Abstract
For the purpose of investigating the mechanism of electro-depositing in the anodized coating, various anodized coatings have been observed by the electron-microscope. The results of the observations are as follows:
i) The cell structure of the anodized coating is clear and the pore diameter is increased with voltage rise, and the latter is decreased with treating time increase.
ii) Further, it seems that the pore diameter is affected by the concentration of the bath. In the case of about 10% or less solutions of phosphoric acid the diameter is the largest, whereas in the case of more than 30% it is almost unaffected by the concentration.
iii) The number of the pores in the case of phosphoric acid is (6-47)×109/cm2 and the diameters of the pores are 0.03-0.19μ. In case of oxalic acid, the number of the pore are near the highest range and the diameters the lowest range.
iv) A number of fine asperities appear all over the surface treated by the phosphoric acid bath. The eroded traces are left on each surface treated by oxalic or sulphuric acid which are quite different from the former.
v) The observations of the oxide film replica and the carbon replica show that even under same treating conditions these appearances are markedly defferent, but appreciable analogies exist between them.
