The NaCl single electrode potential of aluminium refered to IN calomel cell in NaCl aquores solution as affected by its surface condition was studied by specially made vacume tube potentio meter (fig. 1). Potential of aluminium varies largely by its surface treatment. The potential of aluminium with its natural oxide film is nobler then the case when its film was removed by special treatment as electrolytic polishing in acetic unhydrat and perchloric acid bath. The specimen with no oxide film show special corrosion behavior in acid and alkali solution as shown in fig. 4. But its oxide film groth rapidly when the specimen was dried or immersed in mater which contains oxygen.
