Electrochemical Reduction of Chromium VI Oxide

3 Electrochemical Reduction of Chromium(VI) Oxide ( Chromic acid ) 

The electrochemical deposition of chromium upon metals is usually carried out in chromium(VI) oxide-containing baths to which ca. 1% sulfuric acid has been added. The material to be coated is used as the cathode, the anode usually being lead. A diaphragm is not necessary. The baths contain ca. 300 g/L of chromium) VI) oxide, in addition to a number of other components. The yield on the basis of electricity consumed is very poor, due to hydrogen being preferentially produced at the cathode. The energy consumption amounts to ca. 75 kWh/kg chromium. The chromium obtained is relatively pure. 

This process is suitable both for the production of metallic chromium and for the coating of objects with thin, decorative or thicker hard chromium layers (chromium electroplating). 

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