Nitto-denko Corporation

Keisuke Taihaku

Katsuya Kume

Izumi Ozeki

Tomohiro Omure

Takashi Ozaki

Keisuke Hirano

Toshiaki Okuno

Takashi Yamamoto

Toshinobu Hoshino

There are provided a rare-earth permanent magnet and a manufacturing method of a rare-earth permanent magnet capable of preventing deterioration of magnet properties. In the method, magnet material is milled into magnet powder. Next, a mixtureis prepared by mixing the magnet powder and a binder, and the mixtureis formed into a sheet-like shape to obtain a green sheet. Thereafter, magnetic field orientation is performed to the green sheet, which is then held for several hours in a non-oxidizing atmosphere at a pressure higher than normal atmospheric pressure, at 200 through 900 degrees Celsius for calcination. Thereafter, the calcined green sheetis sintered at a sintering temperature. Thereby a permanent magnetis manufactured.

Rare-earth permanent magnet and method for manufacturing rare-earth permanent magnet

Provided are a rare-earth permanent magnet whose magnet density after sintering is very high and a method for manufacturing a rare-earth permanent magnet. Thus, a magnet raw material is milled into magnet powder, and then, a compoundis formed by mixing the magnet powder thus milled with a binder. Next, the compoundthus formed is subjected to a hot-melt molding onto a supporting substrateso as to form a green sheetmolded to a sheet-like shape. Thereafter, while the green sheetthus molded is softened by heating, magnetic field orientation is carried out by applying a magnetic field to the green sheetthus heated; and further, the green sheethaving been subjected to the magnetic field orientation is calcined by a vacuum sintering, which is further followed by a pressure sintering to produce a permanent magnet

Rare earth permanent magnet and method for producing rare earth permanent magnet

There are provided a rare-earth permanent magnet, and a method for manufacturing a rare-earth permanent magnet and a system for manufacturing a rare-earth permanent magnet, capable of achieving improved shape uniformity. Magnet material is milled into magnet powder, and the milled magnet powder is formed into a formed body. The formed bodyis calcined and then sintered using a spark plasma sintering apparatus, so that a permanent magnetis manufactured. A die unitincluded in the spark plasma sintering apparatusthat performs spark plasma sintering at least includes in one direction an inflow holeconfigured to receive inflow of part of the pressurized formed body.

Rare-earth permanent magnet, method for manufacturing rare-earth permanent magnet and system for manufacturing rare-earth permanent magnet

There are provided a rare-earth permanent magnet and a manufacturing method thereof capable of preventing deterioration of magnet properties. In the method, magnet material is milled into magnet powder. Next, a mixture is prepared by mixing the magnet powder and a binder made of long-chain hydrocarbon and/or of a polymer or a copolymer consisting of monomers having no oxygen atoms. Next, the mixture is formed into a sheet-like shape so as to obtain a green sheet. After that, the green sheet is held for a predetermined length of time at binder decomposition temperature in a non-oxidizing atmosphere so as to remove the binder by causing depolymerization reaction or the like to the binder, which turns into monomer. The green sheet from which the binder has been removed is sintered by raising temperature up to sintering temperature. Thereby a permanent magnetis obtained.

There are provided a permanent magnet and a manufacturing method thereof enabling carbon content contained in magnet particles to be reduced in advance before sintering even when wet milling is employed. Coarsely-milled magnet powder is further milled by a bead mill in a solvent together with an organometallic compound expressed with a structural formula of M&#x2212;(OR)(M includes at least one of neodymium, praseodymium, dysprosium and terbium, each being a rare earth element, R represents a substituent group consisting of a straight-chain or branched-chain hydrocarbon, x represents an arbitrary integer) so as to uniformly adhere the organometallic compound to particle surfaces of the magnet powder. Thereafter, a compact body of compacted magnet powder is held for several hours in hydrogen atmosphere at 200 through 900 degrees Celsius to perform hydrogen calcination process. Thereafter, through sintering process, a permanent magnetis manufactured.

Permanent magnet and manufacturing method thereof

There are provided a permanent magnet and a manufacturing method thereof capable of decreasing an activity level of a calcined body activated by a calcination process. To fine powder of milled neodymium magnet is added an organometallic compound solution containing an organometallic compound expressed with a structural formula of M&#x2212;(OR)(M represents Dy or Tb, R represents a substituent group consisting of a straight-chain or branched-chain hydrocarbon,represents an arbitrary integer) so as to uniformly adhere the organometallic compound to particle surfaces of the neodymium magnet powder. Thereafter, desiccated magnet powder is held for several hours in hydrogen atmosphere at 200 through 900 degrees Celsius. Thereafter, the powdery calcined body calcined through the calcination process in hydrogen is held for several hours in vacuum atmosphere at 200 through 600 degrees Celsius for a dehydrogenation process. Thereafter, through powder compaction and sintering process, the powdery calcined body is formed into a permanent magnet.

