ELECTROCHEMICAL METHOD OF OBTAINING OXIDE COLOURED COATING ON ALUMINIUM AND ITS ALLOYS Russian patent published in 2015 - IPC C25D11/22 

FIELD: chemistry.

SUBSTANCE: method includes the preliminary processing of aluminium or its alloys with solutions of etching and clearing, the following submergence into an acid-containing solution under the influence of electric current, as the acid-containing solution applied is a mixture of sulphuric acid and its salts of different metals, with an impact by reverse current with the basic current density 10 mA/cm² and the quantity of electricity in anode Q_a and cathode Q_c cycles from 0.001 to 18.0 Kl with the total time of the impact of 900-1800, and Qa≥Q_c.

EFFECT: method makes it possible to control the process of colouring, regulate the colour range of obtained coatings, reduce production areas due to the reduction of the process stages, quantity of washing water, the total time for processing the products and reduce power consumption.