Mg—Al—Si—O—N系统玻璃的结构与晶化

本文采用X射线光电子能谱(XPS)、透射电镜(TEM)和拉曼光谱(Raman)等现代测试方法详细地研究了Mg-Al-Si-O-N系统玻璃的结构与晶化过程。发现在玻璃中除只与硅相键合的桥氮存在外,还有不与硅相键合的非桥氮存在。引入玻璃中的氮一方面取代玻璃中氧的位置进入玻璃网络,使结构紧密交联,降低了玻璃的晶化能力,另一方面氮的引入使玻璃中出现了均匀分布的Si_2ON_2微晶粒子,作为异相核促进了其他晶相的析出,而且其数量和大小以及有利于玻璃晶化的非桥氮的数量均随Si_3N_4含量增大。这两个方面矛盾作用的结果使堇青石晶相的析出量随Si_3N_4含量的变化出现极小值。

STRUCTURE AND CRYSTALLIZATION OF Mg-Al-Si-O-N GLASSES

The structure and crystallization of Mg-Al-Si-O-N glass(BN-glasses) were studied by ineans of XPS, TEM/EDX, Raman spectrum. The result of XPS shows that in the BN-glasses, bosides bridging nitrogen, non-bridging nitrogen exists and its number becomes more as increasing amount of Si_3N_4 added into the BN-glasses. The partial nitrogen atoms bond with silicon atoms and exist in the form of bridging nitrogen to produce a more highly cross-linked and more compact glass network, which inhibits crystallization of the BN-glasses. On the other hand, a great number of Si_2ON_2 microcrystals uniformly distributed in the BN-glasses can act as heterogeneous nuclei to induce the oxynitrido glass to crystallize bulkily during heat-treatment. And as increasing Si_3N_4 content, the number of Si_2ON_2 crystal particles increases and the size of them also becomes larger, at the same time, the number of non-bridging nitrogen which is advantagoous to crystallization also increases. As a result of contradictory role ofthe nitrogen atoms in tho BN-glasses, a minimum value is shown on the change of amount of cordierite precipitated with Si_3N_4 content.