Characteristics of Electrodeposited Chromium

Organic complexants are essential components for the electrodeposition of chromium from chromium (III) based electrolytes. However, during electrolysis these complexants suffer decomposition and their compounds become incorporated in the deposit. The properties are considerably altered by the presence of these inclusions. In this paper the effect of addition of glycine to a high speed and still chromium (III) electrolyte was studied. Component analysis of the deposits indicated the presence of carbon, nitrogen and hydrogen. The effects of current density, concentration of complexant, bath temperature and electrolyte velocity on the concentration of the above elements are presented.

The hardness of the deposits was greatly increased after heat treatment at 400 to 800° C. X-ray diffraction show the as-deposited chromium to be amorphous and the formation of carbide compounds after heat treatment.

The corrosion behaviour of chromium deposits was investigated by using salt spray test and electrochemical techniques.