Abstract: On a surface of a rare earth permanent magnet R-T-M-B wherein R is a rare earth element, T is Fe or Fe and Co, M is Ti, Nb, Al, V, Mn, Sn, Ca, Mg, Pb, Sb, Zn, Si, Zr, Cr, Ni, Cu, Ga, Mo, W or Ta, 5 wt %≦R≦40 wt %, 50 wt %≦90 wt %, 0 wt %≦M≦8 wt %, and 0.2 wt %≦B≦8 wt %, a solution comprising a flake fine powder of Al, Mg, Ca, Zn, Si, Mn or an alloy thereof and a silicone resin is applied and baked to form an adherent composite coating, thereby providing a corrosion resistant rare earth permanent magnet.

Abstract: A method of recovering magnetic powder from rare earth bond magnet comprising a process of soaking the rare earth bond magnet in a decomposing solution, or holding it in a gas phase of the decomposing solution, containing at least one solvent selected from a group comprising tetralin, naphthalene, 1,4-hydroxynaphthalene, naphthol, biphenyl, 2-hexanone, acetonylacetone, phorone cyclohexanone and methlcyclohexanone, and heating at a temperature not lower than 230° C. A method of recycling recovered magnetic powder by substituting at least a part or all of magnetic powder in the molding compound of a second rare earth bond magnet. For preventing deterioration of magnetic powder from oxidation at surface, air in the decomposition vessel is substituted with nitrogen gas, helium gas and argon gas or is reduced to a pressure not higher than 10−2 Torr.

Abstract: There is disclosed a powder magnetic core in which a permeability does not easily drop even when an applied magnetic field intensifies, comprising: a bulk body containing a main component of a powder of an Fe-base alloy having a soft magnetic property, and the balance substantially including a heat-treated insulation binder and a void.

Abstract: This invention aims to provide a manufacturing method of an anisotropic magnet powder from which a bonded magnet with an improved loss of magnetization due to structural changes can be achieved. This is achieved by employing a low-temperature hydrogenation process, high-temperature hydrogenation process and the first evacuation process to an RFeB material (R: rare earth element) to manufacture a hydride powder (RFeBHx); the obtained RFeBHx powder (the precursory anisotropic magnet powder) is subsequently blended with a diffusion powder composed of hydride of dysprosium or the like and a diffusion heat-treatment process and a dehydrogenation process are employed. Through this series of processes, an anisotropic magnet powder with a great coercivity and a great degree of anisotropy can be achieved.

Abstract: Magnetic materials having a coercivity not less than about 1000 Oersted are prepared in a single step procedure. A molten mixture of a desired composition having a relatively high boron content is cooled at a rate slower than about 105 degrees Celsius per second. Preferably, the molten mixture is cooled by depositing it on a chilled surface such that it forms a layer between about 120 and about 300, and preferably between about 120 and about 150, microns thick.

Abstract: A rare earth-iron-boron magnetic powder comprising a rare earth element, iron and boron, which has a coercive force of 80 to 400 kA/m, a saturation magnetization of 10 to 25 &mgr;W/g, an average particle size of 5 to 200 nm, and a particulate or ellipsoidal particle shape, and a magnetic recording medium having a magnetic layer which contains this magnetic powder and a binder, in which magnetic recording medium it is possible to practically use a very thin magnetic layer of 0.3 &mgr;m or less.

Abstract: A method of making a material alloy for an iron-based rare earth magnet includes the step of forming a melt of an alloy with a composition of (Fe1−mTm)100−x−y−z−n(1−pCp)xRyTizMn. T is Co and/or Ni; R is at least one element selected from Y (yttrium) and the rare earth elements; and M is at least one element selected from Al, Si, V, Cr, Mn, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au and Pb, wherein the following inequalities are satisfied: 10<x≦25 at %, *6≦y<10 at %, 0.5≦z≦12 at %, 0≦m≦0.5, 0≦n≦10 at % and 0≦p≦0.25. Next, the melt is fed onto a shoot with a guide surface tilted at about 1 degree to about 80 degrees with respect to a horizontal plane, thereby moving the melt onto a melt/roller contact region. The melt is then rapidly cooled using a chill roller to make a rapidly solidified alloy including an R2Fe14B phase.

