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首页> 外文期刊>Journal of the American Ceramic Society >THE EVOLUTIONARY PROCESS DURING PYROLYTIC TRANSFORMATION OF POLY(N-METHYLSILAZANE) FROM A PRECERAMIC POLYMER INTO AN AMORPHOUS SILICON NITRIDE CARBON COMPOSITE
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THE EVOLUTIONARY PROCESS DURING PYROLYTIC TRANSFORMATION OF POLY(N-METHYLSILAZANE) FROM A PRECERAMIC POLYMER INTO AN AMORPHOUS SILICON NITRIDE CARBON COMPOSITE

机译：聚（N-甲基硅氮烷）从陶瓷先热转变为非晶态氮化硅碳复合材料的演化过程

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The pyrolytic evolution of poly(N-methylsilazane),-[H(2)SiNMe](x)-, from preceramic polymer to ceramic product is followed by heating samples of the partially cross-linked polymer, in 200 degrees C increments, from ambient temperature to 1400 degrees C. The intermediate products are characterized by chemical analysis, diffuse reflectance Fourier transform IR spectroscopy (DRIFTS), Raman spectroscopy, and Si-29 and C-13 magic-angle spinning (MAS) solid-state NMR. Spectroscopic characterization indicates that the 1400 degrees C pyrolysis products are amorphous silicon nitride mixed with amorphous and graphitic carbon (as determined by Raman spectroscopy), rather than silicon carbide nitride, as expected based on the presence of up to 20 mol% retained carbon. Efforts to crystallize the silicon nitride through heat treatments up to 1400 degrees C do not lead to any crystalline phases, as established by transmission electron microscopy (TEM) and small-area electron diffraction (SAD). It appears that the presence of free carbon, along with the absence of oxygen, strongly inhibits crystallization of amorphous silicon nitride, These results contrast with the isostructural poly(Si-methylsilazane), -[MeHSiNH](x)-, which is reported to form silicon carbide nitride on pyrolysis. [References: 48]
机译：聚（N-甲基硅氮烷）-[H（2）SiNMe]（x）-从陶瓷前热分解为陶瓷产物，然后以200摄氏度的增量加热部分交联的聚合物样品环境温度至1400摄氏度。中间产物的特征在于化学分析，漫反射傅里叶变换红外光谱（DRIFTS），拉曼光谱以及Si-29和C-13魔角旋转（MAS）固态NMR。光谱表征表明，1400℃热解产物是混合有非晶碳和石墨碳的非晶氮化硅（由拉曼光谱法测定），而不是碳化硅，这是基于存在高达20mol％的保留碳而预期的。如通过透射电子显微镜（TEM）和小面积电子衍射（SAD）建立的那样，通过高达1400摄氏度的热处理使氮化硅结晶的努力不会导致任何晶相。似乎自由碳的存在以及氧气的存在会强烈抑制非晶态氮化硅的结晶。这些结果与同结构的聚（Si-甲基硅氮烷）-[MeHSiNH]（x）-形成了对比。在热解过程中形成碳化硅氮化物。 [参考：48]

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