It follows from coulometric measurements that Al from Al-amalgam goes into solution in basic electrolytes as a trivalent ion. In all probability the same also happens in acidic solutions. Therefore, the deviation from Faraday's law cannot be explained by the formation of lower valency ions as a first step in anodic dissolution of Al. Experiments made in aqueous solutions of NaOH, 11N0 3 , KNO 3 and K 2 Cr 2 O 7 showed that at anodic current densities between 20 and 300 ma/cm 2 dark, nearly

more »

... films, which constantly broke down, are formed on the Al electrode. Microscopic examinations revealed the presence of a multitude of metallic particles entangled in the hydrated Al-oxide flakes, causing the dark color of the latter. Depending upon the conditions, the diameter of the metallic pacticles varied from almost 10-5 to 10-2 mm. Such a disintegration of Al was also observed when the partially amalgamated metal came simply in contact with distilled H20: dark flakes of hydrox'de, containing a multitude of smallest Al particles, were formed.