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US4360441A
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Glass-encapsulated magnetic materials and methods for making them
Assignee: Corning Glass Works
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Filing: 1981-06-25
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Granted: 1982-11-23
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Expires: 2001-06-25
Abstract
Abstract Magnetic materials exhibiting ferrimagnetic and/or superparamagnetic behavior, produced by impregnating porous glasses with iron and, optionally, manganese, cobalt and nickel compounds, reacting the compounds with the porous glass to form bound complexes, heating the glass to expel unreacted organometallics, and further heating to convert the bound complexes to ferrimagnetic and/or superparamagnetic oxide crystallites, are described. Ferrimagnetic iron oxide crystallites exhibiting coercivities above 10,000 Oe can be made.
Inventors
- 👤 Nicholas F. Borrelli
- 👤 David L. Morse
- 👤 Jan W. H. Schreurs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:06
CPC Classifications
C; C03; C03C; C03C23/00; C03C23/0095; C03C10/00; C03C10/0081
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
65 words
A ferrimagnetic material consisting of ferrimagnetic iron oxide crystallites dispersed in a glass matrix, the crystallites being selected from the group consisting of gamma-Fe 2 O 3 , Fe 3 O 4 , and mixtures or solid solutions thereof, said crystallites having a maximum diameter not exceeding about 0.05 microns and said material having a coercivity of at least about 1000 Oe at 25° C.
Claim 2
Dependent Claim
65 words
A ferrimagnetic material consisting of ferrimagnetic iron oxide crystallites dispersed in a glass matrix, the crystallites being selected from the group consisting of gamma-Fe 2 O 3 , Fe 3 O 4 , and mixtures or solid solutions thereof, said crystallites having a maximum diameter not exceeding about 0.05 microns and said material having a coercivity of at least about 1000 Oe at 25° C.
Claim 3
Independent Claim
73 words
A method of making a ferrimagnetic material which comprises the steps of: impregnating a porous glass with an organometallic iron compound; reacting the iron compound with the pore walls of the porous glass at a temperature below the thermal decomposition temperature of the iron compound; and heating the glass to a temperature at least sufficient to expel unreacted iron compound from the glass and convert the iron in the glass to iron oxide.
Claim 4
Independent Claim
73 words
A method of making a ferrimagnetic material which comprises the steps of: impregnating a porous glass with an organometallic iron compound; reacting the iron compound with the pore walls of the porous glass at a temperature below the thermal decomposition temperature of the iron compound; and heating the glass to a temperature at least sufficient to expel unreacted iron compound from the glass and convert the iron in the glass to iron oxide.
Claim 5
Dependent Claim
16 words
A method in accordance with claim 2 wherein the porous glass is a 96% silica glass.
Claim 6
Dependent Claim
16 words
A method in accordance with claim 2 wherein the organometallic iron compound is an iron carbonyl.
Claim 7
Dependent Claim
16 words
A method in accordance with claim 4 wherein the organometallic iron compound is [Fe(CO) 5 ].
Claim 8
Dependent Claim
22 words
A method in accordance with claim 2 wherein the organometallic compound is photolytically reacted with the pore walls of the porous glass.
Claim 9
Dependent Claim
14 words
A method in accordance with claim 2 wherein the glass is heated in air.
Claim 10
Dependent Claim
46 words
A method in accordance with claim 7 wherein the glass is heated to a temperature sufficient to convert the iron therein to iron oxide crystallites selected from the group consisting of gamma-Fe 2 O 3 , Fe 3 O 4 and mixtures and solid solutions thereof.
Claim 11
Dependent Claim
21 words
A method in accordance with claim 7 wherein the glass is heated to a temperature sufficient to consolidate the pores thereof.
Claim 12
Independent Claim
87 words
A method of making a superparamagnetic material which comprises the steps of: impregnating a porous glass with an organometallic iron compound and at least one compound selected from the group consisting of organometallic manganese, nickel and cobalt compounds; reacting the compounds with the pore walls of the porous glass at a temperature below the thermal decomposition temperatures of the compounds; and heating the glass to a temperature at least sufficient to expel unreacted organometallic compounds from the glass and to convert the metals therein to metal oxides.
Claim 13
Independent Claim
87 words
A method of making a superparamagnetic material which comprises the steps of: impregnating a porous glass with an organometallic iron compound and at least one compound selected from the group consisting of organometallic manganese, nickel and cobalt compounds; reacting the compounds with the pore walls of the porous glass at a temperature below the thermal decomposition temperatures of the compounds; and heating the glass to a temperature at least sufficient to expel unreacted organometallic compounds from the glass and to convert the metals therein to metal oxides.
Claim 14
Dependent Claim
23 words
A method in accordance with claim 10 wherein the glass is heated to a temperature sufficient to consolidate the pores of the glass.
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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) | 1985-11-22 | 1986-05-24 | 1986-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-22 | 1990-05-24 | 1990-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-22 | 1994-05-24 | 1994-11-23 | $7700.00 | Window Closed / Lapsed |