Abstract: A magnetic powder is disclosed which is characterized by possessing a powder compression characteristic such that the magnetic powder, after being packed in a closed container, pressed at a load of 400 kgf/cm.sup.3, and relieved of the load, exhibits a packing density in the range of 2.5 to 3.5 g/cm.sup.3 and a geometric standard deviation of not more than 1.5 in the particle diameter distribution. A magnetic recording medium using the magnetic powder mentioned above has high packing and, consequently, secures high output, and has ample diminution of noise.

Abstract: Sonochemistry permits extremely rapid cooling to form nanoscale amorphous metal particles. If magnetic, these particles are valuable for magnetic recording media, manufacture of permanent magnets, and other uses. The nanoscale particles agglomerate, however, which limits their utility for these magnetic applications. To keep the particles isolated, we extract the particles from the n-alkane reaction solvent in a polar solvent and cast the extracted particles with a polymer, such as polyvinylpyrrolidone.

Abstract: A method for manufacturing a powder for sendust core is disclosed which is used in power supplies, converters and invertors, and in which the sendust powder is manufactured by applying the atomizing process, and the powder is coated with a special ceramic mixture insulator, so that the core loss would be small after forming a product. The method for manufacturing the powder for a sendust core includes the steps of: preparing a sendust alloy melt composed of (in wt %) 4-13% of Si, 4-7% of Al, and balance of Fe under an inert atmosphere; spouting water with a pressure of 1500-3500 psi to a flow of said sendust alloy melt through four or more nozzles having a diameter of 10-20 mm, so as to form a relatively regular polyhedral powder; adding 0.1-1.0 wt % of kaoline to the powder, and heat-treating it at a temperature of 700.degree.-850.degree. C. for 30 minutes or more under a reducing atmosphere; and carrying out a wet coating on the heat-treated powder by using 0.

Abstract: The present invention is a method for making highly stable magnetic alloy particles with high coercivities and high saturation magnetization comprising the steps of:a) providing a precursor selected from the group consisting of iron oxide hydroxide particles and iron oxide particles, wherein the precursor particle comprises from about 15 to about 45 atomic % Co based on amount of Fe present,b) reducing the precursor particles to magnetic alloy particles,c) passivating the magnetic alloy particles in an oxygen-containing atmosphere at a temperature between about 20.degree. and 100.degree. C.,d) annealing the passivated magnetic alloy particles in an inert atmosphere at a temperature from about 120.degree. to about 450.degree. C., ande) further oxidizing the annealed magnetic alloy particles in an oxygen-containing atmosphere.

Abstract: A process is provided for a technologically controllable, economic production of hard-magnetic parts from Sm.sub.2 --(Fe,M).sub.17 --C.sub.y -base work materials with interstitial inclusions, where M designates gallium and/or at least one metallic element serving to stabilize a rhombohedral 2:17 structure. A Sm.sub.2 Fe.sub.17-x M.sub.x C.sub.y powder mixture is produced, where x>0.1 and 3.gtoreq.y.gtoreq.0. The mixture is subjected to an intensive fine grinding process in a ball mill. The finely ground mixture is heat-treated in a temperature range from 650.degree. C. to 900.degree. C. for partial or complete recrystallization. The resulting ultra-fine-grain Sm.sub.2 Fe.sub.17-x M.sub.x C.sub.y magnetic powder is compacted to produce magnet bodies by a hot pressing processing in a temperature range from 650.degree. C. to 900.degree. C. The process is applicable, for example, for the production of hard-magnetic parts based on interstitial Sm.sub.2 Fe.sub.17 C.sub.y compounds.