Abstract: A process of preparing individually-isolated, carbon-coated nanoscale metal particles is disclosed. The process is effected by sonicating a mixture of a metal carbonyl and a hydrocarbon solvent that is selected so as to polymerize during sonication. Air-stable and aqueous solution-stable, carbon-coated nanoscale metal particles and a process of preparing same are also disclosed.

Abstract: The method for manufacturing alloy powder for R—Fe—B type rare earth magnets of the present invention includes a first pulverization step of coarsely pulverizing a material alloy for rare earth magnets and a second pulverization step of finely pulverizing the material alloy. In the first pulverization step, the material alloy is pulverized by a hydrogen pulverization method. In the second pulverization step, easily oxidized super-fine powder (particle size: 1.0 &mgr;m or less) is removed to adjust the particle quantity of the super-fine powder to 10% or less of the particle quantity of the entire powder.

Abstract: Secondary agglomerates of magnetic metal particles for magnetic recording, have a sodium content of not more than 20 ppm and a calcium content of not more than 40 ppm, an average particle diameter of 300 to 800 &mgr;m and an upper limit of particle diameters of 2,000 &mgr;m, and comprise magnetic metal primary particles having an average major axis diameter of 0.05 to 0.25 &mgr;m.

Abstract: Disclosed is a method for the compaction of a soft magnetic powder capable of manufacturing a green compact which has attained high density and high strength, is excellent in mechanical properties and magnetic properties and does not cause a reduction in electrical resistance. Soft magnetic powder particles individually surface-coated with an insulating vitreous layer containing P, Mg, B, and Fe as essential components are used, and a lubricant is applied to the inner wall surface of a compaction die. The soft magnetic powder is subjected to compaction at from not less than room temperature to less than 50° C. without mixing the lubricant with the soft magnetic powder, followed by annealing at from 50 to 300° C..

Abstract: The method for manufacturing alloy powder for R—Fe—B type rare earth magnets of the present invention includes a first pulverization step of coarsely pulverizing a material alloy for rare earth magnets and a second pulverization step of finely pulverizing the material alloy. In the first pulverization step, the material alloy is pulverized by a hydrogen pulverization method. In the second pulverization step, easily oxidized super-fine powder (particle size: 1.0 &mgr;m or less) is removed to adjust the particle quantity of the super-fine powder to 10% or less of the particle quantity of the entire powder.

Abstract: Rotors for stepping motors used in analog timepieces are produced from a mixture of prealloyed rare earth magnetic particles and a thermoplastic binder. The mixture is either tape cast in a magnetic field following blanking of green rotors or injection molded in a magnetic field. Following extraction of the binder the green parts are sintered to net shape. Improved magnetic properties, smaller dimensions, better tolerances and 100% material utilization are claimed.

Abstract: The inventive method for preparing nanocomposite magnet powder includes the step of preparing material alloy powder for a nanocomposite magnet represented by a general formula Fe100−x−y−z−uRxByCozMu where R is a rare-earth element of which 90-100 atomic percent is Pr and/or Nd while 0-10 atomic percent is another lanthanoid and/or Y, and the molar fractions x, y, z and u meet the inequalities of 2≦x≦6, 16≦y≦20, 0.2≦z≦7 and 0.01≦u≦7, respectively. The powder includes a metastable phase and an amorphous structure existing in a metal structure. Heat treatment is performed for the material alloy powder to crystallize Fe3B and Fe—R—B compounds from the amorphous structure. An integral value of the difference between a temperature-time curve represented by the temperature of the material alloy powder as a function of the heat treatment time during the heat treatment and a reference temperature-time curve is in a range from 10° C.

