The research and application of electrozinc-nickel alloy in automobile parts are more and more extensive. Due to its good protection and cost effectiveness, excellent corrosion resistance and low hydrogen brittleness, it has become an excellent cadmium replacement coating. The wide application of zinc-nickel alloy is of great significance to improve the quality of protective layer, save metal resources, reduce pollution and reduce the cost of automobile parts. The future development direction is:

(1) Development of color zinc-nickel alloy electroplating layer
At present, the appearance of zinc-nickel alloy coatings on the market is mainly white and black. With the progress of science and technology, not only the protection has been put forward more stringent requirements, appearance requirements are also more stringent. The development of zinc-nickel coatings in a variety of colours is likely to be necessary.

(2) Acid zinc-nickel alloy system
At present, the main electroplating additive factories at home and abroad mainly use alkaline zinc-nickel alloy system. Acidic zinc-nickel alloy systems are still rarely used due to the instability of plating solutions. With the demand of automobile manufacturers for the corrosion resistance of castings and high-strength steel with the improvement of the market, acidic zinc-nickel alloy system will have a large market space.

(3) The corrosion resistance of black zinc-nickel alloy needs to be improved
Because the surface of the black zinc-nickel alloy coating reacts with the passivator and appears black, the corrosion resistance of the black zinc-nickel alloy coating used in the market is much lower than that of the white zinc-nickel alloy. The corrosion resistance of black zn-Ni alloy needs to be further improved.

When the nickel content is 8% to 15%, the zinc-nickel alloy coating has high corrosion resistance. Can be color, green, black, transparent passivation and other post-processing. The subsequent corrosion resistance far exceeds that of the zinc coating. It is 4 to 8 times that of pure zinc. The corrosion resistance of the coating is mainly related to the nickel content. In order to obtain sufficient nickel content, the control of process parameters is very important. Electrogalvanizing nickel alloy

At present, many parts of the car are made of zinc-nickel alloy parts. According to the requirements of the auto-Volkswagen TL244 standard, when the nickel content of the coating is between 12% and 15%, the corrosion resistance of the coating is strong.

Temperature:
The basic zn-Ni alloy bath has strict temperature requirements, which has great influence on the distribution of zn-Ni alloy in the coating.

The temperature is maintained at 33~37℃, the plating solution is stable, and the nickel content of the coating is 12%~15%. When the bath temperature is higher than 37℃, the codeposition rate of nickel ions increases sharply. The content of nickel ions in the alloy coating is more than 15%, the coating is bright silver white, and the passivation film is colorless or blue-yellow after rainbow passivation. After black passivation, a black iridescent passivation film will appear.

When the temperature is lower than 33℃, the co-deposition rate of zinc ions increases, the content of zinc ions in the alloy coating increases, the content of nickel ions is less than 12%, the passivation film becomes light yellow or colorless, and the light yellow passivation film is easy to wipe.

Therefore, the temperature of the bath must be strictly controlled in the production process, and an automatic device should be used to control it to ensure the stability of the bath.