Effect of Ca and B incorporation into silicon oxycarbide on its microstructure and phase composition
Effect of Ca and B incorporation into silicon oxycarbide on its microstructure and phase composition
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DOI：
10.1111/jace.16620
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发表时间：
2019-12
影响因子：
3.9
通讯作者：
Fang Xie;I. Gonzalo-Juan;H. Breitzke;C. Fasel;Maximilian Trapp;G. Buntkowsky;H. Kleebe;R. Riedel;A. Boccaccini;E. Ionescu
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文献类型：
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作者：
Fang Xie;I. Gonzalo-Juan;H. Breitzke;C. Fasel;Maximilian Trapp;G. Buntkowsky;H. Kleebe;R. Riedel;A. Boccaccini;E. Ionescu
通过热解合适的基于聚倍半硅氧烷的单源前体，合成了 Ca 和/或 B 改性的碳氧化硅。通过热重分析和原位逸出气体分析研究了它们的聚合物到陶瓷的转变。研究了所制备的碳氧化硅的结晶行为、网络结构和化学组成。碳氧化硅中的网络连接性可以使用两种不同的“工具”来影响/调整：（i）首先，使用网络修饰剂（例如我们研究中的 Ca），通过生成少量 Q3 位点导致网络轻微解聚； (ii)其次，B/Ca对碳氧化硅的改性导致网络中碳含量的降低，从而导致其连通性显着降低。通过利用这两种不同的效应，可以对碳氧化硅中的网络连接进行微调。
Ca and/or B modified silicon oxycarbides were synthesized via pyrolysis of suitable polysilsesquioxane‐based single‐source precursors. Their polymer‐to‐ceramic transformation was investigated with thermogravimetric analysis, coupled with in situ evolved gas analysis. The prepared silicon oxycarbides were investigated with respect to their crystallization behavior, network architecture and chemical compositions. The network connectivity in silicon oxycarbides can be affected / tuned upon using two different “tools”: (i) firstly, the use of network modifiers, such as Ca in our study, leads to a slight depolymerization of the network via generation of a small amount of Q3 sites; (ii) secondly, the modification of silicon oxycarbide with B/Ca leads to a decrease of the carbon content in the network and thus to a significant decrease of its connectivity. By using these two different effects, the network connectivity in silicon oxycarbides can be finely tuned.