US3840378A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Insulative coatings for electrical steels
Assignee: Armco Inc
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Filing: 1972-03-23
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Granted: 1974-10-08
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Expires: 1992-03-23
Abstract
Abstract Insulative coatings for electrical steels having improved resistance to deterioration during stress relief anneals or other heat treatments carried on in reducing atmospheres. They may be produced by coating electrical steel with an aqueous solution of phosphoric acid, magnesium oxide and one or more additional mineral acids present in an amount sufficient to adjust the pH level of the solution to from about 0.5 to about 3.0. The mole ratio Mg/PO4 should be from about 0.6 to about 1.5.
Inventors
- 👤 J Evans
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:52
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/147; H01F1/14766; H01F1/14775; H01F1/14783; C; C23; C23C; C23C22/00; C23C22/73; C23C22/74; C23C24/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
57 words
A COMPOSITION FOR FORMING AN INSULATIVE COATING DIRECTLY ON ORIENTED SILICON STEEL FOR ELECTRICAL USES ANS AN ORIENTED SILICON STEEL HAVING A MILL GLASS THEREON, SAID COMPOSITION COMPRISING AN AQUEOUS SOLUTION HAVING A MG/PO4 RATIO OF FROM ABOUT 0.6 TO ABOUT 1.5, SAID SOLUTION CONSISTING ESSENTIALLY OF AN AQUEOUS SOLUTION OF PHOSPHORIC ACID, MAGNESIA, AND AT LEAST
Claim 2
Dependent Claim
57 words
A COMPOSITION FOR FORMING AN INSULATIVE COATING DIRECTLY ON ORIENTED SILICON STEEL FOR ELECTRICAL USES ANS AN ORIENTED SILICON STEEL HAVING A MILL GLASS THEREON, SAID COMPOSITION COMPRISING AN AQUEOUS SOLUTION HAVING A MG/PO4 RATIO OF FROM ABOUT 0.6 TO ABOUT 1.5, SAID SOLUTION CONSISTING ESSENTIALLY OF AN AQUEOUS SOLUTION OF PHOSPHORIC ACID, MAGNESIA, AND AT LEAST
Claim 3
Dependent Claim
17 words
The composition claimed in claim 1 wherein said mole ratio is from about 0.7 to about 1.3.
Claim 4
Dependent Claim
29 words
The composition claimed in claim 1 wherein said substance is present in an amount sufficient for said solution to have a pH of from about 1 to about 2.
Claim 5
Dependent Claim
119 words
A composition for forming an insulative coating directly on oriented silicon steel for electrical uses and an oriented silicon steel having a mill glass thereon, said composition comprising an aqueous solution having a Mg/PO4 radical mole ratio of from about 0.6 to about 1.5, said solution consisting essentially of an aqueous solution of compounds chosen from the class consisting of mono-basic magnesium phosphate plus magnesia, di-basic magnesium phosphate, tri-basic magnesium phosphate plus phosphoric acid and magnesia plus phosphoric acid, plus at least one substance chosen from the class consisting of sulfuric acid, nitric acid and magnesium salts thereof, said substance being present in an amount sufficient for said solution to have a pH of from about 0.5 to 3.0.
Claim 6
Dependent Claim
119 words
A composition for forming an insulative coating directly on oriented silicon steel for electrical uses and an oriented silicon steel having a mill glass thereon, said composition comprising an aqueous solution having a Mg/PO4 radical mole ratio of from about 0.6 to about 1.5, said solution consisting essentially of an aqueous solution of compounds chosen from the class consisting of mono-basic magnesium phosphate plus magnesia, di-basic magnesium phosphate, tri-basic magnesium phosphate plus phosphoric acid and magnesia plus phosphoric acid, plus at least one substance chosen from the class consisting of sulfuric acid, nitric acid and magnesium salts thereof, said substance being present in an amount sufficient for said solution to have a pH of from about 0.5 to 3.0.
Claim 7
Dependent Claim
17 words
The composition claimed in claim 4 wherein said mole ratio is from about 0.7 to about 1.3.
Claim 8
Dependent Claim
29 words
The composition claimed in claim 4 wherein said substance is present in an amount sufficient for said solution to have a pH of from about 1 to about 2.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-07 | 1978-04-08 | 1978-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-07 | 1982-04-08 | 1982-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-07 | 1986-04-08 | 1986-10-08 | $7700.00 | Window Closed / Lapsed |