Powder mixture for use in compaction to produce rare earth iron sintered permanent magnets
US5486224A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Dec 27, 1994 |
| Grant date | Jan 23, 1996 |
| Priority date | — |
| Expiry date | Dec 27, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2991
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
To a fine R--Fe--B alloy powder comprised predominantly of 10-30 atomic % of R (wherein R stands for at least one element selected from rare earth elements including yttrium), 2-28 atomic % of B, and 65-82 atomic % of Fe in which up to 50 atomic % of Fe may be replaced by Co, at least one boric acid ester compound such as tributyl borate is added as a lubricant in a proportion of 0.01%-2% by weight and mixed uniformly before, during, or after fine grinding of the alloy powder. The resulting powder mixture is compacted by compression molding in a magnetic field and the green compacts are sintered and aged. Compression molding can be performed continuously without need of mold lubrication, and the resulting magnets have improved magnet properties with respect to residual flux density, maximum energy product, and intrinsic coercive force.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.