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    Magnetic materials comprising spin-coupled hard and soft magnetic phases
    1.
    发明专利
    Magnetic materials comprising spin-coupled hard and soft magnetic phases 未知

    公开(公告)号：DE4120663A1

    公开(公告)日：1992-12-24

    申请号：DE4120663

    申请日：1991-06-22

    Applicant: BASF AG

    Inventor： RICHTER HANS JUERGEN DR ,  SCHWAB EKKEHARD DR ,  JAKUSCH HELMUT DR ,  HIBST HARTMUT DR ,  GRAU WERNER DR ,  KNELLER ECKHART PROF DR ,  HAWIG REINHARDT

    IPC: G11B5/706 ,  H01F1/03 ,  H01F1/057 ,  H01Q17/00 ,  H02K1/02

    Abstract: A magnetisable material consists of at least two ferro- and/or ferrimagnetic phases which are magnetically coupled to each other by magnetic exchange coupling. At least one of the phases is a hard magnetic phase and at least one of the phases is a soft magnetic phase. The vol. percentage of the soft magnetic phase is at least 30%. At least 65% of the original saturation remanence is obtd. again after prior magnetic saturation in a direction corresp. to the application of an opposite magnetic field which is the same as the coercive field strength of the magnetic material, and after removing the field. The saturation remanence is at least 50% of the saturation magnetisation. The material is mfd. by spraying a melt of rare earth metals, Fe, B, a transition metal and Si on to a rotating metal roll in an inert atmos., and annealing the flakes produced at 670-780 deg.C to give the desired ratio of hard- to soft magnetic phases. Pref. an alloy of compsn. RExFeyBzSiuTv is used as the magnetic material, where RE is one or more rare earth metals and/or Y, Zr and Hf, and T is one or more transition metal with a body-centred cubic structure, and where x is not greater than 10 atom %, y is not greater than 85 atom %, z is not greater than 25 atom %, u is not greater than 10 atom %, and v is not greater than 10 atom %. Up to 10 atom % Fe may be replaced by Ni and/or Co. The soft magnetic phases comprises alpha-Fe and Fe3B, and the hard magnetic phase comprises Nd2Fe14B.

    2.
    发明专利
    未知

    公开(公告)号：DE3644823A1

    公开(公告)日：1988-07-14

    申请号：DE3644823

    申请日：1986-12-31

    Applicant: BASF AG

    Inventor： HITZFELD MICHAEL DR ,  GRAU WERNER DR ,  HACK JOACHIM

    IPC: G11B5/72 ,  G11B5/64 ,  G11B5/71 ,  G11B5/725 ,  G11B5/82 ,  G11B5/84

    Abstract: 1. A magnetic recording medium consisting of a flexible disk-shaped nonmagnetic base, a cobalt/chromium alloy layer applied thereto snd suitable for vertical recording, and a friction-reducing layer present on this alloy layer, wherein the friction-reducing layer is a 5-100 nm thick amorphous carbon layer produced by sputtering.

    6.
    发明专利
    未知

    公开(公告)号：DE2428875A1

    公开(公告)日：1976-01-02

    申请号：DE2428875

    申请日：1974-06-14

    Applicant: BASF AG

    Inventor： GRAU WERNER DR ,  KOPKE HELMUT ,  OHLINGER MANFRED DR ,  SCHNEEHAGE HENNING DR ,  SCHOENAFINGER EDUARD DR

    IPC: C01G49/06 ,  G11B5/706 ,  H01F1/11 ,  G11B5/68

    Abstract: A process for the manufacture of acicular gamma-iron(III) oxide which, because of its improved dispersibility in organic binders, is suitable for the manufacture of magnetic recording media exhibiting a particularly high orientation ratio. For this purpose, the non-magnetic acicular alpha -iron(III) oxide or goethite pigment is treated with from 0.5 to 10% by weight, based on the pigment, of a compound of the formula I: (I) where R1, R2 and R3 are hydrogen, alkyl of 1 to 24 carbon atoms or alkenyl of 1 to 24 carbon atoms and (RX)- is selected from the group consisting of an aliphatic carboxylic acid of 1 to 18 carbon atoms, an aromatic carboxylic acid of 1 to 18 carbon atoms, a sulfonic acid and an ester of phosphoric acid and is then further processed by conventional methods to give gamma-iron(III) oxide.

    7.
    发明专利
    未知

    公开(公告)号：DE3761931D1

    公开(公告)日：1990-04-19

    申请号：DE3761931

    申请日：1987-12-19

    Applicant: BASF AG

    Inventor： HITZFELD MICHAEL DR ,  GRAU WERNER DR ,  HACK JOACHIM

    IPC: G11B5/72 ,  G11B5/64 ,  G11B5/71 ,  G11B5/725 ,  G11B5/82 ,  G11B5/84

    Abstract: 1. A magnetic recording medium consisting of a flexible disk-shaped nonmagnetic base, a cobalt/chromium alloy layer applied thereto snd suitable for vertical recording, and a friction-reducing layer present on this alloy layer, wherein the friction-reducing layer is a 5-100 nm thick amorphous carbon layer produced by sputtering.

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