Abstract: The method for preparation of sintered permanent magnets according to the present invention comprises the steps of: mixing fully fine powder of a crystalline mother alloy for permanent magnet containing a rare-earth element, Fe and B as the essential components with fine powder of zinc oxide, compaction molding the resulted mixture in the presence of a magnetic field, sintering the compacted mixture in vacuum to cause generation of oxygen and metallic zinc by thermal decomposition of the zinc oxide; segregation of a part of metallic component in the mother alloy at the boundary and inside of the mother alloy crystal; formation of amorphous metallic oxide by forced oxidation of the segregated metal with the generated oxygen; crystallization of the amorphous metallic oxide; formation of an epitaxial junction between the crystallized metallic oxide and the mother alloy crystal; and evaporation of the metallic zinc into the vacuum, and quenching the sintered compact.

Abstract: The present invention is directed to provide a method of preparing a raw material powder for permanent magnets superior in moldability, especially in moldability and productivity of bonded magnets. The method comprises subjecting an acicular iron powder having an aspect ratio of not smaller than 5:1 to heating at 800-900.degree. C. in fluidized state with a gas stream containing no oxygen until the acicular iron powder is transformed into a columnar shape iron powder having an aspect ratio of not larger than 3:1, a die-like shape iron powder or a spherical shape iron powder. The acicular iron powder may contain or may be attached by such a component effective for improving magnetic properties as a rare earth element metal, a rare earth element metal oxide, boron, cobalt and nickel.

Abstract: The present invention is directed to provide a raw material powder for modified permanent magnets capable of enhancing magnetic properties of iron.rare earth element metal.boron permanent magnets and reducing the production cost, and further to provide its production method. The raw material powder is a pulverized powder of sintered mass obtained by sintering in vacuum or in a non-oxidative gas a mixture of an acicular iron powder and an alloy powder containing iron, a rare earth element metal and boron.

Abstract: The object of the invention is to provide a composition for permanent magnet with excellent magnetic properties exhibiting well the latent ability of the RFeB system tetragonal compounds. The composition for permanent magnet according to the present invention is a complex of (1) a crystalline RFeB or RFeCoB system compound having a tetragonal crystal structure with lattice constants of a.sub.o about 8.8 .ANG. and c.sub.o about 12 .ANG., in which R is at least one of rare earth elements, and (2) a crystalline neodymium oxide having a cubic crystal structure, in which both crystal grains are epitaxially connected and the RFeB or RFeCoB crystal grains are oriented to the c.sub.o direction. The lattice constant a.sub.o of the cubic Nd.sub.2 O.sub.3 is about 4.4 .ANG. which is the half length of the lattice constant a.sub.o about 8.8 .ANG. for the RFeB or RFeCoB tetragonal crystal, and the epitaxial connection is achieved, and the RFeB or RFeCoB crystal grains are oriented to the c.sub.o direction.

Abstract: The present invention is directed to provide a method of preparing a raw material powder for permanent magnets superior in moldability, especially in moldability and productivity of bonded magnets. The method comprises subjecting an acicular iron powder having an aspect ratio of not smaller than 5:1 to heating at 800.degree.-900.degree. C. in fluidized state with a gas stream containing no oxygen until the acicular iron powder is transformed into a columnar shape iron powder having an aspect ratio of not larger than 3:1, a die-like shape iron powder or a spherical shape iron powder. The acicular iron powder may contain or may be attached by such a component effective for improving magnetic properties as a rare earth element metal, a rare earth element metal oxide, boron, cobalt and nickel.

Abstract: It is an object of the present invention to provide a method of producing sintered- or bond- rare earth element.iron.boron magnets obtainable easily and superior in magnetic properties with stable performance. The method of producing sintered rare earth element.iron.boron magnets according to the present invention is characterized by that it comprises steps of mixing in a scheduled ratio an acicular iron powder coated with a coating material, a rare earth element powder coated with a coating material and a boron powder coated with a coating material, and subjecting the mixture to compression molding followed by sintering of the molded mixture in the presence of a magnetic field. The method of producing bond rare earth element.iron.

Abstract: The present invention aims at providing a powdery raw material composition for a permanent magnet superior in the magnetic properties and easy in preparation, a magnetically anisotropic permanent magnet, and a method for producing the magnet by use of the powdery raw material composition. A powdery raw material composition for a permanent magnet according to the present invention is one prepared by subjecting a mixture composed of 13-18 weight % of a neodymium powder, 4-10 weight % of a boron powder and the rest of an acicular iron powder coated with aluminum phosphate to a temperature above 600.degree. C. in an atmosphere initially of a hydrogen-containing reducing gas followed later by an inert gas, and a magnetically anisotropic permanent magnet is prepared by compression molding a mixture obtained from the powdery composition and a binder under heating in the presence of a magnetic field.

