In the decorative electroplating process of zinc alloy die-casting machines, the most crucial step is pre-copper plating. Why? Because it plays a bridging role, the pre-treated workpieces, after being pre-plated with copper, can provide good coating adhesion for subsequent processes such as electroplating acid copper. However, if not handled properly, it often leads to coating failure. In this issue's article, we will analyze how to do it well and how alkaline copper plating additives affect the quality of the coating.
Generally speaking, the pre-copper plating process takes eight to ten minutes for electroplating, and the coating thickness is at least three to four microns. If the plating is done for too long, the coating may become rough. If acid copper is plated later, the roughness of the coating will be even more obvious.
The concentration of free sodium cyanide in the plating solution is recommended to be between high and low concentrations. A slightly higher concentration of free sodium cyanide is beneficial for preventing the coating from bubbling and becoming rough.
When the workpiece is first placed in the bath, a higher current density should be adopted. After one to three minutes of plating, the current density should be restored to the normal level. This helps to enhance the adhesion of the coating.
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Guangdong Bigely Technology Co., Ltd. ,founded in 2003, is a high-tech enterprise integrating R & D，production, sales and service, specializing in the production of electroplating chemicals. As a fast growing electroplating chemicals supplier in China, Bigely has over 20 years' experience in electroplating additives production and own production base of 5000 square meters. We can produce 15,000 tons of electroplating additives every year, which can fully meet the needs of customers.
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