METHOD OF OBTAINING PRODUCTS BASED ON SILICON NITRIDE Russian patent published in 2018 - IPC C04B35/591 C04B35/65 C04B35/596 

FIELD: manufacturing technology.

SUBSTANCE: invention relates to the production of chemically bonded silicon nitride and is intended for the production of a wide range of products – elements and assemblies of chemical equipment, crucibles and lining elements used in non-ferrous metallurgy, parts and assemblies of propulsion systems of motor, sea, air transport, as well as ground power plants and other equipment that operate at temperatures up to 1500 °C in the air, in the atmosphere of combustion products of fuels and other corrosive environments. Method for obtaining articles from silicon nitride involves mixing the ground technical silica with a plasticizer, molding of blanks, removal of plasticizer from them and subsequent nitriding. Plasticizer is removed in two stages, the first of which is carried out in an oven in a backfill of alumina at a temperature of up to 200 °C for 15–30 hours, the second – in the air at a temperature of up to 600 °C for 70–100 h, and the nitriding of the blanks is conducted in the reactor with technical nitrogen at an excess pressure of up to 2.0 atm and a temperature of 1170 °C, at which the chemical reaction between silicon and nitrogen begins. Nitriding process is carried out for 12–20 hours and ends at a temperature of 1400 °C.

EFFECT: technical result of the invention is the development of a method for obtaining articles based on silicon nitride from available raw materials, possessing increased mechanical strength, as well as resistance to thermal shocks and high-temperature oxidation.

1 cl, 2 ex