Treatment of pulverant magnetic materials and products thus obtained
US5580396A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 5, 1994 |
| Grant date | Dec 3, 1996 |
| Priority date | — |
| Expiry date | Oct 5, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F1/0573
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
There is disclosed a process for optimizing the magnetic properties of a multiphase product of composition rare earth/iron/boron endowed with permanent magnet properties at ambient temperature. This composition serves as a precursor, which is first subjected to a decrepitation treatment by hydrogenation under low pressure at low temperature to obtain an intermediate hydride in pulverulent form. The pulverulent intermediate hydride is subsequently subjected to a first heat treatment under vacuum for partial dehydrogenation at a temperature below its element separation temperature. The non-separated product thereby obtained is subjected to a second heat post-treatment under an initial primary vacuum and extensively dehydrogenated until the primary vacuum is reestablished at a temperature close to 600.degree. C. The precursor can be an isotropic material obtained by fast quenching, such as wheel quenching or hot welding with a forging ratio of at least 10. According to another aspect of the invention the dehydrogenated product obtained is subjected to a third heat post-treatment under a neutral atmosphere or under vacuum, at a temperature of between 450.degree. and 1000.degree. C. The…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.