Method for deposition of steel protective coating

• US 7,514,153 B1
• Filed: 03/03/2005
• Issued: 04/07/2009
• Est. Priority Date: 03/03/2005
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Menke, Josephs T., Archer, Harry L. Jr., Powell, Wayne J.
• Primary Examiner(s): Zimmerman; John J
• Application Number:
  US11/076,456
• Time in Patent Office: 1,496 Days
• Field of Search: None
• US Class Current: 428/623
• CPC Class Codes: C23C 22/34 containing fluorides or complex fluorides
• CPC Class Codes: C23C 22/73 characterised by the process
• CPC Class Codes: C23C 22/83 Chemical after-treatment
• CPC Class Codes: C23C 2222/10 Use of solutions containing trivalent chromium but free of hexavalent chromium
• CPC Class Codes: C23C 28/00 Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
• CPC Class Codes: C23C 28/021 including at least one metal alloy layer
• CPC Class Codes: Y10T 428/12549 Adjacent to each other
• CPC Class Codes: Y10T 428/12611 Oxide-containing component
• CPC Class Codes: Y10T 428/12799 Next to Fe-base component [e.g., galvanized]
• CPC Class Codes: Y10T 428/12937 Co- or Ni-base component next to Fe-base component

Abstract

A method is provided for coating a steel surface of a workpiece. According to an aspect of the invention, a steel workpiece is subjected to a first embrittlement-relief baking operation to form a protective oxide layer on the steel surface. The protective oxide layer is de-scaled, and the steel surface is activated. A hydrogen barrier coating is deposited on the activated steel surface, and activated. A zinc-nickel alloy is plated on the barrier coating, and subjected to a second embrittlement-relief baking operation. The porous plating is sealed with a conversion coat. The method is especially useful in making low to no hydrogen embrittlement cadmium-replacement steel parts. Also provided is a corrosion resistant coated steel workpiece.

Claims

1. A coated steel article, comprising:

a workpiece having a steel surface;

a hydrogen barrier coating comprising a thickness not greater than about 2.54 microns on the steel surface;

a zinc-nickel alloy layer on the hydrogen barrier coating, the zinc-nickel alloy layer comprising about 85 weight percent to about 95 weight percent zinc and about 5 weight percent to about 15 weight percent nickel; and

a conversion coat sealing the zinc-nickel alloy layer,

wherein said hydrogen barrier coating is a previously activated hydrogen barrier coating, and

wherein the conversion coat is comprised of zinc phosphate, which forms a first coating layer, and trivalent chromate, which forms a second layer, where the first coating layer coats said zinc-nickel alloy layer.

2. The coated steel article according to claim 1, wherein the hydrogen barrier coating comprises a nickel-phosphorus coating where the phosphorous content is at least 10 weight percent.

3. The coated steel article according to claim 1, wherein the thickness of the hydrogen barrier coating is in a predetermined range of about 1.27 microns to about 2.54 microns.

4. The coated steel article according to claim 1, wherein the zinc-nickel alloy layer comprises about 85 to about 91 weight percent zinc and about 9 to about 15 weight percent nickel.

5. The coated steel article according to claim 1, wherein the zinc-nickel alloy layer comprises about 93 to about 95 weight percent zinc and about 5 to about 7 weight percent nickel.

6. The coated steel article according to claim 1, wherein the zinc-nickel alloy layer is a stress-relief baked zinc-nickel alloy layer.