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公开(公告)号：JPS53141604A
公开(公告)日：1978-12-09
申请号：JP5670078
申请日：1978-05-15
Applicant: BASF AG
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公开(公告)号：FR2391526B1
公开(公告)日：1982-06-25
申请号：FR7814420
申请日：1978-05-16
Applicant: BASF AG
Inventor： HUEBNER WERNER DIPL ING , HARTMANN JOB-WERNER DIPL CHEM , DOMAS FRIEDRICH DIPL ING , NAGEL PETER DIPL ING , DEIGNER PAUL DR , KOESTER EBERHARD DIPL PHYS DR , HAUSER HANS
Abstract: A process and apparatus for the manufacture of magnetic recording media, in which, immediately before the magnetic dispersion is applied to a base, the dispersion is subjected to shear by means of a disc rotatably mounted in a housing, by introducing it at the center of rotation of the disc and forcing it through a gap formed between the face of the disc and the wall of the housing, which gap tapers toward the rim of the disc.
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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：DE2520643A1
公开(公告)日：1976-11-18
申请号：DE2520643
申请日：1975-05-09
Applicant: BASF AG
Inventor： KOESTER EBERHARD DIPL PHYS DR , WUNSCH GERD DIPL CHEM DR , SCHOENAFINGER EDUARD DIPL CHEM , SCHNEEHAGE HANS HENNING DIPL C
Abstract: 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 (I) where R1 and R2 are or O-R5, R3 is H, OH, or O-R5, R4 is alkyl or cycloalkyl of 1 to 16 carbon atoms and the R4's may be identical or different, and R5 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.
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公开(公告)号：DE2405623A1
公开(公告)日：1976-01-08
申请号：DE2405623
申请日：1974-02-06
Applicant: BASF AG
Inventor： KOESTER EBERHARD DIPL PHYS DR , WUNSCH GERD DIPL CHEM DR , DEIGNER PAUL DR , UHL KARL DIPL ING DR , STECK WERNER DIPL CHEM DR
Abstract: The magnetic matls., for magnetic recording media, consisting of a non-magnetic substrate and >=2 layers, one of a ferromagnetic phase A and one of an antiferromagnetic phase B, which have a common boundary and thus are coupled magnetically, so that a remanence of different value occurs after satn. in the 2 magnetic polarisation directions below a characteristic temp., the Neel temp., have the alloy CoxNi-x as phase A and the oxide (CoO)x(NiO)1-x as phase B (in which x = 0.04-0.98). The layers of phases A and B pref. are 100-2000 angstrom and 40-2000 angstrom thick respectively and a no. of alternating layers can be used. The layer next to the substrate can contain either phse A or phase B. The matls. have an asymmetrical hysteresis loop, due to the effect of exchange anisotropy, and the Neel temp. can be controlled within wide limits by the compsn.
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Patent Agency Ranking
公开(公告)号：DE2365179A1
公开(公告)日：1975-07-10
申请号：DE2365179
申请日：1973-12-29
Applicant: BASF AG
Inventor： KOESTER EBERHARD DIPL PHYS DR , WUNSCH GERD DIPL CHEM DR , DEIGNER PAUL DR , GRAW DIETER DIPL CHEM DR , UHL KARL DIPL ING DR , STECK WERNER DIPL CHEM DR
Abstract: Magnetic materials which essentially consist of a phase A with a ferromagnetic spin system and a phase B with an anti-ferromagnetic spin system, phases A and B interacting by exchange coupling, and the manufacture of such materials. The materials consist essentially of two-phase magnetic single-domain particles, with the alloy [CoxNi1-x] as the ferromagnetic phase A and its oxidized form [(CoO)x(NiO)1-x] as the anti-ferromagnetic phase B, with values of x of 0.04 to 0.96. They are manufactured by surface oxidation of a pigment layer, which at least covers the surface but may extend deeper, having the composition of phase A, to form an oxide layer, at least 40 A thick, of the phase B, followed by heating in an inert gas atmosphere, or by reduction of a corresponding layer of phase B to a layer of phase A. Magnetic single-domain particles of this composition have a Neel temperature which varies with X. As a result, materials are obtained which have an asymmetrical hysteresis loop, attributable to exchange anisotropy, at temperatures which can be varied within wide limits in accordance with the intended use of the material.
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公开(公告)号：DE2722078B2
公开(公告)日：1979-10-31
申请号：DE2722078
申请日：1977-05-16
Applicant: BASF AG
Inventor： HUEBNER WERNER DIPL ING , HARTMANN JOB-WERNER DIPL CHEM , DOMAS FRIEDRICH DIPL ING , NAGEL PETER DIPL ING , DEIGNER PAUL DR , KOESTER EBERHARD DIPL PHYS DR , HAUSER HANS
Abstract: A process and apparatus for the manufacture of magnetic recording media, in which, immediately before the magnetic dispersion is applied to a base, the dispersion is subjected to shear by means of a disc rotatably mounted in a housing, by introducing it at the center of rotation of the disc and forcing it through a gap formed between the face of the disc and the wall of the housing, which gap tapers toward the rim of the disc.
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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：DE2743298A1
公开(公告)日：1979-04-05
申请号：DE2743298
申请日：1977-09-27
Applicant: BASF AG
Inventor： JAECKH CHRISTOPHER DIPL CHEM D , STECK WERNER DIPL CHEM DR , BRODT RUDOLF DIPL CHEM DR , OHLINGER MANFRED DIPL CHEM DR , LOESER WERNER DIPL ING DR , KOESTER EBERHARD DIPL PHYS DR
Abstract: Acicular ferromagnetic metal particles essentially contain iron and carry, on their surface, from 0.02 to 0.6% by weight of boron in the form of a borate. Such particles may be obtained by reducing an acicular iron oxide with a gaseous reducing agent at from 250 to 500 DEG C, if boron oxyacid or an inorganic salt thereof is deposited on the said iron oxide before reduction. The acicular, ferromagnetic particles are principally used in magnetic recording media and the invention seeks to overcome the difficulty of providing such particles distinguished by a narrow particle size spectrum and pronounced acicular shape.
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公开(公告)号：DE2550308A1
公开(公告)日：1977-05-18
申请号：DE2550308
申请日：1975-11-08
Applicant: BASF AG
Inventor： OHLINGER MANFRED DIPL CHEM DR , SCHOENAFINGER EDUARD DIPL CHEM , VAETH GUENTER , STRITZINGER HEINZ DIPL ING , KOESTER EBERHARD DIPL PHYS DR , SCHNEEHAGE HANS HENNING DIPL C , STECK WERNER DIPL CHEM DR
Abstract: Goethite is obtained by reacting an aqueous solution of an iron (II) salt with an aqueous solution of an alkali metal hydroxide and oxidizing the resulting iron(II) hydroxide. The oxidation is carried out in three stages. In the first stage, from 4 to 15% by weight are oxidized in the course of from 0.4 to 5 hours, in the second stage from 60 to 85% by weight are oxidized in the course of from 1.5 to 6 hours and in a third stage the remaining amount of iron is oxidized.
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