Atomic-scale description of interfaces in rutile/sodium silicate glass-crystal composites.
Atomic-scale description of interfaces in rutile/sodium silicate glass-crystal composites.
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DOI：
10.1039/c8cp00675j
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发表时间：
2018-07
期刊：
影响因子：
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通讯作者：
Paul C. M. Fossati;M. Rushton;William E Lee
中科院分区：
文献类型：
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作者：
Paul C. M. Fossati;M. Rushton;William E Lee
在这项工作中，（Na_2 O）_x（SiO_2）_（1-x）玻璃（x = 0.0，0.1和0.2）和TiO_2晶体之间的界面模拟使用分子动力学和经验势。本文提出了米勒指数≤2的TiO_2不同终止表面的界面，并利用原子模型研究了其性质。模拟结果表明，部分有序层已被诱导在玻璃中接近界面，连续富氧和富阳离子的平面被注意到。与晶体接触的第一硅酸盐层倾向于高度结构化，Si离子占据取决于界面处晶体取向的明确位置，并显示取决于玻璃组合物的二维有序。最后计算了界面能。这些表明，与保持自由表面相比，界面形成可以稳定晶体表面。结果表明，玻璃网络的结构的灵活性，使其符合晶体，从而提供电荷补偿，避免大松弛的晶体结构接近的接口。这样的界面性能可能是至关重要的，以改善玻璃-晶体复合材料性能的唯象模型。
In this work interfaces between (Na2O)x(SiO2)1-x glasses (for x = 0.0, 0.1 and 0.2) and TiO2 crystals are simulated using molecular dynamics and empirical potentials. Interfaces are presented for the distinct terminating surfaces of TiO2 with Miller indices ≤2, the properties of which have been investigated using atomistic models. Simulations showed that partially ordered layers had been induced in the glass close to the interfaces, with successive oxygen-rich and cation-rich planes being noted. The first silicate layer in contact with the crystal tended to be highly-structured, with Si ions occupying well-defined positions that depend on the orientation of the crystal at the interface, and showing 2-dimensional ordering depending on glass composition. Finally, interface energies were calculated. These indicated that the interface formation may stabilise a crystal surface in comparison to maintaining a free surface. Results are presented suggesting that the structural flexibility of the glass network allows it to conform to the crystal, thereby providing charge compensation and avoiding large relaxation of the crystal structure close to the interfaces. Such interfacial properties could be crucial to improving phenomenological models of glass-crystal composite properties.