Metal treatment – Stock – Magnetic
Reexamination Certificate
2007-02-20
2007-02-20
Sheehan, John P. (Department: 1742)
Metal treatment
Stock
Magnetic
C148S301000
Reexamination Certificate
active
11157816
ABSTRACT:
The object of the present invention is to provide a rare earth magnet which enables to achieve a good balance between high coercive force and high residual magnetic flux density, and its manufacturing method. The present invention provides a rare earth magnet in which a layered grain boundary phase is formed on a surface or a potion of a grain boundary of Nd2Fe14B which is a main phase of an R—Fe—B (R is a rare-earth element) based magnet, and wherein the grain boundary phase contains a fluoride compound, and wherein a thickness of the fluoride compound is 10 μm or less, or a thickness of the fluoride compound is from 0.1 μm to 10 μm, and wherein the coverage of the fluoride compound over a main phase particle is 50% or more on average. Moreover, after layering fluoride compound powder, which is formed in plate-like shape, in the grain boundary phase, the rare earth magnet is manufactured by quenching the layered compound after melting it at a vacuum atmosphere at a predetermined temperature, or by heating and pressing the main phase and the fluoride compound to make the fluoride compound into a layered fluoride compound along the grain boundary phase.
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patent: 6960240 (2005-11-01), Hirota et al.
patent: 2003/0106615 (2003-06-01), Hirota et al.
patent: 2005/0081959 (2005-04-01), Kim et al.
patent: 2003-282312 (2003-10-01), None
Komuro Matahiro
Satsu Yuichi
Antonelli, Terry Stout and Kraus, LLP.
Sheehan John P.
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