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： US677920申请日： 1976-04-19
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公开(公告)号： US4071610A公开(公告)日： 1978-01-31
- 发明人: Eberhard Koester , Gerd Wunsch , Eduard Schoenafinger , Hans Henning Schneehage
- 申请人： Eberhard Koester , Gerd Wunsch , Eduard Schoenafinger , Hans Henning Schneehage
- 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： DT2520643 19750509
- 主分类号： C01G49/08
- IPC分类号： C01G49/08 ; C01G49/00 ; C01G49/06 ; C01G51/00 ; G11B5/706 ; H01F1/11 ; C01G49/02
摘要：
A process for the manufacture of acicular gamma-iron(III) oxide, in which the non-magnetic, acicular iron(III) oxide is treated with a solution of a compound of the formula I ##STR1## where R.sup.1 and R.sup.2 are ##STR2## or O--R.sup.5, R.sup.3 is H, OH, ##STR3## or O--R.sup.5, R.sup.4 is alkyl or cycloalkyl of 1 to 16 carbon atoms and the R.sup.4 's may be identical or different, and R.sup.5 is alkyl, cycloalkyl or aralkyl of 3 to 18 carbon atoms, and is then converted to gamma-iron(III) oxide by reduction to magnetite, followed by oxidation.The gamma-iron(III) oxide obtained is distinguished by a high coercive force and improved magnetic orientation when used as a magnetic pigment for the manufacture of magnetic recording media.