Method for surface treating aluminum products
AssigneeAlcoa Inc.
InventorsLuis F. Vega, Kevin M. Robare, Mark A. Holtz, John R. Grassi, Neal R. Dando
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Abstract
There is disclosed a method for surface treating aluminum products, especially vehicle wheels, to improve their brightness. The method comprises: (a) applying a chemical brightening composition to these products; (b) deoxidizing the surface of these wheel products in a nitric acid-based bath; (c) forming a porous oxide on that with an electrolytic bath containing phosphoric acid; and (d) applying, preferably spraying, a siloxane-based film to that porous oxide. In many instances, intermediate rinsing substeps are performed between these respective main steps.
Claims42
A method for surface treating an aluminum wheel product to improve its brightness, said method comprising the main steps of:
- (a) applying a chemical brightening composition to the product;
- (b) deoxidizing the product surface in a nitric acid-based bath;
- (c) electrochemically forming a porous oxide/phosphate on said product surface by contacting with an electrolytic bath containing phosphoric acid, said oxide/phosphate being less than about 500 angstroms thick;
- and
- (d) chemically bonding a siloxane-based outer layer to the porous oxide/phosphate.
A method for surface treating aluminum wheel products to improve their brightness and abrasion resistance, said method comprising the steps of:
- (a) applying a chemical brightening composition to said wheel products;
- (b) deoxidizing the surface of said wheel products in a nitric acid-based bath;
- (c) electrochemically forming a porous oxide/phosphate on said surface by contacting with an electrolytic bath containing phosphoric acid, said oxide/phosphate being less than about 500 angstroms thick;
- (d) chemically bonding a siloxane-based film to the porous oxide/phosphate;
- and
- (e) thermally curing the siloxane-based film on said surface.
A method for surface treating cleaned and rinsed, 6000 Series aluminum wheel products to improve their brightness, soil and abrasion resistance, said method comprising the steps of:
- (a) chemically brightening said wheel products with a composition that includes phosphoric acid and nitric acid;
- (b) rinsing said wheel products;
- (c) deoxidizing the surface of said wheel products in a nitric acid-based bath;
- (d) rinsing said wheel products;
- (e) electrochemically forming a porous oxide/phosphate on said surface by contacting with an electrolytic bath containing phosphoric acid, said oxide/phosphate being less than about 500 angstroms thick;
- (f) rinsing said wheel products;
- (g) chemically bonding a siloxane-based film to said oxide/phosphate;
- and
- (h) thermally curing the siloxane-based film on said wheel products.
Dependencies are inferred from the claim text.