Abstract: An alloy powder for bonded rare earth magnets is prepared by melting an alloy consisting essentially of 20-30 wt % of Sm or a mixture of rare earth elements (inclusive of Y) containing at least 50 wt % of Sm, 10-45 wt % of Fe, 1-10 wt % of Cu, 0.5-5 wt % of Zr, and the balance of Co, quenching the melt by a strip casting technique, to form a rare earth alloy strip containing at least 20% by volume of equiaxed crystals with a grain size of 1-200 &mgr;m and having a gage of 0.05-3 mm, and heat treating the strip in a non-oxidizing atmosphere at 1000-1300° C. for 0.5-20 hours, followed by aging treatment and grinding.

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 rare-earth alloy ingot is produced by melting an alloy composed of 20-30 wt % of a rare-earth constituent which is Sm alone or at least 50 wt % Sm in combination with at least one other rare-earth element, 10-45 wt % of Fe, 1-10 wt % of Cu and 0.5-5 wt % of Zr, with the balance being Co, and quenching the molten alloy in a strip casting process. The strip-cast alloy ingot has a content of 1-200 &mgr;m size equiaxed crystal grains of at least 20 vol % and a thickness of 0.05-3 mm. Rare-earth sintered magnets made from such alloys exhibit excellent magnetic properties and can be manufactured under a broad optimal temperature range during sintering and solution treatment.

Abstract: A suspension for magnetic head, for supporting a magnetic head slider on which a magnetic head for recording/reproduction of information on a magnetic recording medium is mounted, wherein one end of the suspension is fixed to a stator portion fixed to the tip end of a load beam of the suspension, a gimbal portion and a rotor portion oscillatably supported by metallic micro-beams formed by bending are provided on the side of the other end of the suspension, and the magnetic head slider is attached to the gimbal portion, whereby the rotor portion and the magnetic head slider attached to the gimbal portion as one body with the rotor portion can be oscillated in parallel to the surface of a magnetic recording disk, independently of the driving of the slider by a coarse actuator.

Abstract: A magnetic head actuator for a magnetic recording disk drive, comprising a micro-actuator which is provided at a tip end portion of a load beam attached to an arm of a voice coil motor and which is for oscillating a magnetic head slider, wherein one end of the micro-actuator is fixed to a stator portion fixed to the load beam, a gimbal portion and a rotor portion oscillatably supported by metallic micro-beams formed by bending are provided on the side of the other end of the micro-actuator, the magnetic head slider is attached to the gimbal portion, either one of a permanent magnet and a coil is disposed at the stator portion, the other of the permanent magnet and the coil is disposed at the rotor portion, and the rotor portion and the magnetic head slider attached to the gimbal portion as one body with the rotor portion are oscillated by passing an electric current to the coil in a magnetic field formed by the permanent magnet.

Abstract: An R—Fe—B permanent magnet wherein R is Nd or a combination of Nd with a rare earth element is prepared by casting an R—Fe—B alloy, crushing the alloy in an oxygen-free atmosphere of argon, nitrogen or vacuum, effecting comminution, compaction, sintering, aging, and cutting and/or polishing the magnet to give a finished surface. The magnet is then heat treated in an argon, nitrogen or low-pressure vacuum atmosphere having a limited oxygen partial pressure, obtaining a highly oil resistant sintered permanent magnet having corrosion resistance and hydrogen barrier property even in a high pressure hot environment of refrigerant and/or lubricant as encountered in compressors.

Abstract: An R—Fe—B base sintered magnet having a composition of 12-17 at % of R (wherein R stands for at least two of yttrium and rare earth elements and essentially contains Nd and Pr), 0.1-3 at % of Si, 5-5.9 at % of B, 0-10 at % of Co, and the balance of Fe, containing a R2(Fe,(Co),Si)14B intermetallic compound primary phase and at least 1% by volume of an R—Fe(Co)—Si grain boundary phase, and being free of a B-rich phase exhibits a coercive force of at least 10 kOe despite a reduced content of heavy rare earth.

