In the production process of using electroless nickel plating solution, we sometimes find that the plating tank is easy to deposit nickel metal. What is going on?
Bigolly Technology made an analysis based on the field experience and the characteristics of the product's electroless nickel plating solution Ni-809,There are 4 main reasons:
1. Some solid particles are produced in the plating solution.The plating solution needs to be poured into the spare tank, then washed with 30% HNO3 at 40 °C (can not be cold washed), soaked in the plating tank for 5 hours, and then washed with nitric acid with water.Then use clean cotton yarn to scrub the attachments on the plating tank, and then rinse with clean water.
2. The anti-plating effect of the plating tank is not good.In order to prevent the deposition of the coating on the plating tank, the corresponding anti-plating method should be adopted.When the reference potential of the stainless steel plating tank relative to the workpiece to be plated is maintained at +350~550 mv in the plating solution at 75~85℃, the plating tank has good passivation performance.The anode current density at this time is 20~90 mA/m2.When mechanical impurities enter the plating tank or a coating is produced on the plating tank, the passive current will rise, but will soon drop to the normal level.In this way, the anti-plating effect is good, and the plating speed can be increased by 10% to 20%, and it has no obvious effect on the quality of the coating.
3. The ratio of heating tube power to its surface area is improper.The heating tube of the same power should be made as long as possible, the tube should be thicker, and the ratio of the power of the heating tube to its surface area should be reduced.
4. The plating equipment and hangers are not cleaned enough with nitric acid.Soak the plating tank, heating tube, hanger, roller, etc. with nitric acid before opening the cylinder each time, even if no chemical nickel coating is found.
Therefore, we need to pay attention to these 5 points in the production process of using electroless nickel plating solution, which can effectively solve the trouble of easily depositing nickel metal in the plating tank, prolong the service life of the plating solution, and reduce the production cost.