Cobalt-containing magnetic iron oxide and process for producing the same

• Main Authors: SUITA; TOKUO, TAKATORI; SHIGERU, ASANO; KIYOSHI, KOYAMA; ARATA, TAKUMI; NOBUSUKE, TAMURA; KOUICHI
• Format: Patent
• Language: English
• Published: 11.03.1997
• Edition: 6
• Subjects: CHEMISTRY; COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSESC01D OR C01F; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OFSOLID INORGANIC COMPOUNDS; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; INORGANIC CHEMISTRY; METALLURGY; PHYSICS; TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

Cobalt-containing magnetic iron oxide particles extremely suitable for magnetic recording mediums, especially for image recording mediums and a process for producing the same from the precursor, gamma -FeOOH which is advantageous in industry are disclosed. Cobalt-containing magnetic iron oxide particles satisfying the following equations (1), (2) and (3):20</=SSA</=50(1)-16.70</=log [V]</=-3.05 log [SSA]-11.35(2)0.10</=Fe2+/total Fe</=0.30(3)where SSA is a BET specific surface area (m2/g), and V is a magnetic switching unit (cm3), can be produced by producing iron oxide particles having a concentration of Fe2+ of 0.10 to 0.36 as expressed by Fe2+/total Fe from the precursor, gamma -FeOOH, and coating a cobalt compound or a combination of a cobalt compound and other metal compounds on the surfaces of the iron oxide particles.