Abstract: Disclosed is a permanent magnet motor consisting of a rotor which is a multi polar-magnetized cylindrical permanent magnet such as a neodymium/iron/boron magnet, and a stator having a plurality of stator teeth. Different from conventional but expensive multi-radial orientation of the magnetic anisotropy, the cylindrical permanent magnet has a direction of orientation along a single diameter of the cylinder that is perpendicular to the cylinder axis when a definite relationship is held between the number of the multipolar magnetic poles and the number of the stator teeth. Even when using such a simple and inexpensive cylindrical permanent magnet as the rotor, high performance of the permanent magnet motor can be ensured with regard to a large induced voltage and small torque ripples.

Abstract: A sintered rare earth magnet consisting essentially of 20-30% by weight of R (wherein R is Sm or a mixture of Sm and another rare earth element), 10-45% by weight of Fe, 1-10% by weight of Cu, 0.5-5% by weight of Zr, and the balance of Co has on its surface a composite layer containing Sm2O3 and/or CoFe2O4 in Co or Co and Fe. The magnet is resistant to hydrogen embrittlement.

Abstract: A radial anisotropic sintered magnet formed into a cylindrical shape includes a portion oriented in directions tilted at an angle of 30° or more from radial directions, the portion being contained in the magnet at a volume ratio in a range of 2% or more and 50% or less, and a portion oriented in radial directions or in directions tilted at an angle less than 30° from radial directions, the portion being the rest of the total volume of the magnet. The radial anisotropic sintered magnet has excellent magnet characteristics without occurrence of cracks in the steps of sintering and cooling for aging, even if the magnet has a shape of a small ratio between an inner diameter and an outer diameter.

Abstract: Rare earth magnet scrap and/or sludge is remelted for reuse. Once a rare earth-free magnet-constituent metal feed is loaded in a melting furnace and heated into a melt, a rare earth-containing metal feed and the rare earth magnet scrap and/or sludge are added to the melt, a particulate flux of an alkali metal, alkaline earth metal or rare earth metal halide and having an average particle size of 1-50 &mgr;m, preferably wrapped in a metal foil, is added to the melt, and the resulting mixture is melted, from which an alloy ingot is obtained. The valuable elements in the scrap and/or sludge can be recycled. Better separation between the slag and the molten metal ensures that the ingot is obtained from the melt in a high yield.

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: The invention discloses an iron-based alloy sheet as a material for preparing a magnetic yoke member to build up a magnetic circuit in a hard-disk voice-coil motor as well as a magnetic yoke member made from such a sheet material. With an object to improve the magnetic circuit in respect of compactness and flatness, the iron-based alloy forming the sheet material contains inherent side elements including C, Si, Mn, P, S, Al, O and N each in a specified amount and is characterized by specified values of saturated magnetic flux density, maximum magnetic permeability and coercive force. The iron-based alloy may further contain up to 10% by weight of cobalt and/or one or a combination of adjuvant elements selected from Ti, Zr, Nb, Mo, Cr, V, Ni, W, Ta and B.

Abstract: An alloy powder for bonded rare earth magnets is prepared by melting an alloy consisting essentially of 20-30 wt % of Sm or a mixture of rare earth elements (inclusive of Y) containing at least 50 wt % of Sm, 10-45 wt % of Fe, 1-10 wt % of Cu, 0.5-5 wt % of Zr, and the balance of Co, quenching the melt by a strip casting technique, to form a rare earth alloy strip containing at least 20% by volume of equiaxed crystals with a grain size of 1-200 &mgr;m and having a gage of 0.05-3 mm, and heat treating the strip in a non-oxidizing atmosphere at 1000-1300° C. for 0.5-20 hours, followed by aging treatment and grinding.

