In situ X-ray diffraction study of solid state transformations during catalytic graphitisation of amorphous carbon

Here we report on the results of an in situ X-ray diffraction study of phas e transformations during catalytic graphitisation of amorphous carbon. It i s demonstrated that there is unusual change of iron catalyst reflection int ensity at low temperature similar to 640 degreesC. This unusual intensity c hange may possibly be caused by the transition of some part of metal into l iquid state at low temperature. It was also shown by electron microscopy th at although no graphite reflections were detected 80-90% of amorphous carbo n becomes graphite after sample heating in a high temperature vacuum chambe r. (C) 2001 Elsevier Science B.V. All rights reserved.