METHOD OF PORE-FREE SOLID CHROMIUM-PLATING OF ARTICLES OF CAST IRON AND STEEL Russian patent published in 2016 - IPC C25D15/00 

FIELD: electroplating.

SUBSTANCE: invention relates to application of galvanic coatings on articles made of cast iron and steel. Method involves successive deposition of layers of coating from electrolyte at direct current polarity, wherein article is heated and subjected to cathode treatment at cathodic current density of 100-150 A/dm² and temperature of 70-75 °C in same bath at continuous circulation of electrolyte, at end of cathodic treatment current density is reduced to 32 A/dm² and chromium-plating is continued until coating thickness reaches 8-10 mcm, then without current supply electrolyte is cooled to temperature of 45-50 °C by means of heat exchanger with cold water flow, and when specified temperature is achieved, article is subjected to minimum cathode current with gradual rise of density up to 45-50 A/dm²  and chromium-plating is performed up to required coating thickness. Chromium-plating process of any cast iron and steel including nitrated, is performed in electrolyte of one composition and in one bath without application of anode interlayer treatment.

EFFECT: technical result is upgraded micro hardness - from 1,000 HV at satisfactory adhesion of coating.

1 cl, 1 dwg