Abstract: The material for permanent magnet according to the present invention comprises an acicular iron powder having successively on the surface (1) a coated layer of aluminum phosphate, (2) a diffused layer of rare earth element or a diffused layer of rare earth element.cndot.boron or a diffused layer of rare earth element.cndot.boron.cndot.nitrogen, and (3) a coated layer of aluminum phosphate.The material for permanent magnet can be produced by (a) a step of mixing and covering an acicular goethite (FeOOH) crystal with aluminum phosphate, (b) a step of preparing an acicular iron powder coated with a layer of aluminum phosphate by reducing under hydrogen atmosphere at 300.degree.-500.degree. C. the acicular goethite (FeOOH) crystal covered by the aluminum phosphate, (c) a step of diffusing a rare earth element or a rare earth element and boron into the surface layer of aluminum phosphate by heating under argon atmosphere at 650.degree.-1000.degree. C.

Abstract: The material for permanent magnet according to the present invention comprises an acicular iron powder having successively on the surface (1) a coated layer of aluminum phosphate, (2) a diffused, layer of rare earth element or a diffused layer of rare earth element.multidot.boron or a diffused layer of rare earth element.multidot.boron.multidot.nitrogen, and (3) a coated layer of aluminum phosphate.The material for permanent magnet can be produced by (a) a step of mixing and covering an acicular goethite (FeOOH) crystal with aluminum phosphate, (b) a step of preparing an acicular iron powder coated with a layer of aluminum phosphate by reducing under hydrogen atmosphere at 300.degree.-500.degree. C. the acicular goethite (FeOOH) crystal covered by the aluminum phosphate, (c) a step of diffusing a rare earth element or a rare earth element and boron into the surface layer of aluminum phosphate by heating under argon atmosphere at 650.degree.-1000.degree. C.

Abstract: The material for permanent magnet according to the present invention comprises an acicular iron powder having successively on the surface (1) a coated layer of aluminum phosphate, (2) a diffused layer of rare earth element or a diffused layer of rare earth element.boron or a diffused layer of rare earth element.boron.nitrogen, and (3) a coated layer of aluminum phosphate.The material for permanent magnet can be produced by (a) a step of mixing and covering an acicular goethite (FeOOH) crystal with aluminum phosphate, (b) a step of preparing an acicular iron powder coated with a layer of aluminum phosphate by reducing under hydrogen atmosphere at 300.degree.-500.degree. C. the acicular goethite (FeOOH) crystal covered by the aluminum phosphate, (c) a step of diffusing a rare earth element or a rare earth element and boron into the surface layer of aluminum phosphate by heating under argon atmosphere at 650.degree.-1000.degree. C.

Abstract: The present invention aims at providing a powdery raw material composition for a permanent magnet superior in the magnetic properties and easy in preparation, a magnetically anisotropic permanent magnet, and a method for producing the magnet by use of the powdery raw material composition. A powdery raw material composition for a permanent magnet according to the present invention is one prepared by subjecting a mixture composed of 13-18 weight % of a neodymium powder, 4-10 weight % of a boron powder and the rest of an acicular iron powder coated with aluminum phosphate to a temperature above 600.degree. C. in an atmosphere initially of a hydrogen-containing reducing gas followed later by an inert gas, and a magnetically anisotropic permanent magnet is prepared by compression molding a mixture obtained from the powdery composition and a binder under heating in the presence of a magnetic field.

Abstract: It is an object of the present invention to provide a method of producing sintered- or bond- rare earth element.iron.boron magnets obtainable easily and superior in magnetic properties with stable performance. The method of producing sintered rare earth element.iron.boron magnets according to the present invention is characterized by that it comprises steps of mixing in a scheduled ratio an acicular iron powder coated with a coating material, a rare earth element powder coated with a coating material and a boron powder coated with a coating material, and subjecting the mixture to compression molding followed by sintering of the molded mixture in the presence of a magnetic field. The method of producing bond rare earth element.iron.

Abstract: The material for permanent magnet according to the present invention comprises an acicular iron powder having successively on the surface (1) a coated layer of aluminum phosphate, (2) a diffused layer of rare earth element or a diffused layer of rare earth element.boron or a diffused layer of rare earth element.boron.nitrogen, and (3) a coated layer of aluminum phosphate. The material for permanent magnet can be produced by (a) a step of mixing and covering an acicular goethite (FeOOH) crystal with aluminum phosphate, (b) a step of preparing an acicular iron powder coated with a layer of aluminum phosphate by reducing under hydrogen atmosphere at 300.degree.-500.degree. C. the acicular goethite (FeOOH) crystal covered by the aluminum phosphate, (c) a step of diffusing a rare earth element or a rare earth element and boron into the surface layer of aluminum phosphate by heating under argon atmosphere at 650.degree.-1000.degree. C.

Abstract: The present invention aims at providing a powdery raw material composition for a permanent magnet superior in the magnetic properties and easy in preparation, a magnetically anisotropic permanent magnet, and a method for producing the magnet by use of the powdery raw material composition. A powdery raw material composition for a permanent magnet according to the present invention is one prepared by subjecting a mixture composed of 13-18 weight % of a neodymium powder, 4-10 weight % of a boron powder and the rest of an acicular iron powder coated with aluminum phosphate to a temperature above 600.degree. C. in an atmosphere initially of a hydrogen-containing reducing gas followed later by an inert gas, and a magnetically anisotropic permanent magnet is prepared by compression molding a mixture obtained from the powdery composition and a binder under heating in the presence of a magnetic field.