Passivation with hexavalent chromium is used in electrical and electronic equipment, particularly for coating of electro-galvanised steel and aluminium. The treatment generates a very thin surface consisting of chromium salts that make the metal part especially corrosion-resistant. The corrosion resistance of a large number of metals, including zinc, aluminium, cadmium, copper and stainless steel, can be strengthened by treatment with chromate-based solutions. Passivation (also called chromating) with hexavalent chromium is used to protect metal surfaces against corrosion. Pigments in plastic parts and paint/enamel ģ.2 Use of hexavalent chromium for anticorrosive coatings.Traditionally, the most common applications of hexavalent chromium in electrical and electronic equipment have been: Hexavalent chromium will not be present in electrical and electronic products as a natural contamination element, so it is only necessary to check for hexavalent chromium where it can be deliberately used in the products. ![]() When sampling, it should therefore be noted that a chemical reaction by which the hexavalent chromium is changed to the trivalent form is not allowed. iron(II)), thereby reducing the chromium to a lower oxidation state. Hexavalent chromium released from a product will relatively quickly react with other substances (e.g. Normally, hexavalent chromium is not present in nature, and salts with hexavalent chromium are almost always man-made. ![]() This is why the RoHS Directive only comprises hexavalent chromium. Hexavalent chromium is highly oxidising and the form that is most hazardous to the environment and to health. ![]() Correspondingly, the two other forms are called trivalent chromium, Cr(III), and divalent chromium, Cr(II), while metallic chromium in oxidation state 0 is often called Cr(0). It is also called chromium(VI) or Cr(VI). Chromium in oxidation state 6 is also called hexavalent chromium, because of the atom's ability to bond with six other atoms. The two most common oxidation states for chromium ions are 3 and 6, but occasionally, chromium ions may also be present in oxidation state 2. Chromium ions may occur in three different forms known as oxidation states, which determine how the chromium ions react with other substances.
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