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Yellow Zinc ¿What is?

bichromated screw

Yellow zinc is a surface treatment for irons or steels, which prevents corrosion. Following European Union regulations, Chrome 6 was banned, and now only trivalent zinc, Cr3 + can be used. In appearance they are practically the same.

Why was it banned in the European Union?

In Europe there is a chemical agency called ECHA, which decided to include hexavalent chromium or Cr6, in the list of carcinogenic, mutagenic and reprotoxic products, since they used to include lead, mercury or cadmium. This caused the elimination of use in the market since September 21, 2017, replacing it with trivalent Zinc plating or Cr3 +.

According to a study by the National Technological University of Buenos Aires, Argentina. Cr6 damages the intestine from very low concentrations, between 25 and 100 ppm (parts per million). While Cr3 does no damage.

I leave you the link to the study published by the university. Read more.

Differences between Cr6 and Cr3 +

When evaluating the hours that one finish or another can withstand corrosion, we hardly find any differences. Trivalent zinc plating reaches around 360 hours without damage with sea water.

If it is not enough, perhaps it is better to consider other materials such as stainless steel or aluminum with hard anodizing, since they are better for areas near the sea.

So when you talk about it, you already know that its correct name is trivalent zinc plating. Will you look like a professional!

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