METHOD OF FORMING COLOURED DECORATIVE COATING BY ANODISATION Russian patent published in 2017 - IPC B32B33/00 C25D11/08 C25D11/12 C25D11/14 C25D11/24 C25D11/34 C30B30/02 C30B29/16 G02F1/01 G02F1/21 G02F1/23 B82B3/00 B82Y20/00 B82Y30/00 B82Y40/00 

FIELD: chemistry.

SUBSTANCE: method of obtaining a decorative coating with a changing colour during visual angle variation consists in the formation of one-dimensional photonic crystal with photonic bandgap in the visible range by anodising the surface of a valve metal or its alloy containing not less than 50% of valve metal at a cyclically varying parameters: current and voltage, wherein each cycle consists of two stages: anodization is carried out at the first stage at current stabilization in the range of 0.1 to 50 mA /cm² for a time ensuring charge flow from 0.05 to 5 C/cm²; anodization is carried out at the second stage at voltage stabilization, increasing it from the voltage value at the end of the first stage to a value lying in the range from 10 to 200 V, with a decreasing voltage rise rate from 5 V/s to 0 V/s, and is held at this value for a time ensuring charge flow from 0.05 to 5 C/cm², ensuring more than 1.4 ratio ofmaximal voltage at the second stage to minimal voltage at the first stage, wherein metal surface serves as anode during production of the decorative coating, and inert material is used as cathode, wherein anodisation charge is reduced by 0.01-10% at the first and the second stages at every next anodisation cycle, which amount lies in the range from 20 to 300.

EFFECT: invention allows to obtain coloured decorative coatings of high quality using simple and reproducible method characterized by safety and environmental friendliness due to elimination of toxic substances from the technology.

9 cl, 10 dwg, 2 tbl, 5 ex