Abstract: A raw material for samarium.iron.boron-permanent magnets superior in magnetic properties is provided together with the production method. The material for the permanent magnets comprises an acicular iron powder being prepared by reducing acicular FeOOH (goethite) crystal with hydrogen and having diffused layer of samarium and boron on the surface. The raw material is produced by mixing acicular iron powder obtained by hydrogen reduction of acicular FeOOH crystal with powder of a samarium.cobalt alloy having a melting point lower than 700.degree. C. and powder of boron or powder of a ferro-boron alloy; heating the mixed powder under a hydrogen-nitrogen atmosphere at a temperature between the melting point of the samarium.cobalt alloy and 1200.degree. C. to form coated and diffused layer with the samarium and boron on the surface of the acicular iron powder; and pulverizing the product thus obtained.

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 provides acicular fine particles made up of iron and carbon, and these acicular metal iron fine particles can be prepared by contacting acicular iron carbide fine particles with a reducing agent containing no carbon atom. Further, the present invention provides a magnetic coating composition and magnetic recording medium containing the above acicular metal iron fine particles.

Abstract: There is provided an alloy with ultrafine crystal grains excellent in corrosion resistance, at least 50% of the alloy structure being occupied by ultrafine crystal grains, the alloy having a surface layer containing hydroxide components in a total proportion of 65% or more based on oxide components.

Abstract: A magnetic powder containing MnBi, in which an average particle size of the magnetic powder is from 0.1 .mu.m to 20 .mu.m; a coercive force is from 3000 to 15,000 Oe at 300 K. and 50 to 1000 Oe at 80 K. when measured with applying a magnetic field of 16 KOe; an amount of magnetization is from 20 emu/g to 60 emu/g when measured at 300 K. with applying a magnetic field of 16 KOe; a degree of decrease of an amount of magnetization is 40% or less after being maintained in an atmosphere of 60.degree. C. and 90% RH for 7 days; and a content of metal bismuth (Bi) satisfies the following equation: Metal Bi/(MnBi+metal Bi)<0.

Abstract: An alloy ingot for permanent magnet consists essentially of rare earth metal and iron and optionally boron. The two-component alloy ingot contains 90 vol % or more of crystals having a crystal grain size along a short axis of 0.1 to 100 .mu.m and that along a long axis of 0.1 to 100 .mu.m. The three-component alloy ingot contains 90 vol % or more of crystals having a crystal grain size along a short axis of 0.1 to 50 .mu.m and that along a long axis of 0.1 to 100 .mu.m. The alloy ingot is produced by solidifying the molten alloy uniformly at a cooling rate of 10.degree. to 1000.degree. C./sec. at a sub-cooling degree of 10.degree. to 500.degree. C. A permanent magnet and anisotropic powders are produced from the alloy ingot.

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 5 kgf/cm.sup.2 or more, thus conducting coarse crushing treatment.

Abstract: Disclosed herein is magneto-plumbite ferrite particles for magnetic cards, which are represented by the following general formula:AO.multidot.n{(Fe.sub.1-(a+b) Bi.sub.a M.sub.b).sub.2 O.sub.3 }wherein A represents at least one metal selected from the group consisting of Ba, Sr and Ca, M represents either Co and Sn or Co, Ti and Sn, n is 5.5 to 6.1, a is 0.001 to 0.010 and b is 0.010 to 0.200, and in which the change of the coercive force with temperature in the temperature range of -10.degree. to 120.degree. C. is -1.5 to +1.5 Oe/.degree.C.

Abstract: An assembly of a dry coating (A) that has a magnetic powder with a saturation flux density of at least 100 emu/g is dispersed in a binder. A magnetostrictive metal (B), when the coating (A) is magnetized, resonates mechanically at a predetermined frequency in the range of varying frequencies. The varying frequencies are generated from an applied alternating magnetic field. Changes in flux density and permeability are experienced. When the coating (A) is not magnetized, metal (B) does not resonate at the predetermined frequency, thus experiencing no changes in flux density or permeability. The dry coating (A) and the metal (B) have a superposed relationship in such a way that the latter is capable of mechanical resonance, the marker being so adapted that when said coating (A) is magnetized, the predetermined frequency at which the flux density or permeability will change is generated as a signal in response to the applied alternating magnetic field.

