Permanent magnets and methods for their fabrication
US5781843A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 20, 1994 |
| Grant date | Jul 14, 1998 |
| Priority date | — |
| Expiry date | Oct 20, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB22F2998/10
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Novel permanent magnets of Sm.sub.2 Co.sub.17 type crystal structure are provided herein. The magnets preferably have samarium, cobalt, iron, copper and zirconium in specified amounts. They have superior magnetic properties, including maximum energy product, intrinsic coercivity and second quadrant loop squareness. The compositions of the magnets can be expressed by a general formula Co.sub.a Fe.sub.b Cu.sub.c Zr.sub.d !.sub.e Sm. Preferred embodiments, wherein a is about 0.6 to about 0.7, b is about 0.2 to about 0.3, c is about 0.06 to about 0.07, d is about 0.02 to about 0.03, and e is about 7.2 to about 7.4, have unexpectedly high maximum energy product, high intrinsic coercive force and squareness. Processes for producing the improved alloy are also provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.