METHOD OF PRODUCING COMPOSITE MATERIAL BASED ON SILICON NITRIDE Russian patent published in 2024 - IPC B22F3/23 C22C1/51 C04B35/584 C04B35/591 

FIELD: powder metallurgy.

SUBSTANCE: invention relates to powder metallurgy, particularly to a method of producing composite material based on silicon nitride by self-propagating high-temperature synthesis. It can be used to produce silicon nitride for use in metallurgy. Initial charge containing 45–95 wt.% of ferrosilicon powder with specific surface area of more than 0.02 m²/g, containing 65–85 % of silicon, with particle size less than 0.5 mm and inclusion of at least 30 % of particles with size less than 0.1 mm and 5–55 wt.% of powder based on silicon nitride with specific surface area of more than 0.05 m²/g, containing 65–95 % of silicon nitride, with particle size less than 0.315 mm and inclusion of not less than 40 % of particles with size less than 0.1 mm, it is filled into the crucible and compacted to obtain porosity of 45–65 %. Crucible is placed in the SHS reactor and the SHS reactor is filled with nitrogen at a pressure higher than 0.1 MPa. Performing local heating of part of said charge surface to temperature of 1,250–2,050 °C, initiating the beginning of the chemical reaction of interaction of silicon with nitrogen, and saturated with nitrogen in the mode of self-propagating high-temperature synthesis at temperature of 1,650–2,100 °C in a nitrogen atmosphere at pressure of 0.14–14.0 MPa.

EFFECT: obtaining a porous composite material with a high content of nitrogen in the form of silicon nitride with its uniform distribution throughout the volume of the material.

7 cl, 3 tbl, 1 ex