| 摘要 |
PURPOSE:To obtain high purity diamond having a superior crystal form when diamond is synthesized at high temp. and superhigh pressure using carbon and a solvent metal, by using composite carbon consisting of specified easily graphitizable carbon and specified hardly graphitizable carbon as the carbon as a starting material. CONSTITUTION:When diamond is synthesized at high temp. and superhigh pressure using carbon and a solvent metal such as Fe, Co, Ni, Cr, Ta or Pt, graphite having <=6,715 lattice constant Co (002) or easily graphitizable carbon is coated with hardly graphitizable carbon and used as the carbon as a starting material. The easily graphitizable carbon has <=6,740 lattice constant Co (002), and when it is graphitized at 3,000 deg.C, the lattice constant is reduced to <=6,715. The hardly graphitizable carbon has >=6,800 lattice constant, and when it is graphitized at 3,000 deg.C, the lattice constant is reduced to >=6,740. High purity diamond having a superior crystal form is obtd. |
