Measuring self-diffusion coefficients up to 1500 K: a powerful tool to investigate the dynamics and the local structure of inorganic melts.
Measuring self-diffusion coefficients up to 1500 K: a powerful tool to investigate the dynamics and the local structure of inorganic melts.
复制标题
测量高达 1500 K 的自扩散系数：研究无机熔体动力学和局部结构的强大工具。
DOI：
10.1021/ic9010086
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发表时间：
2009
影响因子：
4.6
通讯作者：
C. Bessada
中科院分区：
文献类型：
--
作者：
A. Rollet;V. Sarou;C. Bessada
自扩散是液体动力学的一个基本性质，也提供了重要的结构信息。为了探索高液相线温度的无机熔体的动力学，我们提出了一种新的装置，基于脉冲场梯度NMR结合激光加热，使原位自扩散系数测量高达1500 K。应用于几种腐蚀性熔融氟化物在广泛的组成和温度范围内，我们证明了不同的关键参数的运动沿着与他们的结构特征。在碱金属氟化物中，与温度相比，氟的自扩散系数略微取决于组成，显示这些系统是可极化硬球的理想浴。相比之下，稀土和碱金属氟化物混合物中的自扩散呈现出温度和离子长寿命单元的网络形成过程之间的复杂平衡。这些结果为高温液体的研究开辟了广阔的前景。
Self-diffusion is a fundamental property of liquid dynamics that also provides important structural information. To explore the dynamics in inorganic melts with high liquidus temperature, we propose a new setup based on pulsed field gradient NMR combined with laser heating that makes possible in situ self-diffusion coefficient measurements up to 1500 K. Applied to several corrosive molten fluorides in a wide range of compositions and temperature, we have evidenced the different key parameters of their motion along with their structural characteristics. In alkali fluorides, the self-diffusion coefficient of fluorine depends slightly on the composition compared to the temperature, displaying these systems as an ideal bath of polarizable hard spheres. In contrast, self-diffusion in rare earth and alkali fluorides mixtures presents a complicated balance between temperature and the network-forming process of the ionic long-lived units. These results open wide perspectives in the study of high temperature liquids.