Abstract: Disclosed herein are spindle-shaped magnetic iron based alloy particles containing at least one selected from the group consisting of Ni, Al, Si, P, Co, Mg, B and Zn, which have a particle length of 0.05 to 0.40 .mu.m, a crystallite size of 110 to 180 .ANG., a specific surface area of 30 to 60 m.sup.2 /g, a coercive force of 1,300 to 1,700 Oe and a saturation magnetization (.sigma.s) of not less than 100 emu/g and a process for producing the same.

Abstract: A method for stress relieving a compression molded magnetic body is provided for purposes of enhancing the magnetic permeability of the magnetic body. The method involves encapsulating ferromagnetic particles with a thermoplastic polymer coating selected from the group consisting of polybenzimidazole and polyimides having heat deflection temperatures of at least about 400.degree. C. which are capable of withstanding elevated temperatures for a duration which is sufficient to anneal the magnetic body formed from the coated metal particles. As a result, the stresses induced in the magnetic core by the compression molding process can be relieved without detriment to the mechanical properties and magnetic characteristics of the magnetic core.

Abstract: A solid resin-coated composite magnet powder for producing an improved anisotropic bonded magnet contains individual anisotropic magnet powder particles each having a surface coated with a solid resin layer thereon. A method is disclosed for producing a solid resin-coated magnet powder, including the steps of kneading an anisotropic magnet powder with a solid resin under a reduced pressure, granulating the resultant mixture to produce a solid resin-coated composite magnet powder, and milling the composite magnet powder produced to separate the solid resin-coated composite magnet powder into individual anisotropic magnet powder particles coated with the solid resin.

Abstract: Disclosed is a process using an electric field for contacting a substantially neutrally charged material, that is responsive to an electric field, with a substrate. Also disclosed is a disposable absorbent product, including the electrically responsive material, that is intended for the absorption of body fluids, prepared by the process.

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: A resin magnetic compound is disclosed, comprising (i) from 65 to 77% by weight of a magnetic powder having been surface treated with from 0.01 to 5% by weight, based on the magnetic powder, of a mercaptosilane represented by the following formula (I) or a hydrolysis product of the mercaptosilane:(RO).sub.n R'.sub.(3-n) SiR"SH (I)wherein R and R' each represents an alkyl group having 1 or 2 carbon atoms; R" represents an alkylene group having from 2 to 6 carbon atoms; and n represents 2 or 3, (ii) from 14 to 30% by weight of polyphenylene sulfide resin, and (iii) from 9 to 21% by weight of glass fiber. The resin magnetic compound and a molded article obtained from the compound are excellent in thermal shock resistance, magnetic characteristics, and heat resistance.

Abstract: A polymeric coating material is provided for coating powdered materials, and more particularly, for coating powdered metals which are compression molded to form magnetic cores. The preferred polymeric materials are polybenzimidazole, an aromatic polyamide such as polyphthalamide, and appropriate polyimides which, when properly applied to metal particles to form a magnetic core, are characterized as having a sufficiently high heat deflection temperature of at least about 270.degree. C., so as to prevent the degradation of the mechanical and magnetic properties of the magnetic core at exposure at elevated temperatures. Each of these preferred coating materials is characterized by excellent mechanical properties, chemical resistance and dielectric characteristics within this temperature range.

Abstract: A metal or alloy nanoparticle is provided which exhibits hysteresis at room temperature having a carbon coating. The nanoparticle has a diameter in the range of approximately 0.5 to 50 nm, and may crystalline or amorphous. The metal, alloy, or metal carbide nanoparticle is formed by preparing graphite rods which are packed with the magnetic metal or alloy. or an oxide of the metal or alloy. The packed graphite rods are subjected to a carbon arc discharge to produce soot containing metal, alloy, or metal carbide nanoparticles and non-magnetic species. The spot is subsequently subjected to a magnetic field gradient to separate the metal, alloy, or metal carbide nanoparticles from the non-magnetic species.

