The electrolytic polishing of aluminium and aluminium alloys in a universal perchloric acid-bath

The paper reports a detailed systematic study of the parameters such as current density, voltage and bath temperature, for the electroplating of super pure and commercial grade aluminium and five aluminium alloys. Optimum conditions for getting a bright, fault-free surface on the subject specimens have been obtained by drawing voltage versus current density curves. The beneficial effect of stirring on the voltage/current density of electroplating has also been observed. Some observations have also been made of the 'etch polishing' effect in the electropolished samples, while studying the characteristics of the electro polished surfaces. (Dr. Y.N. Trehan, Scientist and Shri T.L. Sharma, Senior Scientific Assistant, National Metallurgical Laboratory)