A nickel-free electrolytic coloring and blackening additive and its application method

Abstract

The invention discloses a nickel-free electrolytic coloring and blackening additive, which comprises 25-30 parts by weight of complexing agent, 5-10 parts of pH stabilizer, 10-20 parts of reducing agent, 35-50 parts of blackening agent, 4 to 8 parts of penetrating agent; the present invention also discloses the use method of nickel-free electrolytic coloring blackening additive, using the above-mentioned nickel-free electrolytic coloring blackening additive, sulfuric acid, stannous sulfate and water to make electrolytic coloring liquid, which is used for aluminum And aluminum alloy for electrolytic coloring. The color is uniform and stable after the electrolytic coloring of the present invention, and the blackness of true black reaches the level of traditional electrolytic coloring with nickel, and the environmental protection property is obviously better than that of traditional electrolytic coloring with nickel.

Description

technical field [0001] The invention relates to the technical field of material surface treatment, in particular to a nickel-free electrolytic coloring and blackening additive and a use method thereof. Background technique [0002] The electrolytic coloring of aluminum and aluminum alloy is a process of color development through the reduction of metal ions on the bottom of the anodized film of aluminum and aluminum alloy, which interferes with light and develops color. It has the advantages of stable color, good weather resistance, and low production cost. Commonly used color development process in alloy anode surface treatment. [0003] The traditional electrolytic coloring process mostly uses double-salt electrolytic coloring additives, that is, nickel sulfate-stannous sulfate system. In this system, nickel sulfate has excellent electrical conductivity and current dispersion, which has an important influence on the uniformity and color depth of electrolytic coloring. In ...

AI Technical Summary

Problems solved by technology

Patent CN201811438369 provides an environmentally friendly monotin salt electrolytic coloring additive, which is mainly composed of lactose, sodium erythorbate, complexing agent, auxiliary agent, organic phosphoric acid compound and supplemented by phytic acid to ensure the stability of stannous sulfate. The above method Can solve the "picture frame" phenomenon in nickel-free electrolytic coloring, but organophosphides have higher requirements for disposal

At the same time, these two methods do not solve the problem of insufficient stannous ion reduction deposition, and cannot obtain the same true black as the double-salt electrolytic coloring additive.