Abstract: An iron powder composition comprising an iron powder coated with a substantially uniform coating of a thermoplastic material and admixed with a boron nitride powder and a method of utilizing the mixture to produce a magnetic core component is provided. The iron powder mixture is formulated with up to about 1% by weight of boron nitride which reduces the stripping and sliding die ejection pressures during high temperature molding and also improves the permeability of the magnetic part over an extended frequency range.

Abstract: Sonochemistry permits extremely rapid cooling from the melt which is necessary for forming amorphous metals. Sonochemistry also functions at an extremely small scale to produce nanophase particles. If magnetic, these particles are valuable for magnetic recording media, manufacture of permanent magnets, and other uses. The nanophase particles agglomerate, however, which limits their utility for these magnetic applications. To keep the particles isolated, we extract the particles from the n-alkane reaction solvent in a polar solvent and cast the extracted particles with a polymer, such as polyvinylpyrrolidone.

Abstract: A doped magnetic iron oxide particle suitable for use in magnetic recording media, and methods of preparing the doped magnetic iron oxide particle, are disclosed. The doped magnetic iron oxide particle has the general formula:Co.sub.x Fe.sup.+2.sub.1-x Fe.sub.2.sup.+3 O.sub.4, wherein O<x.ltoreq.1,wherein essentially all of the cobalt(II) and iron(II) dopants are present in a shell surrounding a core of a magnetic iron oxide particle. The doped magnetic iron oxide particle has a narrow switching distribution, high squareness, high coercivity and high remanence.

Abstract: A method for preparing a structure having enhanced magneto-resistance, and use of the structure, in which it is possible to prepare a structure having enhanced magnetoresistance on the basis of the system of materials Cu--Co, especially for a magnetoresistive sensor. An intermediate of the structure is formed initially from an alloy having Cu mixed crystals supersaturated with Co by means of a rapid-solidification technique and this intermediate is subsequently converted by means of a predefined heat treatment into an end product of the desired structure having precipitations of or including Co in a Cu matrix.

Abstract: Disclosed is an absorbent composition including a hydrogel-forming polymeric material and a magnetically-responsive material; disposable absorbent products, including the absorbent composition, intended for the absorption of body fluids; and a method for incorporating the absorbent composition into disposable absorbent products.

Abstract: Biocompatability and orders greater magnetic responsiveness characterize a uniquely useful new product, magnetoferritin, comprising ferritin having a ferrimagnetically ordered ferrite core in place of the naturally occurring ferrihydrite core. A method of preparation is disclosed.

Abstract: A magnetically anisotropic R-T-B-M powder material which is starting with an R-T-B-M raw alloy material having a c-axis crystal orientation of an R.sub.2 T.sub.14 B-type intermetallic compound phase. In one embodiment, the starting material is compressed sintered in a magnetic field and recompressed in a magnetic field. In a second embodiment, the starting material is hot-pressed and homogenized. A method of manufacturing anisotropic magnets such as bond and full density magnets made from the magnetically anisotropic R-T-B-M powder material is disclosed.

Abstract: Acicular cobalt-containing magnetic iron oxides having a high coercive force and a core/shell structure and hence low temperature dependence of the coercive force are prepared by a process in which, in a first stage, surface activation is effected by means of iron(II) and cobalt ions under alkaline conditions on the iron oxide core under an inert gas atmosphere and thereafter, in a second stage, an epitactic coating of cobalt ferrite is applied, which coating is formed oxidatively from iron (II) and cobalt (II) hydroxide, likewise under alkaline reaction conditions. The total amount of cobalt ions used for doping remains unchanged compared with the known doped iron oxides or is even smaller. In the second process stage, the achievable coercive force can be controlled by the proportion of air in the gas mixture during the formation of the epitactic coating.

