Transmission electron microscopy studies of nanofibers formed on Fe7C3-carbide

Carbon nanofibers have been formed on iron details of the high isostatic pressure (HIP) apparatus. Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) techniques proved the existence of faceted catalyst particles found in the middle part of fibers and allowed identification of their lattice and composition as the pseudo-hexagonal crystalline lattice of Fe7C3. Two systems of arc-reflections with 0.335-nm spacing were ascribed to two different orientations of graphite layers and a trace analysis showed that the growth direction of the fiber coincides with the [210]-direction of pseudo-hexagonal Fe7C3-lattice. This direction is compared with directions of fibers formed on bcc-Fe and Fe3C. (C) 2002 Elsevier Science B.V. All rights reserved.