METHOD FOR PRODUCING COMPOSITE POWDER MB2-SIC, WHERE M = ZR, HF Russian patent published in 2017 - IPC C01B31/36 C01B35/04 C04B35/565 C04B35/58 C04B35/624 C04B35/626 C04B35/628 C04B35/632 B22F9/06 C22C29/02 C22C29/14 B82B3/00 B82Y30/00 B82Y40/00 

FIELD: chemistry.

SUBSTANCE: invention relates to the production of powder materials composition MB₂-SiC, wherein M = Zr, Hf, containing nanocrystalline silicon carbide. The resulting composite powders are ZrB₂-SiC and/or HfB₂-SiC can be used to apply protective coatings on carbon-containing antioxidant materials, including reinforced carbon and silicon carbide fibers, graphite materials, and for the manufacture of ultra-ceramic materials used primarily to create aerospace and missile technology, heating systems, thermal power, nuclear energy technologies, chemical and petrochemical industries. Composite powder is obtained, having increased oxidative stability, which is a composition of zirconium diboride and / or hafnium diboride 10÷65 vol. % nanocrystalline silicon carbide, which is prepared phenol-formaldehyde resin solution with a mass of carbon content of from 5 to 40% in an organic solvent in which are dispersed powder of zirconium diboride and/or hafnium diboride, whereupon the resulting slurry is tetraethoxysilane at a concentration of⋅ 1⋅10^-3 to 2 mol/l, providing a stoichiometric synthesis of silicon carbide, and the acid catalyst tetraethoxysilane hydrolysis, further hydrolysis is carried out with stirring at a temperature of 0÷95°C tetraethoxysilane hydrolyzing solutions to form a gel, followed by drying the resulting gel, then drying the resulting gel at a temperature of 02÷50°C and a pressure of 1⋅10^-4÷1 atm until the mass change ceases, the resulting xerogel is subjected to a two-stage heat treatment under reduced pressure, in a first stage at a temperature of 400 to 1000°C for 0.5÷12 hours, in a second stage at a temperature of 1100 Up to 1450°C for 0.5÷12 hours. Get composite powders MB₂-SiC, wherein M = Zr, Hf, containing nanocrystalline silicon carbide.

EFFECT: absence of foreign phases and increased oxidative stability in air flow as compared with the powders of individual HfB₂ and ZrB₂.

5 cl, 4 dwg, 4 ex