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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 >Nitrogen-rich La-Si-Al-O-N oxynitride glass structures probed by solid state NMR
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Nitrogen-rich La-Si-Al-O-N oxynitride glass structures probed by solid state NMR

机译：固态NMR探测富氮La-Si-Al-O-N氮氧化物玻璃结构

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摘要

We investigate the local structures of oxynitride La-Si-(Al)-O-N glasses by Si-29 and Al-27 magic-angle spinning (MAS) solid state Nuclear Magnetic Resonance (NMR). The glasses studied span an unprecedented range of compositions, up to >50 at.% lanthanum and nitrogen out of the cations and anions, respectively, and achievable through a recently introduced glass preparation route. Transmission as well as scanning electron microscopy verified homogeneous samples over length-scales down to 20 nm. As the nitrogen content of the glasses increased, Si-29 NMR evidenced a progressive formation of Si-N bonds, with SiO2N2 tetrahedra dominating in the nitrogen-rich glass networks. In the oxygen-rich end of the series, aluminum is predominantly present in tetrahedral coordination as AlO4, whereas the glasses with highest nitrogen contents have a major fraction of AlO3N structural units. Trends in isotropic Si-29 and Al-27 chemical shifts and Al-27 quadrupolar couplings are compared with results of La-Si-Al-O glasses and are discussed in relation to the glass compositions and their proposed structures. (c) 2007 Elsevier B.V. All rights reserved.
机译：我们通过Si-29和Al-27幻角旋转（MAS）固态核磁共振（NMR）研究了氮氧化物La-Si-（Al）-O-N玻璃的局部结构。所研究的玻璃具有前所未有的组成范围，从阳离子和阴离子中分别最多可析出> 50 at。％的镧和氮，并且可以通过最近引入的玻璃制备路线来实现。透射和扫描电子显微镜验证了长度小于20 nm的均匀样品。随着玻璃中氮含量的增加，Si-29 NMR证明了Si-N键的逐步形成，其中SiO2N2四面体在富氮玻璃网络中占主导地位。在该系列的富氧端，铝主要以四面体配位形式存在，即AlO4，而氮含量最高的玻璃则占AlO3N结构单元的大部分。将各向同性的Si-29和Al-27化学位移趋势以及Al-27四极耦合的趋势与La-Si-Al-O玻璃的结果进行了比较，并就玻璃成分及其拟议结构进行了讨论。 （c）2007 Elsevier B.V.保留所有权利。

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