Rare earth permanent magnets and their preparation
US11482377B2 · kind B2 · utility
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Key dates
| Filing date | Feb 26, 2020 |
| Grant date | Oct 25, 2022 |
| Priority date | — |
| Expiry date | Jul 10, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F1/0577
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A sintered magnet body (RaT1bMcBd) coated with a powder mixture of an intermetallic compound (R1iM1j, R1xT2yM1z, R1iM1jHk), alloy (M1dM2e) or metal (M1) powder and a rare earth (R2) oxide is diffusion treated. The R2 oxide is partially reduced during the diffusion treatment, so a significant amount of R2 can be introduced near interfaces of primary phase grains within the magnet through the passages in the form of grain boundaries. The coercive force is increased while minimizing a decline of remanence.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.