Abstract: Disclosed is a novel thin ribbon of a rare earth/iron/boron-based magnet alloy prepared by quenching of an alloy melt by the method of strip casting, from which a sintered permanent magnet is obtained by the powder metallurgical method.

Abstract: An iron alloy strip having a gage of 0.1 to 5 mm and a magnetic field strength variation within the strip of 0 to 10 Hz, made of an iron alloy consisting essentially of, in % by weight, 0.0001-0.02% of C, 0.0001-5% of Si, 0.001-0.2% of Mn, 0.0001-0.05% of P, 0.0001-0.05% of S, 0.0001-5% of Al, 0.001-0.1% of O, 0.0001-0.03% of N, 0-10% of Co, 0-10% of Cr, 0.01-5% in total of Ti, Zr, Nb, Mo, V, Ni, W, Ta and/or B, and the balance of Fe, and having a saturation magnetic flux density of 1.7-2.3 Tesla, a maximum relative permeability of 1,200-22,000 and a coercive force of 20-380 A/m is suited for use as yokes in voice coil motor magnetic circuits. The iron alloy strip is highly resistant to corrosion and eliminates a need for a corrosion resistant coating.

Abstract: Provided is an abrasive-bladed multiple cutting wheel assembly composed of a plurality of abrasive-bladed cutting wheels and spacers each between two adjacent cutting wheels to define the spacing therebetween on a rotation shaft. While each of the cutting wheels consists of an annular base wheel provided on the outer periphery thereof with an abrasive blade layer containing particles of an abrasive such as diamond particles, the base wheels in the inventive assembly are made from a cemented metal carbide such as tungsten carbide cemented with cobalt having a specified Young's modulus or specified Vickers hardness Hv instead of conventional steel materials so that the thickness of the base wheel can be as small as 0.1 mm and, despite the very small thickness of the base wheel, the cutting wheel assembly serves for the cutting or slicing works of a very hard and brittle material such as sintered rare earth-based permanent magnets with outstandingly high cutting accuracy and durability.

Abstract: A R—Fe—B base permanent magnet material is composed of a R—Fe—B magnet alloy which contains 87.5-97.5 vol % of a Fe14R2B1 primary phase and 0.1-3 vol % of a rare earth oxide or a rare earth and transition metal oxide. The alloy contains as a major component in its metal structure a compound selected from among zirconium-boron compounds, niobium-boron compounds and hafnium-boron compounds. The compound has an average grain size of at most 5 &mgr;m and is uniformly distributed within the alloy such that the maximum interval between neighboring grains of the compound is at most 50 &mgr;m. Rare-earth permanent magnet materials of this composition and structure have excellent magnetic properties.

Abstract: The invention discloses an iron-based alloy sheet as a material for preparing a magnetic yoke member to build up a magnetic circuit in a hard-disk voice-coil motor as well as a magnetic yoke member made from such a sheet material. With an object to improve the magnetic circuit in respect of compactness and flatness, the iron-based alloy forming the sheet material contains inherent side elements including C, Si, Mn, P, S, Al, O and N each in a specified amount and is characterized by specified values of saturated magnetic flux density, maximum magnetic permeability and coercive force. The iron-based alloy may further contain up to 10% by weight of cobalt and/or one or a combination of adjuvant elements selected from Ti, Zr, Nb, Mo, Cr, V, Ni, W, Ta and B.

Abstract: Disclosed is a thin alloy ribbon prepared by the strip casting method as an intermediate for the preparation of a sintered rare earth-based permanent magnet or, in particular, a neodymium/iron/boron-type permanent magnet. The thin alloy ribbon is characterized by a specific volume fraction of the four-phase coexisting region consisting of the &agr;-iron phase, R-rich phase, RXT4B4 phase and R2T14B phase each having an average grain diameter in a specified range and a specific volume fraction of the chill crystalline phase. When these requirements are satisfied, the sintered rare earth-based permanent magnet prepared from the thin alloy ribbons can be imparted with improved magnetic properties and high sintering density even without increasing the sintering temperature.