R-T-B based permanent magnet
US11837392B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 2021 |
| Grant date | Dec 5, 2023 |
| Priority date | — |
| Expiry date | May 25, 2042 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C2202/02
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A permanent magnet includes a rare earth element R; a transition metal element T; and B. The permanent magnet includes Nd as R. The permanent magnet includes Fe as T. The permanent magnet contains main phase grains and R-rich phases. The main phase grains include R, T, and B. The R-rich phases include R. The main phase grains observed in a cross section of the permanent magnet are flat. The cross section is parallel to an easy magnetization axis direction of the permanent magnet. Each of the R-rich phases is located between the main phase grains. An average value of intervals between the R-rich phases in a direction substantially perpendicular to the easy magnetization axis direction is from 30 μm to 1,000 μm. An average value of lengths of short axes of the main phase grains observed in the cross section is from 20 nm to 200 nm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.