When we use the zinc plating color passivator, the passivation film of the workpiece will appear black spots. Is this due to the influence of metal impurities?
According to the analysis of field experience and product characteristics, Bigolly Technology found that the "black spots" on these colored zinc passivation films are not black, but dark green.This is caused by alkaline hydroxide in the passivation solution, not by metal impurities.
The operating range of some zinc plating color passivators on the market is low due to their immature formulations.In the production process, if the pH value of the passivation solution is too high, the passivation time is too long or the air stop time after passivation is too long, "black spots" will appear on the passivation film of the workpiece.The pH value, passivation time and air stop time of such passivator need to be well controlled during use. If the operation is improper, the failure rate is also high.
The trivalent chromium color passivator BZ-208 for zinc plating, which is mainly developed by Bigolly Technology, is made of imported raw materials and has good chemical stability.It has a wide operating range, with a pH value of 1.6~3.5 and a passivation time of 30~90 seconds. It can obtain a pleasing color appearance, and the passivation solution is easy to maintain and manage.In addition, it has strong corrosion resistance, and the coating thickness is ≥ 8 μm, the neutral salt spray test can last more than 120 hours.
Therefore, if the workpiece passivation film is prone to black spots when we use the zinc plating color passivation agent for production, it is recommended to use this zinc plating color passivator BZ-208.It has good stability, wide operation range, easy operation and maintenance, and no black spots.If you are interested in the zinc plating color passivator, please contact the Bigolly customer service for free samples and detailed technical information!
If you want to know more about zinc plating,you can click to view "Common problem".