Citation: MI Yan, HUANG Zai-Yin, JIANG Jun-Ying, LI Yan-Fen. In situ Microcalorimetry Insight into the Growth of CaMoO4 Microcrystallites[J]. Acta Physico-Chimica Sinica, 2009, 25(12): 2422-2426. doi: 10.3866/PKU.WHXB20091215
CaMoO4微晶生长过程的原位微量热法研究
在碱性条件下采用原位微量热法对CaMoO4微晶的构建进行了研究. 首次呈现了CaMoO4微晶生长过程能量变化的特征热谱曲线; 该特征热谱曲线由一个反映最初反应成核的典型吸热曲线和随后晶体生长的两个相对较弱的不连续放热曲线组成. 在导向机制的基础上, 结合CaMoO4微晶生长过程的形貌演变, 简要地讨论了CaMoO4微晶生长过程的热动力学信息. 反应成核过程、晶化过程及微晶的二次生长过程的速率常数分别为1.54×10-4、1.09×10-4和0.71×10-4 s-1. 由于晶体的聚集和扩散二者之间强烈的相互作用, 使得反应速率下降, 从而呈现出一个相对较平坦的第二次放热曲线.
English
In situ Microcalorimetry Insight into the Growth of CaMoO4 Microcrystallites
In situ calorimetric studies of CaMoO4 microcrystallite fabrication were performed in an alkalescent aqueous solution. We first presented an oscillatory microcalorimetric heat flow curve pattern which traced the energy evolution of the CaMoO4 microcrystallite growth process. A characteristic endothermic peak for the initial reaction and double relatively weak and discontiguous exothermic peaks for the subsequent crystal growth were observed. We briefly discussed the morphology evolution and the thermokinetics information of the growth process of CaMoO4 microcrystallites on the basis of the oriented attachment mechanism. The rate constants of the reaction and nucleation, crystal crystallization, and microcrystalline secondary growth were found to be 1.54×10-4, 1.09×10-4, and 0.71×10-4 s-1, respectively. As the crystals aggregated and repelled each other, the reaction slowed leading to a relatively flatter second exothermic curve.
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