In the production process of using high-phosphorus electroless nickel plating solution, sometimes the plating solution will be poisoned.That is, the amount of hydrogen evolution on the workpiece is less than that under normal conditions, the deposition rate is very slow, and some workpieces stop deposition after entering the plating solution for a few minutes.How can the plating solution be poisoned?
Bigolly Technology made an analysis based on the field experience and the characteristics of the product's high-phosphorus electroless nickel plating solution Ni-811,It is mainly caused by the excess of stabilizers and certain metal ions.
We all know that the general stabilizer is to form particles between phosphorous acid and nickel cores through coordination, thereby inhibiting the self-decomposition of the plating solution.When the stabilizer is excessive, the plating solution loses its catalytic activity and the deposition rate of the plating layer is slowed down.
In addition, some stabilizers rely on metal cations to lose their catalytic activity by preferentially adsorbing on the tiny nickel core particles or the surface of the colloidal particles that have catalytic activity in the plating solution.Therefore, the metal ion concentration of this type of stabilizer should not be high, such as Pb2+<3mg/L, Cd2+<10mg/L, Sb2+ and Sn2+ should also be less than 100mg/L, otherwise it is easy to make the entire plating solution fail.
When the stabilizer in the electroless nickel plating solution is slightly excessive, the parts can be used as the cathode, the stainless steel plate can be used as the anode, and the production can be resumed by electrolysis at a current density of 0.6~1.0A/dm2 for 15 minutes.When the content of stabilizer in the plating solution is too much, only part of the plating solution can be discarded, and then an appropriate amount of high-phosphorus electroless nickel plating solution can be added after adding water.
Therefore, we should strictly control the content of stabilizers and certain metal ions in the plating solution when using high-phosphorus electroless nickel plating solution to avoid the poisoning of the plating solution and reduce the increase in production costs due to failures.If you are interested in high-phosphorus electroless nickel plating solution,please contact Bigolly customer service, you can get free samples and detailed technical information!
If you want to know more about electroless nickel plating, you can check "common problem".