氧化处理对MCMB为基体的C/C复合材料性能的影响
INFLUENCE OF OXIDATION TREATMENT ON THE PERFORMANCE OF C/C COMPOSITES USING MESOCARBON MICROBEADS AS MATRIX
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摘要: 以自烧结性中间相沥青炭微球(MCMB)为基体,以沥青基磨碎炭纤维为增强体,采用简单的氧化处理、混合、热压成型、炭化等工艺一步制备C/C复合材料。研究了MCMB氧化处理深度对C/C复合材料的密度、失重、体积收缩率、弯曲强度及断面形态的影响。结果表明:C/C复合材料的密度和体积收缩率均较无炭纤维添加的炭块有所下降,当添加的炭纤维氧化程度足够深时,炭材料的抗弯强度得到明显提高;随着MCMB氧化时间的延长,C/C复合材料的断面逐渐变得平整;经250℃氧化60 min的MCMB与硝酸90℃氧化10h的炭纤维混合,热压成型后1000℃炭化1h得到的C/C复合材料的密度可达1.64 g/cm3,抗弯强度可达72.0 MPa。与现行的制备C/C复合材料的方法相比,本技术具有工艺简单、制备成本低廉等特点,是一种具有很大发展潜力的制备高性能C/C复合材料的新方法。Abstract: C/C composites using mesocarbon microbeads (MCMB) as matrix and pitch based carbon fibers (CF) as reinforcement were prepared through simple oxidation treatment,mechanical blend,hot press molding and carbonization. The influences of oxidation treatments of MCMB and carbon fiber on the properties of C/C composites such as bulk density,volume shrinkage and bending strength were investigated in detail. It was found that the bulk density and volume shrinkage of C/C composites declined after adding CF, while the bending strength increased when CF was oxidized under appropriate conditions. High strength C/C composite with a density of 1.64 g/cm3 and bending strength of 72.0 MPa was obtained by hot press molding and carbonization at 1000℃ for 1h from MCMB oxidized at 250℃ in air for 60min and CF treated in nitric acid for 10h. This novel and simple approach constituted a more practical method to prepare high performance C/C composites than the present ones.