Abstract: The present invention relates to a casting method which employs rapid solidification of metal, rare-earth metal or the like, as well as to a casting apparatus and a cast alloy. A centrifugal casting method includes the steps of pouring a molten material onto a rotary body; sprinkling the molten material by the effect of rotation of the rotary body; and causing the sprinkled molten material to be deposited and to solidify on the inner surface of a rotating cylindrical mold. The axis of rotation of the rotary body and the axis of rotation of the cylindrical mold are caused not to run parallel to each other. The centrifugal casting method can attain a decrease in average deposition rate. As a result, generation of the dendritic &agr;Fe phase or generation of a segregation phase of Mn or the like is suppressed, thereby realizing a high-performance R-T-B-type rare-earth magnet alloy.

Abstract: Magnetic acicular alloy particles containing iron as a main component according to the present invention, have an average major axial diameter of 0.05 to 0.2 &mgr;m, and pH values of water suspensions of said magnetic acicular alloy particles containing iron as a main component, which satisfies the formula: (pH value of water suspension treated by A method)−(pH value of water suspension treated by B method)<0 Such magnetic acicular alloy particles containing iron as a main component exhibit an excellent dispersibility in a vehicle, especially such a vehicle composed of a binder resin having a polar group such as —SO3M (wherein M is H, Na or K), —COOH or the like, and in which an orientation and a packing density in coating film are improved.

Abstract: The magnet powder-resin compound particles substantially composed of rare earth magnet powder and a binder resin are in such a round shape that a ratio of the longitudinal size a to the transverse size b (a/b) is more than 1.00 and 3 or less, and that an average particle size defined by (a/b)/2 is 50-300 &mgr;m. They are produced by charging a mixture of rare earth magnet powder and a binder resin into an extruder equipped with nozzle orifices each having a diameter of 300 &mgr;m or less; extruding the mixture while blending under pressure though the nozzle orifices to form substantially cylindrical, fine pellets; and rounding the pellets by rotation.

Abstract: A resin-bonded magnet composed substantially of (a) an R-T-N-based magnetic powder having a basic composition of R&agr;T100-&agr;-&bgr;N&bgr;, wherein R is at least one selected form the group consisting of rare earth elements including Y, T is Fe or Fe and Co, 5≦&agr;≦20, and 5≦&bgr;≦30, (b) a ferrite magnetic powder having a substantially magnetoplumbite-type crystal structure and a basic composition represented by (A1-xR′x)O[(Fe1-yMy)2O3] by atomic ratio, wherein A is Sr and/or Ba, R′ is at least one selected from the group consisting of rare earth elements including Y, La being indispensable, M is Co or Co and Zn, 0.01≦x≦0.4, 0.005≦y≦0.04, and 5.0≦n≦6.4, and (c) a binder. The ferrite magnet powder is preferably an anisotropic, granulated powder or an anisotropic, sintered ferrite magnet powder.

Abstract: A method of manufacturing magnetic powder is disclosed. This method can provide magnetic powder from which a bonded magnet having excellent magnetic properties and reliability can be manufactured. A melt spinning apparatus 1 is provided with a tube 2 having a nozzle 3 at the bottom thereof, a coil 4 for heating the tube and a cooling roll 5. The cooling roll 5 is constructed from a roll base 51 and a circumferential surface 53 in which gas flow passages 54 for expelling gas are formed. A melt spun ribbon 8 is formed by injecting the molten alloy 6 from the nozzle 3 so as to be collided with the circumferential surface 53 of the cooling roll 5, so that the molten alloy 6 is cooled and then solidified. In this process, gas is likely to enter between a puddle 7 of the molten alloy 6 and the circumferential surface 53, but such gas is expelled by means of the gas flow passages 54. The magnetic powder is obtained by milling thus formed melt spun ribbon 8.

Abstract: The objects of the present invention are to provide a method of producing highly weather-resistant iron-based magnet powder containing a rare-earth element, particularly characterized by high coercive force in a practically important humid atmosphere, highly weather-resistant magnet powder produced by the same method, resin composition containing the same powder for bonded magnets, and bonded magnet containing the same powder. The present invention provides a method of producing a magnet powder by crushing an iron-based magnet powder containing a rare-earth element in an organic solvent, wherein phosphoric acid is added to the solvent in which the powder is crushed.

