Some customers are asking, when using alkaline zinc-nickel alloy additives, in order to ensure the stability of nickel content in the coating, how to control the current density better?
In fact, the alkaline zinc-nickel alloy process is similar to the alkaline zincate process, and as the current density increases, the current efficiency drops sharply.No matter how the ratio between zinc ions and nickel ions in the bath changes, they all have the following rules:As the current density increases, the nickel content in the coating increases initially and stabilizes at around 13% soon after.
Bigolly Technology made an analysis based on the field experience and the characteristics of the alkaline zinc-nickel alloy additive BZ-617. Pay attention to these two points to better control the cathode current density:
1. Control the ratio of zinc ion to nickel ion.At the same current density, the smaller the ratio of zinc ions to nickel ions, the higher the nickel content in the coating and the higher the current efficiency.A good coating appearance can be obtained at the current density of 1~5A/dm2, and the change of the current density has little effect on the nickel content of the coating.
2. The control of the operating conditions of the plating solution.The size of the cathode current density is closely related to the concentration and temperature of the plating solution. Properly increasing the concentration and temperature of the plating solution can appropriately increase the cathode current density.When the temperature is low, the conductivity of the plating solution is poor, the adsorption of additives is strong, and the desorption is difficult.
The general control principle of cathode current density is that it can be properly opened under the allowable current density.The current density is small, the coating is brittle, and it is easy to foam and produce yin and yang surfaces;If the current density is too large, the crystallization of the coating is rough, and the high area is easy to be scorched.
In this way, we can control the current density of the cathode when using alkaline zinc-nickel alloy additives, which can effectively reduce the occurrence of failures.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 zinc-nickel alloys, you can click to view "Common problem".