US4599184A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing ferromagnetic liquid
Assignee: National Research Institute
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Filing: 1985-01-29
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Granted: 1986-07-08
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Expires: 2005-01-29
Abstract
Abstract A process for producing a ferromagnetic liquid comprising fine particles of a ferromagnetic material and a surface-active liquid, which comprises a step of heating said ferromagnetic material to evaporate it, and a step of bringing the resulting vapor of the ferromagnetic material into contact with the surface-active liquid being stirred.
Inventors
- 👤 Isao Nakatani
- 👤 Katashi Masumoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:14
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/44
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
122 words
A process for producing a ferromagnetic liquid comprising fine particles of a ferromagnetic material having a particle diameter of 10-100 Å and a surface-active liquid, wherein a step of heating said ferromagnetic material to evaporate it and a step of bringing the resulting vapor of the ferromagnetic material obtained from said heating and evaporating step into contact with the surface-active liquid being stirred are carried out substantially simultaneously in one and the same vessel, the surface-active agent of the surface-active liquid having a saturation or dissociation vapor pressure of not more than 10 -1 mmHg at 50°-200° C., and the liquid of the surface-active liquid having a saturation or dissociation vapor pressure of not more than 10 -1 mmHg at 50° C.
Claim 2
Dependent Claim
122 words
A process for producing a ferromagnetic liquid comprising fine particles of a ferromagnetic material having a particle diameter of 10-100 Å and a surface-active liquid, wherein a step of heating said ferromagnetic material to evaporate it and a step of bringing the resulting vapor of the ferromagnetic material obtained from said heating and evaporating step into contact with the surface-active liquid being stirred are carried out substantially simultaneously in one and the same vessel, the surface-active agent of the surface-active liquid having a saturation or dissociation vapor pressure of not more than 10 -1 mmHg at 50°-200° C., and the liquid of the surface-active liquid having a saturation or dissociation vapor pressure of not more than 10 -1 mmHg at 50° C.
Claim 3
Dependent Claim
30 words
The process of claim 1 wherein the resulting vapor of the ferromagnetic material is brought into contact with the surface-active liquid being fluidized, and thereafter, the surface-active liquid is stirred.
Claim 4
Dependent Claim
31 words
The process of claim 1 wherein both the evaporating step and the contacting step are carried out in an atmosphere kept at a pressure of not more than 10 -1 mmHg.
Claim 5
Dependent Claim
34 words
The process of claim 1 wherein both the evaporating step and the contacting step are carried out in the presence of an inert gas under a gaseous pressure of not more than 760 mmHg.
Claim 6
Dependent Claim
24 words
The process of claim 4 wherein the inert gas is at least one gas selected from the group consisting of helium, neon and argon.
Claim 7
Dependent Claim
35 words
The process of claim 1 wherein both the evaporating step and the contacting step are carried out in the presence of a nitrogen gas under a gaseous pressure of 760 mmHg to 10 -5 mmHg.
Claim 8
Dependent Claim
33 words
The process of claim 1 wherein both the evaporating step and the contacting step are carried out in the presence of oxygen gas under a gaseous pressure of 200 to 10 -5 mmHg.
Claim 9
Dependent Claim
20 words
The process of claim 1 wherein the ferromagnetic material is a ferromagnetic metal, a ferromagnetic alloy or a ferromagnetic compound.
Claim 10
Dependent Claim
27 words
The process of claim 8 wherein the ferromagnetic metal is at least one metal selected from the group consisting of iron, cobalt, nickel and rare earth elements.
Claim 11
Dependent Claim
50 words
The process of claim 8 wherein the ferromagnetic alloy and the ferromagnetic compound contains as constituent elements at least one metal element selected from the group consisting of iron, cobalt, nickel and rare earth elements and/or at least one element selected from the group consisting of manganese, chromium and vanadium.
Claim 12
Dependent Claim
19 words
The process of claim 1 wherein the surface-active liquid contains 0.1 to 30% by weight of the surface-active agent.
References Cited (Backward Citations)
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US4197347A
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Cited
US4416751A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-07-07 | 1990-01-06 | 1990-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-07 | 1994-01-06 | 1994-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-07 | 1998-01-06 | 1998-07-08 | $7700.00 | Window Closed / Lapsed |