 1 400°C is improved clearly, and which could be used in plasma spray coatings.