Preparation And Characterization Of Blocky Carbon Nanofibers And Carbon/Carbon Composites

Blocky carbon nanofibers (CNFs) were successfully prepared through chemical vapor deposition method, using C2H2 as carbon source, copper-nickel alloy as catalyst, self-made model to control the volume. Straight carbon nanofibers with 100nm-500nm and helical carbon nanofibers with about 100nm were synthesized. While the graphite platelets are not aligned well with low graphitization degree.It was experimentally found that four main factors, including Cu contents in Cu-Ni alloy catalysts, dosage of catalysts, reaction temperature and reaction time affected the yield and morphology of CNFs. The presence of Cu in the Cu-Ni catalysts had a dramatic effect on the growth of CNFs, increased the activity and lifetime of the catalysts, and improved the yield of CNFs. And with contents of Cu increased the proportion of helical CNFs was increased gradually.When blocky CNFs were used as reinforcements and phenolic resin were used as precursor of matrix to prepare C/C composites, the optimal concentration of phenolic resin-ethanol was 45-60%. Friction coefficient of all four kinds of C/C composites was under 0.3, and with the concentration of phenolic resin-ethanol was increased, friction coefficients and mass loss rate of C/C composites were decreased. The friction coefficient of C/C composite prepared by 60%phenolic resin-ethanol and blocky CNFs was only 0.1068. The resistibility of C/C composites decreased with the concentration of phenolic resin-ethanol increased, and the minimum of resistibility was 0.569Ω·mm.