Method for manufacturing polycrystalline diamond and its manufacturing method, scribe tool, scribe wheel, dresser, rotary tool, orifices for water jet, wire drawing die, cutting tool, electrode and polycrystalline diamond

摘要

To provide a polycrystalline diamond covered with a non-aqueous protective film, capable of preventing tribo-plasma.SOLUTION: The polycrystalline diamond has a diamond single phase as a basic composition and is constituted by a plurality of crystal particles, wherein the polycrystalline diamond contains boron, nitrogen, a nitrogen compound, silicon and the balance comprising carbon and a trace amount of impurities. The boron is dispersed in the crystal particles at atom level, 90 atom% or more thereof exists as an isolated substituted type; the nitrogen, the nitrogen compound and the silicon exist as the isolated substituted type or an immersion type in the crystal particles; the nitrogen compound is one or both of boron nitride and silicon nitride; the crystal particles have a particle diameter of 500 nm or less; and the surface of the polycrystalline diamond is covered with a protective film.SELECTED DRAWING: None