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 dia mond by pulsed-laser-induced liquid-solid interface reaction (PLIIR) was st udied by calculating the probability of phase transition of the carbon atom s over a potential barrier in the pressure-temperature (P-T) phase diagram of carbon. It is found that the probability of phase transition from graphi te to diamond is as high as 10(-3)-10(-4) in the C pressure-temperature reg ion 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 diag ram. The distribution of the probability of the phase transformation from g raphite to diamond was obtained in the corresponding pressure-temperature r egion, in which diamonds are prepared by PLIIR. In addition, the dependence of the probability for the transformation of graphite to diamond on temper ature was investigated and found to be in agreement with the Arrhenius rule .