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

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 of more elements selected from the group consisting of C, N, P, F, B and S at a content of each element in a amount of 0.1 mass % more, and wherein the ceramic coating comprises one or more selected from the group consisting of carbides expressed by MC, wherein M is any of Si, Ti, Zr, Hf, V, Nb, Ta and Mo;

• carbides expressed by M2C, wherein M is any of V, Ta, Mo and W;
• carbides expressed by M3C, wherein M is any of Mn, Fe, Co and Ni;
• and carbides expressed by M3C2, wherein M is Cr, 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 μm or more.

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, and excluding chromium oxides, 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 μm or more.