Magnetically attractable particles and method
US5662824A · kind A · utility
23Cited by
10References
10Claims
0Family size
Assignee
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Key dates
| Filing date | Nov 29, 1994 |
| Grant date | Sep 2, 1997 |
| Priority date | — |
| Expiry date | Nov 29, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2989
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Magnetically attractable particles comprise a core of magnetic material encapsulated in a metal oxide coating. They may be made by emulsifying an aqueous solution or dispersion of the magnetic material or precursor, and an aqueous solution or sol of a coating inorganic oxide or precursor, in an inert water-immiscible liquid. The aqueous droplets are gelled, e.g. by ammonia or an amine, recovered, and heated at 250.degree.-2000.degree. C. The resulting particles are generally smooth spheres below 100 microns in diameter and often of sub-micron size.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.