Coated metal strip

• US 5,489,490 A
• Filed: 11/17/1994
• Issued: 02/06/1996
• Est. Priority Date: 04/05/1993
• Status: Expired due to Term

• Current Assignee: Revere Copper Products, Inc.
• Original Assignee: The Louis Berkman Company
• Inventors: Zamanzadeh, Mehrooz, Carey, Jay F. II
• Primary Examiner(s): ZIMMERMAN, JOHN J
• Application Number:
  US08/341,365
• Time in Patent Office: 446 Days
• Field of Search: 428/648, 428/659, 428/939, 428/679, 428/685, 428/658, 428/647
• US Class Current: 428/647
• CPC Class Codes: B32B 15/18 comprising iron or steel B32B15/011, B32B15/012 and B32B15/013 take precedence
• CPC Class Codes: B32B 15/20 comprising aluminium or copper B32B15/016 and B32B15/017 take precedence
• CPC Class Codes: C22C 18/00 Alloys based on zinc
• CPC Class Codes: C23C 2/02 Pretreatment of the material to be coated, e.g. for coating on selected surface areas C23C2/30 takes precedence
• CPC Class Codes: C23C 2/06 Zinc or cadmium or alloys based thereon
• CPC Class Codes: C23C 2/08 Tin or alloys based thereon
• CPC Class Codes: C23C 2/26 After-treatment C23C2/14 takes precedence
• CPC Class Codes: C23C 28/025 with at least one zinc-based layer
• CPC Class Codes: C25D 3/565 containing more than 50% by weight of zinc
• CPC Class Codes: C25D 3/60 containing more than 50% by weight of tin
• CPC Class Codes: C25D 5/10 Electroplating with more than one layer of the same or of different metals for bearings C25D7/10
• CPC Class Codes: Y10S 428/939 Molten or fused coating
• CPC Class Codes: Y10T 428/12715 Next to Group IB metal-base component
• CPC Class Codes: Y10T 428/12722 Next to Group VIII metal-base component

Abstract

A corrosion-resistant strip roofing material which is essentially lead free and is not highly reflective. The coating on the roofing material is a two-phase metallic coating comprised of a large weight percentage of tin and a relatively large weight percentage of zinc. The tin-zinc composition provides for both a highly corrosive-resistant coating which protects the surface of the roofing material from oxidation and also a gray surface coloring which is not highly reflective.

Claims

1. A coated metal strip including a base strip of steel or copper with parallel surfaces both of which are coated with a highly corrosive-resistant, homogeneous two-phase tin-zinc alloy with tin being the primary constituent and zinc forming one of said two-phases, said coating being applied by continuously passing the continuous metal strip through a bath of molten tin-zinc alloy at a speed to deposit onto said base strip an impervious two-phase layer of said tin-zinc alloy having a uniform thickness on both surfaces in the range of 0.001-0.003 inch, said two-phase tin-zinc alloy coating comprising discrete sections of zinc in a tin rich matrix, said two-phases being formed by proportioning the zinc and tin to provide about 10 to about 30 percent by weight zinc, a majority of tin and an effective amount of metallic stabilizer, which metallic stabilizer does not change the two-phase characteristic of said coating alloy deposited on the moving strip and is selected from the group consisting of antimony, bismuth and mixtures thereof.

2. A coated metal strip as defined in claim 1, wherein said two-phase coating comprises:

space="preserve" listing-type="tabular">______________________________________ Tin [more than 70%] 70-90% Zinc [up to 30%] 10-30% Antimony more than 0.01% ______________________________________

3. A coated metal strip as defined in claim 1, wherein said two-phase coating comprises:

space="preserve" listing-type="tabular">______________________________________ Tin [more than 70%] 70-90% Zinc [up to - 30%] 10-30% Bismuth 0.01-1.7% ______________________________________

4. A coated metal strip as defined in claim 1, wherein said two-phase coating comprises:

space="preserve" listing-type="tabular">______________________________________ Tin [more than 70%] 70-90% Zinc [up to - 30%] 10-30% Iron 0.1-2.0% ______________________________________

5. A coated metal strip as defined in claim 1, wherein said two-phase coating comprises:

space="preserve" listing-type="tabular">______________________________________ Tin [more than 70%] 70-90% Zinc [up to - 30%] 10-30% Copper 0.1-2.0% ______________________________________

6. A coated metal strip as defined in claim 1, wherein said base metal strip is plated with a thin nickel layer prior to applying said two-phase metallic coating.

7. A coated metal strip as defined in claim 6, wherein said nickel layer thickness ranges between 0.0001 to 0.003 inches.

8. A coated metal strip as defined in claim 6, wherein said nickel layer is electroplated onto said steel sheet.

9. A coated metal strip as defined in claim 1, wherein said two-phase coating alloy includes lead.

10. A coated metal metal strip as defined in claim 9, wherein said lead is less than 0.01 percent by weight.

11. A coated metal strip as defined in claim 1 including additional non-phase affecting metal selected from the group consisting of antimony, bismuth, copper, iron, lead and mixtures thereof.

