Abstract: A method for producing a compact of rare earth alloy powder of the present invention includes: a powder-filling step of filling rare earth allow powder in a cavity formed by inserting a lower punch into a through hall of a die of a powder compacting machine; and a compression step of pressing the rare earth alloy powder while applying a magnetic field, the steps being repeated a plurality of times. When the (n+1)th (n is an integer equal to or more than 1) stage compression step is to be carried out, the top surface of a compact produced in the n-th stage compression step is placed at a position above the bottom surface of a magnetic portion of a die.

Abstract: A compact is produced from an alloy powder for R—Fe—B type rare earth magnets including particles having a size in a range of about 2.0 &mgr;m to about 5.0 &mgr;m as measured by a light scattering method using a Fraunhofer forward scattering in a proportion of approximately 45 vol. % or more and particles having a size larger than about 10 &mgr;m in a proportion of less than about 1 vol. %. The compact is then sintered to obtain a R—Fe—B type rare earth magnet having an average crystal grain size in a range of about 5 &mgr;m to about 7.5 &mgr;m, and an oxygen concentration in a range of about 2.2 at. % to about 3.0 at. %.

Abstract: A case according to the present invention is used in a sintering process to produce a rare-earth magnet. The case includes: a body with an opening; a door for opening or closing the opening of the body; and supporting rods for horizontally sliding a sintering plate, on which green compacts of rare-earth magnetic alloy powder are placed. The supporting rods are secured inside the body. At least the body and the door are made of molybdenum.

Abstract: With the blasting apparatus in which the injection nozzle is disposed to inject the blast material against the work pieces from the outside of the tubular barrel formed of the mesh net for accommodation of the work pieces and rotatable about the center axis, the work pieces can be stirred homogenously and efficiently without excessive occurrence of the collision of the work pieces against one another and without occurrence of the collision of the work pieces against one another and with a strong shock force. Therefore, the treating efficiency is enhanced and, it is possible to inhibit the occurrence of the cracking and breaking of the work pieces. Further, with the blasting apparatus in which the tubular barrel is supported circumferentially outside the center axis of the support member rotatable about the center axis, it is possible to more inhibit the occurrence of the cracking and breaking of the work pieces.

Abstract: A milling apparatus comprises a mill for milling of an object material such as a rare-earth alloy. The mill includes a mill main body. A classifying rotor for classification of a powder is provided inside and at an upper portion of the mill main body. The mill main body has an outer circumference provided with three leg portions spaced equally from each other. Each of the leg portions supports the mill main body at a position above the center of gravity of the mill. Each of the leg portions is provided with a weight detector for detection of a weight of the mill holding the object material remaining in the mill. A flexible pipe is provided between the mill and a raw material feeder for supply of the object material to the mill. Another flexible pipe is provided between the mill and a collecting tank for collection of the powder.

Abstract: A dielectric ceramic composition for microwave use having a relative permittivity &egr;r of 35 to 45, Qf0 value of more than 50,000 GHz (at 7 GHz), and dielectric characteristic of &tgr;f=0±10 ppm/° C includes an La2O3.Al2O3.SrO.TiO2 based ceramic composition and a specific quantity of Ga2O3 to increase the Qf0 value and a specific amount of Pr2O3to control the &tgr;f value.

Abstract: A melt of an alloy, represented (Fe1-mTm)100-x-y-zQxRyMz, where T is Co and/or Ni, Q is B and/or C, R is at least one rare-earth element, M is selected from Al, Si, Ti, V, Cr, Mn, Cu, Zn, Ga, Zr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au and Pb; 10 at %≦x≦35 at %; 2 at %≦y≦10 at %; 0 at %≦z≦10 at %; and 0≦m≦0.5, is prepared. Next, the melt is brought into contact with, and rapidly cooled and solidified by, the surface of a rotating chill roller. The melt is teemed onto a guide member, of which the guide surface defines a tilt angle with a horizontal plane, runs down on the guide surface, and then is fed through at least one tubular hole onto a contact area on the surface of the chill roller.

