What precautions should we pay attention to during the passivation process of different workpieces when using trivalent chromium colored zinc passivation agent?
Based on on-site experience and the characteristics of the trivalent chromium colored zinc passivation agent BZ-208, Bigley Technology has analyzed the following 5 points to pay attention to when passivating different workpieces:
1. Passivation of long string components: The time for the upper and lower ends of the workpiece to enter and exit the passivation solution is sequential, and the swing amplitude of the lower end of the workpiece is greater than that of the upper end; When the workpiece is passivated and stays in the air, the passivation liquid on the workpiece will flow from top to bottom, allowing more reaction time between the lower end of the workpiece and the passivation liquid, making the color of the passivation film on the lower end darker than that on the upper end. In order to reduce the color of the upper and lower ends of the workpiece, the workpiece can be horizontally grooved, compressed air can be blown into the workpiece from top to bottom after grooving, and cleaning water can be sprayed from top to bottom.
2. Passivation of flat workpieces: Generally, when passivating flat workpieces, the oscillation at the edges is more severe than in the middle, and the color of the passivation film is also darker or uneven. This problem can be solved by using compressed air stirring, and the effect is relatively good. In addition, attention should be paid to the uniformity of current distribution during the galvanizing process to prevent rough coating at the edges due to excessive current, which affects the color and uniformity of the passivation film.
3. Passivation of surface smooth parts: For workpieces with a relatively smooth surface, after color zinc passivation, due to the smoothness of the surface, the passivation film is difficult to adsorb on the surface of the workpiece and is easy to fall off. Therefore, the time for such workpieces to remain in passivation and in air should be appropriately extended, otherwise the color of the passivation film of the workpieces will be lighter.
4. Workpieces that are prone to splashing: These types of workpieces are prone to splashing out passivation solution during passivation, so excessive loss of passivation solution and environmental pollution should be avoided during production, and the quality of the passivation film can also be guaranteed.
5. Small workpiece: This type of workpiece can be passivated by tying the entire string of workpieces and placing them in a plastic basket frame to avoid rework or scrapping caused by the workpiece falling into the groove bottom due to shaking during passivation.
So, in the production process of using trivalent chromium color zinc passivation agent, we need to pay attention to the above 5 points during passivation according to different workpieces, effectively improving the yield of workpiece passivation. If you are interested in trivalent chromium zinc passivation agent, please contact Bigley customer service to obtain free samples and detailed technical information!
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