METHOD FOR PRODUCING SELF-LUBRICATING MATERIAL BASED ON ARTIFICIAL FINE-GRAINED GRAPHITE Russian patent published in 2021 - IPC C04B35/532 C04B35/626 

FIELD: mechanical engineering.

SUBSTANCE: invention relates to the field of mechanical engineering and can be used in mechanical seals of friction units of aviation and ground equipment, where the performance of materials is required under vacuum, excessive pressures, dry friction, high humidity and negative temperatures. The product of mechanical processing of artificial fine-grained graphite (artificial graphite with a processing temperature of at least 2400°C) is scattered to obtain a fractional composition of minus 90 microns of at least 97%. High-temperature coal tar pitch is crushed to obtain at least 97% of the fraction with a particle size of minus 90 microns. The selected fractions of artificial graphite of the required size and solid lubricant - boron nitride are mixed in a heated mixer until the temperature of the mass reaches 150-200°C, then high-temperature pitch, an organic additive (oleic acid) are added and heated to a mass temperature of 160-200°C. The resulting mass is crushed to a press powder with a granulometric composition of at least 97% of the fraction minus 90 microns, magnetic separation is carried out, then workpieces are formed, after which firing is carried out at a temperature of up to 1000°C. In the range of 400–600°C, the heating rate is no more than 5°C per hour. Fired workpieces containing a product of mechanical processing of artificial fine-grained graphite in an amount of 70–75 wt%, boron nitride in an amount of 8–12 wt%, bound by pitch coke in an amount of 16–22 wt%, with an open porosity of 10–20% are additionally provided with coal tar pitch with a softening temperature of 65–110°C and high-temperature treatment is carried out at 1500–2050°C, then the workpieces are impregnated with a solution of furfuryl alcohol and polymerized at temperatures of 250–300°C until the required material tightness is achieved.

EFFECT: invention makes it possible to achieve higher tightness values and reduce the gas permeability of the self-lubricating material.

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