Abstract: A permanent magnet alloy and method for production thereof. The permanent magnet alloy has a rare earth element including Nd, B, Fe, C, and oxygen, with additions of Co and at least one of Cu, Ga and Ag. The alloy may be produced by contacting particles thereof with carbon- and oxygen-containing material to achieve desired carbon and oxygen contents.

Abstract: A method of forming a magnetically anisotropic powder includes the steps of forming a substantially spherical powder having a major magnetic phase and an average particle size of less than about 200 microns, diffusing hydrogen into the spherical powder at elevated temperatures in an amount sufficient to disproportionate the major magnetic phase, and desorbing the hydrogen by heating the disproportionated powder under vacuum. The magnetic material from which the spherical powder is formed may be a rare earth-transition metal-boron alloy including at least one element from the iron group, at least one rare earth element, and boron. A method of forming a bonded magnet containing magnetically anisotropic particles further includes the steps of mixing the dehydrogenated powder with a binder to form a mixture, and aligning and magnetizing the powder particles in the mixture in a magnetic field.

Abstract: The present invention is directed to a method for a continuous mass-production, on an industrial scale at a high efficiency, of magnetic metal particles having excellent magnetic properties by preventing particle deformation and mutual sintering of the particles in a reduction process, and/or by preventing deterioration of the magnetic properties and unevenness in the properties, particularly in the saturation magnetization, upon oxidation in a stabilization process. In this method, an iron compound based on iron oxyhydroxide can be thermally dehydrated in a thermal dehydration process. These processes can be conducted using apparatuses of the present invention which have a gas flow reactor; a belt conveyor being installed in the reactor and having a gass-passable belt for transporting the material; a gas dispersion plate; and a heating means.

Abstract: A method of manufacturing an inorganic bonding type rapidly solidified magnet, which is formed by energizing and sintering, after an instantaneous mutual attractive force has been applied intermittently in accordance with the electromagnetic force upon a thin piece shaped rapidly solidified magnet powder in a mold. A thin piece shaped inorganic glass having a thermal expansion ratio 9.times.10.sup.-6 /.degree. C. or less is used as the inorganic coupling agent. The magnet of the present invention having a ring shape, is effective to improve reliability as a rotor magnet in consideration of size, safety, mechanical strength, etc. of the present magnet formed in a ring shape. The electric resistance of the magnet is 10.sup.-3 through 10.sup.-1 .OMEGA.cm and is desirable as a rotor magnet of a PWM driving brushless electric motor.

Abstract: A magnetic metal or metal carbide nanoparticle is provided having a carbon coating. The nanoparticle has a diameter in the range of approximately 5 to 60 nm, and may be crystalline or amorphous. The magnetic metal or metal carbide nanoparticle is formed by preparing graphite rods which are packed with a magnetic metal oxide. The packed graphite rods are subjected to a carbon arc discharge to produce soot containing magnetic metal or metal carbide nanoparticles and non-magnetic species. The soot is subsequently subjected to a magnetic field gradient to separate the magnetic metal or metal carbide nanoparticles from the non-magnetic species. Ferromagnetic or paramagnetic compounds are made by starting with graphite rods packed with the oxides of iron, cobalt, nickel and manganese bismuth, or a rare earth element excluding lanthanum, lutetium and promethium, or a paramagnetic transition metal.

Abstract: Acicular magnetic iron particles comprising acicular iron substrate particles having first layer consisting of at least one of hydrous oxides and anhydrous oxides of aluminum and zirconium and mixtures thereof and second layer consisting of hydrous oxides and anhydrous oxides of aluminum and mixtures thereof coated on the surfaces of the particles are produced by coating the surfaces of hydrated iron oxide particles as substrate with at least one of aluminum compounds and zirconium compounds, then heating the coated substrate particles to convert to hematite particles, thereafter coating the surfaces of the resultant hematite substrate particles with at least one of aluminum compounds, and then reducing under heat the coated hematite particles.

