公开(公告)号：DE58909109D1

公开(公告)日：1995-04-20

申请号：DE58909109

申请日：1989-10-27

Applicant: BASF AG

Inventor： MUELLER MICHAEL WOLFGANG DR ,  SCHWAB EKKEHARD DR ,  AUWETER HELMUT DR ,  FESER RAINER DR ,  LEHNERT RUDI DR ,  MUELLER NORBERT DR ,  OHLINGER MANFRED DR

IPC: C01G37/027 ,  C09D5/23 ,  C09D7/12 ,  C01G49/00 ,  G11B5/706 ,  H01F1/11

Abstract: The invention relates to a highly coercive, acicular ferromagnetic material essentially consisting of chromium dioxide with iron, and to a process for its preparation by thermal decomposition of hydrated chromium(III) chromate under elevated pressure.

公开(公告)号：DE3322746C2

公开(公告)日：1994-06-23

申请号：DE3322746

申请日：1983-06-24

Applicant: BASF AG

Inventor： BALZ WERNER DR ,  BAUR REINHOLD DR ,  FESER RAINER DR ,  JAKUSCH HELMUT DR ,  KOVACS JENOE DR ,  OHLINGER MANFRED DR ,  RUDOLF PETER DR

IPC: G11B5/706 ,  G11B5/714

公开(公告)号：DE3927622A1

公开(公告)日：1991-02-28

申请号：DE3927622

申请日：1989-08-22

Applicant: BASF AG

Inventor： OHLINGER MANFRED DR ,  KOVACS JENOE DR

IPC: C09D5/23 ,  C09D7/12 ,  G11B5/706

Abstract: The invention relates to magnetic recording media comprising a nonmagnetic substrate and a magnetisable layer arranged thereon, essentially consisting of a magnetic material from the group comprising the cobalt-modified iron oxides and the hexagonal ferrites and inorganic supporting substances finely distributed in organic binders, the inorganic supporting substance used being ferromagnetic chromium dioxide.

公开(公告)号：DE3375849D1

公开(公告)日：1988-04-07

申请号：DE3375849

申请日：1983-04-28

Applicant: BASF AG

Inventor： MELZER MILENA ,  JAKUSCH HELMUT ,  GRAU WERNER DR ,  KOESTER EBERHARD DR ,  LOESER WERNER DR ,  POLKE REINHARD DR ,  SCHAEDEL GUENTER DR ,  OHLINGER MANFRED DR ,  VAETH GUENTER

IPC: G11B5/70 ,  C09D5/23 ,  G11B5/68 ,  G11B5/706 ,  G11B5/84 ,  H01F1/11 ,  H01F1/113 ,  H01F1/44

Abstract: A magnetic dispersion which can be applied to a non-magnetic base to produce a recording medium is prepared by dispersing a magnetically anisotropic material in a polymer binder and in an organic solvent by a method wherein the magnetically anisotropic material is worked in a jet mill before and/or during dispersing.

公开(公告)号：DE3224325A1

公开(公告)日：1984-01-05

申请号：DE3224325

申请日：1982-06-30

Applicant: BASF AG

Inventor： OHLINGER MANFRED DR ,  VAETH GUENTER ,  RUDOLF PETER DR ,  SARNECKI WILHELM DR ,  JAKUSCH HELMUT DR ,  KOESTER EBERHARD DR ,  MELZER MILENA

IPC: C01G49/02 ,  C01G49/06 ,  G11B5/706 ,  H01F1/11 ,  B05D5/12 ,  G11B5/62

Abstract: A process for the preparation of acicular ferrimagnetic iron oxides by reducing gamma-iron(III) oxide hydroxide to magnetite, at from 280 DEG to 620 DEG C., by means of an organic compound which is decomposable at this temperature in the presence of iron oxide, and, optionally, a stream of reducing gas, and, if desired, then oxidizing the magnetite with oxygen-containing gases, at from 150 DEG to 450 DEG C., to acicular ferrimagnetic iron oxide of the formula FeOx, where x is from above 1.33 to 1.50, wherein the organic compound used for the reduction is a non-polar glycerol ester of a fatty acid which is introduced into the aqueous reaction suspension during the preparation of the gamma-iron(III) oxide hydroxide.

