US4233169A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Porous magnetic glass structure
Assignee: Corning Glass Works
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Filing: 1979-04-13
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Granted: 1980-11-11
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Expires: 1999-04-13
Abstract
Abstract The present invention provides a method for making porous bodies of magnetic glass and/or crystal-containing materials having magnetic crystals incorporated therein with dimensions less than about 1000A. Preferably, the crystals have dimensions less than 500A such that the porous bodies demonstrate essential superparamagnetic behavior. The method involves preparing a body which, upon heat treatment, will separate into at least two vitreous phases and at least one crystal phase. One of the vitreous phases is etched away leaving a structure remaining which contains said magnetic crystals. When present as fine particles, the porous magnetic bodies are especially suitable for use in biological assays.
Inventors
- 👤 George H. Beall
- 👤 Gerald R. Mansfield
- 👤 Jan W. H. Schreurs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:53
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0081; C03C11/00; C03C11/005; C03C3/00; C03C3/04; C03C3/076; C03C3/089; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/34; H01F1/36; H01F1/37; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
87 words
Porous bodies of magnetic glass and/or crystal-containing material with interconnected pores less than 10,000 A in diameter and having iron-containing, magnetic crystals incorporated therein with dimensions of less than about 1000 A which are essentially enveloped within the glass and/or crystal structure, wherein said glass consists essentially of a vitreous silica skeleton with said magnetic crystals enveloped therewithin, said crystal-containing material consists essentially of a glassy-crystalline skeleton with said magnetic crystals enveloped therewithin, and said crystal portion of said glassy-crystalline skeleton consists essentially of a silica-containing species.
Claim 2
Dependent Claim
87 words
Porous bodies of magnetic glass and/or crystal-containing material with interconnected pores less than 10,000 A in diameter and having iron-containing, magnetic crystals incorporated therein with dimensions of less than about 1000 A which are essentially enveloped within the glass and/or crystal structure, wherein said glass consists essentially of a vitreous silica skeleton with said magnetic crystals enveloped therewithin, said crystal-containing material consists essentially of a glassy-crystalline skeleton with said magnetic crystals enveloped therewithin, and said crystal portion of said glassy-crystalline skeleton consists essentially of a silica-containing species.
Claim 3
Dependent Claim
35 words
Porous bodies according to claim 1 wherein said magnetic crystals are magnetite and/or solid solutions of magnetite with γ-Fe 2 O 3 and/or other ferrite solid solutions having crystal structures similar to that of magnetite.
Claim 4
Dependent Claim
31 words
Porous bodies according to claim 1 demonstrating essentially superparamagnetic behavior wherein said magnetic crystals have dimensions of less than 500 A and exhibit a coercive force of less than 100 oersteds.
Claim 5
Dependent Claim
19 words
Porous bodies according to claim 3 wherein said magnetic crystals exhibit a coercive force of less than 40 oersteds.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-11-11 | 1984-05-12 | 1984-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-11 | 1988-05-12 | 1988-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-11 | 1992-05-12 | 1992-11-11 | $7700.00 | Window Closed / Lapsed |