| 摘要 |
PURPOSE: To obtain an appropriate pore radius distribution of the anodically oxidized film as a caralyst carrier surface by controlling the treating temp. at the time of subjecting an alumina coating film, that is formed through subjecting aluminum, an aluminum alloy or the like to anodic oxidation, to hydration sealing treatment. CONSTITUTION: In this formation, hydration sealing treatment of an alumina film after anodic oxidation of aluminum or the like is performed at a temp. within the range of 5 to 45 deg.C for several minutes to several hours by using deaerated water having a >=2×10<5>Ωspecific resistance and then, the treated coating film is calcined at a temp. within the range of 300 to 500 deg.C. By performing this treatment, an oxide coating film having at least one peak of the pore radius distribution within the range of 25 to 250Åis formed. As the water used for the hydration sealing treatment, deionized water is desired because of the easiness of its production. In this sealing treatment, the lower the treating temp. and the longer the treating time, the more closely the pore radius distribution in the range of 25 to 250Åapproaches a flat and on the other hand, the higher the treating temp., the more the tendency of having a maximum of the pore radius distribution within the range of 25 to 250Åbecomes noticeable and also, even a pore size distribution curve having two maxima within the range of 20 to 300Åcan easily be obtained. Therefore, the treating temp. and treating time are adjusted so as to obtain a desired pore radius distribution.
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