R-T-B-based rare earth magnet particles, and bonded magnets containing R-T-B-based rare earth magnet particles
US11120932B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 12, 2014 |
| Grant date | Sep 14, 2021 |
| Priority date | — |
| Expiry date | Mar 12, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F1/0578
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An object of the present invention is to enhance a coercive force of magnetic particles by promoting formation of a continuous R-rich grain boundary phase in a crystal grain boundary of a magnetic phase of the particles, and to thereby obtain R-T-B-based rare earth magnet particles further having a high residual magnetic flux density. The present invention relates to production of R-T-B-based rare earth magnet particles capable of exhibiting a high coercive force even when a content of Al therein is reduced, and a high residual magnetic flux density, in which formation of an R-rich grain boundary phase therein can be promoted by heat-treating Al-containing R-T-B-based rare earth magnet particles obtained by HDDR treatment in vacuum or in an Ar atmosphere at a temperature of not lower than 670° C. and not higher than 820° C. for a period of not less than 30 min and not more than 300 min.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.