METHOD OF ELECTROPLATING CHROMIUM COATINGS FROM ELECTROLYTE BASED ON HEXAHYDRATE OF CHROMIUM (III) SULPHATE AND SODIUM FORMATE Russian patent published in 2024 - IPC C25D3/06 

FIELD: electroplating.

SUBSTANCE: invention relates to electroplating, particularly to electrodeposition of chromium coatings from electrolytes containing trivalent chromium compounds. Invention can be used to produce lustrous chrome coatings. Method involves electrodeposition of chromium coatings from an electrolyte containing hexahydrate of chromium (III) sulphate and sodium formate in the following ratio of components, mol/l: Cr₂(SO₄)₃⋅6H₂O — 0.5, HCOONa — 1.4. Electrodeposition is carried out on a copper cathode in an electrolysis cell without separation of the cathode and anode spaces, and the anodes used are platinum plates or a platinum mesh. Electrodeposition is carried out at electrolyte pH 1.7–1.9 at temperature of 25–30 °C 5–60 minutes at cathode current density of 30–40 A/dm², wherein preliminary processing of electrolyte is carried out in working range of current density of 30–40 A/dm² for 3 hours, after which solution is held for 24–48 hours.

EFFECT: providing electrodeposition of high-quality chromium coatings from an electrolyte containing trivalent chromium compounds, having a simple composition, in a given range of operating current densities, with given parameters of preliminary processing and with a given electrodeposition time.

1 cl, 4 ex