Anodic oxide layer and ceramic coating for aluminum alloy excellent in resistance to gas and plasma corrosion

1. Field of the Invention Aluminum alloy comprising an anodic oxidation coating and a ceramic coating formed on a surface of the anodic oxidation coating, wherein the anodic oxidation coating contains one or more elements selected from the group consisting of C, N, P, F, B and S at a content of each element in an amount of 0.1 mass % or more, and wherein the ceramic coating comprises one or more selected from the group consisting of oxide, nitride, carbonitride, boride and silicide, wherein when the anodic oxidation coating contains S only, the surface of the aluminum alloy or of the anodic oxidation coating has an average roughness Ra of 0.3 m or more.