发明授权
- 专利标题: Manufacture of gamma-iron (III) oxide
- 专利标题(中): 制造γ-铁(III)氧化物
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申请号: US616863申请日: 1975-09-25
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公开(公告)号: US4018882A公开(公告)日: 1977-04-19
- 发明人: Eberhard Koester , Gerd Wunsch , Eduard Schoenafinger , Hans Henning Schneehage , Helmut Jakusch
- 申请人: Eberhard Koester , Gerd Wunsch , Eduard Schoenafinger , Hans Henning Schneehage , Helmut Jakusch
- 申请人地址: DT Ludwigshafen
- 专利权人: BASF Aktiengesellschaft
- 当前专利权人: BASF Aktiengesellschaft
- 当前专利权人地址: DT Ludwigshafen
- 优先权: DT2447386 19741004
- 主分类号: C01G49/06
- IPC分类号: C01G49/06 ; G11B5/706 ; H01F1/11 ; C01G49/02
摘要:
A process for the manufacture of acicular magnetic gamma-iron(III) oxide by reducing acicular alpha-iron(III) oxide to magnetite and then oxidizing it to gamma-iron(III) oxide, wherein the alpha-iron(III) oxide is treated with a water-soluble alkaline earth metal compound and an alkylphenol with one to three alkyl radicals, each of 4 to 24 carbon atoms, on the benzene nucleus. Gamma-iron(III) oxides manufactured in this way show better magnetic orientability in the binder-containing dispersion, and a higher coercive force than prior art magnetic pigments.