Corrosion resistant aluminum alloy substrates and methods of producing the same

• US 7,732,068 B2
• Filed: 08/28/2007
• Issued: 06/08/2010
• Est. Priority Date: 08/28/2007
• Status: Active Grant

• Current Assignee: Howmet Aerospace, Inc.
• Original Assignee: Alcoa Incorporated (Howmet Aerospace, Inc.)
• Inventors: Levendusky, Thomas L., Robare, Kevin M., Guthrie, Joseph D., Askin, Albert, Vega, Luis Fanor, Zediak, Clinton
• Primary Examiner(s): Zimmerman; John J
• Assistant Examiner(s): Katz; Vera
• Application Number:
  US11/846,483
• Publication Number:
  US 20090061216A1
• Time in Patent Office: 1,015 Days
• Field of Search: None
• US Class Current: 428/704
• CPC Class Codes: C23C 18/122 Inorganic polymers, e.g. silanes, polysilazanes, polysiloxanes
• CPC Class Codes: C25D 11/08 containing inorganic acids
• CPC Class Codes: C25D 11/16 Pretreatment , e.g. desmutting
• CPC Class Codes: C25D 11/24 Chemical after-treatment
• CPC Class Codes: Y10T 428/12569 Synthetic resin
• CPC Class Codes: Y10T 428/249953 Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/264 Up to 3 mils
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

Aluminum alloy products comprising an aluminum alloy base and a sulfate-phosphate oxide zone integral therewith are disclosed. Methods of making the same are also disclosed.

Claims

1. An aluminum alloy product comprising:

(A) an aluminum alloy base having an electrochemically formed porous sulfate-phosphate oxide zone, the porous sulfate-phosphate oxide zone having a plurality of pores;

(i) wherein the ratio of sulfur atoms to phosphorous atoms in the porous sulfate-phosphate oxide zone is from about 5;

1 to about 100;

1; and

(ii) wherein the porous sulfate-phosphate oxide zone has a thickness of at least about 5 microns; and

(B) a silicon-containing polymer zone coupled to the electrochemically formed porous sulfate-phosphate oxide zone;

(i) wherein the silicon-containing polymer zone comprises a coating portion on a surface of the aluminum alloy base; and

(ii) wherein the silicon-containing polymer zone comprises a silicon polymer having a backbone of the formula —

Si—

X—

Si—

, wherein X is either N or O; and

(iii) wherein at least some of the silicon polymer is contained within at least some of the pores of the porous sulfate-phosphate oxide zone.

2. The aluminum alloy product of claim 1, wherein the pores of the porous sulfate-phosphate oxide zone have an average pore size of at least about 10 nm.

3. The aluminum alloy product of claim 2, wherein the average pore size is not greater than about 15 nm.

4. The aluminum alloy product of claim 1, wherein the thickness of the porous sulfate-phosphate oxide zone is not greater than about 25 microns.

5. The aluminum alloy product of claim 1, wherein the aluminum alloy is a 6061 series alloy.

6. The aluminum alloy product of claim 5, wherein the aluminum alloy product is a forged product.

7. The aluminum alloy product of claim 6, wherein the aluminum alloy product is a wheel product.

8. The aluminum alloy product of claim 1, wherein the aluminum alloy product is capable of passing a copper-accelerated acetic acid salt spray test (CASS), as defined by ASTM B368-97(2003)e1.

9. The aluminum alloy product of claim 1, wherein the coating portion of the silicon-containing polymer zone has a thickness of at least about 8 micron.

10. The aluminum alloy product of claim 1, wherein the coating portion of the silicon-containing polymer zone has a thickness of at least about 35 micron.

11. The aluminum alloy product of claim 10, wherein the coating portion of the silicon-containing polymer is substantially crack-free.

12. The aluminum alloy product of claim 11, wherein the polymer of the silicon-containing polymer zone is polysilazane.

13. The aluminum alloy product of claim 1, wherein the ratio of sulfur atoms to phosphorous atoms in the sulfate-phosphate oxide zone is from about 10:

1 to about 75;

1.

14. The aluminum alloy product of claim 1, wherein the ratio of sulfur atoms to phosphorous atoms in the sulfate-phosphate oxide zone is from about 20:

1 to about 75;

1.

15. The aluminum alloy product of claim 1, wherein the sulfate-phosphate oxide zone consists essentially of sulfur, phosphorous, oxygen and aluminum.