摘要
以硅粉、碳黑、活性炭为原料,以聚四氟乙烯为添加剂,在氮气中分别用直接燃烧合成和预热燃烧合成工艺制备了高纯β-SiC微粉。用扫描电镜测得产物呈等轴球形,平均粒径为100nm。添加剂聚四氟乙烯的质量分数(下同)为5%以上时,均可以直接点燃合成高纯度亚微米级的β-SiC,2%的添加剂就可以使理论预热温度由1023K降到673K,降低了成本。另外,以活性炭代替碳黑为原料,对比了硅和碳的摩尔比为1:1和1:1.25的2个配方对产物物相的影响,说明用足够纯净的活性炭为原料代替碳黑制备β-SiC是可行的。将预热法、氮气助燃法以及化学活化法成功的进行了结合,布料方式由以往的压块改为直接粉状布料,且在60L燃烧合成反应器中单炉装料1kg条件下,合成了高纯度的β-SiC粉体,适应了中试生产的需要。
Ultra-fine β-SiC powder has been obtained by two methods, direct combustion synthesis and preheating combustion synthesis, in nitrogen atmosphere using Si, carbon, activated carbon as raw materials and teflon （-C2F4-）n as additive. The crystallites of combustion products measured by a scanning electron microscopy showed that they are global and the average diameters are about 100 nm. Pure and ultra-free β-SiC powders can be obtained on direct combustion when the mass fraction（the same below） of additive is more than 5%. The theoretic preheating-temperature can decrease from 1 023 K to 673 K by decreasing the amount of additive to 2% and thus saving the cost. The same time, using activated carbon as substitution of carbon, the effect on combustion products of two batches of mole ratio of Si to active C with 1 ： 1 and 1：1.25 was compared, it illustrated that the substitution of purer active C for carbon as raw material in preparing the β-SiC is possible. Three methods of preheating combustion synthesis, combustion synthesis in nitrogen atmosphere and chemical stimulation combustion synthesis were successfully combined, and the material introduce from pressed block to powdery spread, the ultra-free β-SiC powders were fabricated through combustion synthesis in 60 L reactor with a single load of more than 1 kg materials. It makes the needs of pilot-plant.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2007年第7期817-821,共5页
Journal of The Chinese Ceramic Society
关键词
燃烧合成
β-碳化硅
亚微米粉末
预热自蔓延反应
化学活化自蔓延反应
combustion synthesis
beta silicon carbide
ultra-fme powder
preheating combustion synthesis
chemical stimulation combustion synthesis
作者简介
张利锋（1982-），男，硕士。
