The Electrolytic Polishing of Amphoteric Metals

Experimental determinations of conditions necessary for the electrolytic polishing of amphoteric metals in alkali hydroxide solutions are described. The effects of temperature, electrolyte concentration, current density, and time of current flow are presented, as are differences among lithium, sodium, and potassium hydroxide solutions. Interpretation of the results in terms of a theory involving anodic polarizations has indicated the importance of the formation and maintenance of an anodic film whose electrical and mechanical properties determine critically the nature of the surface resulting from anodic treatment. Further applications of such studies toward the elucidation of mechanisms of anodic processes are indicated.