Rare earth magnet and method for producing the magnet
US7138017B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 21, 2003 |
| Grant date | Nov 21, 2006 |
| Priority date | — |
| Expiry date | Sep 25, 2024 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB22F2999/00
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method of making an alloy powder for an R—Fe—B-type rare earth magnet includes the steps of preparing a material alloy that is to be used for forming the R—Fe—B-type rare earth magnet and that has a chilled structure that constitutes about 2 volume percent to about 20 volume percent of the material alloy, coarsely pulverizing the material alloy for the R—Fe—B-type rare earth magnet by utilizing a hydrogen occlusion phenomenon to obtain a coarsely pulverized powder, finely pulverizing the coarsely pulverized powder and removing at least some of fine powder particles having particle sizes of about 1.0 μm or less from the finely pulverized powder, thereby reducing the volume fraction of the fine powder particles with the particle sizes of about 1.0 μm or less, and covering the surface of remaining ones of the powder particles with a lubricant after the step of removing has been performed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.