METHOD OF OBTAINING FIRE-PROOF MATERIAL BASED ON SILICON BETA-NITRIDE β-SiN Russian patent published in 2013 - IPC C04B35/584 

FIELD: chemistry.

SUBSTANCE: invention relates to methods of obtaining fire-proof materials on non-oxide basis, namely to fire-proof materials based on silicon beta-nitride β-Si₃N₄, which can be used as strengthening additives into non-formed fire-proof masses. Ferrosilicium powder, representing two-phase alloy of silicon with iron, is selected as initial raw material for high-temperature processing of silicon-containing powder-like alloy in atmosphere of nitrogen-containing gas under its higher pressure. Powder of initial ferrosilicium, with particle size not exceeding 2.0 mm, is mixed with powder of initial fire-proof material based on Si₃N₄, with particle size not exceeding 1.0. Obtained mixture is placed into nitrogen-containing atmosphere, which contains not less than 97.5% vol. of nitrogen, in which pressure is supported in the interval 0.15-25.0 MPa during entire process. After that mixture is set in fire by local heating to the temperature of beginning of exothermal reaction of silicon with nitrogen interaction. Nitration is carried out first in mode of layer-by-layer burning at temperature 1750-2250°C and further in mode of volumetric burning at temperature 2250-1250°C for the time, sufficient for converting more than 50% of initial silicon into silicon nitride, which consists of nitride of beta-modification β-Si₃N₄ for not less than 90 wt %.

EFFECT: creation of novel method of obtaining fire-proof material based on silicon β-nitride, which would make it possible to produce components of non-formed grogs for protection of metallurgical thermal aggregates, based on silicon nitride with crystalline structure β-Si₃N₄, with practically absent energy consumption.

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