Abstract: This invention aims to provide a manufacturing method of an anisotropic magnet powder from which a bonded magnet with an improved loss of magnetization due to structural changes can be achieved. This is achieved by employing a low-temperature hydrogenation process, high-temperature hydrogenation process and the first evacuation process to an RFeB material (R: rare earth element) to manufacture a hydride powder (RFeBHx); the obtained RFeBHx powder (the precursory anisotropic magnet powder) is subsequently blended with a diffusion powder composed of hydride of dysprosium or the like and a diffusion heat-treatment process and a dehydrogenation process are employed. Through this series of processes, an anisotropic magnet powder with a great coercivity and a great degree of anisotropy can be achieved.

Abstract: A sintered rare earth magnet is produced by finely pulverizing a coarse rare earth magnet alloy powder to an average particle size of 1-10 &mgr;m in a non-oxidizing atmosphere; introducing the resultant fine rare earth magnet alloy powder into a non-oxidizing liquid comprising at least one oil selected from the group consisting of mineral oils, synthetic oils and vegetable oils, and at least one lubricant selected from the group consisting of esters of aliphatic acids and monovalent alcohols, esters of polybasic acids and monovalent alcohols, esters of aliphatic acids and polyvalent alcohols and their derivatives to prepare a slurry; molding the slurry; degreasing the resultant green body; sintering the degreased green body; and then heat-treating the green body.

Abstract: A soft magnetism metal powder having a majority of particles, each of which, when cross-sectioned, has no greater than ten crystal particles on average, may be coated on an outer surface of each of the particles with a resistive material having a higher resistivity than the underlying parent phase. The soft magnetism metal powder may be prepared by heating a soft magnetism metal powder to a high temperature in a high temperature atmosphere, thereby reducing the number of crystal particles in each of the soft magnetism metal powder particles. A soft magnetism metal formed body may be prepared by pressing the soft magnetism metal particles at a sufficient temperature and pressure.

Abstract: Disclosed herein is a magnetic powder which can provide magnets having excellent magnetic properties and having excellent reliability especially excellent heat stability. The magnetic powder is composed of an alloy composition represented by Rx(Fe1-aCoa)100-x-y-zByMz (where R is at least one kind of rare-earth element excepting Dy, M is at least one kind of element selected from Ti, Cr, Nb, Mo, Hf, W, Mn, Zr and Dy, x is 7.1-9.9 at %, y is 4.6-8.0 at %, z is 0.1-3.0 at %, and a is 0-0.30, and the magnetic powder being constituted from a composite structure having a soft magnetic phase and a hard magnetic phase, wherein when the magnetic powder is mixed with a binding resin and then the mixture is subjected to compaction molding to form a bonded magnet having a density &rgr;[Mg/m3], the maximum magnetic energy product (BH)max[kJ/m3] of the bonded magnet at a room temperature satisfies the relationship represented by the formula (BH)max/&rgr;2[×10−9 Jm3/g2]2.

Abstract: A magnetic powder of an Sm—Fe—N alloy, which has a mean particle diameter of 0.5 to 10 &mgr;m, and either an average acicularity of 75% or above or an average sphericity of 78% or above. The powder exhibits an extremely high residual magnetization and an extremely high coercive force, since particles characterized by the above acicularity or sphericity have particle diameters approximately equal to that of the single domain particle and nearly spherical particle shapes. The powder can be produced by preparing an Sm—Fe oxide by firing a coprecipitate corresponding to the oxide, mixing the obtained oxide with metallic calcium and subjecting the mixture to reduction/diffusion and nitriding successively.

Abstract: A method is disclosed enabling a technologically controllable and economical production of a hard-magnetic powder composed of a samarium-cobalt base alloy for highly coercive permanent magnets. The method is based on a HDDR treatment in which a starting powder is subjected to hydrogenation with disproportionation of the alloy in a first method step under hydrogen and, in a subsequent, second method step under vacuum conditions, a hydrogen desorption with recombination of the alloy. A starting powder containing samarium and cobalt is treated in the first method step either at a high temperature in the range of 500° C. to 900° C. and with a high hydrogen pressure of >0.5 MPa or by applying an intensive fine grinding at a low temperature in the range of 50° C. to 500° C. and with a hydrogen pressure of >0.15 MPa.

