Dependence of carbon fiber morphology with deposition conditions

Carbon fibers with different morphologies including carbon nanotubes, short crossed carbon fibers, carbon nanofiber network structures, and nodular carbon fibers covered with carbon microbeads were synthesized using a floating catalyst method by changing the flow rate of xylene solution containing ferrocene, the concentration of ferrocene in xylene, and carrier gas. The general tendency is: Higher flow rate of xylene solution contributed to the formation of short crossed carbon fibers and deteriorated the graphitic crystalline of carbon fibers, which might play a critical role in their connection. Lower ferrocene concentration in xylene solution improved the graphitization of carbon nanofibers and changed the connection way of carbon nanofibers. Nodular carbon fibers covered with microbeads were obtained in N2 ambience. Carbon nanotubes with well graphitic crystal were prepared with the concentration of ferrocene in xylene 1.5 g/100 ml, the flow rate of xylene solution 0.12 ml/min and hydrogen 150 ml/min.