发明授权
- 专利标题: Improving the magnetic properties of gamma-iron (III) oxide
- 专利标题(中): 提高γ-铁(III)氧化物的磁性能
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申请号: US770989申请日: 1977-02-22
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公开(公告)号: US4212903A公开(公告)日: 1980-07-15
- 发明人: Georg Schnell , Fritz Hammon , Manfred Ohlinger
- 申请人: Georg Schnell , Fritz Hammon , Manfred Ohlinger
- 申请人地址: DEX
- 专利权人: BASF Aktiengesellschaft
- 当前专利权人: BASF Aktiengesellschaft
- 当前专利权人地址: DEX
- 优先权: DEX2254810 19721109
- 主分类号: G11B5/706
- IPC分类号: G11B5/706 ; H01F10/00 ; B05D5/12
摘要:
The invention relates to a process for improving the magnetic properties, especially the remanent magnetization, of gamma-iron(III) oxide which can be used advantageously as the magnetic component in magnetic recording media exhibiting reduced print-through. For this purpose, a gamma-iron(III) oxide manufactured according to known processes is heated at temperatures of from 400.degree. to 700.degree. C., the magnetic pigment having basic compounds on the crystal surface during this heat treatment and retaining a pH value above 8 until heating is over. Gamma-iron(III) oxide magnetic pigments treated in this way are particularly suitable for the manufacture of low-noise magnetic recording media with high remanent magnetization and particularly low print-through.
公开/授权文献
- US5716284A Billiard/checkers game 公开/授权日:1998-02-10