Abstract: Near-net-shape soft magnetic components can be produced from iron powder-lubricant compositions using powder metallurgy techniques. The resulting components have isotropic magnetic and thermal properties and may be shaped into complex geometry using conventional compaction techniques. A non-coated ferromagnetic powder is mixed with a lubricant and compacted. After compaction, the components are thermally treated at a moderate temperature to burn out the lubricant, and possibly also relieve the stresses induced during pressing and reduce the hysteresis losses. Depending on the application, the properties of the material may be tailored by varying the content and type of the lubricant and the thermal treatment conditions.

Abstract: Disclosed herein is a magnetic powder which can provide a bonded magnet having high mechanical strength and excellent magnetic properties. The magnetic powder has an alloy composition containing a rare-earth element and a transition metal, wherein the magnetic powder includes particles each of which is formed with a number of ridges or recesses on at least a part of a surface thereof. In this magnetic powder, it is preferable that when the mean particle size of the magnetic powder is defined by a&mgr;m, the average length of the ridges or recesses is equal to or greater than a/40&mgr;m. Further, preferably, the ridges or recesses are arranged in roughly parallel with each other so as to have an average pitch of 0.5-100&mgr;m.

Abstract: Secondary agglomerates of magnetic metal particles containing primary particles having an average major axial diameter of 0.05 to 0.25 &mgr;m, said secondary agglomerates having an average particle diameter of 300 to 800 &mgr;m, an upper limit of particle diameter of 2,000 &mgr;m and a repose angle of 38 to 45°. The secondary agglomerates exhibit not only excellent handing property due to high storage efficiency, high transport efficiency and good flowability thereof, but also excellent kneading property when kneaded with various binder resins and organic solvents in a kneader, and excellent dilution-dispersibility when diluted with an additional amount of the organic solvent, upon the production of coating-type magnetic recording media, so as to more improve a surface smoothness and squareness of a magnetic coating film obtained therefrom, and a process for producing such secondary agglomerates of magnetic metal particles for magnetic recording.

Abstract: The method for manufacturing alloy powder for R—Fe—B type rare earth magnets of the present invention includes a first pulverization step of coarsely pulverizing a material alloy for rare earth magnets and a second pulverization step of finely pulverizing the material alloy. In the first pulverization step, the material alloy is pulverized by a hydrogen pulverization method. In the second pulverization step, easily oxidized super-fine powder (particle size: 1.0 &mgr;m or less) is removed to adjust the particle quantity of the super-fine powder to 10% or less of the particle quantity of the entire powder.

Abstract: A ferromagnetic powder comprising ferromagnetic particles coated with a material that does not degrade at temperatures above 150° C. and permits adjacent particles to strongly bind together after compaction such that parts made from the ferromagnetic powder have a transverse rupture strength of about 8,000 to about 20,000 pounds/square inch before sintering. The coating includes from 2 to 4 parts of an oxide and one part of a chromate, molybdate, oxalate, phosphate, or tungstate. The coating may be substantially free of organic materials. The invention also includes a method of making the ferromagnetic powder, a method of making soft magnetic parts from the ferromagnetic powder, and soft magnetic parts made from the ferromagnetic powder.

Abstract: There is provided a powder for permanent magnet comprising needle-like fine particles of Fe or Fe—Co alloy as a base material, a hard magnetic layer and a separation layer of an oxide of rare earth element provided outside said hard magnetic layer.

Abstract: A magnetic powder core comprises a molded article of a mixture of a glassy alloy powder and an insulating material. The glassy alloy comprises Fe and at least one element selected from Al, P, C, Si, and B, and has a texture primarily composed of an amorphous phase. The glassy alloy exhibits a temperature difference &Dgr;Tx, which is represented by the equation &Dgr;Tx=Tx−Tg, of at least 20 K in a supercooled liquid, wherein Tx indicates the crystallization temperature and Tg indicates the glass transition temperature. The magnetic core precursor is produced mixing the glassy alloy powder with the insulating material, compacting the mixture to form a magnetic core precursor, and annealing the magnetic core precursor at a temperature in the range between (Tg−170) K and Tg K to relieve the internal stress of the magnetic core precursor. The glassy alloy exhibits low coercive force and low core loss.

