PERMANENT MAGNET AND METHOD FOR PREPARATION THEREOF

• Main Authors: ODA, ETSUSHI, TOYOTA, SACHIO, HOSOKAWA, SEIICHI
• Format: Patent
• Language: English; French; Japanese
• Published: 04.07.2002
• Edition: 7
• Subjects: ARTIFICIAL STONE; BASIC ELECTRIC ELEMENTS; CEMENTS; CERAMICS; CHEMISTRY; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDINGMATERIALS; COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSESC01D OR C01F; CONCRETE; ELECTRICITY; 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; INDUCTANCES; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; INORGANIC CHEMISTRY; LIME, MAGNESIA; MAGNETS; METALLURGY; PHYSICS; REFRACTORIES; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES; SLAG; 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; TRANSFORMERS; TREATMENT OF NATURAL STONE

A ferrite magnet which is prepared by a method comprising providing a ferrite having a hexagonal M type magneto-plumbite structure substituted with at least one selected from the group consisting of rare earth elements containing Y and Bi for a part of Sr, Ba, Pb, or Ca, with the proviso that the at least one element contains La, adding an oxide of Mn or oxides of Mn and Co to the ferrite during pulverization thereof, and subjecting the resultant powder to calcination and/or sintering. The method allows the improvement of magnetic characteristics with a reduced amount of Mn or Mn and Co through the addition thereof to a ferrite already having a hexagonal M type magneto-plumbite structure during pulverization. L'invention concerne un aimant en ferrite préparé par un procédé consistant à fournir un ferrite présentant une structure hexagonale magnétoplumbite de type M substitué avec au moins un des éléments choisi dans le groupe comprenant des éléments terreux rares contenant du Y et du Bi pour une part de Sr, Ba, Pb ou Ca, pour autant que ledit élément contienne du La; à ajouter un oxyde de Mn ou des oxydes de Mn et de Co au ferrite pendant la pulvérisation de celui-ci; puis à soumettre la poudre ainsi obtenue à la calcination et/ou au frittage. Le procédé décrit dans cette invention permet d'améliorer les caractéristiques magnétiques avec une quantité réduite de Mn ou de Mn et de Co ajoutée à un ferrite présentant déjà une structure hexagonale magnétoplumbite de type M pendant la pulvérisation.