Abstract
In situ electrical resistivity measurement of graphite compressed in two different pressure cycles in one single experiment at room temperature in the pressure range of 0-34 GPa has been reported. The electrical results indicate that less superhard graphite formed in the second cycle than in the first one. Our experiments identify the phase transition of the graphite at 15.1 and 17.9 GPa for the first and second pressure cycles, respectively, and explain why the superhard post-graphite cannot indent diamond films. The scanning electron microscopy of the graphite powders before and after pressure annealing helps to support the conclusion that both the phase transitions and the formation of superhard post-graphite are sensitive to the grain size of the initial graphite sample under high pressure.
Original language | English |
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Article number | 103707 |
Journal | Journal of Applied Physics |
Volume | 112 |
Issue number | 10 |
DOIs | |
State | Published - Nov 15 2012 |