Magnetic fluid and process for the production thereof
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United States of America Patent
Stats
-
Aug 27, 2002
Grant Date -
N/A
app pub date -
Jun 9, 2000
filing date -
Sep 16, 1997
priority date (Note) -
Expired
status (Latency Note)
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Abstract
A magnetic fluid and a process for producing the same are provided. The magnetic fluid is an excellent fluid which mightily and precisely actuates by the action of an external magnetic field so that its viscosity can be significantly increased and be easily and precisely controlled by regulating the external magnetic field applied thereto. The magnetic fluid is also excellent in the unsusceptibility to oxidation and dispersibility of the particles and has a sufficiently wide viscosity range. The magnetic fluid comprises magnetic metal particles coated with an oxidation-preventive film stably dispersed in a solvent, wherein the dispersion conditions are maintained, and the process for producing the fluid comprises forming an oxide film on the surface of raw oxide particles of magnetic metal particles, reducing the raw oxide particles coated with the oxide film to obtain magnetic metal particles coated with an oxidation-preventive film, and stably dispersing the magnetic metal particles coated with an oxidation-preventive film in a solvent.

First Claim
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- 15 United States
- 10 France
- 8 Japan
- 7 China
- 5 Korea
- 2 Other
Patent Owner(s)
Patent Owner | Address | |
---|---|---|
NITTETSU MINING CO LTD | TOKYO 100-8377 | |
NAKATSUKA KATSUTO | TAIHAKU-KU 3-5-1403 MONIWADAI 4-CHOME SENDAI-SHI MIYAGI |
International Classification(s)
Inventor(s)
Inventor Name | Address | # of filed Patents | Total Citations |
---|---|---|---|
Atarashi, Takafumi | Tokyo, JP | 23 | 270 |
Fujita, Toyohisa | Akita, JP | 7 | 48 |
Kim, Young-sam | Pusan, KR | 40 | 339 |
Nakatsuka, Katsuto | 3-5-1403, Moniwadai 4-chome, Taihaku-ku, Sendai-shi, Miyagi 982-0252, JP | 23 | 277 |
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Maintenance Fees
Fee | Large entity fee | small entity fee | micro entity fee | due date |
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Fee | Large entity fee | small entity fee | micro entity fee |
---|---|---|---|
Surcharge after expiration - Late payment is unavoidable | $700.00 | $350.00 | $175.00 |
Surcharge after expiration - Late payment is unintentional | $1,640.00 | $820.00 | $410.00 |
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