聚硅氮烷的热分解特性研究

研究了由有机氯硅烷氨解制得的聚硅氮烷（ＰＳＺ）在Ｎ２与ＮＨ３气氛中的热分解特性．结果表明，在Ｎ２气氛中，ＰＳＺ经三个阶段转化为无定形陶瓷，在更高温度下则得到α－Ｓｉ３Ｎ４结晶与β－ＳｉＣ微晶的复合体．β－ＳｉＣ的形成来源于Ｓｉ－ＣＨ３基团的热分解，降低ＰＳＺ中Ｓｉ—ＣＨ３，含量能提高产物中Ｓｉ３Ｎ４的含量．在ＮＨ３气氛中热分解时产生脱碳反应，导致形成无定形态的无机物，它在１５００℃转化为几乎为纯的α－ＳｉＮ４．

STUDY ON THE PYROLYTIC PROPERTIES OF POLYSILAZANE

he pyrolytic properties of polysilazane (PSZ), synthesized from ammonolysis of mixture of halosilanes, in N2 or NH3 atmosphere have been studied.The result showed that PSZ can be convertedinto amorphous ceramics through three pyrolytic process in N2 atmosphere and a composite of a-Si3N4 crystal and β-SiC microcrystal at higher temperature. The β-SiC is formed by the pyrolysis of Si-CH3 group, therefore. the content of Si3N4 in ceramics can be increased by decreasing of Si-CH3 group in PSZ. When pyrolyzed in NH3 atmosphere, the process of carbon removal takes place, resulted in the formation of an amorphous inorganic materials which transformed into almost pure a-Si3N4 crystal at 1500℃.