采用短纤维树脂模压+液态聚合物浸渍/裂解+原位反应的工艺制备了C/C-SiC复合材料,对其催化石墨化过程进行初步研究。首先分析"炭硅反应"工艺对石墨化度的影响,发现"炭硅反应"加强了硅对硼的活化作用,使炭材料的石墨化度从87.9%提高到97.3%;对制备样品的形貌分析及成分测试表明,石墨化过程伴随着"炭硅反应",碳化硅在材料内部分布均匀;其次探讨了硼对石墨化的催化作用,C/C-SiC复合材料中硼酚醛树脂炭的质量分数从69.9%降低至46.3%时,石墨化度随之由91.6%降至70.4%;最后研究了硅对石墨化的影响,提出硅硼协同催化石墨化机理,当硅的添加量从0增至6.3%,石墨化度由78.1%提高至90.7%。
Compression moulding of short carbon fiber and resin,liquid resin impregnation and pyrolysis was included in C/C-SiC composites fabrication.Firstly,the analysis on graphitization shows carbon-silicon reaction enhanced Si activation to B and its graphitization rises from 87.9% to 97.3%.Investigation of morphologies and gradients shows graphitization occurred with carbon-silicon reaction.SiC shows uniform distribution inside materials.Secondly,boron-catalytic graphitization is discussed.With mass fractions of boracic formaldehyde-phenol resin,decreased from 69.9% to 46.3%,the graphitization degrees reduce from 91.6% to 70.4%.Finally,catalytic graphitization mechanism of Si is put forward.As contents of Si rises from 0 to 6.3%,graphitization degree of composites rises from 78.1% to 90.7%.