Abstract: Disclosed herein are magnetic composite iron oxide particles comprising spinel-type Fe.sub.3 O.sub.4 particles as core particles and spinel-type CoFe.sub.2 O.sub.4 outerlayer of the composite iron oxide particles, a process for producing the same, and a magnetic recording medium comprising a substrate and a magnetic recording layer containing the said magnetic iron oxide particles.

Abstract: A magnetic core having a low core loss and having stable characteristics in a low magnetic permeability region can be obtained at a high yield by applying a heat treatment to a magnetic core main body obtained by winding or laminating a ferrous amorphous ribbon In a wet atmosphere containing a limited amount of steam.

Abstract: The invention concerns a method of protecting magnetic powders and permanent magnets containing at least one rare earth, at least one transition metal and boron from oxidation and atmospheric corrosion, by the introduction of gaseous fluorine during the grinding of the powders. It is characterized in that the fluorine is introduced by a mixture of F.sub.2 +N.sub.2 during the fine grinding of the powders, the mixture containing from 1 to 100 ppm (by volume) of fluorine, and preferably from 1 to 10 ppm. The powders thus obtained are far less reactive and the densified magnets are far more resistant to atmospheric corrosion than non fluorinated powders and magnets obtained therefrom.

Abstract: A magnetic material consisting essentially of A1 and 10 to 50 at. % of at least one capable of alloying with A1 to form quasicrystals (for example, 5 to 25 at. % of at least one member selected between Cu and Pd and 5 to 35 at. % of Mn) and up to 25 at. % of at least one element having a smaller atomic radius than those of the above elements (for example, B). The magnetic material is produced by adding, to a mixture consisting of A1 and at least one element capable of alloying with A1 to form quasicrystals and including at least one transition metal, at least one element having a smaller atomic radius than those of A1 and the above elements to dissolve the element having a smaller atomic radius in a solid solution form in a quasicrystalline phase. The thus obtained magnetic crystal is useful in various applications, such as magnetic recording heads, and a process for producing the same.

Abstract: A process for producing a starting powder material for use in the fabrication of high performance R--Fe--B permanent magnets comprising an R.sub.2 Fe.sub.14 B compound as the principal phase, which is characterized by adding 70% by weight or less of a specified alloy powder for adjusting the composition comprising an R.sub.2 Fe.sub.17 compound to a specified principal phase R--Fe--B alloy powder comprising an R.sub.2 Fe.sub.14 B compound as the principal phase. This process enables production of a starting alloy powder material considerably reduced in contents of the unfavorable B-rich and R-rich phases which impair the magnetic properties of the final magnet, because the starting powder blend allows the B-rich and R-rich compounds in the principal phase alloy powder to react with the R.sub.2 Fe.sub.17 compound being incorporated in the alloy powder for adjusting the composition.

Abstract: A method for preparing a barium-ferrite-coated, needle-shaped .gamma.-Fe.sub.2 O.sub.3 magnetic powder of better properties is provided. The method includes the following steps of a) letting an iron-containing solution undergo a reaction to precipitate a needle-shaped .alpha.-FeOOH phase powder, b) mixing said .alpha.-FeOOH powder into a barium-containing solution in a predetermined Fe/Ba ratio, c) filtering without washing the precipitated powder, and d) subjecting the precipitated powder to heat treatments including calcination, reduction and oxidation.

Abstract: A magnet base, having a flux density equal to that of an Fe-50%Co alloy and an input current response equal to that of an Fe--Si alloy, is used as a component of the magnetic circuit employed for a printing head of a wire dot printer, the magnetic circuit further having by-pass and armature components. The material of the magnetic base is an Fe-50% Co alloy and the base has an end face which is perpendicular to the magnetic circuit of the printing head. A layer, of a material selected from the class consisting of metals and metal alloys which function to increase the specific resistance of a magnet bases of an Fe-50% Co alloy, is formed on the end face of the magnet base and reduces eddy current loss therein, particularly at high frequency energization of the magnetic circuit, further serving to increase the input current response.

