Abstract: A magnetic head and production method with excellent productivity with which a surface with fine irregularities is formed only on the bearing surface of the sliding member facing the magnetic recording medium to form a fine air flow path without changing the properties of the smooth surface of the core member that has been finish polished. The sliding properties and the magnetic properties can be improved with no damage to the magnetic recording medium by this surface with fine irregularities.

Abstract: A hydrogen pulverizer according to the present invention is an apparatus for subjecting a rare-earth alloy magnetic material to a hydrogen pulverization process. The apparatus includes: a hermetically sealable hydrogen furnace, which includes a furnace body with an opening and a cap for closing the opening; a loading chamber for temporarily enclosing the rare-earth alloy magnetic material when the rare-earth alloy magnetic material, which has been pulverized with hydrogen, is unloaded from the furnace body through the opening; and an inert gas supply for supplying an inert gas into the loading chamber.

Abstract: An Fe—B—R based permanent magnet has a metal oxide film having a thickness of 0.01 &mgr;m to 1 &mgr;m on its surface with a metal film interposed therebetween. Thus, the film is excellent in adhesion to the surface of the magnet. Even if the permanent magnet is left to stand under high-temperature and high-humidity of a temperature of 80° C. and a relative humidity of 90% for a long period of time, the magnetic characteristic of the magnet cannot be degraded. The magnet has a thermal shock resistance enough to resist even a heat cycle for a long period of time in a temperature range of −40° C. to 85° C., and can exhibit a stable high magnetic characteristic. Therefore, it is possible to produce an Fe—B—R based permanent magnet having a corrosion-resistant film free from hexa-valent chromium.

Abstract: A rare earth metal-based permanent magnet has a film layer formed substantially of only a fine metal powder on a metal forming the surface of the magnet. The rare earth metal-based permanent magnet having the film layer on its surface is produced in the following manner: A rare earth metal-based permanent magnet and a fine metal powder forming material are placed into a treating vessel, where both of them are vibrated and/or agitated, whereby a film layer made of a fine metal powder produced from the fine metal powder producing material is formed on a metal forming the surface of the magnet. Thus, the formation of a corrosion-resistant film such as plated film can be achieved at a high thickness accuracy by forming an electrically conductive layer uniformly and firmly on the entire surface of the magnet without use of a third component such as a resin and a coupling agent.

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 resin molded product and a fine metal powder producing material are placed into a treating vessel. The fine metal powder producing material is brought into flowing contact with the surface of the resin molded product, thereby producing a fine metal powder, and forming a metal layer of the fine metal powder on the surface of the resin molded product. In this process, the metal layer of the fine metal powder can be formed firmly and at high density on the surface of the resin molded product. The metal layer exhibits a function as an electrically conductive layer. Therefore, a metal film having an excellent thickness accuracy, an excellent surface smoothness and a high peel strength can be formed in a simple manner on the metal layer by carrying out an electroplating treatment. In addition, it is possible for the metal layer itself to exhibit functions or properties such as an ornamentality.

Abstract: A magnet member cutting apparatus comprises a temperature controller for temperature control of a coolant. The coolant at a temperature controlled by the temperature controller is supplied to a cutting region from a coolant discharging device via a coolant supplying path. While the coolant is supplied to the cutting region, a magnet member which is a sintered rare-earth magnet member is cut by a cutting blade having a cutting edge including a mixture of abrasive grain made of a super hard abrasive grain and heat resistant resin made of a phenol resin. Preferably, the coolant is used in circulation, the coolant temperature is maintained at 20° C.˜35° C., the cutting blade rotating speed is 1000 m/min˜3000 m/min, a volume rate of the abrasive grain to the cutting edge is 10%˜50%, and the cutting edge further includes metal powder.

Abstract: The present invention is presented with the object of providing a manufacturing method for thin-plate magnets that, as cast, exhibit an intrinsic coercive force iHc of 2.5 kOe or greater and a residual magnetic flux density Br of 9 kG or greater, exhibit a performance-to-cost ratio comparable to hard ferrite magnets, and exhibit a fine crystalline structure with a thickness of 70 to 500 &mgr;m wherewith magnetic circuits can be made smaller and thinner. By employing alloy melts to which specific elements have been added, in a process wherein alloy melts of specific composition are continuously cast on a rotating cooling roller or rollers in a reduced-pressure inert or inactive gas atmosphere at 30 kPa or less, and fine crystalline permanent magnets having a fine crystalline structure of 10 to 50 nm are fabricated, fine crystalline permanent magnets having a thickness of 70 to 500 &mgr;m can be obtained wherein iHc is improved to 2.

Abstract: A method for cutting a rare earth alloy according to the present invention includes the steps of: a) supplying slurry containing abrasive grains onto a wire; and b) machining the rare earth alloy with the abrasive grains, interposed between the wire and the rare earth alloy, by running and pressing the wire against the rare earth alloy. The slurry contains, as a main component, oil in which the abrasive grains are dispersed, and the viscosity of the slurry at 25° C. is in the range from 92 to 175 mPa.sec.

Abstract: A rare earth metal-based permanent magnet has a metal oxide film formed on the surface thereof by a sol-gel coating process. The rare earth metal-based permanent magnet is produced by forming a metal oxide film on the surface thereof by a sol-gel coating process. The metal oxide film is thin and dense. The adhesion of the film to the surface of the magnet is excellent. The film exhibits an excellent corrosion resistance. Typical examples of the metal oxide films are Al, Si, Ti and Zr oxide films. An interfacial layer with R (rare earth element) atom chemically bonded with a film forming metal atom through oxygen atom is formed between the metal oxide film and the entire surface of the magnet.

