Method of making magnetically attractable particles
US5039559A · kind A · utility
37Cited by
9References
11Claims
0Family size
Inventors
Key dates
| Filing date | Nov 22, 1989 |
| Grant date | Aug 13, 1991 |
| Priority date | — |
| Expiry date | Nov 22, 2009 |
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., recoverd, 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.