Often there will be the problem of blackening of the electroplated gold layer, which will affect the quality and performance of the circuit board. So, what are the reasons for the blackening of the electroplated gold layer of the PCB copy board?
1. Thickness control of electroplating nickel layer
PCB electroplating gold layer is generally very thin, which is reflected on the electroplating gold surface, and many of them are caused by poor performance of electroplating nickel. Generally, the thinner electroplating nickel layer will cause the appearance of the product to be whitish and black. Generally, the thickness of the nickel layer needs to be electroplated to about 5UM to be sufficient.
2. The status of the electroplating nickel cylinder potion
If the nickel tank potion is not well maintained for a long time, and the carbon treatment is not carried out in time, then the plated nickel layer will easily produce flaky crystals, and the hardness and brittleness of the coating will increase. Severe black coating problems will occur. Therefore, it is necessary to carefully check the potion status of the production line of the circuit board factory, conduct comparative analysis, and conduct thorough carbon treatment in time to restore the potion activity and clean the plating solution.
3. Golden cylinder control
As long as the potion is well filtered and replenished, the pollution degree and stability of the gold tank will be better than that of the nickel tank. However, it is necessary to pay attention to check whether the gold tank supplements are sufficient and excessive, how the PH value of the potion is controlled, and how the conductive salt is. If there is no problem in the inspection, use the AA machine to analyze the impurity content in the solution. Margin vat potion status. Finally, check whether the gold cylinder filter cotton core has not been replaced for a long time.
