发明名称 |
Ferromagnetic particles with stable magnetic characteristics and method of preparing same |
摘要 |
Cobalt-free ferromagnetic particles are disclosed. The particles are comprised of ferromagnetic metal inner cores and an outer oxidized layer. The particles have a saturation magnetization of 60 to 100 emu/g and a coercive force of 500 Oe or more. The outer layer provides a means for stabilizing the magnetic characteristics of the particles at temperatures not higher than 80 DEG C. in air. The particles are produced by gradually oxidizing ferromagnetic metal particles containing no cobalt in oxygen-containing gas such that the surface-oxidized metal particles have a saturation magnetization of 60 to 100 emu/g. The particles provided have good magnetic characteristics which are maintained with the passage of time even when the particles are subjected to adverse temperature and humidity conditions.
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申请公布号 |
US4554089(A) |
申请公布日期 |
1985.11.19 |
申请号 |
US19830545289 |
申请日期 |
1983.10.25 |
申请人 |
FUJI PHOTO FILM CO., LTD. |
发明人 |
UMEMURA, SHIZUO;KITAMOTO, TATSUJI |
分类号 |
G11B5/706;B22F1/02;C09D5/23;C09D7/12;H01F1/06;H01F1/09;(IPC1-7):C01G49/08;C04B35/26 |
主分类号 |
G11B5/706 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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