US5030332A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making magnetic oxide precipitates
Assignee: Massachusetts Institute of Technology
•
Filing: 1990-04-19
•
Granted: 1991-07-09
•
Expires: 2010-04-19
Abstract
Abstract A mixture including at least one iron oxide and a mon-magnetic matrix material is melted or vaporized and then heat is rapidly removed from the material. The resulting magnetic oxide precipitates are densely packed in the non-magnetic matrix. The precipitates have a narrow particle size distribution which results in a high signal-to-noise ratio when the oxides are used for magnetic recording purposes. The non-magnetic matrix can be removed to yield homogeneous, small particle iron oxide containing magnetic powder. Alternatively, the non-magnetic matrix/iron oxide material can be processed to yield a shaped recording medium.
Inventors
- 👤 Laura J. Henderson
- 👤 Benjamin L. Averbach
- 👤 Robert C. O'Handley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:47
CPC Classifications
C; C01; C01G; C01G49/00; C01G49/02; C01G49/06; G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/84; G11B5/851; C01P; C01P2004/00; C01P2004/01; C01P2004/03; C01P2004/60; C01P2004/62; C01P2004/80; C01P2004/82; C01P2006/00; C01P2006/42; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 48
Claim 1
Independent Claim
48 words
A method for producing iron oxide containing magnetic oxide precipitates embedded in a non-magnetic glass matrix for recording media comprising: forming a mixture including at least one iron oxide and a matrix material; melting or vaporizing the mixture; and rapidly removing heat from the melted or vaporized mixture.
Claim 2
Independent Claim
48 words
A method for producing iron oxide containing magnetic oxide precipitates embedded in a non-magnetic glass matrix for recording media comprising: forming a mixture including at least one iron oxide and a matrix material; melting or vaporizing the mixture; and rapidly removing heat from the melted or vaporized mixture.
Claim 3
Independent Claim
52 words
A method for producing iron oxide containing magnetic oxide powder comprising: forming a mixture including at least one iron oxide and a melting the mixture; rapidly removing heat from the melted mixture to form an iron oxide/matrix material solid; removing the matrix material; and collecting the iron oxide containing magnetic oxide particles.
Claim 4
Independent Claim
52 words
A method for producing iron oxide containing magnetic oxide powder comprising: forming a mixture including at least one iron oxide and a melting the mixture; rapidly removing heat from the melted mixture to form an iron oxide/matrix material solid; removing the matrix material; and collecting the iron oxide containing magnetic oxide particles.
Claim 5
Independent Claim
73 words
A method for producing a recording medium from iron oxide containing magnetic oxide precipitates embedded in a non-magnetic matrix comprising: forming a mixture including at least one iron oxide and a matrix material; melting the mixture; rapidly removing heat from the melted mixture to form an iron oxide/matrix material solid; crushing the iron oxide/matrix material solid; forming the crushed iron oxide/matrix material into shaped articles; sintering the shaped articles to produce recording media.
Claim 6
Independent Claim
73 words
A method for producing a recording medium from iron oxide containing magnetic oxide precipitates embedded in a non-magnetic matrix comprising: forming a mixture including at least one iron oxide and a matrix material; melting the mixture; rapidly removing heat from the melted mixture to form an iron oxide/matrix material solid; crushing the iron oxide/matrix material solid; forming the crushed iron oxide/matrix material into shaped articles; sintering the shaped articles to produce recording media.
Claim 7
Independent Claim
86 words
A method for producing a recording medium from iron oxide containing magnetic oxide precipitates embedded in a non-magnetic matrix comprising: forming a mixture including at least one iron oxide and a matrix material; melting the mixture; rapidly removing heat from the melted mixture to form an iron oxide/matrix material solid; removing the matrix material; collecting the iron oxide containing magnetic oxide particles; combining the particles with a liquid dispersant to form an ink; and painting the ink on a shaped substrate to produce a recording medium.
Claim 8
Independent Claim
86 words
A method for producing a recording medium from iron oxide containing magnetic oxide precipitates embedded in a non-magnetic matrix comprising: forming a mixture including at least one iron oxide and a matrix material; melting the mixture; rapidly removing heat from the melted mixture to form an iron oxide/matrix material solid; removing the matrix material; collecting the iron oxide containing magnetic oxide particles; combining the particles with a liquid dispersant to form an ink; and painting the ink on a shaped substrate to produce a recording medium.
