アルミニウムの陽極酸化膜への電着について (第4報)

核形成の拠点について

抄録

During the anodizing of aluminium the surface state varies by oxidation and dissolution.
The appearance is not always the same according to the kind of electrolyte; for example, in the case of using sulphuric acid bath, the surface shows an extremly irregular appearance, and in the case of using phosphoric acid bath, it consists of the collection of pits, which are very much like those etched by sodium hydroxide. The observations of the forming-points of nuclei by instantaneous electroplating of such surfaces revealed the followings:
In the case of using sulphuric acid bath, the nuclei are formed starting from the defects on the surface, having nothing to do with the state of oxidized surface, and in the case of using phosphoric acid bath, they are formed mostly around the pits on the surface. The sections across the surface also show that these nuclei have settled mostly on the protrusions from the surface.