When aluminum workpieces are produced using medium-phosphorus electroless nickel plating solution, sometimes the coating appears mottled. Although it does not affect the bonding force and corrosion resistance of the workpiece, it seriously affects the appearance of the workpiece.So, how does the coating of the workpiece appear mottled?
Bigolly Technology made an analysis based on the field experience and the characteristics of the product's medium-phosphorus electroless nickel plating solution Ni-809,there are 4 main reasons:
1. The pretreatment of the workpiece is not clean or the washing is not clean.Before the electroless nickel plating of the workpiece, if there is oil or other dirt on the surface, the deposited electroless nickel layer will have mottled phenomenon.At this time, the pretreatment process should be strengthened or the cleaning water should be replaced.
2. The electroless nickel coating is too thin.Very thin electroless nickel layer and zinc immersion layer will form the phenomenon of mottled,At this time, the thickness of the chemical nickel layer should be thickened.
3. The surface of aluminum workpiece is oxidized before electroless nickel plating.Try to shorten the time that the workpiece stays in the washing tank, and electroless nickel should be carried out as soon as possible after the workpiece sinks zinc.
4. The plating solution is contaminated by organic impurities.The plating solution should be treated with activated carbon and filtered to remove impurities.
Therefore, in the production process of using medium-phosphorus electroless nickel plating solution, we need to pay attention to the above four points, which can avoid the phenomenon of mottled on the surface of the workpiece, reduce the failure rate and improve the production efficiency.If you are interested in medium-phosphorus electroless nickel plating solution,please contact Bigolly customer service to get free samples and detailed technical information!
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