CHARACTERISTICS OF ELECTRODEPOSITED CHROMIUM

Organic complexants are essential components for the electrodeposition of chromium from chromium (III) based electrolytes. However, during e lectrolysis these complexants suffer decomposition and their compounds become incorporated in the deposit. The properties are considerably a ltered by the presence of these inclusions. In this paper the effect o f addition of glycine to a high speed and still chromium (III) electro lyte was studied. Component analysis of the deposits indicated the pre sence of carbon, nitrogen and hydrogen. The effects of current density , concentration of complexant, both temperature and electrolyte veloci ty on the concentration of the above elements are presented. The hardn ess of the deposits was greatly increased after heat treatment at 400 to 800 degrees C. X-ray diffraction show the as-deposited chromium to be amorphous and the formation of carbide compounds after heat treatme nt. The corrosion behaviour of chromium deposits was investigated by u sing salt spray test and electrochemical techniques.