To provide a thin annular magnet having high (BH)max and high long-term preservability instead of Nd2Fe14B isotropic composite magnet.
The anisotropic composite magnet consists of (a) 5-40 wt.% unsaturated polyester alkyd and an aryl group copolymerizable monomer, (b) an anisotropic rare earth-iron system magnetic powder in which weight proportion of a magnetic powder of an average grain size of 1-5 μm and a magnetic powder of an average grain size of 50-150 μm is 20:80-50:50, and (c) an organic peroxides, and includes (d) an esterification object of one or more kinds of compound higher fatty acids and pentaerythritol, wherein the group (b) is 94-98 wt.% in a composite product and the group (d) is 5 weight parts or more in 100 weight parts of the group (a). The anisotropic composite magnet is formed in such a way that the compound which is collectively kneaded with (b) at a melting point not less than melting points of groups (a), (c) and (d) is especially molded in a magnetic field, wherein the magnetic power of the average grain size of 1-5 μm in the group (b) is Sm2Fe17N3, the magnetic powder of the average grain size of 1-5 μm included therein is Nd2Fe14B and (BH)max140 kJ/m3 or more.
| JP2004103871A | 2004-04-02 | |||
| JP2004179378A | 2004-06-24 |
Hiroki Naito
Daisuke Nagano