abstract |
The surface-treated steel sheet excellent in corrosion resistance is composed of a zinc-based plated steel sheet or an aluminum-based plated steel sheet, a composite oxide film formed on the surface of the plated steel sheet, and an organic film formed on the composite oxide film. The composite oxide film contains oxide fine particles, phosphoric acid and / or phosphoric acid compound. The said organic film has a film thickness of 0.1-5 micrometers. |