POLYCRYSTALLINE DIAMOND

摘要

Polycrystalline diamond usable in many applications is provided. Also provided are a water-jetting orifice, stylus tool for gravure printing, scriber tool, diamond tool for cutting, and scribing wheel each employing the polycrystalline diamond. The polycrystalline diamond is one obtained from non-diamond carbon by conversion and sintering under ultrahigh-pressure high-temperature conditions without the need of adding any sintering aid or catalyst. The polycrystalline diamond is characterized in that the diamond sinter grains constituting the polycrystalline diamond have an average grain diameter of 50-2,500 nm, excluding 50 nm and 2,500 nm, and that the diamond has a purity of 99% or higher and a D90 grain diameter not larger than [(average grain diameter)+(average grain diameter)×0.9].