POLYCRYSTALLINE DIAMOND METHOD FOR PRODUCING SAME, SCRIBE TOOL, SCRIBE WHEEL, DRESSER, ROTATING IMPLEMENT, WIRE DRAWING DIE, CUTTING IMPLEMENT, ELECTRODE, AND PROCESSING METHOD IN WHICH POLYCRYSTALLINE DIAMOND IS USED

摘要

Provided is polycrystalline diamond having a diamond single phase as basic composition, in which the polycrystalline diamond includes a plurality of crystal grains and contains boron, hydrogen, oxygen, and the remainder including carbon and trace impurities; the boron is dispersed in the crystal grains at an atomic level, and greater than or equal to 90 atomic% of the boron is present in an isolated substitutional type; hydrogen and oxygen are present in an isolated substitutional type or an interstitial type in the crystal grains; each of the crystal grains has a grain size of less than or equal to 500 nm; and the polycrystalline diamond has a surface covered with a protective film.