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以硅粉和液态酚醛树脂为原料,硝酸镍为催化剂前驱体,采用催化反应的方法制备了碳化硅粉体。研究了反应温度、催化剂用量、保温时间和碳硅摩尔比等对合成碳化硅粉体的影响,采用X射线衍射、场发射扫描电子显微镜和透射电子显微镜分析了产物的物相组成和显微结构。结果表明:无催化剂时,β-SiC的合成条件为1 350℃保温3 h,所合成的β-SiC大部分为颗粒状,仅有极少量晶须生成;当添加0.50%的Ni作催化剂、n(C):n(Si)=1.2:1.0时,1 300℃保温3h即可合成纯相的β-SiC,且制备的试样中有大量β-SiC晶须生成。β-SiC晶须的生长机理主要为固-液-气-固机理。
Using silicon powder and liquid phenolic resin as raw materials, nickel nitrate as a catalyst precursor, a silicon carbide powder was prepared by a catalytic reaction method. The effects of reaction temperature, amount of catalyst, holding time and molar ratio of carbon to silicon on the synthesized silicon carbide powders were investigated. The phase composition and microstructure of the products were analyzed by X-ray diffraction, field emission scanning electron microscope and transmission electron microscope . The results show that the synthesis conditions of β-SiC are 1 350 ℃ for 3 h in the absence of catalyst, most of the synthesized β-SiC is granular and only a very small amount of whiskers are formed. When 0.50% Ni is added as catalyst, When n (Si) = 1.2: 1.0, the pure β-SiC can be synthesized by heating at 300 ℃ for 3h, and a large amount of β-SiC whiskers were formed in the samples. The growth mechanism of β-SiC whiskers is mainly solid-liquid-gas-solid mechanism.