Abstract: A flat-shaped fine Fe-Ni alloy powder suitable for use as a magnetic shield coating material for cards or the like. The powder has a mean particle size of 0.1 to 30 .mu.m, a mean thickness not greater than 2 .mu.m and a coercive force not greater than 400 A/m. The flat-shaped fine powder is produced by preparing an Fe-Ni alloy powder of a composition which exhibits, in a bulk state, a saturated magnetostriction constant value falling within the range of .+-.15.times.10.sup.-6 and which contains, by weight, 70 to 83% Ni, 2 to 6% Mo, 3 to 6% Cu, 1 to 2% Mn, not more than 0.05% C and the balance Fe and incidental impurities, pulverizing the alloy powder by an attrition mill, and annealing the pulverized powder in a fluidized or moving state in a substantially non-oxidizing atmosphere.

Abstract: A method is disclosed for producing a rapidly solidified, fine grained, magnetically anisotropic powder of the RE-Fe-B type. The rapidly solidified material is optimally quenched or slightly overquenched and is subjected to a hydrogen absorption-hydrogen desorption process that produces a fine grained material containing the essential magnetic phase RE.sub.2 TM.sub.14 B and an intergranular phase and is magnetically anisotropic.

Abstract: An iron powder composition comprising an iron powder coated with a substantially uniform coating of a thermoplastic material and admixed with a boron nitride powder and a method of utilizing the mixture to produce a magnetic core component is provided. The iron powder mixture is formulated with up to about 1% by weight of boron nitride which reduces the stripping and sliding die ejection pressures during high temperature molding and also improves the permeability of the magnetic part over an extended frequency range.

Abstract: A highly rustproof resin-bonded magnet made by using a specific rustproofing resin for coating the particles of a magnetic powder, bonding them to form a molded body, or coating its surface, or for two or all of those purposes. The specific resin is selected from ones containing groups of atoms having a power of forming a coordinate bond and a reducing action. More specifically, it is (a) a high molecular compound produced by reacting with an epoxy resin one or more of a polyhydric phenol having adjacent hydroxyls, a polyhydric phenolic carboxylic acid having adjacent hydroxyls, an ester of a polyhydric phenol and a polyhydric alcohol having adjacent hydroxyls, and a polycyclic and polyhydric phenol having adjacent hydroxyls, (b) a redox resin as a reduction agent, or (c) a high molecular compound produced by curing a mixture of ascorbic acid, or a derivative thereof, and an epoxy resin.

Abstract: A sintered or bonded permanent magnet formed from a material consisting mainly of iron, particularly a Nd-Fe-B alloy, and having a high corrosion resistance has a surface coated with a resin obtained by the polycondensation of tannic acid, phenols and aldehydes. A bonded magnet is also made from a powder of any such material composed of particles coated with any such resin.

Abstract: Ultrafine particles of Fe-Co-P material with a Fe/Co atomic ratio of from 95/5 to 70/30 and a (Fe+Co)/P atomic ratio of from 85/15 to 60/40 show improved ferromagnetic properties. The average particle size is from 0.005 to 0.1 .mu.m. Such ultrafine particles are prepared through gas phase reaction by evaporating a source material. They are useful in both magnetic and thermomagnetic recording media ensuring high density recording.

Abstract: A permanent magnet made of an R--Fe--B--C or R--Fe--Co--B--C based alloy, where R is at least one rare-earth element, comprising individual magnetic crystal grains that are covered with an oxidation-resistant protective film. The protective film surrounding the individual magnetic crystal grains having a thickness of 0.001-30 .mu.m and 0.05-16 wt. % of the protective film comprising C.