A customer has reported that during the production process using chemical nickel plating additives, the porosity of the workpiece coating is large and the corrosion resistance is poor. What is the reason for this phenomenon?
Based on on-site experience and analysis of the characteristics of Ni-809, a chemical nickel plating additive, Bigley Technology found that the porosity of chemical nickel coatings is generally related to these three factors:
1. The roughness of the workpiece surface. The smoother and smoother the surface of the workpiece, the smaller the porosity of the coating. After sandblasting treatment, the surface of the workpiece usually requires a coating thickness greater than 30 microns before pores appear. A coating with the same thickness, such as being applied twice, can also reduce the porosity. For example, the chemical nickel coating on a certain workpiece is 10 microns, with a porosity of 4-5 points/square centimeter. However, after being applied twice, the porosity of the coating decreases to 2.0-2.5 points/square centimeter.
2. The system of plating solution. Generally, coatings obtained using alkaline chemical nickel plating solution have a larger porosity than acidic plating solution, and coatings obtained using hydrazine as a reducing agent are higher than those obtained using sodium hypophosphite. In addition, the influence of additives on the porosity of coatings with fast deposition speed is also significant, and impurities and suspended solids in the plating solution also increase the porosity.
3. Post processing of workpieces. Heat treatment of general workpieces can reduce the porosity of the coating. For materials such as steel and aluminum, chemical nickel plating is a cathodic coating. If there are many pores on the surface of the coating, it will form a corrosion battery with a large cathode and a small anode, accelerating the corrosion of the coating. At this time, heat treatment of the workpiece can reduce the porosity of the coating.
Therefore, we need to pay attention to the above three points in the production process of using chemical nickel plating additives to avoid the phenomenon of large pores in the chemical nickel coating of the workpiece and reduce the occurrence of faults. If you are interested in chemical nickel plating additives, please contact Bigley customer service to obtain free samples and detailed technical information!
If you want to learn more about chemical nickel, you can check out "Industry news".