公开(公告)号：DE2538792A1

公开(公告)日：1977-03-17

申请号：DE2538792

申请日：1975-09-01

Applicant: BASF AG

Inventor： SCHOENAFINGER EDUARD DR ,  DEIGNER PAUL DR ,  KOESTER EBERHARD DR ,  OHLINGER MANFRED DR ,  SCHAEFER DIETER DR ,  STUMPFI WERNER DR ,  AMORT JUERGEN DR ,  SEILER CLAUS-DIETRICH DR ,  NESTLER HEINZ DR ,  AMBROS OTTO DR

IPC: C09C1/34 ,  C09C3/12 ,  G11B5/706 ,  G11B5/62

Abstract: Stabilisation of magnetic dioxide pigments for prepn. of magnetic registering matls. is effected by (a) suspending the pigment in an aqs. and/or alcoholic medium (b) treating the suspended pigment with a silane of formula RnSi(OR')4-n (where R is a 1-18C org. gp; R' is a 1-8C aliphatic org. gp.; and n is 1-3), or with a hydrolysis prod. of this silane, so that least partly hydrolysed silane is situated on the surface of the pigment, after the latter has been separated from the medium, and (c) drying the separated pigment at 50-200 degrees C. Retain their good magnetic properties, even under unfavourable climatic, e.g. hot and humid conditions. The pigments are also easily dispersed and worked.

公开(公告)号：DE2254810A1

公开(公告)日：1974-05-22

申请号：DE2254810

申请日：1972-11-09

Applicant: BASF AG

Inventor： SCHNELL GEORG DR ,  HAMMON FRITZ ,  OHLINGER MANFRED DR

IPC: G11B5/706 ,  C01G49/06 ,  G11B5/62

Abstract: The invention relates to a process for improving the magnetic properties, especially the remanent magnetization, of gamma-iron(III) oxide which can be used advantageously as the magnetic component in magnetic recording media exhibiting reduced print-through. For this purpose, a gamma-iron(III) oxide manufactured according to known processes is heated at temperatures of from 400 DEG to 700 DEG C., the magnetic pigment having basic compounds on the crystal surface during this heat treatment and retaining a pH value above 8 until heating is over. Gamma-iron(III) oxide magnetic pigments treated in this way are particularly suitable for the manufacture of low-noise magnetic recording media with high remanent magnetization and particularly low print-through.

公开(公告)号：DE3231192A1

公开(公告)日：1984-02-23

申请号：DE3231192

申请日：1982-08-21

Applicant: BASF AG

Inventor： FRANK GERHARD DR ,  RUDOLF PETER DR ,  NEUBAUER GERALD DR ,  OHLINGER MANFRED DR ,  WILFINGER HANS JOERG DR ,  PFANNEBECKER EMIL ,  DUFFNER PAUL DR

IPC: B01J23/74 ,  B01J23/745 ,  B01J37/00 ,  C07B61/00 ,  C07C67/00 ,  C07C209/00 ,  C07C209/48 ,  C07C211/09 ,  C07C85/12 ,  C07C87/12 ,  C07C87/14

公开(公告)号：DE3061361D1

公开(公告)日：1983-01-20

申请号：DE3061361

申请日：1980-10-16

Applicant: BASF AG

Inventor： OHLINGER MANFRED DR ,  VAETH GUENTER ,  MUELLER NORBERT DR ,  WETTSTEIN EUGEN

IPC: C01G37/00 ,  C01G37/027 ,  G11B5/62 ,  G11B5/706 ,  H01F1/11

Abstract: A process for the manufacture of ferromagnetic chromium dioxide modified with foreign elements, by reacting oxides of trivalent and hexavalent chromium under superatmospheric pressure at an elevated temperature in the presence of water and of antimony(III) oxide as modifier, with or without other modifiers in an amount not exceeding 15% by weight, wherein the antimony(III) oxide employed as modifier is, to the extent of more than one-third, present as the senarmontite cubic modification, has a specific surface area, measured by the BET method, of from 1.5 to 15 m2/g, and is added in a total amount of up to 0.5% by weight, based on the resulting chromium dioxide.

公开(公告)号：DE2860071D1

公开(公告)日：1980-11-13

申请号：DE2860071

申请日：1978-07-28

Applicant: BASF AG

Inventor： BRODT RUDOLF DR ,  JAKUSCH HELMUT DR ,  KOESTER EBERHARD DR ,  LOESER WERNER DR ,  OHLINGER MANFRED DR ,  SARNECKI WILHELM DR ,  STECK WERNER DR

IPC: C01G49/08 ,  C01G49/06 ,  G11B5/62 ,  G11B5/70 ,  G11B5/706 ,  H01F1/11

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.