Iron-based oxide magnetic particle powder and method for producing iron-based oxide magnetic particle powder
US10504548B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 17, 2015 |
| Grant date | Dec 10, 2019 |
| Priority date | — |
| Expiry date | Feb 1, 2036 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S977/943
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An e-type iron-based oxide magnetic particle powder has narrow particle size distribution and has a low content of fine particles which do not contribute to magnetic recording characteristics. As a result, a narrow coercive force distribution is achieved and the powder is suitable for increasing recording density of a magnetic recording medium. The powder containing substituting metal elements can be obtained by: adding an alkali to an aqueous solution containing trivalent iron ions and ions of the metals for partially substituting Fe sites to neutralize the aqueous solution to a pH of 1.5 to 2.5; then adding a hydroxycarboxylic acid; further adding the alkali to neutralize the aqueous solution to a pH of 8.0 to 9.0; washing with water a precipitation of an iron oxyhydroxide containing the substituting metal elements produced; and coating the iron oxyhydroxide containing the substituting metal elements with a silicon oxide and heating the resultant.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.