Abstract: A method of making an iron base magnetic material alloy powder includes the steps of: preparing an iron base magnetic material alloy containing at least 50% by mass of iron; and pulverizing the magnetic material alloy using a pin mill. A portion of the mill, which comes into contact with the magnetic material alloy, is made of a cemented carbide material at least partially.

Abstract: A method and structure for forming magnetic alloy nanoparticles includes forming a metal salt solution with a reducing agent and stabilizing ligands, introducing an organometallic compound into the metal salt solution to form a mixture, heating the mixture to a temperature between 260° and 300° C., and adding a flocculent to cause the magnetic alloy nanoparticles to precipitate out of the mixture without permanent agglomeration. The deposition of the alkane dispersion of FePt alloy particles, followed by the annealing results in the formation of a shiny FePt nanocrystalline thin film with coercivity ranging from 500 Oe to 6500 Oe.

Abstract: A process for producing a compound for a rare earth metal resin-bonded magnet includes: a slurry preparation step of mixing materials containing a magnetic alloy powder of a rare earth metal alloy, a resin binder, and an organic solvent into a slurry; and a drying step of spraying and drying the slurry by means of a spray dryer apparatus to produce the compound containing the magnetic alloy powder of the rare earth metal alloy and the resin binder.

Abstract: Ceramic-coated powdered ferromagnetic materials for forming magnetic articles, and which maintain the mechanical and magnetic properties of the articles at high temperatures, such as during annealing to relieve stresses induced during the forming operation. The ceramic coatings are formed by one of several techniques to provide an encapsulating layer on each ferromagnetic particle. The particles are then compacted to form a solid magnetic article, which can be annealed without concern for degrading the ceramic coating.

Abstract: A composite structure and method for manufacturing same, the composite structure being comprised of metal particles and an inorganic bonding media. The method comprises the steps of coating particles of a metal powder with a thin layer of an inorganic bonding media selected from the group of powders consisting of a ceramic, glass, and glass-ceramic. The particles are assembled in a cavity and heat, with or without the addition of pressure, is thereafter applied to the particles until the layer of inorganic bonding media forms a strong bond with the particles and with the layer of inorganic bonding media on adjacent particles. The resulting composite structure is strong and remains cohesive at high temperatures.

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 relates to a magnetic powder that contains resin-coated magnetic particles. The resin-coated magnetic particles include magnetic particles A and B that are formed in non-spherical shapes, with the magnetic particles A and B coated with a resin C. The resin-coated magnetic particles make it possible to increase the filling quantity of the magnetic particles A and B when the magnetic powder is employed to constitute a magnetic molded article, to ultimately improve the electromagnetic characteristics of the magnetic molded article.

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 present invention relates to the preparation of Nd--Fe--B permanent magnetic alloys and more particularly to a process of preparing Nd--Fe--B permanent magnetic alloys with neodymium, iron and boron as their basic constituents, wherein ammonium hydroxide (concentrated ammonia water) and ammonium carbonate are used as the precipitant, and neodymium salts, ferrous salts and soluble boron compounds as the starting materials for alloy elements such as neodymium, iron and boron, in addition, machining surplus or wastes of Nd--Fe--B alloys can also be used as raw materials so as to avoid the use of expensive rare earth metal. The process of the present invention comprises the steps of co-precipitation, hydrogen pre-reduction, calcium reduction-diffusion, rinsing, drying and powder manufacturing etc. and is capable of significantly reducing the costs compared with any of the existing processes.

