| 摘要 |
PROBLEM TO BE SOLVED: To improve the corrosion resistance of a sealing surface in a vacuum processor and abbreviate its processing manhours, by forming on the sealing surface of the portion of aluminum-based constituent members abutting against each other therein the film subjected to an oxalic-acid anodic oxidation processing which has a specific surface roughness and film thickness. SOLUTION: As the material of a gate valve 8 of a vacuum processor, e.g. an aluminum alloy material of Japanese Industrial Standards A6061 is used, and prior to its anodic oxidation processing, its processing condition is so selected that the surface roughness (Ry) of a sealing surface 8a of the gate valve 8 is made not larger than 1.6μm. Also, in the case of such a severely used condition as the gate valve 8, a film thickness not smaller than 5μm, preferably a film thickness of 20-50μm is given to the sealing surface 8a to achieve its function. In comparison with the film subjected to a sulphuric-acid anodic oxidation processing, the film subjected to an oxalicacid anodic oxidation processing exhibits excellent characteristics in corrosion and abrasion resistances, and especially, in such a case as the sealing surface 8a receiving a repeated stress, the latter film exhibits largely the effect of its abrasion resistance.
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