US3816082A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of improving the corrosion resistance of zinc coated ferrous metal substrates and the corrosion resistant substrates thus produced
Assignee: National Steel Corp
•
Filing: 1972-05-22
•
Granted: 1974-06-11
•
Expires: 1992-05-22
Abstract
Abstract The corrosion resistance of zinc coated ferrous metal substrates is increased markedly by electroplating at least a portion of the zinc surface thereof with a coating of metallic chromium having a thickness of about 0.1-0.5 microinch, and thereafter electrochemically treating the resultant metallic chromium coated substrate as a cathode in an aqueous electrolyte containing a water soluble hexavalent chromium compound to deposit a metallic chromium and chromium oxide containing film thereon. In one preferred variant, the zinc surface is brightened prior to the electrodeposition of the metallic chromium coating to thereby increase the brightness of the final product and to render it more pleasing in appearance. The chromium plated and electrochemically treated zinc coated ferrous metal substrate is an excellent base for protective organic coatings, and protective organic coatings may be applied thereto to further increase the corrosion resistance and/or for decorative purposes. The method of the invention is easily adapted to high speed electroplating lines operating at strip speeds of at least 500 feet per minute and costs may be reduced substantially. The invention also provides the corrosion resistant substrates prepared by the method of the invention.
Inventors
- 👤 L Austin
- 👤 L Beale
- 👤 E Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 01:10
CPC Classifications
C; C25; C25D; C25D11/00; C25D11/38; C25D5/00; C25D5/48; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/923; Y10S428/924; Y10S428/926; Y10S428/9335; Y10S428/934; Y10S428/935; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12535; Y10T428/12556; Y10T428/1266; Y10T428/12667; Y10T428/12771; Y10T428/12785; Y10T428/12792; Y10T428/12799; Y10T428/12806; Y10T428/12826; Y10T428/12847
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
41 words
The method of claim 1 wherein the zinc coated ferrous metal substrate is steel electroplated with a coating of metallic zinc, the substrate being substantially free of an iron-zinc alloy layer between the steel base and the electroplated coating of zinc.
Claim 2
Dependent Claim
17 words
The method of claim 1 wherein the metallic chromium coating has a thickness of about 0.2-0.5 microinch.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein the metallic chromium coating has a thickness of about 0.1-0.3 microinch.
Claim 4
Dependent Claim
27 words
The method of claim 1 wherein the said metallic chromium and chromium oxide containing film contains a total of 0.6- 5 miligrams of chromium per square foot.
Claim 5
Dependent Claim
39 words
The method of claim 1 wherein the metallic chromium coating has a thickness of about 0.1-0.3 microinch and the said metallic chromium and chromium oxide containing film contains a total of about 0.8-1.5 milligrams of chromium per square foot.
Claim 6
Dependent Claim
25 words
The method of claim 1 wherein the zinc surface of the zinc coated steel substrate is brightened prior to electroplating the metallic chromium coating thereon.
Claim 7
Dependent Claim
20 words
The method of claim 1 wherein a protective organic coating is applied on the electrochemically treated metallic chromium coated substrate.
Claim 8
Dependent Claim
24 words
The method of claim 1 wherein the zinc coating on the zinc coated ferrous metal substrate contains 0.05-0.5 ounce of zinc per square foot.
Claim 9
Dependent Claim
20 words
The method of claim 1 wherein the zinc coated ferrous metal substrate is prepared by a hot dip galvanizing process.
Claim 10
Dependent Claim
17 words
The method of claim 10 wherein the metallic chromium coating has a thickness of about 0.2-0.5 microinch.
Claim 11
Dependent Claim
17 words
The method of claim 10 wherein the metallic chromium coating has a thickness of about 0.1-0.3 microinch.
Claim 12
Dependent Claim
26 words
The method of claim 10 wherein the said metallic chromium and chromium oxide containing film contains a total of 0.6-5 miligrams of chromium per square foot.
Claim 13
Dependent Claim
39 words
The method of claim 10 wherein the metallic chromium coating has a thickness of about 0.1-0.3 microinch and the said metallic chromium and chromium oxide containing film contains a total of about 0.8-1.5 miligrams of chromium per square foot.
Claim 14
Dependent Claim
26 words
The method of claim 10 wherein the zinc surface of the zinc coated ferrous metal substrate is brightened prior to electroplating the metallic chromium coating thereon.
Claim 15
Dependent Claim
20 words
The method of claim 10 wherein a protective organic coating is applied on the electrochemically treated metallic chromium coated substrate.
Claim 16
Dependent Claim
65 words
The method of claim 1 wherein the zinc coated ferrous metal substrate is zinc coated ferrous metal strip, the metallic chromium coating is electroplated thereon while passing through a high speed electroplating line at a strip speed of at least 500 feet per minute, and thereafter the metallic chromium coated substrate is electrochemically treated at a strip speed of at least 500 feet per minute.
Claim 17
Dependent Claim
54 words
The method of claim 17 wherein the said high speed electroplating line also includes a zinc electroplating zone and the zinc coating is electroplated on the steel strip as it is passing therethrough, The metallic chromium coating is electroplated on the zinc electroplated strip, and thereafter the metallic chromium coated strip is electrochemically treated.
Claim 18
Dependent Claim
24 words
The method of claim 18 wherein the zinc coating on the zinc coated ferrous metal substrate contains 0.05-0.5 ounce of zinc per square foot.
Claim 19
Dependent Claim
20 words
The method of claim 19 wherein a protective organic coating is applied on the electrochemically treated metallic chromium coated substrate.
Claim 20
Dependent Claim
27 words
The method of claim 17 wherein the zinc coated strip is rolled under pressure to brighten the surface prior to electroplating the said metallic chromium coating thereon.
Claim 21
Dependent Claim
20 words
The method of claim 1 wherein a protective organic coating is applied on the electrochemically treated metallic chromium coated substrate.
Claim 22
Dependent Claim
11 words
The corrosion resistant substrate prepared by the method of claim 22.
Claim 23
Dependent Claim
11 words
The corrosion resistant substrate prepared by the method of claim 1.
Claim 24
Dependent Claim
17 words
The method of claim 1 wherein the metallic chromium coating has a thickness of about 0.2-0.5 microinch.
Claim 25
Dependent Claim
17 words
The method of claim 1 wherein the metallic chromium coating has a thickness of about 0.1-0.3 microinch.
Claim 26
Dependent Claim
26 words
The method of claim 1 wherein the said metallic chromium and chromium oxide containing film contains a total of 0.6-5 miligrams of chromium per square foot.
Claim 27
Dependent Claim
28 words
The method of claim 1 wherein the zinc surface of the zinc coated ferrous metal substrate is brightened prior to the electrodeposition of the metallic chromium coating thereon.
Claim 28
Dependent Claim
24 words
The method of claim 1 wherein the zinc coating on the zinc coated ferrous metal substrate contains 0.05-0.5 ounce of zinc per square foot.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |