Corrosion resistant aluminum alloy substrates and methods of producing the same

1. A wrought aluminum alloy product comprising:

(a) an aluminum alloy base;

(b) a porous sulfate-phosphate oxide zone integral with the base, the porous sulfate-phosphate oxide zone having:

(i) a plurality of pores,

(ii) sulfur atoms,

(iii) phosphorous atoms,

(iv) wherein the porous sulfate-phosphate oxide zone has a ratio of the sulfur atoms (S) to the phosphorous atoms (P) of from about 5:1 (S:P) to about 100:1 (S:P), and

(v) wherein the porous sulfate-phosphate oxide zone has an average thickness of at least about 8 microns; and

(c) a silicon-containing polymer zone at least partially overlapping the porous sulfate-phosphate oxide zone,

(i) wherein the silicon-containing polymer zone comprises silicon-containing polymer; and

(ii) wherein the pores of the porous sulfate-phosphate oxide zone contain at least some of the silicon-containing polymer.

2. The product of claim 1 , wherein the wrought aluminum alloy product is a forged aluminum alloy product.

3. The product of claim 2 , wherein the forged aluminum alloy product is an aluminum alloy wheel product.

4. The product of claim 3 , wherein the aluminum alloy wheel product comprises at least one of a 2XXX, a 6XXX and a 7xxx series aluminum alloy.

5. The product of claim 4 , wherein the aluminum alloy wheel product has a cornering fatigue life that is better than the cornering fatigue life of a Type-II anodized aluminum alloy wheel product of similar composition, shape and temper and having a similar oxide thickness.

6. The product of claim 4 , wherein the aluminum alloy wheel product has a radial fatigue life that is better than the radial fatigue life of a Type-II anodized aluminum alloy wheel product of similar composition, shape and temper and having a similar oxide thickness.

7. The product of claim 1 , wherein the wrought aluminum alloy product is a sheet or plate product.

8. The product of claim 1 , wherein the wrought aluminum alloy product is an extrusion product.

9. The product of claim 1 , wherein the porous sulfate-phosphate oxide zone has an average thickness of at least about 12 microns.

10. The product of claim 1 , wherein the silicon-containing polymer is polysilazane.

11. The product of claim 1 , wherein the wrought aluminum alloy product has a fatigue life that is better than the fatigue life of a Type-II anodized and sodium dichromate sealed aluminum alloy product of similar composition, shape and temper and having a similar oxide thickness.

12. The product of claim 1 , wherein the ratio of the sulfur atoms (S) to the phosphorous atoms (P) is at least about 10:1.

13. The product of claim 1 , wherein the ratio of the sulfur atoms (S) to the phosphorous atoms (P) is at least about 20:1.

14. The product of any of claims 12 and 13 , wherein the ratio of the sulfur atoms (S) to the phosphorous atoms (P) is not greater than about 75:1.

15. The product of claim 14 , wherein the porous sulfate-phosphate oxide zone consists essentially of sulfur, phosphorous, oxygen and aluminum.

16. The product of claim 1 wherein the porous sulphate-phosphate oxide zone has an amorphous morphology.