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

摘要

To provide a polycrystalline diamond having high abrasion resistance which can form a protection film for surface protection.SOLUTION: A polycrystalline diamond is composed of a plurality of crystal grains with a diamond single phase as a basic composition, and contains boron, a boron compound, hydrogen, and oxygen, with the balance being carbon and trace impurities. The boron is dispersed in the crystal grains at an atom level, and 90 atom% or more thereof is present as an isolated substitutional type. The boron compound, the hydrogen and the oxygen are present in the crystal grains as an isolated substitutional type or an intrusion type. The boron compound contains a boron compound containing oxygen. The crystal grains have a particle size of 500 nm or less, and a surface of the polycrystalline diamond is coated with a protection film.SELECTED DRAWING: None