| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a nano-polycrystalline diamond having high hardness and high wear resistance against an iron-based material.SOLUTION: A nano-polycrystalline diamond 3 comprises carbon and heterogeneous elements introduced as a dopant into a crystalline structure composed of carbon. The heterogeneous elements comprise a first element (for example, boron) that is one element selected from a group consisting of group-13 elements and a second element (for example, nitrogen) that is one element selected from a group consisting of group-15 elements; and each atomic concentration of the first element and the second element is 1×10/cmor more and 1×10/cmor less. The nano-polycrystalline diamond 3 has an electric resistivity of 10Ωcm or more. The nano-polycrystalline diamond 3, for example, is produced by subjecting graphite formed on a substrate 2 by a CVD method to a high-temperature and high-pressure environment so as to convert the graphite into the nano-polycrystalline diamond 3.</p> |
