Passivation composition and process for zinciferous and aluminiferous surfaces
AssigneeHenkel Corporation
InventorBruce H. Goodreau
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Abstract
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.
Claims20
An aqueous liquid composition suitable for use either directly as such or after dilution with water to passivate a metallic surface that consists predominantly of aluminum, zinc, or both, said composition comprising water and:
- (A) dissolved phosphate anions;
- and
- (B) dissolved, stably dispersed, or both dissolved and stably dispersed molybdenum-containing anions, compounds, or both compounds and anions in which molybdenum has an oxidation state less than +6.
Dependencies are inferred from the claim text.