Nanocrystallization in Oxyfluoride Glasses Controlled by Amorphous Phase Separation
Nanocrystallization in Oxyfluoride Glasses Controlled by Amorphous Phase Separation
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DOI：
10.1021/acs.nanolett.5b02605
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发表时间：
2015-10-01
期刊：
影响因子：
10.8
通讯作者：
Ruessel, Christian
中科院分区：
文献类型：
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作者：
Lin, Changgui;Bocker, Christian;Ruessel, Christian
首次从xKF-xZnF（2）-（100-2x）SiO_2氟氧化物玻璃中成功地制备了含ZnF_2、K_2SiF_6和KZnF_3纳米晶的透明块体微晶玻璃。热处理样品的玻璃化转变温度随着时间的推移而增加，并且接近类似于热处理所选择的温度的值。在成核和晶体生长期间，晶体周围的残余玻璃中的氟化物耗尽，氟化物作为玻璃组分通常导致粘度降低。结晶行为显著地取决于玻璃组成，并且在x = 20至22.5摩尔%的小范围内变化。依赖于组成的液/液相分离的发生是物理化学变化的原因。利用复型透射电子显微镜技术观察了多组分玻璃体系中液滴和互穿相分离两种不同的微观结构及其成分演变。这一研究表明，可以通过初始相分离来控制沉淀微晶的尺寸和晶相。
Transparent bulk glass-ceramics containing ZnF2, K2SiF6, and KZnF3 nanocrystals are successfully obtained from xKF-xZnF(2)-(100-2x)SiO2 oxyfluoride glasses for the first time to the best of our knowledge. The glass transition temperatures of heat-treated samples increase with time and approach values that resemble the temperatures chosen for thermal treatment. During nucleation and crystal growth, the residual glass around the crystals is depleted in fluoride which as glass component usually leads to a decrease in viscosity. The crystallization behavior notably depends on the glass composition and changes within a small range from x = 20 to 22.5 mol %. The occurrence of liquid/liquid phase separation in dependence of the composition is responsible for the physicochemical changes. Two different microstructures of droplet and interpenetrating phase separation and their compositional evolution are observed by replica transmission electron microscopy technique in the multicomponent glassy system. This study suggests that the size and crystal phase of precipitated crystallites can be controlled by the initial phase separation.