METHOD OF WEAR-RESISTANT COATING FORMATION ON SURFACE OF ARTICLES MADE OF STRUCTURAL STEEL Russian patent published in 1999 - IPC

FIELD: formation of wear-resistant coatings on structural steel articles. SUBSTANCE: method includes ion-plasma nitriding in medium of reactive nitrogen gas, cleaning of part surface and deposition of titanium nitride from plasma phase. In so doing, nitriding, surface cleaning and deposition of titanium nitride are carried out in one vacuum chamber in plasma of arc and gaseous discharge with incandescent cathode in single cycle to form three-layer structure on surface of parts. Nitriding is carried out at pressure of reactive gas of 5^*10^-3-2^*10^-2 mm Hg, negative bias voltage across parts of 300-1000 V and ion current density of 2-8 mA/sq.cm for 30-90 min. Cleaning is carried out in plasma of inert gas - argon at pressure 3^*10^-4-7^*10^-4 mm Hg current density of 3-5 mA/sq.cm. Titanium nitride is deposited rate of 2 mcm/h for 60-90 min with concurrent operation of generator of gas discharge plasma and arc-heated evaporator with negative bias voltage across part of 300-600 V, arc-heated evaporator current of 50-200 A, reactive gas pressure of 3^*10^-4-2^*10^-3 mm Hg. EFFECT: intensified process, increased stability in operation of machines exposed to high unit loads in friction. 1 tbl