Permanent magnet containing rare earth metal, boron and iron
US5690752A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 27, 1995 |
| Grant date | Nov 25, 1997 |
| Priority date | — |
| Expiry date | Jul 27, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F1/0577
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A permanent magnet is obtained by pulverizing, molding and sintering a starting material containing an alloy ingot. The alloy ingot contains not less than 90% by volume of columnar crystals each having a columnar crystal grain size of 0.1 to 50 .mu.m along a short axis thereof and a columnar crystal grain size of larger than 100 .mu.m and not larger than 300 .mu.m along a long axis thereof, and is obtained by uniformly solidifying by a single roll method a molten alloy containing 25 to 31% by weight of a rare earth metal, 0.5 to 1.5% by weight of boron and iron under cooling conditions of a cooling rate of higher than 500.degree. C./sec. and not higher than 10,000.degree. C./sec. and a supercooling degree of 50.degree. to 500.degree. C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.