Mechanism of mixed alkali effect in silicate glass/liquid: Pathway and network analysis
Mechanism of mixed alkali effect in silicate glass/liquid: Pathway and network analysis
复制标题
硅酸盐玻璃/液体中混碱效应的机理：路径和网络分析
DOI：
10.1016/j.jnoncrysol.2023.122321
复制
发表时间：
2023
影响因子：
3.5
通讯作者：
S. Naito
中科院分区：
文献类型：
--
作者：
F. Noritake;S. Naito
硅酸盐玻璃/液体中的混合碱效应导致两个异常现象：碱离子的自扩散率降低和剪切粘度降低。先前的研究使用分子动力学（MD）模拟提出，碱金属离子的扩散率的降低是通路阻断的结果。然而，该途径的实际统计数据从未提供。在这项研究中，我们重新使用MD模拟钠钾硅酸盐玻璃/液体中的混合碱效应。货车霍韦函数的不同部分表明，不同的碱物种之间的网站交换是显着慢于相同的物种之间。通过引入单形球分析及其在不同组分下的聚类统计，阐明了碱混合引起的通道断开。此外，我们还精确地分析了SiO 4四面体共角网络的几何和拓扑结构。几何和拓扑结构的变化与推进碱取代线性，而计算的剪切粘度有一个最小值的混合碱组合物。因此，需要一种定量分析弛豫动力学变化的方法来澄清混合碱液中的粘度异常。
The mixed alkali effect in silicate glass/liquid causes two anomalies: a decrease in the self-diffusivity of alkali ions and a decrease in shear viscosity. Previous studies using molecular dynamics (MD) simulations proposed that the decrease in diffusivity of alkali ions is the result of pathway blocking. However, the actual statistics of the pathway have never been presented. In this study, we revisited the mixed alkali effect in sodium–potassium silicate glass/liquid using MD simulations. The distinct part of van Hove's function indicates that site exchange between different alkali species is significantly slower than between the same species. By introducing simplex sphere analysis and its cluster statistics with varying compositions, we clarified the pathway disconnection caused by alkali mixing. Moreover, we analyzed the geometry and topology of the corner-shared network of the SiO4tetrahedra precisely. Both the geometry and topology change linearly with advancing alkali substitution, whereas the calculated shear viscosities have a minimum in the mixed alkali composition. Consequently, a method to quantitatively analyze the changes in relaxation dynamics is required to clarify the viscosity anomaly in mixed alkali liquids.