CdF_2-BaF_2-LiF系统玻璃的X射线衍射与分子动力学研究  

X-ray Diffraction and Molecular Dynamics Study of CdF_2-BdF_2-LiF Glass

作　　者：蒋洋[1] 赵修建[1] 梁开明[2] 

机构地区：[1]武汉工业大学新材料研究所,武汉430070 [2]清华大学材料科学与工程系,北京100084

出　　处：《无机材料学报》1998年第2期138-144,共7页Journal of Inorganic Materials

基　　金：国家自然科学基金!59102014

摘　　要：采用无水氟化物直接熔化法得到了CdF2－BaF2－LiF系统玻璃的玻璃形成区，用X射线衍射和分子动力学计算机结构模拟等手段研究了成分为36CdF2－34BaF2－30LiF（mol％）的玻璃的结构．研究表明，Cd原子主要为6、7和8配位，Ba原子主要为8配位，Cd－F的平均键长为2.29玻璃结构可以看作是由Li+连接的[CdF72]多面体共边或共角堆积而成．Cd－Cd键长在共边连接时为3.52共角时为4.03对氟化物玻璃中Li+原子所起的作用进行了比较．Glass forming regions in the CdF2-BaF2-LiF system were determined through melting-quenching technique. The structure of 36CdF2-34BaF2-30LiF (mol%) (CBL glass) was studied by Xray diffraction and molecular dynamics simulation methods. The Cd atoms are six-, seven- and eightfold coordinated by fluorines. The average Cd--F bond length is 2.29A. The Cd--Cd atom distance is about 3.52A for edge-sharing and 4.03A for corner-sharing in the MD-derived glass.The glass structure can be discribed as a network made up of edge--sharing and corner-sharing [CdFn] polyhedra which are partial linked by Li+ ions. Tile role of Li+ ions in the fluoride glasses was discussed. It was proposed that Li+ may play tile outpolarization effort in fluoride glass as it does in the oxide one. This effort can play a positive role to the connectivity of the network based on the good glass formers. However, in the glass based on the weak--bonded glass formers,the relative strong Li--F bond results in a decrease of its chemical durability as it does in the CdF2-BaF2-LiF system.

关 键 词：氟化物玻璃 玻璃结构 分子动力学 X射线衍射 

分 类 号：TQ171.716[化学工程—玻璃工业]