Control points of electroplating process when using alkaline zinc-nickel alloy additives

Control points of electroplating process when using alkaline zinc-nickel alloy additives

Tue Aug 16 18:11:03 CST 2022

    In the process of using alkaline zinc-nickel alloy additives, we need to control the ratio of zinc and nickel in the plating solution to ensure that the nickel content in the alloy coating is 12~16%.

So what exactly should we do?

    Bigolly Technology made an analysis based on the field experience and the characteristics of the product's alkaline zinc-nickel alloy additives BZ-617,the main points of operation of the electroplating process are as follows:

    1. Supplementation of zinc ions and nickel ions in the bath.1ml/L of nickel additive BZ-617C can increase the nickel ion concentration in the plating solution by 66ppm, and the concentration can be adjusted regularly during the production process.It is recommended to use a zinc-dissolving tank for zinc supplementation, and the size of the zinc-dissolving tank is 20% of that of the zinc-nickel alloy tank.

    2. The content of sodium hydroxide in the plating solution should be controlled at 120~140g/L.At this time, it has better dispersing ability and deep plating ability, and it is better to control the ratio of sodium hydroxide and zinc to 10~12:1.

    3. Appropriate addition of brightening agent BZ-617D can obtain a bright and flat coating, and can prevent burning in high areas and expand the scope of bright areas.When the concentration of brightener BZ-617D is too low, the high area will be rough and matte white;When the concentration is too high, the brittleness of the coating increases, the dispersion ability decreases, and the nickel content in the high area is easy to exceed the standard, and it is not easy to passivate.

    4. The temperature of the plating solution is relatively high. During normal production, the temperature should be kept at 20~28℃ to ensure the normal production.

    5. The insoluble anode in the plating solution should use nickel plate as much as possible, and nickel-plated iron plate can also be used.During the production process, it should be taken out and inspected frequently to avoid anode passivation and damage to the nickel-plated layer of the nickel-plated iron plate.

    6. When the concentration of sodium carbonate in the plating solution exceeds 50g/L, the viscosity of the plating solution will increase, resulting in an increase in the tank voltage and graying in the low area of the plating layer.It is recommended to remove sodium carbonate by freezing method within half a year or one year of production.

    7. The plating solution needs to be continuously filtered, the filter flow rate is at least 4 times that of the plating solution, and the filter element precision is 20μm.

    8. The workpiece should be picked up in time to avoid dissolving too much impurities.When there are too many metal impurities (such as copper, lead, iron) in the plating solution, it is easy to cause failures such as graying, darkening, and blooming in the low area of the coating.The effect of the zinc powder replacement method for the plating solution is not as obvious as that of the alkaline zincate. It is recommended to use the small current electrolysis method for better treatment.

    In this way, we maintain the stability of the plating solution when using alkaline zinc-nickel alloy additives, which can greatly improve the corrosion resistance of the coating, thereby effectively reducing production costs.If you are interested in alkaline zinc nickel alloy additives,please contact Bigolly customer service to get free samples and detailed technical information!

    If you want to know more about nickel plating, you can check "Electroplating encyclopedia".