Phase transformation between diamond and graphite in preparation of diamonds by pulsed-laser induced liquid-solid interface reaction

The phase transformation between diamond and graphite in preparation of diamond by pulsed-laser-induced liquid-solid interface reaction (PLIIR) was studied by calculating the probability of phase transition of the carbon atoms over a potential barrier in the pressure-temperature (P-T) phase diagram of carbon. It is found that the probability of phase transition from graphite to diamond is as high as 10(-3)-10(-4) in the C pressure-temperature region where the pressure and temperature are in the range of 10 GPa to 15 GPa and 4000 K to 5000 K, respectively, in the pressure-temperature phase diagram. The distribution of the probability of the phase transformation from graphite to diamond was obtained in the corresponding pressure-temperature region, in which diamonds are prepared by PLIIR. In addition, the dependence of the probability for the transformation of graphite to diamond on temperature was investigated and found to be in agreement with the Arrhenius rule.