Claim 9
Independent Claim
93 words
A method for producing a recording medium from iron oxide containing magnetic oxide precipitates embedded in a non-magnetic matrix comprising: forming a mixture including at least one iron oxide and a matrix material: melting the mixture; rapidly removing heat from the melted mixture to form an iron oxide/matrix material solid; removing the matrix material; collecting the iron oxide containing magnetic oxide particles; combining the particles with binders and elastomers to produce a preform; applying the preform to a shaped substrate; and sintering the preform and shaped substrate to produce a magnetic recording medium.
Claim 10
Independent Claim
93 words
A method for producing a recording medium from iron oxide containing magnetic oxide precipitates embedded in a non-magnetic matrix comprising: forming a mixture including at least one iron oxide and a matrix material: melting the mixture; rapidly removing heat from the melted mixture to form an iron oxide/matrix material solid; removing the matrix material; collecting the iron oxide containing magnetic oxide particles; combining the particles with binders and elastomers to produce a preform; applying the preform to a shaped substrate; and sintering the preform and shaped substrate to produce a magnetic recording medium.
Claim 11
Independent Claim
20 words
A method according to claims 1, 2, 3, 4 or 5 wherein the matrix material comprises a glass network former.
Claim 12
Dependent Claim
55 words
The method according to claim 6 wherein the matrix material comprises one or more glass network formers selected from the group consisting of: SiO 2 , B 2 O 3 , P 2 O 5 , GeO 2 , As 2 O 5 , Sb 2 O 5 , or Zr 2 O 5 .
Claim 13
Independent Claim
16 words
The method of claims 1, 2, 3, 4, or 5 wherein the matrix material comprises cristobalite.
Claim 14
Independent Claim
20 words
The method of claims 1, 2, 3, 4, or 5 wherein the iron oxide comprises α-Fe 2 O 3 .
Claim 15
Independent Claim
24 words
The method of claims 1, 2, 3, 4, or 5 wherein the mixture comprises α-Fe 2 O 3 and Fe 3 O 4 .
Claim 16
Independent Claim
19 words
The method of claims 1, 2, 3, 4, or 5 wherein the mixture further includes a transition metal oxide.
Claim 17
Dependent Claim
48 words
The method according to claim 11 wherein the transition metal oxide includes one or more transition metal oxides selected from the group consisting of: Sc 2 O 3 , TiO 2 , V 2 O 5 , CrO 3 , MnO 7 , CoO, NiO, CuO, or ZnO.
Claim 18
Independent Claim
20 words
The method according to claims 1, 2, 3, 4, or 5 wherein the mixture further includes a rare earth oxide.
Claim 19
Dependent Claim
53 words
The method according to claim 13 wherein the rare earth oxide includes one or more rare earth oxides selected from the group consisting of: cerium oxide, praseodymium oxide, meodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide or lutetium oxide.
Claim 20
Independent Claim
33 words
The method of claims 1, 2, 3, 4, or 5 wherein the mixture is made by: comminuting the iron oxide and matrix material to form a powder; and pressing and sintering the powder.
Claim 21
Dependent Claim
17 words
The method according to claim 15 wherein the iron oxide and matrix material are comminuted by ball-milling.
Claim 22
Dependent Claim
32 words
The method according to claim 11 wherein the mixture is made by: comminuting the iron oxide, transition metal oxide and matrix material to form a powder; and pressing and sintering the powder.
Claim 23
Dependent Claim
20 words
The method according to claim 17 wherein the iron oxide, transition metal oxide and matrix material are comminuted by ball-milling.
Claim 24
Dependent Claim
32 words
The method according to claim 13 wherein the mixture is made by: comminuting the iron oxide, rare earth oxide and matrix material to form a powder; and pressing and sintering the powder.
Claim 25
Dependent Claim
20 words
The method according to claim 19 wherein the iron oxide, rare earth oxide and matrix material are comminuted by ball-milling.
Claim 26
Dependent Claim
28 words
The method according to claim 16 wherein the iron oxide and matrix material are ball-milled in acetone, dried, pressed into rods, and sintered in flowing O 2 .
Claim 27
Dependent Claim
31 words
The method according to claim 18 wherein the iron oxide, transition metal oxide and matrix material are ball-milled in acetone, dried, pressed into rods, and sintered in flowing O 2 .
