| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide high purity and high hardness polycrystalline nanodiamond and to provide a production method thereof. <P>SOLUTION: This polycrystalline nanodiamond 1 is composed of carbon and a plurality of impurities other than carbon. The concentration of the plurality of impurities is each 0.01 mass% or less, and the crystal grain diameter (maximum length) of the polycrystalline nanodiamond 1 is 500 nm or less. The polycrystalline nanodiamond 1 is producible by preparing graphite with ≤0.01 mass% concentration of impurities, and applying ultrahigh pressure, high temperature treatment to the graphite to convert the graphite into diamond. <P>COPYRIGHT: (C)2013,JPO&INPIT |
