When we use galvanized trivalent chromium passivator, due to improper operation and management, the use of passivation solution is often unstable, which affects the passivation effect of the workpiece.This also shortens the service life of the passivation solution, thereby increasing the production cost.So what points should we pay attention to when using galvanized trivalent chromium passivator?
Bigolly Technology made an analysis based on the field experience and the characteristics of the product galvanized trivalent chromium passivator BZ-208,there are 5 main points:
1. Select the appropriate passivation solution and ensure the mass concentration of the passivation solution.Bigolly's BZ-208 trivalent chromium passivation agent, which is suitable for different galvanizing processes, can produce red-green color passivation in the galvanized layer, and its corrosion resistance is completely comparable to traditional hexavalent chromium passivation.During the production process, the concentration of the passivation solution will gradually decrease. When replenishing the passivation solution, try to ensure that the concentration fluctuation is not too large. For example, the concentration of BZ-208 should be controlled at 8~10%.
2. Control of pH value of passivation solution.The pH value not only affects the dissolution rate of zinc and the re-dissolution rate of the passivation film, but also affects the residence time of the workpiece in the passivation solution.In order to obtain a stable and high-quality passivation film, it is necessary to keep the pH value of the passivation solution relatively stable, otherwise it is easy to cause uneven thickness of the passivation film.For example, the pH value of this BZ-208 should be controlled at 2.0~2.5.
3. Temperature control of passivation solution.The temperature control is closely related to the formation rate of the passivation film. Under the same passivation time and pH value, the higher the temperature of the passivation solution, the more uniform the passivation film and the better corrosion resistance.Generally, the temperature of the passivation solution is controlled at 20~30℃.
4. The passivation time of the passivation solution.The length of the passivation time of the workpiece is different, and the thickness of the passivation film produced is also different.If the passivation film is too thick, it is easy to cause the passivation film to be loose and the bonding force to be weak.The passivation time of this Zn-228 is 45~120 seconds.
5. Control of impurity concentration in passivation solution.The tolerance of galvanized trivalent chromium passivator to impurities is relatively poor.When the impurity concentration in the passivation solution exceeds the allowable value, the passivation film will appear fogging, yellowing and other phenomena, and will significantly reduce the corrosion resistance of the workpiece.Generally, the allowable values of impurities in passivation solution are: zinc ion 10g/L, iron ion 100mg/L, copper ion 5mg/L, lead ion 5mg/L.
Therefore, it is critical to pay attention to these operating points when we use galvanized trivalent chromium passivators.It ensures the stability of the passivation solution, reduces the occurrence of failures, improves production efficiency, and saves maintenance costs.If you are interested in galvanized trivalent chromium passivator,please contact Bigolly customer service, you can get free samples and detailed technical information!
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