When using the trivalent chromium colorful zinc passivation solution, how will the pH value and temperature affect the quality of the film layer?
pH value
The pH value of the trivalent chromium colored passivation solution is an important parameter. If the electroplating factory wants to measure the pH value accurately, it can use precise pH test strips ranging from 0.5 to 5.0.
We found that the film-forming conditions of pH value are similar to those of the low-chromium hexavalent chromium colored passivation solution. When the pH value is between 1.8 and 2.5, the conditions for forming a film layer in the passivation solution are met.
As a manufacturer of trivalent chromium chromate zinc passivation solution, Bigely has discovered these two rules during its long-term research and production process:
① When the pH value is lower than 1.8: The film layer is difficult to form, a thick passivation film cannot be formed, the corrosion resistance is poor, and the passivation color is pale.
② When the pH value is higher than 2.5: The adhesion strength of the passivation film decreases, the film layer becomes loose, and the surface glossiness deteriorates.
Temperature
The self-catalytic property of the trivalent chromium colored passivation solution is relatively weak. Therefore, most of the solutions need to be heated to accelerate the reaction. At normal temperature, although a film can be formed, the film layer is thin and has poor salt spray resistance.
The higher the solution temperature, the thicker the film layer and the better the salt spray resistance. However, if the temperature is too high, the passivation film is prone to fogging. Therefore, if you want to form an ideal passivation film layer with high quality, when using the trivalent chromium colored zinc passivation solution from Bigely, the electroplating plant should control the temperature within the range of 20-30℃. In this way, the color of the film will be consistent with that of the hexavalent chromium passivation.
About us
Guangdong Bigely Technology Co., Ltd. ,founded in 2003, is a high-tech enterprise integrating R & D，production, sales and service, specializing in the production of electroplating additives. As a famous electroplating additives source manufacturer in China, Bigely has over 20 years' experience in electroplating additives production and own production base of 5000 square meters. We can produce 15,000 tons of electroplating additives every year, which can fully meet the needs of customers.
If you need our high-quality electroplating additives, please contact us. We can provide you samples for test, and also provide a series of services.
