The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 03, 1996
Filed:
Oct. 05, 1994
Daniel Fruchart, Echirolles, FR;
Salvatore Miraglia, Grenoble, FR;
Paul Mollard, Domene, FR;
Rene Perrier de la Bathie, Saint Pierre d'Albigny, FR;
Robert Fruchart, La Tronche, FR;
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 two post-treatments are optionally separated by a thermal plateau.