Permanent magnet with inter-grain heavy-rare-earth element, and method of producing same
US11830645B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 2, 2020 |
| Grant date | Nov 28, 2023 |
| Priority date | — |
| Expiry date | May 23, 2042 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F41/0293
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A manufacturing method of a sintered magnet is described. The method includes forming a pre-sintering body from a first magnetic powder and a second magnetic powder (containing a heavy rare earth element, HRE) so that at least part of the second magnetic powder is provided at at least one inner portion of the pre-sintering body and surrounded format least two opposite sides by the first magnetic powder; sintering the pre-sintering body; and annealing the sintered pre-sintering body at an annealing temperature lower than the sintering temperature, thereby causing inter-grain diffusion of HRE from the HRE reservoir zone to the grain boundary phase. After the annealing, the grain boundary phase contains the HRE in a higher concentration than the main phase.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.