Nanocrystallization in Oxyfluoride Glasses Controlled by Amorphous Phase Separation

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• 作者：Changgui Lin ; Christian Bocker ; Christian R眉ssel
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：October 14, 2015
• 年：2015
• 卷：15
• 期：10
• 页码：6764-6769
• 全文大小：518K
• ISSN：1530-6992

文摘

Transparent bulk glass-ceramics containing ZnF₂, K₂SiF₆, and KZnF₃ nanocrystals are successfully obtained from xKF鈥?i>xZnF₂鈥?100 鈥?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.