When using the trivalent chromium blue-white passivation solution, if we want to obtain a high-quality film layer, we need to control the pH value, temperature and passivation time properly. Why is this so? In this article, we will analyze it.
The pH value of the trivalent chromium passivation solution is an important indicator. To obtain a high-quality passivation film, it is necessary to control the pH value properly. If too much dilute nitric acid is introduced, it can be adjusted by adding 10% (by mass) sodium hydroxide or sodium carbonate solution.
The temperature of the trivalent chromium blue-white passivation solution is closely related to the thickness and corrosion resistance of the passivation film. Generally speaking, when the temperature is higher, the passivation film layer is thicker and the corrosion resistance is better. However, increasing the temperature consumes electricity and is not very convenient to operate. Workers always hope to operate at room temperature. If operating at room temperature meets the requirements, it is of course better. But for those with high corrosion resistance requirements, it is necessary to increase the temperature of the passivation solution.
The passivation time is also related to the thickness of the film layer. According to the blue-white passivation solution manual provided by Bigley, the passivation time is between 20 and 45 seconds. It is slightly longer than the film formation time of low-chromium hexavalent chromium blue-white passivation. This is because the parts need a certain period of time to stay in the air, which is beneficial for film formation. If the passivation time is too short, it may result in the passivated products appearing very blue, but turning yellow after baking.
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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 chemicals. As a fast growing electroplating chemicals supplier 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.
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