-
公开(公告)号：DE3044340A1
公开(公告)日：1982-06-24
申请号：DE3044340
申请日：1980-11-25
Applicant: BASF AG
-
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
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：DE2550307A1
公开(公告)日：1977-05-18
申请号：DE2550307
申请日：1975-11-08
Applicant: BASF AG
Inventor： OHLINGER MANFRED DIPL CHEM DR , SCHOENAFINGER EDUARD DIPL CHEM , SCHNEIDER WALTER , STRITZINGER HEINZ DIPL ING , VAETH GUENTER
Abstract: Acicular gamma-iron(III) oxide is manufactured by reacting an iron(II) salt solution with an aqueous solution of an alkali metal hydroxide and oxidizing the resulting suspension of iron(II) hydroxide in three stages. In a first stage, at most from 0.1 to 4% by weight of the amount of iron(II) hydroxide originally present is oxidized in the course of from 0.1 to 4 hours, in a second stage from 10 to 25% by weight of the said original amount are oxidized in the course of from 1.5 to 6 hours and in a third stage the remaining amount is oxidized. After the oxidation, the goethite formed is reduced to magnetite and the latter is then oxidized to acicular gamma-iron(III) oxide.
-
公开(公告)号：DE2461937A1
公开(公告)日：1976-07-08
申请号：DE2461937
申请日：1974-12-31
Applicant: BASF AG
Inventor： OHLINGER MANFRED DIPL CHEM DR , STRITZINGER HEINZ DIPL ING , HARTMANN JOB-WERNER DIPL CHEM , SCHOENAFINGER EDUARD DIPL CHEM
Abstract: In the prodn. of acicular alpha-Fe2O3 (I) by pptn. of hydrated alpha-Fe2O3 (II) from aq. Fe(II) salt solns. with alkali, with simultaneous oxidn. with air, and dehydration, polymers (III) contg. carboxyl gps. with an acid no. of over 50, pref. 80-220, are added during the prodn. of (I). (III) pref. is added to the (II) suspension in an amt. of 1.5-10, esp. 3-6 (wt.) pts/100 pts. (II). (III) can be (co)polymers of an alpha,beta-unsatd. carboxylic acid or reaction prods. of phthalic acid or anhydride with polyalcohols. (I) is used for the prodn. of acicular gamma-Fe2O3 (IV), which is used for low-noise magneto-gram carriers. The (I) obtd. gives esp. low-noise (IV) with good controllability and without additional process stages.
-
公开(公告)号：DE3021111A1
公开(公告)日：1981-12-17
申请号：DE3021111
申请日：1980-06-04
Applicant: BASF AG
Inventor： SIEGLE HANS JOERG DIPL ING DR , REICH HANS HEINER DIPL CHEM DR , AUTZEN HORST DIPL CHEM DR , STECK WERNER DIPL CHEM DR , LOESER WERNER DIPL ING DR , HETZEL ECKHARD DIPL ING , OHLINGER MANFRED DIPL CHEM DR
Abstract: A process for the preparation of acicular ferromagnetic metal particles, consisting essentially of iron, by reducing acicular iron oxides and/or iron oxide hydroxides, which are either pure or are modified with conventional foreign metal ions, by means of a gaseous reducing agent in a fluidized bed furnace in which a stirrer is provided immediately above the fluidizing grid.
-
Patent Agency Ranking
公开(公告)号：DE2935444A1
公开(公告)日：1981-03-19
申请号：DE2935444
申请日：1979-09-01
Applicant: BASF AG
Inventor： SARNECKI WILHELM DIPL CHEM DR , MAROSI LASZLO DIPL CHEM DR , AUTZEN HORST DIPL CHEM DR , OHLINGER MANFRED DIPL CHEM DR , STECK WERNER DIPL CHEM DR
Abstract: A process for the manufacture of acicular ferrimagnetic iron oxide by heating iron(III) oxide or iron(III) oxide hydroxide at 220 DEG -460 DEG C. under a water vapor partial pressure of not less than 30 mbar, reducing the resulting product to magnetite by means of hydrogen and/or CO and/or an organic compound which can decompose in the presence of iron oxide, and then oxidizing the magnetite with an oxygen-containing gas to give acicular ferrimagnetic iron oxide of the formula FeOX, where X is from 1.33 to 1.50.
-
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.
-
公开(公告)号：DE2556188A1
公开(公告)日：1977-06-23
申请号：DE2556188
申请日：1975-12-13
Applicant: BASF AG
-
公开(公告)号：DE2540874A1
公开(公告)日：1977-03-24
申请号：DE2540874
申请日：1975-09-13
Applicant: BASF AG
Inventor： OHLINGER MANFRED DIPL CHEM DR , GRAU WERNER DIPL CHEM DR , STRITZINGER HEINZ DIPL ING , SCHOENAFINGER EDUARD DIPL CHEM
Abstract: Prod. having high coercive force is produced by pptg. Co(OH)2 from a Co(II) salt soln. with ammonia onto goethite crystallised from an alkaline soln. The prod. is subjected to reduction into magnetite. Subsequently the magnetite is oxidised with O2 at 200-400 degrees C to produce cobalt doped gamma-Fe2O3. Process is improved by pretreating the surface of goethite (before the introduction of the Co(II) salt) with an acid having pK 4.8; adjusting pH to 3-7 and maintaining the surface acidity within this range to the end of the redn. process. gamma-Fe2O3 suitable for magnetic recording is produced. Its coercive force is increased (compared with the known material) by the increased quantity of the cobalt dopant. The above process permits an increase in the cobalt doping without impairing the thermal stability and the toughness of the product. The reduction stage can be carried out at temps. as low as 250-290 degrees C.
-
公开(公告)号：DE2942646A1
公开(公告)日：1981-04-30
申请号：DE2942646
申请日：1979-10-22
Applicant: BASF AG
Inventor： OHLINGER MANFRED DIPL CHEM DR , VAETH GUENTER , MUELLER NORBERT DIPL CHEM DR , WETTSTEIN EUGEN
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.
-
-
-
-
-
-
-
-
-
Search Results
33
records
(took 0.039 seconds)
