METHOD OF NITRIDING ITEMS OUT OF STEEL IN PLASMA OF GLOW DISCHARGE Russian patent published in 2016 - IPC C23C8/36 C23C14/06 

FIELD: metallurgy.

SUBSTANCE: invention relates to chemical-thermal treatment of metals in plasma of glow discharge, and can be used in mechanical engineering for surface strengthening of parts of machines and cutting tools. Method of nitriding items out of steel in plasma of glow discharge includes placement of item in vacuum chamber and connection of article to high-voltage power supply, sealing of vacuum chamber and creating high vacuum in it with subsequent replacement of atmosphere to pure nitrogen, obtaining stable plasma of glow discharge in atmosphere of pure nitrogen by means of high-voltage power source and electron flow from tungsten filament arranged parallel to axis of vacuum chamber generated heating filament to temperature of 2,000-2,500 °C. Produced plasma of glow discharge of higher density in atmosphere of pure nitrogen by action on flow of electrons and ions of electromagnetic field using annular electromagnets, providing for electrons and ions of movement along spiral trajectories of variable radius. For heating of items up to nitrogenation temperature in said plasma of glow discharge of higher density on a substrate with articles voltage of 2,000 V is supplied, then reduced voltage on substrate to 1,800-1,500 V to maintain constant temperature, at that, discharge current density equal to 10⁴ A/m² is provided, where nitriding is carried out for 2-3 hours.

EFFECT: higher rate of nitration, as well as microhardness and wear resistance of a nitrated coating.

1 cl, 1 dwg, 1 ex