Abstract: A magnetic sensor of orthogonal flux-gate type is provided with a cylindrical core made of a soft magnetic material; an internal conductor that is placed inside the core; a detection coil wound up on the core; and an external conductor that is placed around the core and electrically connected to the internal conductor. A high-frequency current is allowed to flow through the internal core so that a magnetic field to be measured which resides around the detection coil is changed and the intensity and direction of the magnetic field to be measured is detected on the basis of an output of the detection coil. Since the external conductor is placed on the periphery of the core, it is possible to prevent the magnetic flux formed by the core from magnetizing any space, and consequently to concentrate the magnetic field on the core.

Abstract: A method of making an alloy powder for an R—Fe—B—type rare earth magnet includes the steps of preparing a material alloy that is to be used for forming the R—Fe—B—type rare earth magnet and that has a chilled structure that constitutes about 2 volume percent to about 20 volume percent of the material alloy, coarsely pulverizing the material alloy for the R—Fe—B—type rare earth magnet by utilizing a hydrogen occlusion phenomenon to obtain a coarsely pulverized powder, finely pulverizing the coarsely pulverized powder and removing at least some of fine powder particles having particle sizes of about 1.0 &mgr;m or less from the finely pulverized powder, thereby reducing the volume fraction of the fine powder particles with the particle sizes of about 1.0 &mgr;m or less, and covering the surface of remaining ones of the powder particles with a lubricant after the step of removing has been performed.

Abstract: An iron-based rare earth alloy magnet has a composition represented by the general formula: (Fe1-mTm)100-x-y-zQxRyMz, where T is at least one element selected from the group consisting of Co and Ni; Q is at least one element selected from the group consisting of B and C; R is at least one rare earth element substantially excluding La and Ce; and M is at least one metal element selected from the group consisting of Ti, Zr and Hf and always includes Ti. In this formula, the mole fractions x, y, z and m meet the inequalities of: 10 at %<x≦20 at %; 6 at %≦y<10 at %; 0.1 at %≦z≦12 at %; and 0≦m≦0.5, respectively.

Abstract: A magnetic field generator comprises a pair of plate yokes connected by a column yoke. The pair of plate yokes has a pair of opposed surfaces each provided with a permanent magnet including a plurality of neodymium magnets. In a method in which the neodymium magnets are demagnetized and adhesive is ground, the magnetic field generator is heated to 200° C.˜350° C. After the neodymium magnets are demagnetized, the adhesive is removed and the neodymium magnets are removed and collected from the magnetic field generator. In a method in which the adhesive is carbonized, the magnetic field generator is heated to 350° C.˜1000° C. After carbonizing the adhesive, the neodymium magnets are removed and collected. Surfaces of the collected neodymium magnets are polished and the neodymium magnets are reused. Further, the collected neodymium magnets are re-aged and reused.

Abstract: The method for producing a rare-earth sintered magnet of the present invention includes the steps of: compacting alloy powder for the rare-earth sintered magnet to form a green compact; loading the green compact into a case having a structure restricting a path through which gas flows between the outside and inside of the case, and placing a gas absorbent at least near the path; and sintering the green compact by heating the case including the green compact inside in a decompressed atmosphere.

Abstract: A surface treating process according to the present invention, a vapor deposited film is formed from an easily oxidizable vapor-depositing material on the surface of a work by evaporating the vapor-depositing material in a state in which the vapor deposition controlling gas has been supplied to at least zones near a melting/evaporating source and the work within a treating chamber. Thus, the vapor deposited film can be formed stably on the surface of a desired work without requirement of a long time for providing a high degree of vacuum and without use of a special apparatus. In addition, the use of the surface treating process ensures that a corrosion resistance can be provided to a rare earth metal-based permanent magnet extremely liable to be oxidized, without degradation of a high magnetic characteristic of the magnet.

