After we use the trivalent chromium color zinc passivator normally, the galvanized workpiece can obtain a uniform and bright color film layer.But sometimes the color of the hole position after color passivation of the galvanized workpiece will be darker, showing a yellow-green color.Is this the improper operation of trivalent chromium color zinc passivator?
Bigolly Technology made an analysis based on the field experience and the characteristics of the product's trivalent chromium color zinc passivator BZ-208,In fact, the main points of operation of the color zinc passivation agent in the production process mainly include the concentration, temperature, pH value and passivation time of the passivation solution.Once these details are not well controlled, there may be a phenomenon that the color of the hole is darker after the workpiece is passivated. The specific reasons are as follows:
1. The concentration of passivation solution.The concentration of the passivation solution is higher, that is, the concentration of trivalent chromium ions is higher, the film formation speed of the galvanized layer is faster when the workpiece is passivated, and the color of the hole or edge position will be darker.Therefore, when using the color zinc passivator, the concentration of trivalent chromium ions should be well controlled, and when the concentration is higher, it should be diluted proportionally.
2. The temperature of the passivation solution.The temperature of the passivation solution is high, the film forming speed is relatively fast, and the color of the passivation film is relatively dark.Therefore, we should control the temperature of the passivation solution within the process range during the production process.
3. The pH value of the passivation solution.The temperature of the passivation solution is low, the coloring speed is fast, and the color of the passivation film will be darker.Therefore, we should control the pH value of the passivation solution at 1.8~2.0 during production, and try to ensure that the pH value does not fluctuate greatly.
4. The passivation time of the workpiece is longer.If the workpiece is passivated for a long time, more zinc coating will be dissolved, and the color of the passivation film will be darker.Therefore, we should control the passivation time of the workpiece during production,If there is a workpiece in the passivation tank during shutdown, it should be taken out in time to avoid dissolving more zinc or iron, which will affect the passivation quality of the subsequent workpiece and the service life of the passivation solution.
5. The pumping situation of the passivation solution.In the production process, if the pumping method of the passivation liquid is not appropriate (too large or too small), the passivation liquid will be uneven, and the color of the workpiece will be uneven after passivation, and the local color will be darker or lighter.Therefore, we should check the aeration system of the passivation solution during production to ensure that the passivation solution is evenly pumped.
Therefore, when we use trivalent chrome color zinc passivator, we should combine the operating instructions,And control the concentration, temperature, pH value and passivation time of the passivation solution to ensure that the passivation film after passivation of the workpiece is uniform and bright, and avoid the color of the hole being too dark.If you are interested in trivalent chrome color zinc passivator,please contact Bigolly customer service to get free samples and detailed technical information!
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