| 摘要 |
PURPOSE:To obtain stably diamond crystals of good quality and large grain size, by adding a specific nucleating catalyst to a carbonaceous raw material for synthesizing the diamond, oxidizing or nitriding the raw material, and growing the crystals at a high temperature and pressure. CONSTITUTION:50-75wt% one or more of Ni, Mn, Fe, Cr and Co as a nucleating catalyst for diamond is added to a carbonaceous raw material for synthesizing the diamond, and the resultant mixture is then heated in an atmosphere of oxygen or nitrogen to oxidize or nitride the nulceating catalyst. The resultant oxidized or nitrided nucleating catalyst is then kept at 1,400-1,550 deg.C and 5.6- 6.2X10<4> atm under heating to grow crystals. The amount of the nulceating catalyst is set at 50-75wt% since the nucleation of the diamond can be carried out in the range. If the heating temperature is below 1,400 deg.C, the reaction rate is too low to make the diamond in a massive form. If the temperature is above 1,550 deg.C, many side reactions occur, and beautiful crystals of diamond cannot be produced. |