Abstract: A method of making an alloy powder for an R—Fe—B-type rare earth magnet includes the steps of preparing a material alloy that is to be used for forming the R—Fe—B-type rare earth magnet and that has a chilled structure that constitutes about 2 volume percent to about 20 volume percent of the material alloy, coarsely pulverizing the material alloy for the R—Fe—B-type rare earth magnet by utilizing a hydrogen occlusion phenomenon to obtain a coarsely pulverized powder, finely pulverizing the coarsely pulverized powder and removing at least some of fine powder particles having particle sizes of about 1.0 &mgr;m or less from the finely pulverized powder, thereby reducing the volume fraction of the fine powder particles with the particle sizes of about 1.0 &mgr;m or less, and covering the surface of remaining ones of the powder particles with a lubricant after the step of removing has been performed.

Abstract: The method for producing a solder bump transfer sheet of the invention includes the steps of: providing a sheet having a chromium oxide layer containing substantially no iron oxide as the outermost surface; and forming a plurality of solder bumps placed in a predetermined pattern on the chromium oxide layer.

Abstract: A powder pressing apparatus comprises a powder feeding apparatus. The powder feeding apparatus includes a container having a bottom portion provided with a powder holding portion formed with openings, and an impactor. The impactor is hit against the container to give an impulsive force, thereby feeding the powder contained in the container into the cavity formed in a die via the openings. The powder fed in the cavity is pressed, and the obtained compact is sintered into a sintered magnet. The powder feeding apparatus may include a feeder box containing the powder, and the feeder box may be provided therein with a rod member, and an opening of the feeder box may be provided with a linear member. In this case, the powder is fed into the cavity while moving the rod member in the horizontal direction in the feeder box, when the feeder box is above the cavity.

Abstract: A powder pressing apparatus comprises a die having a through hole, an upper punch and a lower punch. At least one of the upper and lower punches has a punching surface having an edge portion provided with a projection. The projection has a tip chamfered by a width not greater than 0.5 mm. The punching surface has a slope having a surface roughness Ra not greater than 1.0 &mgr;m. A rare-earth alloy powder is fed into a cavity formed in the through hole of the die. The rare-earth alloy powder in the cavity is oriented by magnetic field, and pressed by using the upper and lower punches. The upper punch and the lower punch are brought closest to each other at a minimum distance not smaller than 1.7 mm during the pressing. An obtained compact is used for manufacture of a sintered body and a voice coil motor.

Abstract: A cuboid p-type and an n-type thermoelectric conversion material having a composite of an alloy powder for a rare earth magnet and a bismuth-based thermoelectric conversion material that has been rendered a p-type semiconductor or an n-type semiconductor by the addition of the required dopant, are arranged alternately with a material with low thermal conductivity and high electrical resistivity interposed between them. The low- and the high-temperature sides of these thermoelectric conversion materials are connected with wires, a magnetic field is applied in the x axis direction, a temperature gradient ∇T is imparted in the z axis direction a p-n junction is created, and thermoelectromotive force is extracted from the connection end in a plane in the y axis direction. There is a marked increase in the Seebeck coefficient even though no magnetic field is applied externally.

Abstract: A compact is produced from an alloy powder for R—Fe—B type rare earth magnets including particles having a size in a range of about 2.0 &mgr;m to about 5.0 &mgr;m as measured by a light scattering method using a Fraunhofer forward scattering in a proportion of approximately 45 vol. % or more and particles having a size larger than about 10 &mgr;m in a proportion of less than about 1 vol. %. The compact is then sintered to obtain a R—Fe—B type rare earth magnet having an average crystal grain size in a range of about 5 &mgr;m to about 7.5 &mgr;m, and an oxygen concentration in a range of about 2.2 at. % to about 3.0 at. %.

Abstract: A plate yoke has an upper surface formed with a projection and a guiding rail. A new magnet block is transported by sliding on the upper surface of the plate yoke, and is bonded side by side with the projection or a magnet block which is already fixed. During the above operation, a magnetic member is held above the plate yoke. Preferably, the new magnet block is transported toward a corner portion, with side surfaces of the magnet block held parallel to a side surface of the projection and a side surface of the guiding rail respectively. When the magnet unit and the column yoke is connected, the column yoke or the magnet unit is lowered so that a guiding rod attached to an end face of the column yoke is inserted into a hole formed in the magnetic unit. Further, the column yoke is guided by a guiding member disposed between a permanent magnet on the plate yoke and a position where the column yoke is to be connected on the plate yoke.