Magnetic powder, permanent magnet produced therefrom and process for producing them
AssigneeSeiko Epson Corporation
InventorsAtsunori Kitazawa, Toshiyuki Ishibashi, Koji Akioka
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Abstract
A magnetic powder and a permanent magnet are provided which have magnetic properties enhanced by magnetic interaction. Disclosed are a magnetic powder comprising a mixture of two or more powders including a magnetic powder A (residual magnetic flux density: BrA, coercive force: HcA) and a magnetic powder B (residual magnetic flux density: BrB, coercive force: HcB) of which the residual magnetic flux densities and the coercive forces have the following relationships: BrA>BrB and HcA<HcB, and a bonded magnet or a sintered magnet produced from the magnetic powder, and a method for mixing magnetic powders and a process for producing a magnet.
Claims15
A bonded magnet produced from a magnetic powder comprising a mixture of at least two powders including:
- a magnetic powder A having a residual magnetic flux density BrA and a coercive force HcA;
- and
- a magnetic powder B having a residual magnetic flux density BbR and a coercive force HcB,
- wherein the residual magnetic flux densities and said coercive forces of the magnetic powders A and B have the following relationships:
- Bra>BrB and HcA-HcB, and
- wherein the coercive forces of the magnetic powders A and B have the following relationship:
- HcA.dbd.y.HcB, where 0.1<y<1.
A sintered magnet produced from a magnetic powder comprising a mixture of two or more powders including:
- a magnetic powder A having a residual magnetic flux density BrA and a coercive force HcA, and
- a magnetic powder B having a residual magnetic flux density BrB and a coercive force HcB,
- wherein the residual magnetic flux densities and the coercive forces of the magnetic powders A and B have the following relationships:
- BrA>BrB and HcA<HcB, and
- wherein the coercive forces of the magnetic powders A and B have the following relationship:
- HcA=y.HcB, where 0.1<y<1.
A permanent magnet comprising a mixture of two or more powders including a magnetic powder A having a residual magnetic flux density BrA and a coercive force HcA and magnetic powder B having a residual magnetic flux density BrB and a coercive force HcB, wherein said residual magnetic flux densities and said coercive forces have the following relationships.
- BrA>BrB and
- HcA.dbd.y.HcB wherein 0.1<y<1.
A method of making a bonded magnet, comprising:
- forming a powder mixture comprising at least two powders including:
- a magnetic powder A having a residual magnetic flux density BrA and a coercive force HcA;
- and
- a magnetic powder B having a residual magnetic flux density BrB and a coercive force HcB,
- wherein the residual magnetic flux densities and said coercive forces of the magnetic powders A and B have the following relationships:
- BrA>BrB and HcA<HcB, and
- wherein the coercive forces of the magnetic powders A and B have the following relationship:
- HcA=y.HcB, where 0.1<y<1;
- mixing and kneading the powder mixture with a binder;
- magnetizing the powder mixture;
- and
- molding the magnetized powder mixture and binder.
A method of making a sintered magnet, comprising:
- forming a powder mixture comprising a mixture of two or more powders including:
- a magnetic powder A having a residual magnetic flux density BrA and a coercive force HcA, and
- a magnetic powder B having a residual magnetic flux density BrB and a coercive force HcB,
- wherein the residual magnetic flux densities and the coercive forces of the magnetic powders A and B have the following relationships:
- BrA>BrB and HcA<HcB, and
- wherein the coercive forces of the magnetic powders A and B have the following relationship:
- HcA=y.HcB, where 0.1<y<1;
- mixing and kneading the powder mixture with a binder;
- magnetizing the powder mixture;
- molding the magnetized powder mixture and binder;
- and
- sintering the molded magnetized powder mixture and binder.
Dependencies are inferred from the claim text.