GB719283A - Improvements in or relating to a method of producing finely divided magnetic iron oxide - Google Patents

Improvements in or relating to a method of producing finely divided magnetic iron oxide

Info

Publication number
GB719283A
GB719283A GB23321/52A GB2332152A GB719283A GB 719283 A GB719283 A GB 719283A GB 23321/52 A GB23321/52 A GB 23321/52A GB 2332152 A GB2332152 A GB 2332152A GB 719283 A GB719283 A GB 719283A
Authority
GB
United Kingdom
Prior art keywords
iron
precipitate
solution
cobalt
iron oxide
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB23321/52A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Philips Electrical Industries Ltd
Original Assignee
Philips Electrical Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Philips Electrical Industries Ltd filed Critical Philips Electrical Industries Ltd
Publication of GB719283A publication Critical patent/GB719283A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
    • G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
    • G11B5/706—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material
    • G11B5/70626—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances
    • G11B5/70642—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances iron oxides
    • G11B5/70652—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances iron oxides gamma - Fe2 O3
    • G11B5/70668—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances iron oxides gamma - Fe2 O3 containing a dopant
    • G11B5/70673—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances iron oxides gamma - Fe2 O3 containing a dopant containing Co

Landscapes

  • Hard Magnetic Materials (AREA)

Abstract

Iron oxide containing minor amounts of cobalt is produced by adding an oxidizing agent and a soluble cobalt compound to an aqueous solution of a ferrous salt, preferably in a ratio of 1-6 atomic per cent. of cobalt to 99-94 atomic per cent. of iron, adding sodium or potassium hydroxide to precipitate an iron compound having an oxidation level of more than 2 to not more than 3, separating the precipitate, washing, drying and, if desired, heating in air. Preferred features include rapid and intimate mixing of the hydroxide with the iron-containing solution; heating the dried precipitate to 200-300 DEG C. in air to produce a modified g -Fe2O3; when the preferred oxidizing agent, ammonium nitrate, is used, mixing the iron-containing solution with the alkali-metal hydroxide solution at less than 90 DEG C. and keeping the so-formed precipitate at more than 75 DEG C. for about 30-90 minutes in the solution in which it is produced. Other oxidizing agents specified are hydrogen peroxide and ammonium persulphate. Examples are given.
GB23321/52A 1951-09-20 1952-09-17 Improvements in or relating to a method of producing finely divided magnetic iron oxide Expired GB719283A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL719283X 1951-09-20

Publications (1)

Publication Number Publication Date
GB719283A true GB719283A (en) 1954-12-01

Family

ID=19815045

Family Applications (1)

Application Number Title Priority Date Filing Date
GB23321/52A Expired GB719283A (en) 1951-09-20 1952-09-17 Improvements in or relating to a method of producing finely divided magnetic iron oxide

Country Status (1)

Country Link
GB (1) GB719283A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1162340B (en) * 1957-05-24 1964-02-06 Henricot Usines Emile Sa Process for the production of magnetic iron oxide for magnetic recording devices
DE1226997B (en) * 1959-06-12 1966-10-20 Bayer Ag Process for the production of acicular, cobalt-containing gamma iron (III) oxide
DE2022013A1 (en) * 1969-05-07 1970-11-19 Ampex Process for the production of a needle-shaped, cobalt-doped gamma iron oxide
JPS49108599A (en) * 1973-01-12 1974-10-16

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1162340B (en) * 1957-05-24 1964-02-06 Henricot Usines Emile Sa Process for the production of magnetic iron oxide for magnetic recording devices
DE1226997B (en) * 1959-06-12 1966-10-20 Bayer Ag Process for the production of acicular, cobalt-containing gamma iron (III) oxide
DE2022013A1 (en) * 1969-05-07 1970-11-19 Ampex Process for the production of a needle-shaped, cobalt-doped gamma iron oxide
JPS49108599A (en) * 1973-01-12 1974-10-16
JPS5233319B2 (en) * 1973-01-12 1977-08-27

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