Electroplated colored zinc passivation process is vital in the corrosion protection of steel and metal products. The passivation process is mainly divided into two types: trivalent chromium passivation and hexavalent chromium passivation, and each of these two technologies has its own advantages and disadvantages. In this article, a detailed comparison of trivalent chromium and hexavalent chromium passivation will be made in terms of the performance of the passivated film layer, the production cost and the environmental protection cost, in order to help plating factories to choose the suitable passivation process.
Properties of passivation coatings
1. Hexavalent chromium passivation:
Excellent corrosion resistance: Hexavalent chromium colored zinc passivation film has excellent corrosion resistance and provides long lasting protection.
Good decorative properties: passivated film has a bright surface and uniform color, suitable for decorative purposes.
Layer thickness: usually thicker to provide better protection.
2. Trivalent chromium passivation:
Good corrosion resistance: The corrosion resistance of trivalent chromium passivate films can exceed the level of hexavalent chromium through the use of Bigely galvanized colored passivation solution Zn-237.
Environmental performance: trivalent chromium passivator is more in line with environmental requirements.
Film uniformity: Trivalent chromium passivation film is more uniform, suitable for occasions with higher requirements for film uniformity.
Environmental costs
1. Hexavalent chromium passivation:
High environmental risk: Hexavalent chromium is a known carcinogen with high environmental risk and difficulty in handling.
Difficulty in waste liquid treatment: The waste liquid generated during the hexavalent chromium passivation process requires special treatment and high treatment costs.
2. Trivalent chromium passivation:
Conforms to green trends: Trivalent Chromium passivation is more sustainable as environmental regulations become stricter and stricter.
Summarize and compare
Trivalent chromium passivation and hexavalent chromium passivation have their own advantages and disadvantages:
1. Performance of passivated layers: Trivalent chromium zinc passivation can exceed the corrosion resistance of hexavalent chromium passivated layers by optimizing the process and has better uniformity.
2. Environmental protection cost: trivalent chromium passivation has obvious advantages in environmental protection, in line with the trend of green environmental protection, while hexavalent chromium passivation has higher environmental protection risk and processing difficulty.
When selecting a passivation process, the electroplating plant should consider the performance of the passivated film, production costs and environmental costs. Hexavalent chromium passivation is suitable for the pursuit of a simple process and does not require high environmental protection; while trivalent chromium passivation is more suitable for environmental protection, compliance with regulations and high film uniformity requirements. In the future, as environmental requirements become more stringent, Bigely galvanized colored passivates will become a more promising choice.
If you are interested in galvanized colored passivation solution, please feel free to contact us.
