Abstract: Ultrasharp polycrystalline diamond edges, points, and improved diamond composites of predetermined configuration usable as cutting instruments, as high intensity sources for the emission of electrons, ions, neutrons, x-rays, coherent and incoherent light and high frequency electromagnetic radiation, and as ultraprecision molded mechanical and optical parts, or as high field permanent magnets or electrets, are produced by preparing and classifying natural and synthetic ultrafine uniform graphite particles, preferably of the rhombohedral phase, which are directly converted into diamond particles having a particle size of 3 to 100 angstroms, placing the ultrafine powder, either before or after the synthesis, with or without suitable additives, in a diamond mold defining the ultrafine edge or form to be produced, and applying a pressure of the order of 80 to 90 kb, preferably dynamic or static ultrahigh pressures of 100 to about 1000 kb, while heating the powder to a temperature of the order of 2440.degree. K.

Abstract: Ultrasharp diamond edges and points which are usable as cutting instruments and as high intensity point sources for the emission of electrons, ions, x-rays, coherent and incoherent light and high frequency electromagnetic radiation are produced by preparing and classifying ultrafine diamond powder having a particle size of 10 to 100 angstroms placing the powder in a diamond mold defining the ultrasharp edge or point to be produced and applying a pressure of the order of 80 to 90 kb while heating the powder to a temperature of the order of 2440.degree. to 2500.degree. K in an ultrahigh vacuum or inert atmosphere after degasing to avoid oxidation of the diamond powder.