Ionic Conductivity in Sodium-Alkaline Earth-Aluminosilicate Glasses
Ionic Conductivity in Sodium-Alkaline Earth-Aluminosilicate Glasses
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DOI：
10.1111/jace.14101
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发表时间：
2016-04-01
影响因子：
3.9
通讯作者：
Pantano, Carlo G.
中科院分区：
文献类型：
--
作者：
Amma, Shin-ichi;Lanagan, Michael T.;Pantano, Carlo G.
通过测定Na_2 O-RO-Al_2 O_3-SiO_2系统组成系列（R=Mg，Ca，Sr，Ba）玻璃的离子电导率，研究了碱土金属离子对铝硅酸盐玻璃中Na输运的影响。铝硅酸盐玻璃中的Na输运可能受到铝配位和非桥氧的组成变化以及介电常数、剪切模量和离子填充因子等物理性质的影响。通过仔细的实验设计和测量，确定了这些参数中的主要决定因素。Al-27 MAS-NMR表明，这些玻璃中包含的所有铝物种是四配位的。在[Al] < [Na]的范围内，随着Al含量的增加和碱土离子半径的减小，离子电导激活能减小。当铝含量超过钠含量（[Al] > [Na]）时，活化能的组成依赖性取决于特定的碱土金属。这些结果解释的基础上自由体积和介电常数的变化所造成的AlO 4电荷补偿网站周围的结构变化。这些结构的变化发生在响应的碱土离子的较小的尺寸和较高的场强，并且是最普遍的组合物中，需要桥接的两个AlO 4网站的碱土离子的电荷补偿。
The effect of alkaline-earth ions on Na transport in aluminosilicate glasses was studied by measuring ionic conductivity for a systematic compositional series of Na2O-RO-Al2O3-SiO2 glasses (R=Mg, Ca, Sr, Ba). The Na transport in aluminosilicate glass could be affected by compositional changes in aluminum coordination and nonbridging oxygen as well as physical properties such as dielectric constant, shear modulus, and ionic packing factor. Through careful experimental designs and measurements, the main determinants among these parameters were identified. Al-27 MAS-NMR indicated that all aluminum species contained in these glasses are four-coordinated. The activation energy for ion conductivity decreased with increasing aluminum content and decreasing ionic radii of the alkaline-earth ion in the region where [Al] < [Na]. When the aluminum content exceeded the sodium content ([Al] > [Na]), the composition dependence of the activation energy depended on the specific alkaline earth. These results are explained based on variations in free volume and dielectric constant caused by structural changes around the AlO4 charge compensation sites. These structure changes occur in response to the smaller size and higher field strength of the alkaline-earth ions, and are most prevalent in the compositions which require bridging of two AlO4 sites by the alkaline-earth ion for charge compensation.