【摘要】 以正丙醇为前驱体,N2为载气和稀释气体,采用等温化学气相渗透(ICVI)工艺,沉积温度为1050、1100、1150℃,压力为6kPa,对初始密度为0.43g/cm3的2D针刺炭毡进行致密化,沉积96h制备出表观密度分别为1.64、1.68和1.69/cm3的C/C复合材料.考察了密度随沉积时间的变化规律,利用三点弯曲测试了材料的弯曲强度,采用偏光显微镜、扫描电子显微镜观察了材料的组织结构和断口形貌.结果表明:以正丙醇为前驱体,采用ICVI工艺在1050和1150℃下制备的试样组织为高织构和中织构的混合组织,1100℃制备的试样基体组织为均一的高织构,其弯曲强度可达199.24MPa.在本实验条件下,并未发现正丙醇中的氧元素在高温下对炭纤维的腐蚀作用,正丙醇可以作为前驱体制备高性能C/C复合材料.更多还原

【Abstract】 Two dimension needle-punched carbon fiber felts with an initial bulk density of 0.43 g/cm3 were densified by isothermal-isobaric chemical vapor infiltration(ICVI) at 1050,1100,1150℃ and total pressure of 6kPa,using n-propanol diluted by nitrogen as the precursor of pyrolytic carbon.The bulk density of C/C composite after densified for 96h were 1.64 g/cm3,1.68g/cm3 and 1.69/cm3,respectively.Bulk densities of the infiltrated samples were deter-mined as a function of infiltration time.The flexural strength was investigated by three-point bending test.Texture and fracture surface morphology of the samples were studied by polarized light microscope(PLM) and scanning electron microscope(SEM).A layer of midium-textured carbon followed by a layer of high-textured carbon matrix were formed at 1050 and 1150℃.While C/C composites with pure high-textured pyrolytic carbon matrix was obtained at 1100℃,with the flexural strength of 199.24MPa.No oxidation trace was found on the surface of carbon fiber from PLM and SEM observation.Consequently,n-propanol is a promising precursor in CVI process for the densification of high-performance C/C composites.更多还原