Process for the controlled preparation of a composite of ultrafine magnetic particles homogeneously dispersed in a dielectric matrix
US5316699A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 28, 1990 |
| Grant date | May 31, 1994 |
| Priority date | — |
| Expiry date | Mar 28, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F1/0009
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A chemical process for producing bulk quantities of an iron-silica gel composite in which particle size, form, and magnetic state of the iron can be selected. The process involves polymerizing an ethanolic solution of tetraethylorthosilicate, ferric nitrate and water at low temperature under the influence of an HF catalyst. The chemical and magnetic states of the iron in the resultant composite are modified in situ by exposure to suitable oxidizing or reducing agents at temperatures under 400.degree. C. Iron-containing particles of less than 200 .ANG. diameter, homogeneously dispersed in silica matrices may be prepared in paramagnetic, superparamagnetic, ferrimagnetic and ferromagnetic states.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.