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公开(公告)号：DE2805621A1
公开(公告)日：1979-08-23
申请号：DE2805621
申请日：1978-02-10
Applicant: BASF AG
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公开(公告)号：DE2447386A1
公开(公告)日：1976-04-22
申请号：DE2447386
申请日：1974-10-04
Applicant: BASF AG
Inventor： KOESTER EBERHARD DIPL PHYS DR , WUNSCH GERD DIPL CHEM DR , SCHOENAFINGER EDUARD DIPL CHEM , SCHNEEHAGE HANS HENNING DIPL C , JAKUSCH HELMUT DIPL PHYS DR
Abstract: 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.
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公开(公告)号：DE3116489A1
公开(公告)日：1982-11-11
申请号：DE3116489
申请日：1981-04-25
Applicant: BASF AG
Inventor： JAKUSCH HELMUT DIPL PHYS DR , LOESER WERNER DIPL ING DR , KOESTER EBERHARD DIPL PHYS DR , RUDOLF PETER DIPL CHEM DR , SENKPIEL WERNER DIPL CHEM DR , STECK WERNER DIPL CHEM DR
Abstract: A process for stabilizing pyrophoric acicular metal particles consisting essentially of iron, by reaction with oxygen-containing gases in two stages, wherein, in the first stage, up to 1/3 of the passivating layer present in the final state is formed at from 25 DEG to 45 DEG C. and, in a subsequent second stage, the remainder of the passivating layer is formed at from 50 DEG to 70 DEG C.
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公开(公告)号：DE2535448A1
公开(公告)日：1977-02-24
申请号：DE2535448
申请日：1975-08-08
Applicant: BASF AG
Inventor： LOWENBERG GUSTAV DIPL ING , HARTMANN HANS-JOERG DIPL ING D , SCHAEFER DIETER DIPL CHEM DR , MOTZ HERBERT DIPL ING DR , JAKUSCH HELMUT DIPL PHYS DR
IPC: G11B5/708 , C09D5/23 , C09D7/12 , C09D131/02 , C09D177/00 , C09D177/06 , G11B5/70 , G11B5/702 , G11B5/68
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公开(公告)号：DE2907255A1
公开(公告)日：1980-09-04
申请号：DE2907255
申请日：1979-02-24
Applicant: BASF AG
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Patent Agency Ranking
公开(公告)号：DE2905351A1
公开(公告)日：1980-08-21
申请号：DE2905351
申请日：1979-02-13
Applicant: BASF AG
Inventor： RUDOLF PETER , STECK WERNER DIPL CHEM DR , JAKUSCH HELMUT DIPL PHYS DR , VAETH GUENTER , JAECKH CHRISTOF DIPL CHEM DR
Abstract: A process for the manufacture of acicular magnetic iron oxide consisting of a core of gamma-iron(III) oxide and a ferrite shell which contains, based on the total amount of magnetic material, from 0.2 to 12 percent by weight of cobalt(II) ions and from 0.1 to 15 percent by weight of iron(II) ions, wherein a solution containing cobalt(II) hydroxide and iron(II) hydroxide is applied to acicular gamma-iron(III) oxide particles and the latter are heated at 100 DEG -220 DEG C.
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公开(公告)号：DE2735316A1
公开(公告)日：1979-02-08
申请号：DE2735316
申请日：1977-08-05
Applicant: BASF AG
Inventor： BRODT RUDOLF DIPL CHEM DR , JAKUSCH HELMUT DIPL PHYS DR , KOESTER EBERHARD DIPL PHYS DR , LOESER WERNER DIPL ING DR , OHLINGER MANFRED DIPL CHEM DR , SARNECKI WILHELM DIPL-CHEM DR , STECK WERNER DIPL CHEM DR
Abstract: A process for the manufacture of acicular ferrimagnetic iron oxide by dehydrating acicular iron(III) oxide hydroxides to give acicular iron(III) oxides, then reducing these iron(III) oxides at from 300 DEG to 650 DEG C. by means of an organic compound which decomposes in this temperature range, and oxidizing the reduced product with an oxygen-containing gas at from 200 DEG to 500 DEG C., wherein the acicular iron(III) oxide hydroxides employed consist of a mixture of goethite and lepidocrocite, containing at least 60% of the latter, and the dehydration is carried out at from 250 DEG to 700 DEG C.
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公开(公告)号：DE2744887A1
公开(公告)日：1979-04-19
申请号：DE2744887
申请日：1977-10-06
Applicant: BASF AG
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公开(公告)号：DE2714588A1
公开(公告)日：1978-10-12
申请号：DE2714588
申请日：1977-04-01
Applicant: BASF AG
Inventor： STECK WERNER DIPL CHEM DR , BRODT RUDOLF DIPL CHEM DR , SARNECKI WILHELM DIPL CHEM DR , JAKUSCH HELMUT DIPL PHYS DR , OHLINGER MANFRED DIPL CHEM DR , KOESTER EBERHARD DIPL PHYS DR
IPC: G11B5/706 , B22F9/22 , C09D5/23 , C09D7/12 , C21B15/00 , G11B5/712 , G11B5/714 , H01F1/06 , B22F9/00
Abstract: A process for the manufacture of acicular ferromagnetic iron particles by reducing acicular iron(III) oxide hydroxides which consist of pure synthetic lepidocrocite or a mixture of synthetic goethite and at least 70% by weight of synthetic lepidocrocite. The iron(III) oxide hydroxides used carry, on their surface, an alkaline earth metal cation and an anion of a monobasic, dibasic or tribasic aliphatic carboxylic acid of up to 6 carbon atoms or an organic compound containing at least two groups capable of chelating the alkaline earth metal cation, and are produced in such a way that they consist of at least 70 percent by weight of lepidocrocite and have a length-to-width ratio of not less than 15:1. Reduction of such iron(III) oxide hydroxides gives iron particles with pronounced shape anisotropy, which exhibit both good magnetic properties and a narrow field strength distribution.
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