Acicular ferromagnetic iron oxide particles and process for producing the same
US5512194A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1994 |
| Grant date | Apr 30, 1996 |
| Priority date | — |
| Expiry date | Jun 7, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/70668
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
There are provided acicular berthollide particles comprising crystalline particles expressed by the formula FeOx (1.33.ltoreq.x<1.5) and modified with a specific amount of zinc ions and a process producing the same which comprises the steps of oxidizing acicular magnetic iron oxide particles expressed by the formula FeOx (1.0<x<1.33) and modified with a specific amount of zinc ions which are produced by (a) heating and dehydrating acicular hydrous iron oxide particles containing a specific amount of a zinc component, reducing, and heating the particles under specific conditions, or (b) reducing acicular iron oxide particles containing a specific amount of a zinc component and heating the particles under specific conditions, or (c) heating acicular magnetic iron oxide particles expressed by the formula FeOx (1.0<x<1.33) containing a specific amount of zinc ions under specific conditions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.