• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Non-Crystalline Solids: A Journal Devoted to Oxide, Halide, Chalcogenide and Metallic Glasses, Amorphous Semiconductors, Non-Crystalline Films, Glass-Ceramics and Glassy Composites >WAXS and NMR studies of intermediate and short range order in K2O-SiO2 glasses
【24h】

WAXS and NMR studies of intermediate and short range order in K2O-SiO2 glasses

机译：K2O-SiO2玻璃中短程有序的WAXS和NMR研究

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Wide-angle X-ray scattering and Si-29 NMR have been employed to investigate the medium-range structure of xK(2)O-(1- x)SiO2 glasses, with x varying in the limits 5% < x < 35%. The diffractograms show a first sharp diffraction peak (FSDP) in the 1.4 Angstrom (-1) < q < 2.2 Angstrom (-1) range. The peaks broaden below x = 20%, and at the lowest K2O fraction, a bimodal line shape is found. This broadening is interpreted in terms of phase separation at low K2O fraction. The NMR spectra consist of several (usually three) Gaussian components assigned to the different Q species (SiO4 tetrahedra with different connectivity) present. All three components are uniformly deshielded as K2O is incorporated into the structure. The fraction of non-bridging oxygens (NBOs) derived from the distribution of Q species matches the value obtained from the overall composition, except for the x = 17.41% sample, again indicating phase-separation at x < 20%. The inhomogeneities found by WAXS and NMR in the xK(2)O-(1- x)SiO2 glasses are interpreted in terms of broken bond-bending constraints at the NBOs. Constraint theory assigns the critical concentration for glass forming at x(c) = 20%, which may explain the tendency of the glasses to phase-separate at concentrations below x(c). (C) 2001 Elsevier Science B.V. All rights reserved. [References: 10]
机译：广角X射线散射和Si-29 NMR已用于研究xK（2）O-（1-x）SiO2玻璃的中程结构，x的变化范围为5％

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号