On the low pressure transformation of graphite to diamond in the presence of a 'catalyst-solvent'

A hybrid process for the synthesis of diamond using a low pressure chemical vapor deposition (CVD) technique (microwave assisted CVD) in conjunction w ith the use of graphite powder and a 'catalyst-solvent' as the starting mat erials is reported. Graphite is partially converted into diamond by the low pressure synthesis in the presence of nickel, a commonly considered 'catal yst-solvent' in the high pressure-high temperature (HP-HT) process. The res ulting product is examined in the SEM, low-angle X-ray diffraction, and mu- Raman spectroscopy to show evidence of the conversion to diamond. The hybri d process is compared with the traditional HP-HT process for diamond synthe sis to propose possible similarities of the 'catalyst-solvent' action prese nt at HP-HT conditions and that at LP-HT conditions. (C) 1999 Elsevier Scie nce S.A. All rights reserved.