ACICULAR FERRY MAGNETIC IRON OXIDE PARTICLE FOR RECORDING MAGNETIC SIGNAL

In the preparation of highly orientatable needle-shaped ferrimagnetic iron oxide particles by the reduction and reoxidation of needle-shaped particles of hydrated oxide of iron which have been surface treated against sintering the improvement which comprises effecting the surface treatment by applyi...

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Bibliographische Detailangaben
Hauptverfasser:	INGO FURUGUMATSUHAA, PEETAA BODEITSUSHIYU, GUNTAA BUTSUKUSUBAUMU, FURANTSU FUNTO, FUORUKAA HAANKAMU
Format:	Patent
Sprache:	eng
Schlagworte:	ADHESIVES BASIC ELECTRIC ELEMENTS CHEMICAL PAINT OR INK REMOVERS CHEMISTRY COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSESC01D OR C01F CORRECTING FLUIDS DYES ELECTRICITY FILLING PASTES INDUCTANCES INFORMATION STORAGE INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER INKS INORGANIC CHEMISTRY MAGNETS METALLURGY MISCELLANEOUS APPLICATIONS OF MATERIALS MISCELLANEOUS COMPOSITIONS NATURAL RESINS PAINTS PASTES OR SOLIDS FOR COLOURING OR PRINTING PHYSICS POLISHES PREPARATION OF CARBON BLACK SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES TRANSFORMERS TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS,TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES USE OF MATERIALS THEREFOR WOODSTAINS
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Beschreibung
Zusammenfassung:	In the preparation of highly orientatable needle-shaped ferrimagnetic iron oxide particles by the reduction and reoxidation of needle-shaped particles of hydrated oxide of iron which have been surface treated against sintering the improvement which comprises effecting the surface treatment by applying to the particles of hydrated oxide of iron one layer of oxygen-containing anions and a further layer of polyvalent cations, each layer weighing about 0.02 to 2% by weight of the particle. Advantageously, the polyvalent cation-containing layer is applied between two oxygen-containing anion layers, the oxygen-containing anions used are selected from the group consisting of silicate, phosphate, borate, vanadate, molybdate and tungstate, the polyvalent cations used are selected from the group consisting of aluminum, chromium, manganese, iron and gallium, each layer weighs about 0.1 to 1% of the weight of the particles and before the reduction and reoxidation the surface treated particles of hydrated oxide of iron are tempered at a temperature of about 600 DEG to 900 DEG C.