Thermodynamic Study of Chromium Plating.

The object of this project is the investigation of the fundamental principles of chromium plating baths from the standpoint of thermodynamic theory. Current-voltage curves have been obtained at varying temperatures for a series of plating baths in which sulfate ratio was varied and for another series in which trivalent chromium content was varied. Variation in the heat of activation was thus obtained fro each of these two conditions and values of entropy and free energy of activation estimated. These data inidcate very little effect by the sulfate ion on the chromium deposition reaction but a marked catalyzing effect by the presence of Cr+3 at higher percentages. It has been possible to develop a modified Hull Cell from which I-V curves can be determined similar to those obtained by other techniques. At the present time insufficient data has been obtained in this way to compare to the experiments above.