METHODS OF PRODUCING POLYCRYSTALLINE DIAMOND, CUTTING ELEMENTS AND TOOLS CONTAINING POLYCRYSTALLINE DIAMOND Russian patent published in 2020 - IPC C01B32/28 C30B29/04 B01J3/06 E21B10/42 B24D3/34 

FIELD: soil or rock drilling; mining.

SUBSTANCE: invention can be used in production of drilling and cutting elements, for example, drilling bit for rotary drilling of underground formations. Diamond fragments, carbon oxide and carbon dioxide are encapsulated in a vessel in the absence of a metal catalyst, the vessel is sealed and subjected to a pressure of not less than 4.5 GPa and a temperature of not less than 1400 °C, as a result of which polycrystalline diamond with inter-crystalline bonds is formed between diamond fragments. Vessel may additionally contain inert gas or substrate, chemical composition of which differs from chemical composition of polycrystalline diamond. Part of carbon oxide can be converted into diamond due to formation of intercrystalline bonds. Ratio of partial pressures of oxide and carbon dioxide, which is equal to approximately 5.0 × 10^-3 or lower, is selected in the field of stability of diamond. Resulting polycrystalline diamond has a density of at least 3.49 g/cm³ and a modulus of at least 1000 GPa.

EFFECT: cutting element for a drilling tool made from polycrystalline diamond does not contain graphitised carbon and metal inclusions, is not subject to "reverse graphitization" and peeling of the substrate.

19 cl, 6 dwg, 1 tbl, 2 ex