Magnetically anisotropic spherical powder and method of making same
US5474623A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 28, 1993 |
| Grant date | Dec 12, 1995 |
| Priority date | — |
| Expiry date | May 28, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F1/0573
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method of forming a magnetically anisotropic powder includes the steps of forming a substantially spherical powder having a major magnetic phase and an average particle size of less than about 200 microns, diffusing hydrogen into the spherical powder at elevated temperatures in an amount sufficient to disproportionate the major magnetic phase, and desorbing the hydrogen by heating the disproportionated powder under vacuum. The magnetic material from which the spherical powder is formed may be a rare earth-transition metal-boron alloy including at least one element from the iron group, at least one rare earth element, and boron. A method of forming a bonded magnet containing magnetically anisotropic particles further includes the steps of mixing the dehydrogenated powder with a binder to form a mixture, and aligning and magnetizing the powder particles in the mixture in a magnetic field. Bonded magnets containing spherical, magnetically anisotropic particles of the invention have intrinsic coercivities in excess of 7 kOe.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.