Heat and corrosion resistant plating

• US 5,059,493 A
• Filed: 03/23/1990
• Issued: 10/22/1991
• Est. Priority Date: 03/28/1989
• Status: Expired due to Term

• Current Assignee: USUI Kokusai Sangyo Kaisha Limited 131-2 Nagasawa Shimizu-Cho Sunto-Gun Shizuoka Prefecture Japan
• Original Assignee: Usui Kokusai Sangyo Kaisha Limited
• Inventors: Takahata, Seiya
• Primary Examiner(s): Dean, R.
• Assistant Examiner(s): Koehler, Robert R.
• Application Number:
  US07/498,240
• Time in Patent Office: 578 Days
• Field of Search: 428/659, 428/671, 428/674, 428/676, 428/632, 428/658, 428/679, 428/677, 428/926, 428/936, 148/264, 148/265, 148/266, 148/267
• US Class Current: 428/658
• 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: C25D 5/12 at least one layer being of nickel or chromium
• CPC Class Codes: Y10S 428/926 Thickness of individual layer specified
• CPC Class Codes: Y10S 428/936 Chemical deposition, e.g. electroless plating
• CPC Class Codes: Y10T 428/12792 Zn-base component
• CPC Class Codes: Y10T 428/12937 Co- or Ni-base component next to Fe-base component

Abstract

A multilayer plating showing high corrosion resistance even at elevated temperatures includes a first or undercoat layer formed from cobalt, nickel or a cobalt or nickel alloy on the surface to be protected, and a second or overcoat layer formed on the first layer from zinc or a zinc alloy. The second layer may further be chromated.

Claims

1. A heat and corrosion resistant plating comprising:

a first layer formed on a base surface from a material selected from the group consisting of cobalt, nickel, a cobalt alloy and a nickel alloy, said nickel alloy is selected from the group consisting of an alloy of nickel and phosphorous and an alloy of nickel and boron; and

a second layer formed on said first layer from a material selected from the group consisting of zinc and a zinc alloy.

2. A plating as set forth in claim 1, wherein said cobalt alloy is an alloy of cobalt and nickel.

3. A plating as set forth in any one of claims 1 or 2, wherein said first layer has a thickness of 0.2 to 10 microns.

4. A plating as set forth in claim 3, wherein said second layer has a thickness of at least three microns.

5. A plating as set forth in claim 1, further including a chromate film formed on said second layer.

6. A plating as set forth in claim 5, wherein said cobalt alloy is an alloy of cobalt and nickel.

7. A plating as set forth in any one of claims 5 or 6, wherein said first layer has a thickness of 0.2 to 10 microns.

8. A plating as set forth in claim 7, wherein said second layer has a thickness of at least three microns.