Iron-based oxide magnetic particle powder, method for producing same, coating material, and magnetic recording medium
US10622127B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 28, 2015 |
| Grant date | Apr 14, 2020 |
| Priority date | — |
| Expiry date | Nov 25, 2036 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N23/20075
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An iron-based oxide magnetic particle powder has a narrow particle size distribution a small content of fine particles that do not contribute to magnetic recording characteristics, and a narrow coercive force distribution, to enhance magnetic recording medium density. Neutralizing an aqueous solution containing a trivalent iron ion and an ion of the metal substituting a part of the Fe sites by adding an alkali to make pH of 1.5 or more and 2.5 or less, adding a hydroxycarboxylic acid, and further neutralizing by adding an alkali to make pH of 8.0 or more and 9.0 or less are performed at 5° C. or more and 25° C. or less. A formed iron oxyhydroxide precipitate containing the substituting metal element is rinsed with water, then coated with silicon oxide, and then heated thereby providing e-type iron-based oxide magnetic particle powder. The rinsed precipitate may be subjected to a hydrothermal treatment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.