R-T-B sintered permanent magnet
US6468365B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1999 |
| Grant date | Oct 22, 2002 |
| Priority date | — |
| Expiry date | Oct 14, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F41/0293
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An R—T—B sintered permanent magnet having a composition including 28-33 weight % of R, and 0.5-2 weight % of B, the balance being substantially T and inevitable impurities, wherein R is at least one rare earth element including Y, at least one heavy rare earth element selected from the group consisting of Dy, Tb and Ho being indispensable, and T is Fe or Fe and Co, the permanent magnet having a crystal structure comprising first R2T14B-type, main-phase crystal grain particles having a higher heavy rare earth element concentration than that of a crystal grain boundary phase, and second R2T14B-type, main-phase crystal grain particles having a lower heavy rare earth element concentration than that of the crystal grain boundary phase.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.