When aluminum alloy workpieces are produced with electroless nickel plating solution, the plating solution is easy to be unstable. If the control is not good, the plating solution will be scrapped in advance.So how can we improve the stability of the plating solution?
Bigolly Technology made an analysis based on the field experience and the characteristics of the product's Ni-809,share these 3 methods to improve the stability of the plating solution:
1. The plating solution should be maintained in strict accordance with the process conditions.When working, the temperature of the plating solution should be uniform, and it should not exceed the upper limit of the process range, and it should not be left unloaded for a long time;The pH of the plating solution will increase during the production process and should be controlled within the process range;The plating solution should be regularly analyzed and supplemented with electroless nickel plating solution to ensure that the nickel salt and hypophosphite are within the process range;The loading amount of the plating solution should be controlled at 0.5-1.2dm2/L,Exceeding the process range will affect the quality of the plating layer and cause the plating solution to decompose;To ensure the cleaning quality of the workpiece in the pretreatment, it is not allowed to bring acid, alkali or other heavy metal impurities into the electroless nickel plating tank;When stopping production, it should be covered in time, and if there is sediment in the plating solution or it falls into the workpiece, it should be cleaned up immediately.
2. The plating solution needs to add stabilizer in time.Stabilizers can inhibit the self-decomposition of the plating solution, and generally include 4 types of heavy metal ions, oxo acid salts, sulfur-containing compounds and organic acid derivatives.There are many applications of divalent lead compounds, which can improve the stability of the plating solution. Generally, adding 0.1mg/L can play a role.
3 . Control the concentration of phosphite in the plating solution.Phosphite radicals will be generated in the process of electroless nickel deposition, and as the reaction progresses, phosphite radicals will continue to accumulate and increase.In the production process, three methods can be used: renewing the plating solution, increasing the pH of the plating solution, and chemical precipitation to remove excess phosphite from the plating solution.
Therefore, when aluminum alloy workpieces are produced using electroless nickel plating solution, these three methods can effectively improve the stability of the plating solution and reduce the occurrence of failures.