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: The present invention provides a process for producing a rare earth metal-based permanent magnet having, on its surface, a corrosion-resistant film containing inorganic fine particles having a specific average particle size and dispersed in a film phase formed from a silicon compound. In a heat treatment for forming a film by a hydrolyzing reaction and a thermally decomposing reaction of the silicon compound, followed by a polymerizing reaction, a stress is generated within the film by the shrinkage of the film. In the corrosion-resistant film formed by the producing process according to the present invention, however, such stress is dispersed by the presence of the inorganic fine particles and hence, the generation of physical defects such as cracks is inhibited. In addition, voids between the adjacent inorganic fine particles are filled with the film phase formed from the silicon compound and hence, the formed film is dense.

Abstract: A magnetic field adjusting apparatus calculates a location and the number of magnetic field adjusting pieces to be disposed, by means of a linear programming. An expected magnetic field uniformity is calculated based on the location and the number of adjusting pieces. The location and the number of the adjusting pieces for the expected magnetic field uniformity not greater than a predetermined value are displayed in a display portion. The worker disposes the adjusting piece on a magnetic field generator based on the display. If the expected magnetic field uniformity is greater than the predetermined value, an expected magnetic field uniformity is further calculated by using a direct search. A location and the number of the adjusting pieces that minimize the expected magnetic field uniformity are selected and displayed in the display portion. The worker disposes the adjusting piece on the generator based on the display.

Abstract: A resin molded product and a fine metal powder producing material are placed into a treating vessel. The fine metal powder producing material is brought into flowing contact with the surface of the resin molded product, thereby producing a fine metal powder, and forming a metal layer of the fine metal powder directly on the surface of the resin molded product. In this process, the metal layer of the fine metal powder can be formed firmly and at high density on the surface of the resin molded product. The metal layer exhibits a function as an electrically conductive layer. Therefore, a metal film having an excellent thickness accuracy, an excellent surface smoothness and a high peel strength can be formed in a simple manner on the metal layer by carrying out an electroplating treatment. In addition, it is possible for the metal layer itself to exhibit functions or properties such as an ornamentality.

Abstract: A method of manufacturing R—Fe—B bonded magnets, capable of forming various corrosion resisting films on a R—Fe—B bonded magnet uniformly with a very high bonded strength so as to attain such a very high corrosion resistance thereof that prevents the bonded magnet from being rusted even in a long-period high-temperature high-humidity test; comprising barrel-polishing a porous R—Fe—B bonded magnet by a dry method using as media an abrasive stone formed by sintering inorganic powder of Al2O3, SiC, ZrO and MgO, or a mixture of an abrasive for metal balls and vegetable media, such as vegetable skin chips, sawdust, rind of a fruit and a core of corn, or a mixture of vegetable media the surfaces of which are modified by the above-mentioned abrasive and the above-mentioned inorganic pulverized bodies, so as to enable a surface of the magnet to be smoothed and sealed.

Abstract: The method of producing an R—Fe—B magnet of the present invention is characterized in that R—Fe—B alloy fine powder is molded in a magnetic field and sintered using a lubricant for molding magnets containing specific components, individually or as a mixture, of specific amounts of methyl caproate and/or methyl caprylate, which provide high crystal orientation, and lubricant comprising depolymerized polymer for improving molded article strength, or a lubricant for molding magnets wherein Ti coupling agent that improves crystal orientation is added to this lubricant for molding magnets. Each particle of the fine powder has a high degree of crystal orientation in the direction of the magnetic field, and molded article strength is markedly improved, leading to improved mass-productivity and yield. Moreover, the above-mentioned lubricants do not react with this magnet powder during sintering and are emitted as a gas.

Abstract: A hollow work having a hole communicating with the outside and a fine metal powder producing material are placed into a treating vessel, where the fine metal powder producing material is brought into flowing contact with the surface of the work, thereby adhering a fine metal powder produced from the fine metal powder producing material to the surface of the work. The hollow work may be a ring-shaped bonded magnet. Thus, a film having an excellent corrosion resistance can be formed without use of a third component such as a resin and a coupling agent by providing an electric conductivity to the entire surface of the magnet, i.e., not only to the outer surface (including end faces) but also to the inner surface of the magnet and subjecting the magnet to an electroplating treatment.

Abstract: A dry surface treating apparatus of the present invention comprises, within a treating chamber, a surface-treating material supply section and a tubular barrel having a porous peripheral surface for accommodating a work piece, to treat a surface of the work piece while rotating the tubular barrel horizontally arranged about a horizontal rotational axis, wherein the tubular barrel has a slide stop for stopping a slide of the accommodated work piece along an inner peripheral surface of the tubular barrel due to rotation of the tubular barrel.

Abstract: A rare-earth alloy powder pressing apparatus comprises a die. The die includes a die main body. The die main body includes a through hole for formation of a cavity, and an auxiliary yoke. A rare-earth alloy powder is fed into the cavity. A correcting yoke is disposed near the die, on a side from which a compact is taken out, and an orienting magnetic field is applied. At this time, the correcting yoke is disposed on an upper side of the die if the compact is to be taken out from the upper side of the die whereas the correcting yoke is disposed on a lower side of the die if the compact is to be taken out from the lower side of the die, an inward side surface of the correcting yoke and an inward side surface of the auxiliary yoke are made flush with a plane vertical to a direction in which the orienting magnetic field is applied, and the correcting yoke is urged toward the die. Then, the rare-earth alloy powder is pressed by an upper punch and a lower punch to form a compact.

Abstract: With the invention of establishing fabrication methods for cheaply produced (Fe,Co)—Cr—B—R-type bonded magnets or (Fe,Co)—Cr—B—R—M-type bonded magnets containing few rare earth elements having a coercive force iHc above 5 kOe and a residual magnetic flux density Br above 5.