热化学气相反应法制备SiC纳米粉的研究

The Studies of Synthesizing SiC Nanometer Powders by Chemical Vapour Reaction

利用SiH4-C2H4-H2系统的反应，在1423K～1673K温度范围内对SiC超细粉的合成进行了系统研究。采用的粉末表征方法有透射电镜（TEM）、红外吸收谱（IR）、X射线衍射（XRD）、粉末比表面分析（BET），高分辨透射电镜（HREM）和化学分析。结果表明，改变反应温度和反应气体组成比能获得高纯SiC赵细粉。在1423K～1573K范围内，粉末富硅，当温度超过1623K时粉末富碳，在T=1623K，C2H4／SIH。一1．2，P—0．02MPa时，制备出11urn的纯卜SiC赵细粉，SiC含量高达97．8％，其氧含量为1．3％。游离硅的存在能显著影响最终颗粒尺寸。

SiC ultra fine powders have been synthesized by chemical vapor reaction of SiH4-C2H4-H2 system during 1423K-1673K. The powders were analyzed by transmission electron microscope(TEM), selected-area electron diffraction(SEAD), Fourier transform infrared spectroscope (FTIS), BET, X-ray diffraction(XRD),high resolu microscope(HRFM) and chemical analyses. The results show that the highly pure and ultrafine powder can be obtameo by changmg reactive temperature and C2H4/SiH4 mole ratio. Excess silicon exists in the powder synthesised below 1623K, excess carbon exists in the powder synthesized over 1623K,single-phase β-SiC exists in the powder synthesized at 1623k. The average particle size of the powder synthesized at 1623K is about 11nm , and the powder contains 97. 8wt%SiC, 1. 3wt%O, 0. 9wt %C. Free Si has important effect on particle size of powders.