Abstract: An alloy used for the production of a rare-earth magnet alloy, particularly the boundary-phase alloy in the two-alloy method is provided to improve the crushability.The alloy consists of (a) from 35 to 60% of Nd, Dy and/or Pr, 1% or less of B, and the balance being Fe, or (b) from 35 to 60% of Nd, Dy and/or Pr, 1% or less of B, and at least one element selected from the group consisting of 35% by weight or less of Co, 4% by weight or less of Cu, 3% by weight or less of Al and 3% by weight or less of Ga, and the balance being Fe. The total volume fraction of R.sub.2 Fe.sub.17 and R.sub.2 Fe.sub.14 B phases (Fe may be replaced with Cu, Co, Al or Ga) is 25% or more in the alloy. The average size of each of the R.sub.2 Fe.sub.17 and R.sub.2 Fe.sub.14 B phases is 20 .mu.m or less. The alloy can be produced by a centrifugal casting at an average accumulating rate of melt at 0.1 cm/second or less.

Abstract: A laminated composite structure of alternating metal powder layers, and layers formed of an inorganic bonding media powder, and a method for manufacturing same are discosed. The method includes the steps of assembling in a cavity alternating layers of a metal powder and an inorganic bonding media of a ceramic, glass, and glass-ceramic. Heat, with or without pressure, is applied to the alternating layers until the particles of the metal powder are sintered together and bonded into the laminated composite structure by the layers of sintered inorganic bonding media to form a strong composite structure. The method finds particular application in the manufacture of high performance magnets wherein the metal powder is a magnetic alloy powder.

Abstract: A rare earth-iron-nitrogen based magnetic material has superior magnetic properties. A method of manufacturing the rare earth-iron-nitrogen based magnetic material controls the decline in the magnetic properties of the material during pulverizing processes, and pulverizes the material to a critical particle dimension for single-domain behavior. The fragility of the material is increased since the material includes at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W at 0.05-5% atomic percentage. The material is pulverized by a gas current type jet mill. Sample powder injected from a hopper is introduced from a supply mouth to a pulverizing chamber by nitrogen gas spouting from a pressure nozzle, and the powder is then accelerated to acoustic velocity by high pressure nitrogen gas spouting from gliding nozzles. As a result, the powder particles collide with each other.

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: In HDDR (hydrogenation, disproportionation, desorption and recombination) treatment, a mass production method and its apparatus for anisotropic rare earth magnet powder had not been established because it is difficult to keep a constant temperature of material due to an exothermic/endothermic reaction with hydrogen. The present invention compensates for the heat accompanied with the exothermic/endothermic reaction by a counter reaction by the use of dummy material. The apparatus includes sets of a processing vessel and a heat compensating vessel in contact and in control of their temperature. The apparatus enables the temperature control of HDDR treatment within a desired range and constantly brings out the maximum property from the material. The controlability of the method is independent of the production scale so that mass production by HDDR treatment can be set into practice.

Abstract: The invention concerns a method of compacting and heat-treating iron powders in order to obtain magnetic core components having improved soft magnetic properties. The iron powder consists of fine particles which are insulated by a thin layer having a low phosphorous content. According to the invention, the compacted iron powder is subjected to heat treatment at a temperature between 350.degree. and 550.degree. C.

Abstract: Homogenizing heat-treatment is conducted for changing an ingot containing R (R: Sm or a substance obtained by replacing a part of Sm with one or more kinds of rare earth elements) and T (T: Fe or a substance obtained by replacing a part of Fe with one or more kinds of transition elements) as main component into an alloy ingot mainly containing a R.sub.2 T.sub.17 phase. Next, the above-described alloy ingot is allowed to absorb hydrogen in hydrogen gas in the temperature range of 70.degree. C. to 300.degree. C. and at pressures of 5kgf/cm.sup.2 or more, thus conducting coarse crushing treatment.

Abstract: A the magnetically anisotropic magnetic powder having an average particle size of 1—1000 &mgr;m and made from a magnetically anisotropic R-TM-B-Ga or R-TM-B-Ga-M alloy having an average crystal grain size of 0.01-0.5 &mgr;m, wherein R represents one or more rare earth elements including Y, TM represents Fe which may be partially substituted by Co, B boron, Ga gallium, and M one or more elements selected from the group consisting of Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C and Zn. This is useful for anisotropic resin-bonded magnet with high magnetic properties.