TOXICOLOGICAL AND ENVIRONMENTAL PROPERTIES OF A CrIII/CHOLINE CHLORIDE BASED CHROME PLATING ELECTROLYTE

At present, industrial application of hard chromium electroplating is based on electrolytic baths of sulphuric acid and chromium trioxide solutions in water. Toxicological and environmental properties of these chromium (VI) baths show the convenience of searching for new CrVI free formulations. Research activities have shown that chromium metallic coatings from an ionic liquid (IL) using trivalent chromium salts can be successfully produced. A highly promising CrVI free, bright, thick and hard chromium deposition process has been developed based on an ionic liquid composed of Chromium chloride (CrCl3.6H2O) and Choline chloride (HOC2H4N(CH3)Cl-3+(-)). Jointly with technological properties evaluation, a methodological study on environmental risk analysis and on implications in health & safety for the referred ionic liquid bath has been carried out. With that aim, experimental tests on the basis of toxicological properties, of effects on human health and of environmental effects were conducted. Comparisons of the obtained results with the behaviour of traditional baths used for the same purpose were also accomplished, showing for the ionic liquid formulation a lower toxicity and less environmental risk than for the CrVI formulation.