Non-chromate sealant for porous anodized aluminum

• US 5,863,621 A
• Filed: 06/10/1996
• Issued: 01/26/1999
• Est. Priority Date: 03/08/1995
• Status: Expired due to Term

• Current Assignee: Southwest Research Institute
• Original Assignee: Southwest Research Institute
• Inventors: Lukezich, Stephen J., Dearnaley, Geoffrey
• Primary Examiner(s): PIANALTO, BERNARD D
• Application Number:
  US08/662,728
• Time in Patent Office: 960 Days
• Field of Search: 427/523, 427/525, 427/529, 427/528, 427/385.5, 427/409
• US Class Current: 427/523
• CPC Class Codes: C25D 11/18 After-treatment, e.g. pore-sealing
• CPC Class Codes: C25D 11/246 for sealing layers

Abstract

The present invention provides a method for easily and effectively removing adsorbed water molecules from an anodized surface using low intensity ultraviolet (UV) radiation. The present invention also provides a method for sealing an anodized aluminum surface which does not result in hazardous byproducts. The method involves, in vacuum: (1) vaporizing a selected precursor fluid; (2) condensing a flux of said precursor vapor onto the anodized aluminum surface; (3) and, bombarding said condensed precursor vapor with an energetic beam of ions to convert the porous anodized surface into an inert, solid, impermeable, and mechanically strong surface.

Claims

1. A method for sealing a porous anodized aluminum surface comprising:

placing a component having an anodized aluminum surface in a vacuum chamber evacuated to a pressure of about 10^-6 torr;

condensing onto said surface a precursor material in an amount sufficient, upon ion bombardment, to form an inert, substantially impermeable amorphous carbonaceous seal;

substantially simultaneously bombarding said anodized surface with an energetic beam of ions at an energy between about 1 keV to about 1 Mev for a time and at a linear energy of transfer sufficient to convert said precursor material into said inert, substantially impermeable amorphous carbonaceous seal.

2. The method of claim 1 wherein said energy of ion bombardment is between about 20-100 keV.

3. The method of claim 2 wherein, before condensing said precursor material onto said surface, said surface is exposed to a flux of UV radiation having a wavelength between about 110-180 nm and a power of about 150 watts for a time sufficient to remove adsorbed water molecules from said surface.

4. The method of claim 3 wherein said UV radiation has a wavelength between about 160-170 nm.

5. The method of claim 2 wherein said precursor material is deposited onto said surface to a thickness of between about 1-5μ

.

6. The method of claim 1 wherein said ions are selected from the group consisting of hydrogen, helium, neon, nitrogen, argon, methane, and carbon monoxide.

7. The method of claim 6 wherein said precursor material is deposited onto said surface to a thickness of between about 1-5μ

.

8. The method of claim 1 wherein, before condensing said precursor material onto said surface, said surface is exposed to a flux of UV radiation having a wavelength between about 110-180 nm and a power of about 150 watts for a time sufficient to remove adsorbed water molecules from said surface.

9. The method of claim 8 wherein, before condensing said precursor material onto said surface, said surface is exposed to a flux of UV radiation having a wavelength between about 110-180 nm and a power of about 150 watts for a time sufficient to remove adsorbed water molecules from said surface.

10. The method of claim 9 wherein said UV radiation has a wavelength between about 160-170 nm.

11. The method of claim 8 wherein said precursor material is deposited onto said surface to a thickness of between about 1-5μ

.

12. The method of claim 1 wherein said precursor material is deposited onto said surface to a thickness of between about 1-5μ

.

13. The method of claim 12 wherein said precursor material is deposited onto said surface to a thickness of between about 1-5μ

.

14. A method for sealing a porous anodized aluminum surface comprising:

placing a component having an anodized aluminum surface in a vacuum chamber evacuated to a pressure of about 10^-6 torr;

condensing onto said surface a precursor material in an amount sufficient, upon ion bombardment, to form an inert, substantially impermeable amorphous carbonaceous seal, wherein said precursor material is selected from the group consisting of polyphenyl ether, polydimethyl siloxane, pentaphenyltrimethyl siloxane, and elcosyl napthalene;

substantially simultaneously bombarding said anodized surface with an energetic beam of ions at an energy between about 1 keV to about 1 Mev for a time and at a linear energy of transfer sufficient to convert said precursor material into said inert, substantially impermeable amorphous carbonaceous seal.

15. The method of claim 14 wherein said ions are selected from the group consisting of relatively low mass gaseous elements and compounds.

16. The method of claim 15 wherein said energy of ion bombardment is between about 20-100 keV.

17. The method of claim 16 wherein said ions are selected from the group consisting of hydrogen, helium, neon, nitrogen, argon, methane, and carbon monoxide.

18. The method of claim 16 wherein, before condensing said precursor material onto said surface, said surface is exposed to a flux of UV radiation having a wavelength between about 110-180 nm and a power of about 150 watts for a time sufficient to remove adsorbed water molecules from said surface.

19. The method of claim 18 wherein said UV radiation has a wavelength between about 160-170 nm.

20. The method of claim 15 wherein said ions are selected from the group consisting of hydrogen, helium, neon, nitrogen, argon, methane, and carbon monoxide.

21. The method of claim 15 wherein, before condensing said precursor material onto said surface, said surface is exposed to a flux of UV radiation having a wavelength between about 110-180 nm and a power of about 150 watts for a time sufficient to remove adsorbed water molecules from said surface.

22. The method of claim 21 wherein said UV radiation has a wavelength between about 160-170 nm.

23. The method of claim 22 wherein said UV radiation has a wavelength between about 160-170 nm.

24. The method of claim 22 wherein said precursor material is deposited onto said surface to a thickness of between about 1-5μ

.

25. The method of claim 15 wherein said precursor material is deposited onto said surface to a thickness of between about 1-5μ

.

26. The method of claim 14 wherein said energy of ion bombardment is between about 20-100 keV.

27. A method for sealing a porous anodized aluminum surface comprising:

placing a component having an anodized aluminum surface in a vacuum chamber evacuated to a pressure of about 10^-6 torr;

condensing onto said surface a precursor material in an amount sufficient, upon ion bombardment, to form an inert, substantially impermeable amorphous carbonaceous seal, wherein said precursor material is selected from the group consisting of polyphenyl ether, polydimethyl siloxane, pentaphenyltrimethyl siloxane, and elcosyl napthalene;

substantially simultaneously bombarding said anodized surface with an energetic beam of ions at an energy between about 1 keV to about 1 Mev for a time and at a linear energy of transfer sufficient to convert said precursor material into said inert, substantially impermeable amorphous carbonaceous seal, wherein said ions are selected from the group consisting of hydrogen, helium, neon, nitrogen, argon, methane, and carbon monoxide.