以SrCO3和CeO2为原料, 采用XRD和TG/DTA分析技术研究了SrO-CeO2体系化合物的物相形成过程. 结果发现, 当灼烧温度低于950℃时, 原始粉料只反应生成Sr2CeO4; 而当灼烧温度高于950℃时, 在反应的初始阶段, 原始粉料中同时出现SrCeO3和Sr′CeO4物相, 在950℃附近, 主要产物为Sr2CeO4, 在 1000℃以上, 主要产物为SrCeO3. SrCeO3和Sr2CeO4物相分别存在着两种形成机制, 当温度高于1000℃时, SrCeO3由SrO和CeO2直接反应生成, 而Sr2CeO4则由SrCeO3和SrO反应生成; 当温度低于950℃时, Sr2CeO4由SrO和CeO2直接反应生成, 而在950℃附近SrCeO3则由Sr2CeO4和CeO2反应生成. 依据这些实验结果, 给出了SrO-CeO2体系固相反应规律, 并对SrCeO3衍射数据JCPDS36-980的错误结果进行了分析. 荧光光谱测试结果表明, Sr2CeO4物相的形成机制对其激发光谱产生明显的影响.
The solid state reaction process of the mixture of SrCO3 and CeO2 powders with different Sr/Ce ratios was studied by using XRD and TG/DTA methods. The results show that only Sr2CeO4 phase is formed for a firing temperature lower than 950℃ while Sr2CeO4 and SrCeO3 phases are simultaneously developed in the initial stages of the reaction for a firing temperature above 950℃. In the initial stages of the reaction above 950℃,the major product is Sr2CeO4 for close to 950℃ and it becomes SrCeO3 above 1000℃. There are two types of formation mechanism for SrCeO3 and Sr2CeO4, respectively. When the firing temperature is above 1000℃, SrCeO3 is formed directly by SrO and CeO2 while Sr2CeO4 is created by SrCeO3 and SrO. However, SrO and CeO2 convert directly to Sr2CeO4 below 950℃ and SrCeO3 is produced by the reaction of Sr2CeO4 and CeO2 for close to 950℃. Based on these results, the reaction mechanism of SrO-CeO2 system is derived and the wrong results in the XRD data of SrCeO3 (JCPDS36-980) have been clarified. The fluorescence spectra of Sr2CeO4 show that the formation mechanism has effect on its excitation spectra.
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