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

IPC: C01G49/06 ,  G11B5/68 ,  G11B5/706 ,  H01F1/11 ,  C01G49/00 ,  G11B5/62

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.

公开(公告)号：DE2905352A1

公开(公告)日：1980-08-21

申请号：DE2905352

申请日：1979-02-13

Applicant: BASF AG

Inventor： RUDOLF PETER DIPL CHEM DR ,  STECK WERNER DIPL CHEM DR ,  KOESTER EBERHARD DIPL PHYS DR ,  OHLINGER MANFRED DIPL CHEM DR ,  JAECKH CHRISTOF DIPL CHEM DR

IPC: C01G49/06 ,  G11B5/68 ,  G11B5/706 ,  H01F1/11 ,  C01G49/00 ,  G11B5/62

Abstract: A process for the manufacture of acicular magnetic iron oxide consisting of 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 per cent by weight of cobalt(II) ions and from 0.1 to 15 per cent by weight of iron(II) ions, wherein a precipitate of cobalt(II) hydroxide and iron (II) hydroxide is applied to acicular gamma-iron(III) oxide particles and the latter are heated at 100 DEG -200 DEG C.

公开(公告)号：DE2705967A1

公开(公告)日：1978-08-17

申请号：DE2705967

申请日：1977-02-12

Applicant: BASF AG

Inventor： BECKER HANS-JUERGEN DIPL CHEM ,  JAECKH CHRISTOF DIPL CHEM DR ,  KOESTER EBERHARD DIPL PHYS DR ,  LOESER WERNER DIPL ING DR ,  OHLINGER MANFRED DIPL CHEM DR ,  STECK WERNER DIPL CHEM DR

IPC: C01G49/02 ,  C01G49/00 ,  C01G49/06 ,  G11B5/706 ,  H01F1/11 ,  H01F1/117

Abstract: A process for the manufacture of an acicular magnetic iron oxide containing from 0.5 to 10 percent by weight of cobalt and up to 24 percent by weight of divalent iron, each based on the amount of iron(III) oxide, wherein an aqueous suspension of gamma-iron(III) oxide, containing cobalt(II) and iron(II) ions, the suspension having a hydroxyl ion concentration of more than 3.6x10-6 moles/liter, is heated at from 50 DEG to 100 DEG C. for at least 15 minutes, and the resulting precipitate is filtered off, washed until neutral, dried at below 100 DEG C. and thereafter heated at from 100 DEG to 200 DEG C. The products thus obtained give, even when their cobalt content is low, a very high coercive force, while the effect of temperature on the coercive force and residual induction is very slight.

公开(公告)号：DE2916403A1

公开(公告)日：1980-11-06

申请号：DE2916403

申请日：1979-04-23

Applicant: BASF AG

Inventor： RUDOLF PETER DIPL CHEM DR ,  STECK WERNER DIPL CHEM DR ,  SARNECKI WILHELM DIPL CHEM DR ,  JAECKH CHRISTOF DIPL CHEM DR

IPC: C01G49/00 ,  C01G49/02 ,  C09D5/23 ,  C09D7/12 ,  G11B5/70 ,  G11B5/706 ,  H01F1/11 ,  H01F1/36 ,  G11B5/62 ,  H01F1/00

Abstract: A process for the manufacture of acicular magnetic iron oxides which consist of a core of gamma-iron(III) oxide and a shell of a magnetite modified with zinc(II) ions and/or manganese(II) ions and which contain, based on the total modified gamma-iron(III) oxide, from 0.1 to 20 percent by weight of iron(II) ions, from 0.1 to 10 percent by weight of zinc(II) ions and/or from 0.1 to 10 percent by weight of manganese(II) ions.

公开(公告)号：DE2646348A1

公开(公告)日：1978-04-20

申请号：DE2646348

申请日：1976-10-14

Applicant: BASF AG

Inventor： STECK WERNER DIPL CHEM DR ,  SCHNEEHAGE HANS HEINNING DIPL ,  JAECKH CHRISTOF DIPL CHEM DR ,  HUEBNER WERNER DIPL ING ,  OHLINGER MANFRED DIPL CHEM DR ,  LOESER WERNER DIPL ING DR

IPC: C21B15/02 ,  B22F1/00 ,  B22F9/22 ,  C22C33/02 ,  H01F1/06 ,  H01F1/33 ,  H01F10/00 ,  B05D5/12

Abstract: A method of preparing acicular ferromagnetic metal particles consisting essentially of iron and suitable for magnetic recording, said particles being modified at the surface with 0.02 to 0.2% by weight of carbon and with 0.5 to 1.9% by weight of phosphorus as phosphate, by reducing a finely divided acicular iron compound, wherein there are deposited on said iron compound, prior to reduction, (a) a hydrolysis-resistant substance selected from the group consisting of oxyacids of phosphorus, their esters and inorganic salts, and (b) a compound selected from the group consisting of aliphatic monobasic, dibasic and tribasic carboxylic acids of from 1 to 6 carbon atoms.