In the production process of using acid zinc plating brightener, what is the reason for the blistering phenomenon of poor adhesion of the galvanized layer of the workpiece?
Bigolly Technology made an analysis based on the field experience and the characteristics of the product's acid zinc plating brightener BZ-525,There are 7 main reasons:
1. The oil stain on the surface of the workpiece is not removed cleanly.Generally, it is chemically degreasing and electrolytic degreasing, and the oil stains are not removed cleanly.If the operation is improper or the composition of the degreasing liquid is out of balance, the galvanized layer may be blistered due to residual oil on the surface of the workpiece.
2. The pickling time is too long.When the workpiece is soaked for too long in the process of pickling and rust removal, the workpiece will cause blistering of the galvanized layer due to excessive corrosion.
3. Improper selection of hangers.The hanger is to weld the hook and the rod together with solder or copper, and then carry out plastic dip and varnish wrapping.If the bandage is damaged or the weld is easily corroded by the electrolyte, the corrosion products will adhere to the surface of the workpiece, and the workpiece will produce band-shaped dense bubbles from top to bottom, which will cause blistering of the galvanized layer.
4. Improper operation or maintenance of the plating solution.When the content of acid zinc plating brightener in the plating solution is too high, it is easy to be mixed in the galvanized layer, causing the internal stress to increase sharply and causing the galvanized layer to foam.
5. The content of metal impurities is too high.When the content of copper, lead and other metal impurities in the plating solution is too high, too much copper, lead and other impurities will be mixed in the galvanized layer, resulting in poor adhesion between the plating layer and the substrate and foaming.
6. Improper control of operating conditions.Improper operating conditions in the production process, such as too low temperature and too high current density, will also lead to the inclusion of organic impurities in the galvanized layer and cause foaming.
7. The influence of the passivation process after plating.After the workpiece is galvanized, the light-emitting and passivation operations are improper, and the cleaning is not thorough, and the light-emitting liquid or passivation liquid will remain in the coating, which will easily cause blistering of the galvanized layer after baking and aging.
Therefore, we need to pay attention to these 7 points in the production process of using acid zinc plating brightener, which can avoid the phenomenon of poor adhesion and blistering of the galvanized layer of the workpiece and reduce the occurrence of failures.