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采用溶胶-凝胶-碳热还原法,以正硅酸乙酯和蔗糖为原料,在0.1 MPaAr气气氛中碳热还原合成β-SiC纳米粉体。通过X射线衍射、Raman光谱、扫描电镜和透射电镜对β-SiC纳米粉体的物相、微观结构及形貌进行了表征。结果表明:当合成温度为1 600℃时,已经开始生成β-SiC相,随着温度升高至1 700℃,完全生成了含有C_(Si)缺陷的富碳β-SiC相。β-SiC纳米粉体表现为纳米级的团聚颗粒,平均粒径为40 nm,并生成晶须。对β-SiC纳米粉体的碳热还原反应机理进行了分析,结果表明:溶胶-凝胶法明显降低了生成气态SiO控制反应的温度。
The β-SiC nanopowders were synthesized by sol-gel-carbothermal reduction using tetraethoxysilane and sucrose as carbon sources in 0.1 MPa Ar atmosphere. The phase, microstructure and morphology of β-SiC nanopowders were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The results show that the β-SiC phase has been formed at the synthesis temperature of 1 600 ℃, and the carbon-rich β-SiC phase containing C_ (Si) defects has been completely formed with the temperature increasing to 1700 ℃. β-SiC nano-powder showed nano-scale agglomeration particles, the average particle size of 40 nm, and the formation of whiskers. The mechanism of carbothermal reduction reaction of β-SiC nano-powders was analyzed. The results show that the sol-gel method significantly reduces the temperature of the formation of gaseous SiO control reaction.