抄録
In order to develop the alkali resistance of anodic oxide film of aluminum, anodic oxidation aluminum was treated within the hydrothermal condition. And it is investigated that the effect of the hydrothermal temperature (80- 200°C) and anodic oxide film thickness on the alkali resistance time of the anodic oxide aluminum. The film thickness was controlled by changing the anodizing time from 0 min to 60 min in oxalic solution bath. By means of SEM observation of cross-section of film after hydrothermal treatment at 200°C, in the case of the thick film, then the film was composed three layers, outer cube structure layer and middle layer and inner columnar layer. In the case of the thin film, the columnar layer was disappeared. The alkali resistance time increased with increasing of the hydrothermal temperature. The alkali resistance time was effected the dense layer thickness which was calculated by the subtraction columnar layer thickness from film thickness. And, the value which was divided the alkali resistance time by dense layer thickness became 1.2 ks/μm between the anodizing time for 10 min and 35 min after hydrothermal treatment at 150°C, and became 5 ks/μm below 25 min at 200°C, respectively. Hydrothermal temperature was over 100°C, the value, alkali resistance time/dense layer thickness, of the anodizing film for 30 min was longer than the anodizing film for 60 min. Hydrothermal treatment at 80°C, then that value coincide the anodizing film for 30 min and 60 min.
