Microstructural evolution of droplet phase separation in calcium aluminosilicate glasses
Microstructural evolution of droplet phase separation in calcium aluminosilicate glasses
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DOI：
10.1111/jace.18050
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发表时间：
2021-08
影响因子：
3.9
通讯作者：
N. Clark;S. Chuang;J. Mauro
中科院分区：
文献类型：
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作者：
N. Clark;S. Chuang;J. Mauro
具有纳米级相分离的玻璃有可能在保持其光学透明度的同时具有更高的硬度和断裂韧性。本文介绍了分相钙铝硅酸盐玻璃等温热处理的结果。结果表明，当液滴体积分数为17%时，液滴从Lifshitz-Slozof-Wagner(LSW)型动力学转变为扩散控制的伪合并机制，导致液滴变得越来越细长和相互连接。这两种机制的激活势垒都表明钙扩散是富硅结构域粗化的潜在手段。简单的近似表明，这种转变不能用布朗运动或区域之间的范德华引力来解释，而是表明各种渗透力可能是原因。
Glasses with nanoscale phase separation have the potential to possess improved hardness and fracture toughness while maintaining their optical transparency. Here we present the results of isothermal heat treatments of phase‐separated calcium aluminosilicate glasses. Our results indicate that a transition from Lifshitz–Slozof–Wagner (LSW)‐type kinetics to a diffusion‐controlled pseudo‐coalescence mechanism occurs at ~17% droplet volume fraction, which results in the droplets becoming increasingly elongated and interconnected. The activation barrier for both mechanisms suggests that calcium diffusion is the underlying means for the coarsening of the silica‐rich domains. Simple approximations show the transition cannot be explained by Brownian motion or Van der Waals attraction between domains, and instead suggest various osmotic forces may be responsible.