Formation of nodulated vapor grown carbon fiber

A very unusual form of carbon fibers is reported. While preparing vapor grown carbon fiber at temperatures exceeding 1200 °C, formation of nodulated carbon fibers were found in addition to normal vapor grown carbon fibers. The growth temperature was found to be the primary, if not only, factor influencing the formation of nodules and the frequency of occurrence. The formation of such an unusual structure is related to the defect microstructures found in the fiber during the growth, and explained in terms of a three-dimensional nucleation model.