Claims
- 1. An apparatus for coating an iron-based substrate with a coating of a protective zinc metal alloy or compound which comprises;
- (a) a vessel means containing a molten protective metal of a zinc alloy or compound;
- (b) means for immersing an iron-based substrate into the molten protective metal to coat the iron-based substrate with the protective metal coating,
- (c) means disposed in the atmosphere outside of said vessel means for directing the iron-based substrate from the molten protective metal, the directing means comprising a roll having a metal understructure and a coating of yttria stabilized zirconia for providing a contact surface which engages the protective zinc metal coating when the protective metal is still in a plastic state, and wherein said coating of zirconia has a thickness between 20 and 500 microns and a surface finish of no more than about 20 microinches rms for preventing adhesion to the protective metal.
- 2. The apparatus of claim 1, wherein the thickness of said zirconia coating is between about 50 and about 500 microns.
- 3. The apparatus of claim 1 wherein an undercoat layer is immediately below said zirconia coating.
- 4. The apparatus of claim 3 wherein the undercoat layer comprises an alloy selected from the group consisting of nickel-based alloy, iron-based alloy, and cobalt-based alloy.
- 5. The apparatus of claim 3 wherein the undercoat layer comprises MCrAl, wherein M is selected from the group consisting of nickel, iron, and cobalt.
- 6. The apparatus of claim 5 wherein the undercoat layer additionally comprises yttria.
- 7. The apparatus of claim 3 wherein the undercoat layer comprises nickel and aluminum.
- 8. The apparatus of claim 3 wherein the undercoat layer comprises nickel and chromium.
- 9. The apparatus of claim 3 wherein the thickness of the undercoat layer is between about 20 microns, and about 500 microns.
- 10. The apparatus of claim 3 wherein the thickness of the undercoat layer is between about 50 microns, and about 250 microns.
- 11. The apparatus of claim 1 further comprising a heating zone adapted to receive the protective-metal-coated substrate and adapted to maintain the protective metal coated upon the iron-based substrate at an elevated temperature sufficient to form an alloy of iron and the protective metal.
- 12. The apparatus of claim 11 wherein the directing means is placed after the heating zone.
- 13. The apparatus of claim 1 wherein the protective metal is selected from the group consisting of zinc, aluminum, aluminum-zinc alloy, aluminum-silicon alloy, tin, terne metal, copper, and copper alloy.
- 14. The apparatus of claim 1 wherein the protective metal is selected from the group consisting of zinc, aluminum, and aluminum-zinc alloy.
- 15. A process for coating an iron-based substrate with a protective metal coating of a zinc alloy or compound from a liquid bath of such protective metal which comprises;
- (a) immersing a iron-based substrate into a molten protective metal bath of said zinc metal; and
- (b) directing the iron-based substrate from the molten protective metal bath over a roll disposed in the open atmosphere outside of the molten protective metal bath with the roll having a metal understructure and a coating of yttria stabilized zirconia for providing a contact surface which contacts the protective-metal-coated substrate when the protective metal is still in a plastic state, with said coating of zirconia having a thickness between 20 and 500 microns and a surface finish of no more than about 20 microinches rms for preventing adhesion to the protective metal.
- 16. The process of claim 15 wherein the protective metal is selected from the group consisting of zinc, aluminum, aluminum-zinc alloy, aluminum-silicon alloy, tin, terne metal, copper, and copper alloy.
- 17. The process of claim 15 wherein the thickness of the refractory oxide coating is between about 50 and about 500 microns.
- 18. The process of claim 15 wherein the protective metal is selected from the group consisting of zinc, aluminum, and aluminum-zinc alloy.
- 19. The process of claim 15 wherein an undercoat is immediately below the coating of zirconia.
- 20. The process of claim 19 wherein the undercoat layer comprises an alloy selected from the group consisting of nickel-based alloy, iron-based alloy, and cobalt-based alloy.
- 21. The process of claim 19 wherein the undercoat layer comprises MCrAl, wherein M is selected from the group consisting of nickel, iron, and cobalt.
- 22. The process of claim 21 wherein the undercoat layer additionally comprises yttria.
- 23. The process of claim 19 wherein the undercoat layer comprises nickel and aluminum.
- 24. The process of claim 19 wherein the undercoat layer comprises nickel and chromium.
- 25. The process of claim 19 wherein the thickness of the undercoat layer is between about 20 microns, and about 500 microns.
- 26. The process of claim 19 wherein the thickness of the undercoat layer is between about 50 microns, and about 250 microns.
- 27. The process of claim 15 further comprising a heating zone adapted to receive the protective-metal-coated substrate and adapted to maintain the protective metal coated upon the iron-based substrate at an elevated temperature sufficient to form an alloy of iron and the protective metal.
- 28. The process of claim 27 wherein the directing means is placed after the heating zone.
Parent Case Info
This application is a continuation of prior U.S. application Ser. No. 213,270, filing date June 28, 1988, now abandoned, which is a continuation of application Ser. No. 863,448, filing date May 12, 1986, now abandoned.
US Referenced Citations (3)
Foreign Referenced Citations (1)
Number |
Date |
Country |
1227754 |
Oct 1966 |
DEX |
Non-Patent Literature Citations (1)
Entry |
"The Making, Shaping and Treating of Steel", 10th ed., 1985, Assn. of Iron & Steel Engineers/U.S. Steel Corp. |
Continuations (2)
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Number |
Date |
Country |
Parent |
213270 |
Jun 1988 |
|
Parent |
863448 |
May 1986 |
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