Claim 28
Dependent Claim
31 words
The method according to claim 20 wherein the iron oxide, rare earth oxide and matrix material are ball-milled in acetone, dried, pressed into rods, and sintered in flowing O 2 .
Claim 29
Dependent Claim
29 words
The method according to claim 21 wherein the iron oxide is Fe 3 O 4 , the matrix material is SiO 2 , and sintering is at 1435° C.
Claim 30
Dependent Claim
18 words
The method according to claim 21 wherein the mixture further includes CoO and is sintered at 950° C.
Claim 31
Independent Claim
28 words
The method of claims 1, 2, 3, 4, or 5 wherein the mixture comprises CoFe 2 O 4 , (Co,Fe) 2 O 3 and a glass network former.
Claim 32
Independent Claim
21 words
The method of claims 1, 2, 3, 4, or 5 wherein the rapid heat removal is effected by double roller quenching.
Claim 33
Independent Claim
22 words
The method of claims 1, 2, 3, 4, or 5 wherein the mixture is melted with an H 2 --O 2 torch.
Claim 34
Independent Claim
21 words
The method of claims 1, 2, 3, 4, or 5 wherein the rapid heat removal is effected by the gun technique.
Claim 35
Independent Claim
20 words
The method of claims 1, 2, 3, 4, or 5 wherein the rapid heat removal is effected by splat quenching.
Claim 36
Independent Claim
21 words
The method of claims 1, 2, 3, 4, or 5 wherein the rapid heat removal is effected by single roller quenching.
Claim 37
Independent Claim
20 words
The method of claims 1, 2, 3, 4, or 5 wherein the rapid heat removal is effected by melt extraction.
Claim 38
Independent Claim
19 words
The method of claims 1, 2, 3, 4, or 5 wherein the rapid heat removal is effected by atomization.
Claim 39
Independent Claim
20 words
The method of claims 1, 2, 3, 4, or 5 wherein the rapid heat removal is effected by melt spinning.
Claim 40
Independent Claim
20 words
The method of claims 1, 2, 3, 4, or 5 wherein the rapid heat removal is effected by laser glazing.
Claim 41
Dependent Claim
17 words
The method of claim 1 wherein the rapid heat removal is effected by sputtering onto a substrate.
Claim 42
Independent Claim
27 words
The method of claims 1, 2, 3, 4, or 5 wherein the rapid heat removal results in a cooling rate greater than 10 3 K per second.
Claim 43
Dependent Claim
22 words
The method of claim 1 wherein the rapid heat removal results in a cooling rate of approximately 10 12 K per second.
Claim 44
Independent Claim
15 words
The method of claims 2, 4, or 5 wherein the matrix is removed by dissolution.
Claim 45
Independent Claim
18 words
The method of claims 3, 4, or 5 wherein the shape of the recording medium is a disk.
Claim 46
Independent Claim
18 words
The method of claims 3, 4 or 5 wherein the shape of the recording medium is a drum.
Claim 47
Dependent Claim
11 words
The method of claim 36 wherein the substrate is a metal.
Claim 48
Independent Claim
31 words
The method of claims 1, 2, 3, 4, or 5 wherein the rapid heat removal results in a cooling rate in the range of 10 5 -10 6 K per second.
References Cited (Backward Citations)
US3947373A
Cited
US4133677A
Cited
US4083727A
Cited
JPS55129935A
Cited
JPS5778631A
Cited
JPS586528A
Cited
JPS5914608A
Cited
US4690768A
Cited
US4650712A
Cited
JPS60129922A
Cited
JPS60178607A
Cited
JPS6136048A
Cited
JPS6180618A
Cited
US4697744A
Cited
US4820581A
Cited
US4820565A
Cited
US4816311A
Cited
JPS6242315A
Cited
US4668355A
Cited
JPS6295735A
Cited
JPS62125526A
Cited
JPS62125533A
Cited
US4698140A
Cited
JPS63925A
Cited
JPS62241134A
Cited
US4820584A
Cited
JPS6317775A
Cited
JPS6341852A
Cited
JPS6362205A
Cited
US4814239A
Cited
US4816119A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-07-08 | 1995-01-07 | 1995-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-08 | 1999-01-07 | 1999-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-08 | 2003-01-07 | 2003-07-09 | $7700.00 | Window Closed / Lapsed |