聚碳硅烷的高温陶瓷化机理  

Ceramization mechanism of polycarbosilane treated with high temperature

作　　者：曹柳絮 陈建勋[1] 刘春轩[1] 薛亮[1] 黄启忠[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2014年第1期52-57,共6页Journal of Central South University:Science and Technology

基　　金：国家重点基础研究发展计划("973"计划)项目(2011CB605801);湖南省研究生科研创新项目(CX2012B042)

摘　　要：通过TG-DTA,IR,XRD和SEM等测试方法分析研究聚碳硅烷（PCS）的热分解过程及在真空高温条件下物相成分及晶形的变化过程。研究结果表明：聚碳硅烷质量损失主要发生在300-700℃之间,300-450℃主要发生小分子聚合物以及裂解产生的分子碎片的挥发;450-650℃之间,Si—H和C—H键发生断裂,生成氢气、烷烃等气体;650-900℃,PCS发生有机无机转变,裂解产物开始具有无机特征;900-1200℃,裂解产物基本不再具有有机特征,PCS完全转化为无定型SiC;1 200℃以后,SiC结晶形成β-SiC和α-SiC,温度升高结晶度增加且伴随晶粒的长大,2 000℃时有SiC的升华现象,且2 000℃的XRD可以证明C在PCS的陶瓷化过程中有一定富余。The residual of polycarbosilane （PCS） treated at different temperatures in vacuum were analyzed to study the ceramization of PCS by using Fourier transform infra-red （FT-IR） spectroscopy, simultaneous thermo-gravimetric analysis-differential thermal analysis （TG-DTA）, X-ray diffraction （XRD） and scanning electron microscope （SEM）. The results show that the mass loss of PCS takes place between 300-700 ℃. In the range of 300-450 ℃, small organic molecules and molecular fragments which from cracked PCS are volatilized. In the range of 450-650 ℃, the hydrogen and the alkanes are yielded due to Si-H and C--H bonds broke. In the range of 650-900 ℃, the organic PCS transforms into an inorganic state, and the cracked residue shows the inorganic characteristics. In the range of 900-1 200℃, the cracked residue of PCS has been transformed into an amorphous SiC state completely and shows no inorganic characteristics. After 1 200 ℃, the amorphous SiC is crystallized and forms β-SiC and a-SiC crystal. The crystal degree increases with the increase of the temperature. At the same time, the crystal particle grows bigger. At 2 000 ℃, the sublimation of SiC appears, and the existence of the free carbon is detected by the XRD.

关 键 词：C SIC复合材料 先驱体浸渍裂解法(PIP) 聚碳硅烷(PCS) 裂解 

分 类 号：TB32[一般工业技术—材料科学与工程] TG174.453[金属学及工艺—金属表面处理]