METHOD OF MANUFACTURING DIAMONDS IN FANTASY RED COLOR Russian patent published in 2004 - IPC

FIELD: carbon materials.

SUBSTANCE: invention relates to treatment (refinement) of diamonds to impart them a variety colors, which may find use in jeweller's art. Method consists in that, in crystalline lattice of naturally occurring type IA diamond containing A defects or naturally occurring high-nitrogen type IA diamond containing more than 800 ppm nitrogen impurities in the form of A and B1 defects, individual nitrogen atoms in substitution position (C defects) are formed. Naturally occurring type IA diamond containing A defects is annealed in high-pressure apparatus at temperature above 2150^оС and stabilization pressure 6.0-7.0 GPa and then exposed to electron beam 5 x 10¹⁵ - 5 x 10¹⁸ cm^-2 at 2-4 MeV, after which subjected to annealing in vacuo at temperature at least 1100^оС. Naturally occurring high-nitrogen type IA diamond containing more than 800 ppm nitrogen impurities in the form of A and B1 defects is exposed to high-energy electron beam at radiation dose 10¹⁹ cm^-2, after which subjected to annealing in vacuo at temperature at least 1100^оС. Products are diamonds in fantasy red color appropriate for brilliants with stable N-V coloration sites absorbing within wavelength range 400-640 nm.

EFFECT: expanded diamond refinement possibilities.

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