In the application process of zincate galvanizing additives, there is a procedure called brightening after galvanizing. What is the purpose of brightening?
1. Surface cleaning effect. The alkaline solution adhering to the surface of the workpiece after zincate galvanizing cannot be simply washed off. The residual alkali brought into the passivation solution will cause the pH of the low-chromium passivation process bath solution, which has strict requirements for pH conditions, to rise rapidly, and the pH adjustment of the passivation solution is frequent. If not adjusted in time, the passivation effect will deteriorate and the passivation quality will fluctuate greatly. Therefore, light extraction is an indispensable process.
2. Chemical polishing effect. Brightening is a chemical polishing process for galvanized coatings, which can significantly enhance the brightness of the galvanized coating. Usually, a nitric acid solution of more than 30ml/L can achieve the chemical polishing effect on the galvanized layer.
3. Inspect the severity of impurities in the coating. If the iron content in the coating is high, the coating in the high and medium current density areas will be grayish black. When the lead content in the coating is high, the brightness of the coating after exposure is actually worse than before exposure. When the amount of organic matter mixed in is heavy, the coating in the high current density area turns yellow after luminescence. When this situation occurs, passivation should no longer be carried out, and the effect after passivation will inevitably be very poor. Instead, the plating solution should be decontaminized before production.
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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 Technology is a national high-tech enterprise with a strong research and development team, which has over 10 engineers with more than 20 years' working experience in the electroplating industry.
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