Coexistence of nano-scale phase separation and micro-scale surface crystallization in Gd₂O₃-WO₃-B₂O₃ glasses

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• 作者：Y. Taki ; K. Shinozaki ; T. Honma ; T. Komatsu ; L. Aleks ; rov ; R. Iordanova
• 关键词：Tungsten borate glasses ; Phase separation ; Surface crystallization ; 伪-Gd2(WO4)3 ; TEM observation
• 刊名：Journal of Non-Crystalline Solids
• 出版年：1 December, 2013
• 年：2013
• 卷：381
• 期：Complete
• 页码：17-22
• 全文大小：1295 K

文摘

Glasses with the compositions of 25Gd₂O₃-xWO₃-(75 鈭?#xA0;x)B₂O₃ with x = 25-65 were prepared by using a conventional melt quenching method, and their thermal stability and crystallization behavior were examined. The glass transition and crystallization temperatures decreased with increasing WO₃ content. It was found from observations with the scanning transmission electron microscopy in high angle annular dark-field imaging mode that a glass of 25Gd₂O₃-40WO₃-35B₂O₃ with x = 40 showed the nano-scale (2-3 nm) phase separation of tungsten-rich and boron-rich glassy phases prior to the crystallization. The glass with x = 40 has a prominent surface crystallization, providing the formation of 伪-Gd₂(WO₄)₃. It was also found that even in sufficiently crystallized glasses their micro-structure consists of both nano-scale phase separation and micro-scale 伪-Gd₂(WO₄)₃ crystals. The appearance of the phase separation was discussed from the glass forming tendency in the Gd₂O₃-WO₃-B₂O₃ system.