12. A coated metal strip including a base strip of stainless steel with parallel surfaces both of which are coated with a highly corrosive-resistant, homogeneous two-phase tin-zinc alloy including about 10-30 weight percent zinc, a majority of tin and an effective amount of metallic stabilizer selected from the group consisting of antimony, bismuth and mixtures thereof, said coating being applied by continuously passing the continuous metal strip through a bath of molten tin-zinc alloy at a speed to deposit onto said base strip an impervious two-phase layer of said tin-zinc alloy having a uniform thickness on both surfaces in the range of 0.001-0.003 inch, said two-phase tin-zinc alloy coating comprising discrete sections of zinc in a tin rich matrix.

13. A coated metal strip as defined in claim 12, wherein said base metal strip is plated with a thin nickel layer prior to applying said two-phase metallic coating.

14. A coated metal strip as defined in claim 13, wherein said nickel layer thickness ranges between 0.0001 to 0.003 inches.

15. A coated metal strip as defined in claim 13, wherein said nickel layer is electroplated onto said steel sheet.

16. A coated metal metal strip as defined in claim 12, wherein said two-phase coating alloy includes lead.

17. A coated metal strip including a base strip of steel or copper with parallel surfaces both of which are coated with a highly corrosive-resistant, homogeneous two-phase tin-zinc alloy including about 10-30 weight percent zinc and a majority of tin, said coating being applied by continuously passing the continuous metal strip through a bath of molten tin-zinc alloy at a speed to deposit onto said base strip an impervious two-phase layer of said tin-zinc alloy having a uniform thickness on both surfaces in the range of 0.001-0.003 inch, said two-phase tin-zinc alloy coating comprising discrete sections of zinc in a tin rich matrix and an effective amount of metallic stabilizer selected from the group consisting of antimony, bismuth and mixtures thereof, wherein said base strip is plated with a thin layer of metal prior to applying said two-phase metallic coating.

18. A coated steel strip as defined in claim 17, wherein said thin layer is nickel.

19. A coated metal strip as defined in claim 17, wherein said thin layer of metal thickness ranges between 0.0001 to 0.003 inches.

20. A coated metal strip as defined in claim 17, wherein said layer is electroplated onto said steel sheet.

21. A coated metal strip as defined in claim 17, wherein said two-phase coating alloy includes lead.

22. A coated metal strip as defined in claim 17, wherein said steel is stainless steel.

23. A coated metal strip including a base strip with surfaces coated with a homogeneous two-phase tin-zinc alloy comprising discrete sections of zinc in a tin rich matrix, said two-phases being formed from a majority of tin, about 10-30 weight percent zinc, and an effective amount of metal stabilizer selected from the group consisting of antimony, bismuth and mixtures thereof, said coating being applied by continuously passing a continuous strip said base strip through a bath of molten tin-zinc alloy at a speed to deposit onto said strip an impervious two-phase layer of tin-zinc alloy having an essentially uniform thickness.

24. A coated metal strip as defined in claim 23, wherein said base strip is selected from the group consisting of carbon steel, stainless steel, copper and bronze.

25. A coated metal strip as defined in claim 24, wherein each metal in said metal additive does not exceed 7.5 weight percent of said metal additive.

26. A coated metal strip as defined in claim 25, wherein said base strip is coated with a thin layer of metal prior to applying said hot dip tin-zinc alloy, said thin layer of metal having a thickness of 1 to 3 microns.

27. A coated metal strip as defined in claim 23, wherein said tin-zinc alloy includes a metal additive is selected from the group consisting of antimony, bismuth, copper, iron, lead and mixtures thereof.

28. A coated metal strip as defined in claim 27, wherein said metal additive contains less than 0.05 weight percent lead.

29. A coated metal strip as defined in claim 28, wherein each metal in said metal additive does not exceed 7.5 weight percent of said metal additive.

30. A coated metal strip as defined in claim 29, wherein said base strip is coated with a thin layer of metal prior to applying said hot dip tin-zinc alloy, said thin layer of metal having a thickness of 1 to 3 microns.

31. A coated metal strip as defined in claim 28, wherein said base strip is coated with a thin layer of metal prior to applying said hot dip tin-zinc alloy, said thin layer of metal having a thickness of 1 to 3 microns.

32. A coated metal strip as defined in claim 27, wherein each metal in said metal additive does not exceed 7.5 weight percent of said metal additive.

33. A coated metal strip as defined in claim 32, wherein said base strip is coated with a thin layer of metal prior to applying said hot dip tin-zinc alloy, said thin layer of metal having a thickness of 1 to 3 microns.

34. A coated metal strip as defined in claim 28, wherein said base strip is coated with a thin layer of metal prior to applying said hot dip tin-zinc alloy, said thin layer of metal having a thickness of 1 to 3 microns.

35. A coated metal strip as defined in claim 23, wherein said base strip is coated with a thin layer of metal prior to applying said hot dip tin-zinc alloy, said thin layer of metal having a thickness of 1 to 3 microns.