| 摘要 |
Zinciferous and/or aluminiferous metal surfaces can be passivated by treatment with a chromium-free aqueous solution of phosphoric acid and molybdenum that is at least partially in a valence state lower than +6, to produce, especially with an acrylic overcoating, a surface as resistant to corrosion as the surface of the same substrate after passivation with conventional liquid compositions that contain hexavalent chromium. |
