TeO_2–BaO/BaCl_2系统玻璃的结构和析晶性能

STRUCTURE AND CRYSTALLIZING PROPERTIES OF TeO_2–BaO/BaCl_2 GLASSES

用熔融法制备了不同组成的TeO2–BaO/BaCl2系统玻璃,用差热分析、X射线衍射、红外光谱、紫外–可见光吸收光谱、透射电镜等考察了该系统的成玻璃性和析晶性能,探讨了玻璃的网络结构和组成变化对析晶性能的影响。结果表明:BaO或BaCl2的引入能加强碲氧链间连接,促使碲酸盐玻璃中的[TeO4]基团向[TeO3+1]和[TeO3]基团转变,并改变碲氧链的结构及长度。与TeO2–BaO系统相比,TeO2–BaCl2系统成玻璃区域大大扩展,网络结构中键合及基团种类增多,链间的连接加强且链的断裂减少,网络结构趋于均匀,热稳定性好,有利于AgCl纳米晶体析出。

The forming abilities and crystallizing properties of TeO2-BaO/BaCl2 glasses were investigated by differential thermal analysis, X-ray diffraction, infxared absorption spectroscopy, ultraviolet-visible absorption spectroscopy and transmission electron microscopy. The influences of composition and network on the crystallization of the glasses were also discussed, which contribute to the studies of nanocrystals-doped tellurite optical glasses. It was found that introducing BaO or BaCl2 into tellurite glasses would increase the number of structural units by turning some of the [TeO4] into [TeO3] and [TeO3＋1]; it also changed the structure and length of Te-O chains. Compared with TeO2-BaO glasses, TeO2-BaCl2 glasses has more bridging bonds, more Te-O chains and a more homogeneity of network. Thus the glass forming ability and thermal stability of TeO2-BaCl2 glasses are better than those of TeO2-BaO glasses. ZeO2-BaCl2 glasses are also favorable for the crystallization of AgCl nanocrystals.