Cr3+, A more environmentally friendly galvanizing process

Views : 1559
Author : Francis Ou
Update time : 2020-09-15 19:45:46

Cr3+, A more environmentally friendly galvanizing process

In galvanizing, one of the processes is chromating. For many years the chromating process has been done by hexavalent chromium.

Pic 1. Color Zinc Plated, White Zinc Plated, Cr3+ Blue Zinc Plated, Blue Zinc Plated

Hexavalent chromium is a highly toxic substance, which causes irreversible damage to human body. Meanwhile, the flow of hexavalent chromium from liquid into soil will also cause heavy metal pollution in soil, which is harmful to the environment. In 2010, Guangdong province took control of enterprises with hexavalent chromium and its compounds in the production environment, including enterprises with the concentration of hexavalent chromium and its compounds ≥50%OEL in the workplace as the strict management level (Class A employers) to ensure the physical safety of workers.
 

Because of the harm of hexavalent chromium, Chinese electroplating enterprises have been looking for alternative solutions. Trivalent chromium has been experimented with as an alternative since 2016.In the past, trivalent chromating was easy to be corroded once the surface was scratched due to the immature process. The latest generation of trivalent chromating technology is to add the sealing agent directly into the chromating solution, which greatly improves the corrosion resistance of the film layer, and can reach or even exceed the corrosion resistance of the traditional hexavent chromating process.



Pic 2. Comparison of Cr3+ Blue Zinc Plated(left), Blue Zinc Plated(right)

According to our recent internal test results, the corrosion resistance test time of our trivalent chromium-blue zinc is longer than the corrosion resistance test time of the hexvalent chromium-blue zinc.

 

Despite the added cost, Vansko‘s existing metal machining surfaces are treated with trivalent chromium galvanization, as a support for environmental protection and labor safety.


Pic 3. Salt spray test machine

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