H
Hexavalent Chromium (Cr⁶⁺)
Definition
Hexavalent chromium (Cr⁶⁺, chromium(VI)) is one of the ten restricted hazardous substances under RoHS Directive 2011/65/EU, restricted at a maximum concentration value of 0.1% (1000 ppm) by weight per homogeneous material. Hexavalent chromium is used in decorative and functional electroplating (e.g., hard chrome plating, chromate conversion coatings on aluminium and zinc), corrosion inhibitors in cooling systems, and pigments. In EEE, it is most commonly found in surface finishes and protective coatings on metal components.
Source
Directive 2011/65/EU, Annex II, Article 4(1).
Practical Explanation (Compliance Context)
Manufacturers must screen all metal components for hexavalent chromium surface treatments or coatings. Hexavalent chromium plating and chromate conversion coatings (yellow or clear passivates containing Cr⁶⁺) are common non-conformances in EEE supply chains. IEC 62321-7-2:2017 provides the test method for hexavalent chromium in solid and liquid materials. Trivalent chromium (Cr³⁺) plating is the compliant alternative and is not restricted. Supplier declarations must explicitly confirm chromate treatment type (trivalent vs. hexavalent).