METHOD FOR SINGLE TONE COLORING OF PART(S) OF PRODUCT(S) FROM TITANIUM, TANTALUM, ZIRCONIUM, NIOBIUM, HAFNIUM, TUNGSTEN ALLOYS Russian patent published in 2023 - IPC C25D11/22 

FIELD: electroplating.

SUBSTANCE: invention can be used for painting vehicle bodies, watches, telephones, jewelry, interior and exterior elements, implants and much more. The method includes applying a dielectric to uncoated parts of the product, forming an anodic oxide film by electrochemical method, removing the dielectric, characterized in that the dependence of the current density on the voltage value is established, a graph is calculated applicable to the part of the product, and for coatings formed at the final color-forming voltage value from 51 V to 120 V, a preliminary oxide film is applied, which is formed at a lower voltage value UI, and the value of the secondary voltage UII corresponds to the desired color Ut, the value of the primary voltage UI is determined by subtracting the difference ΔU from the secondary voltage value UI=UII-ΔU, with a secondary voltage of 51 V to 75 V the subtractive difference is 10 V, with a secondary voltage of 76 V to 95 V the subtractive difference is 20 V, with a secondary voltage of 96 V to 120 V the subtractive difference is 35 V, and the current density is chosen according to the voltage on the graph, which corresponds to the desired color.

EFFECT: controlled uniform formation of a decorative coating characterized by color saturation and purity; the method reduces the likelihood of defects such as uneven cell structure of the porous oxide, color smudges, burning and embrittlement.

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