There are provided a permanent magnet and a manufacturing method thereof enabling carbon content contained in magnet particles to be reduced in advance before sintering even when wet milling is employed. Coarsely-milled magnet powder is further milled by a bead mill in a solvent together with an organometallic compound expressed with a structural formula of M-(OR)(M represents V, Mo, Zr, Ta Ti W or Nb, R represents a substituent group consisting of a straight-chain or branched-chain hydrocarbon, X represents an arbitrary integer) so as to uniformly adhere the organometallic compound to particle surfaces of the magnet powder. Thereafter, a compact body of compacted magnet powder is held for several hours in hydrogen atmosphere at 200 through 900 degrees Celsius to perform hydrogen calcination process. Thereafter, through sintering process, a permanent magnetis formed.

There are provided a permanent magnet and a manufacturing method thereof capable of decreasing an activity level of a calcined body activated by a calcination process. To fine powder of milled neodymium magnet is added an organometallic compound solution containing an organometallic compound expressed with a structural formula of M-(OR)(M represents V, Mo, Zr, Ta, Ti, W or Nb, R represents a substituent group consisting of a straight-chain or branched-chain hydrocarbon,represents an arbitrary integer) so as to uniformly adhere the organometallic compound to particle surfaces of the neodymium magnet powder. Thereafter, desiccated magnet powder is held for several hours in hydrogen atmosphere at 200 through 900 degrees Celsius. Thereafter, the powdery calcined body calcined through the calcination process in hydrogen is held for several hours in vacuum atmosphere at 200 through 600 degrees Celsius for a dehydrogenation process.

There are provided a permanent magnet and a manufacturing method thereof capable of manufacturing metal alkoxide in better work environment, simpler production facilities and easier manufacturing process and also reducing the manufacturing costs. An electrolytic solution is obtained through dissolving chloride or injecting hydrogen chloride gas into alcohol which is same alcohol as is a constituent element of metal alkoxide to be manufactured. Then, electrolysis is performed on the electrolytic solution while using, for an anode, a ferroalloy that contains iron and metal which is a constituent element of the metal alkoxide to be manufactured in a predetermined weight ratio (such as 1:1), and, for a cathode, the same ferroalloy, carbon, platinum or stainless steel, so as to obtain an alcohol solution of the metal alkoxide. Then, a permanent magnet is manufactured using the alcohol solution of the metal alkoxide thus obtained.

There are provided a permanent magnet and a manufacturing method thereof capable of densely sintering the entirety of the magnet without making a gap between a main phase and a grain boundary phase in the sintered magnet. To fine powder of milled neodymium magnet is added an organometallic compound solution containing an organometallic compound expressed with a structural formula of M-(OR)(M represents V, Mo, Zr, Ta, Ti, W or Nb, R represents a substituent group consisting of a straight-chain or branched-chain hydrocarbon,represents an arbitrary integer) so as to uniformly adhere the organometallic compound to particle surfaces of the neodymium magnet powder. Thereafter, a compact body formed through powder compaction is held for several hours in hydrogen atmosphere at 200 through 900 degrees Celsius. Thereafter, through sintering process, a permanent magnet is manufactured.

There are provided a permanent magnet and a manufacturing method thereof capable of densely sintering the entirety of the magnet without making a gap between a main phase and a grain boundary phase in the sintered magnet. To fine powder of milled neodymium magnet is added an organometallic compound solution containing an organometallic compound expressed with a structural formula of M-(OR)(M represents V, Mo, Zr, Ta, Ti, W or Nb, R represents a substituent group consisting of a straight-chain or branched-chain hydrocarbon, x represents an arbitrary integer) so as to uniformly adhere the organometallic compound to particle surfaces of the neodymium magnet powder. Thereafter, desiccated magnet powder is held for several hours in hydrogen atmosphere at 200 through 900 degrees Celsius. Thereafter, the powdery calcined body calcined through the calcination process in hydrogen is held for several hours in vacuum atmosphere at 200 through 600 degrees Celsius for a dehydrogenation process.

There are provided a permanent magnet and a manufacturing method thereof that enables concentration of V, Mo, Zr, Ta, Ti, W or Nb contained in an organometallic compound in grain boundaries of the permanent magnet. To fine powder of milled neodymium magnet is added an organometallic compound solution containing an organometallic compound expressed with a structural formula of M-(OR)(M represents V, Mo, Zr, Ta, Ti, W or Nb, R represents a substituent group consisting of a straight-chain or branched-chain hydrocarbon,represents an arbitrary integer) so as to uniformly adhere the organometallic compound to particle surfaces of the neodymium magnet powder. Thereafter, a compact body obtained by compacting the magnet powder is held for several hours in hydrogen atmosphere at 200 through 900 degrees Celsius so as to perform a calcination process in hydrogen. Thereafter, through sintering, a permanent magnet is manufactured.

There are provided a permanent magnet and a manufacturing method thereof capable of preventing degrade in the magnetic properties by densely sintering the entirety of the magnet. To fine powder of milled neodymium magnet is added an organometallic compound solution containing an organometallic compound expressed with a structural formula of M-(OR)(M represents Dy or Tb, R represents a substituent group consisting of a straight-chain or branched-chain hydrocarbon,represents an arbitrary integer) so as to uniformly adhere the organometallic compound to particle surfaces of the neodymium magnet powder. Thereafter, the desiccated magnet powder is calcined by utilizing plasma heating and the powdery calcined body is sintered so as to form a permanent magnet

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Ibaraki, Japan

Keisuke Taihaku