ANODIZED ALUMINUM ALLOY PRODUCTS HAVING IMPROVED APPEARANCE AND/OR ABRASION RESISTANCE, AND METHODS OF MAKING THE SAME

• US 20140083861A1
• Filed: 03/15/2013
• Published: 03/27/2014
• Est. Priority Date: 09/24/2012
• Status: Active Grant

• Current Assignee: Arconic Technologies LLC (Arconic Corp.)
• Original Assignee: Alcoa Incorporated (Howmet Aerospace, Inc.)
• Inventors: Askin, Albert, Serafin, Daniel L., Giocondi, Jennifer L., Denardo, Nicholas M., Brandon, Samantha M.
• Granted Patent: US 10,087,542 B2
• Time in Patent Office: Days
• US Class Current: 205/202
• CPC Class Codes: C25D 11/04 of aluminium or alloys based thereon
• CPC Class Codes: C25D 11/24 Chemical after-treatment
• CPC Class Codes: C25D 11/246 for sealing layers

Abstract

New methods of producing anodized aluminum alloy products having an improved surface appearance properties are disclosed. The methods may include preparing an aluminum alloy body for anodizing, thereby producing an anodized aluminum alloy body, contacting an intended viewing surface of the anodized aluminum alloy body with an acid, thereby producing a prepared intended viewing surface of the anodized aluminum alloy body, and sealing the prepared intended viewing surface of the anodized aluminum alloy body. The anodized aluminum alloy products may realize a preselected color tolerance, such as realizing a b* value that is within a specified tolerance of a preselected b* value.

Claims

1. A method comprising:

(a) preparing an aluminum alloy body for anodizing;

(b) anodizing the aluminum alloy body, thereby producing an anodized aluminum alloy body;

(c) contacting an intended viewing surface of the anodized aluminum alloy body with an acid, thereby producing a prepared intended viewing surface of the anodized aluminum alloy body;

(i) wherein the acid is selected from the group consisting of nitric acid, phosphoric acid, acetic acid, sulfuric acid, and mixtures thereof;

(ii) wherein the contacting occurs for a time of from 1 minute to 60 minutes;

(iii) wherein the contacting occurs at a temperature of from 40°

F. to 110°

F.;

(iv) wherein, when the acid is the nitric acid, the concentration of the nitric acid is from 0.67 wt. % to 67 wt. %; and

(d) sealing the prepared intended viewing surface of the anodized aluminum alloy body.

2. The method of claim 1, comprising:

determining a preselected color tolerance of the intended viewing surface of the aluminum alloy body;

wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves the preselected color tolerance.

3. The method of claim 2, wherein the preselected color tolerance comprises a target b* value, and wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves an actual b* value that is within the 1.0 units of the target b* value.

4. The method of claim 3, wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves an actual b* value that is within the 0.5 unit of the target b* value.

5. The method of claim 3, wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves an actual b* value that is within the 0.4 unit of the target b* value.

6. The method of claim 3, wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves an actual b* value that is within the 0.3 unit of the target b* value.

7. The method of claim 3, wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves an actual b* value that is within the 0.2 unit of the target b* value.

8. The method of claim 3, wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves an actual b* value that is within the 0.1 unit of the target b* value.

9. The method of claim 1, wherein the actual b* value is lower than a b* value of a reference-version of the intended viewing surface of the aluminum alloy body in the anodized and then sealed condition.

10. The method of claim 1, comprising:

pre-selecting an abrasion resistance tolerance for the intended viewing surface of the aluminum alloy body;

wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves the pre-selected abrasion resistance tolerance.

11. The method of claim 1, wherein, after the anodizing step (b) and before the contacting step (c), the intended viewing surface of the anodized aluminum alloy body has an anodic oxide zone thickness of from 0.07 to 4.5 mil.

12. The method of claim 11, wherein the anodic oxide zone thickness is a pre contacting anodic oxide zone thickness, wherein the method comprises:

completing the contacting step so as to achieve a final anodic oxide zone thickness that is within 10% of the pre-contacting anodic oxide zone thickness.

13. The method of claim 12, wherein the final anodic oxide zone thickness is within 5% of the pre-contacting anodic oxide zone thickness.

14. The method of claim 12, wherein the final anodic oxide zone thickness is within 3% of the pre-contacting anodic oxide zone thickness.

15. The method of claim 12, wherein the final anodic oxide zone thickness is within 1% of the pre-contacting anodic oxide zone thickness.

16. The method of claim 1, wherein the aluminum alloy has a longitudinal (L) tensile yield strength of at least 275 MPa.

17. The method of claim 16, wherein the aluminum alloy is selected from the group consisting of the 2xxx, 5xxx, 6xxx and 7xxx aluminum alloys.

18. The method of claim 16, wherein the aluminum alloy is a 7xxx aluminum alloy.

19. The method of claim 18, wherein the 7xxx aluminum alloy is one of a 7x75, 7x50, 7x55, or 7x85 aluminum alloy.

20. The method of claim 1, wherein the method consists of steps (a)-(d).

21. The method of claim 1, comprising:

after the contacting step (c), coloring an anodic oxide zone of the aluminum alloy product.

22. The method of claim 2, wherein the method consists of steps (a)-(d) and the determining step.

23. A method comprising:

(a) determining a preselected color tolerance of an intended viewing surface of an aluminum alloy body;

(b) preparing the aluminum alloy body for anodizing;

(c) anodizing the aluminum alloy body, thereby producing an anodized aluminum alloy body;

(d) contacting an intended viewing surface of the anodized aluminum alloy body with an acid, thereby producing a prepared intended viewing surface of the anodized aluminum alloy body;

(e) sealing the prepared intended viewing surface of the anodized aluminum alloy body;

wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves the preselected color tolerance;

wherein the preselected color tolerance comprises a target b* value, and wherein the contacting step is completed such that the intended viewing surface of the aluminum alloy body achieves an actual b* value that is within the 1.0 units of the target b* value.