1988 年 37 巻 413 号 p. 139-145
Formation of diamond from amorphous carbon was studied under static high pressure (10-18GPa) and high temperature (1120-2000°C) without any planned addition of catalysts. Diamond was formed upon heating amorphous carbon at fixed pressures higher than 10GPa, but was not formed below 8GPa. The formation of diamond occurred via crystallization of amorphous carbon into graphite. The graphitization was not, however, completed prior to the diamond formation. The temperature of diamond formation from amorphous carbon was markedly lower than those from glassy carbon or spectroscopic graphite, being strongly dependent on the temperature for preparing amorphous carbon. The results were interpreted from the two-species model of amorphous carbon.