METHOD TO APPLY DOUBLE-LAYER COATINGS Russian patent published in 2012 - IPC C25D5/06 C25D3/34 B23H9/00 

FIELD: metallurgy.

SUBSTANCE: in the method double-layer coatings are applied onto items from steel, titanium and its alloys. The method includes electric spark application of the first layer of the coating with an electrode, containing 84 wt % of titanium carbonitride, 10.67 wt % of nickel and 5.33 wt % of molybdenum, application of the second antifriction lead-containing layer by the method of galvanic electric rubbing at the pulse current by an electrode tool from stainless steel wrapped with a crimplene fabric impregnated with electrolyte and processing of the produced coating by a polishing agent. To apply the second layer of the coating, electrolyte of the following composition is used, g/l: lead nitrate 200 - 220, nickel acetylacetonate 10 - 12, copper nitrate 2-3, potassium nitrate 100 - 120, molybdenum disulfide 25 - 35, nitric acid 0.5 - 1, wood hide glue 0.3 - 0.4, gelatine 0.15 - 0.2, a preparation OS-20 0.05 - 0.1. Five last stages by an electrode tool are carried out by addition of molybdenum disulfide into electrolyte to 450 - 500 g/l.

EFFECT: invention makes it possible to produce a high-quality double-layer coating with higher wear resistance, corrosion resistance and adhesion with reduction of a friction ratio.

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