Nanostructure and Energetics of Carbon-Rich SiCN Ceramics Derived from Polysilylcarbodiimides: Role of the Nanodomain Interfaces
Nanostructure and Energetics of Carbon-Rich SiCN Ceramics Derived from Polysilylcarbodiimides: Role of the Nanodomain Interfaces
复制标题
DOI：
10.1021/cm2038238
复制
发表时间：
2012-03
影响因子：
8.6
通讯作者：
S. Widgeon;Gabriela Mera;Yan Gao;E. Stoyanov;S. Sen;A. Navrotsky;R. Riedel
中科院分区：
文献类型：
--
作者：
S. Widgeon;Gabriela Mera;Yan Gao;E. Stoyanov;S. Sen;A. Navrotsky;R. Riedel
采用聚（苯基乙烯基硅基碳二亚胺）和聚（苯基硅倍半碳二亚胺）热解合成了不同碳含量的SiCN聚合物衍生陶瓷（PDCs），并利用29Si、13C、15N和1H固体核磁共振（NMR）光谱和氧化物熔体溶液量热法对其结构和能量学进行了研究。在低碳含量（35-40 wt %）和热解温度（800°C）下，这些PDCs的结构主要由sp2碳和氮化硅的无定形纳米畴组成，其界面区域以N、C和Si原子之间的混合键合为特征，这种键合可能因氢的存在而稳定。随着碳含量的增加，碳畴的平均尺寸增大，在55 ~ 60 wt % C的温度下，PDCs中形成连续连接的无定形碳基体，当热解温度升高到1100℃时，界面硅碳键和氮碳键被破坏，同时氢损失。量热法re……
SiCN polymer-derived ceramics (PDCs) with different carbon contents have been synthesized by pyrolysis of poly(phenylvinylsilylcarbodiimide) and of poly(phenylsilsesquicarbodiimide), and their structure and energetics have been studied using 29Si, 13C, 15N, and 1H solid state nuclear magnetic resonance (NMR) spectroscopy and oxide melt solution calorimetry. The structure of these PDCs at lower carbon content (35–40 wt %) and pyrolysis temperatures (800 °C) consists primarily of amorphous nanodomains of sp2 carbon and silicon nitride with an interfacial region characterized by mixed bonding between N, C, and Si atoms that is likely stabilized by the presence of hydrogen. The average size of the carbon domains increases with increasing carbon content, and a continuously connected amorphous carbon matrix is formed in PDCs with 55–60 wt % C. The interfacial silicon–carbon and nitrogen–carbon bonds are destroyed with concomitant hydrogen loss upon increasing the pyrolysis temperature to 1100 °C. Calorimetry re...