Sumitomo Special Metals Co., Ltd.

Neomax Co., Ltd.

Other

Koki Tokuhara

Hitoshi Morimoto

Akiyasu Oota

Kunitoshi Kanno

Tomoiku Ohtani

Futoshi Kuniyoshi

Yuji Kaneko

Naoyuki Ishigaki

Katsumi Okayama

Ryoji Ono

Nobutaka Suzuki

Shuhei Okumura

Masaki Koga

Hitoshi Yamamoto

Akihito Tsujimoto

Hitoshi Saitoh

Tsuyoshi Wada

Shuji Mino

Kenshiro Oyamada

Yasuhiko Imai

A method of making a sintered body for a rare earth magnet includes the steps of (a) preparing a first coarse powder by coarsely pulverizing a rare earth alloy sintered body by a hydrogen pulverization process, (b) preparing a first fine powder by finely pulverizing the first coarse powder, (c) preparing a second fine powder by pulverizing an alloy block of a rare earth alloy material, and (d) sintering a mixed powder including the first and second fine powders. The first and second fine powders each includes a main phase represented by (LRHR)TA, where T is Fe and/or at least one non-Fe transition metal element; A is boron and/or carbon; LR is at least one light rare earth element; HR is at least one heavy rare earth element; and 0&#x2266;x&#x3c;1.

Method of making sintered compact for rare earth magnet

The present invention aims to prevent heating and ignition of a material powder of a rare-earth alloy while reducing the oxygen content thereof so as to improve the magnetic properties of the rare-earth magnet. A rare-earth alloy powder is compacted by using a powder compacting apparatus including: an airtight container capable of storing a rare-earth alloy powder therein; an airtight feeder box moved between a powder-filling position and a retracted position; and an airtight powder supply device capable of supplying the rare-earth alloy powder from the container into the feeder box without exposing the rare-earth alloy powder to the atmospheric air.

Powder compacting apparatus and method of producing a rare-earth magnet using the same

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.

Method for producing rare-earth magnet

A green compact of a rare earth alloy magnetic powder is made by pressing the powder. The powder is pressed within an air environment that has a temperature controlled at 30&deg; C. or less and a relative humidity controlled at 65% or less.

Method of pressing rare earth alloy magnetic powder

Its basic means is a monolithically bonded construct prepared by monolithically bonding together a rare-earth magnet,and a an alloy material that is a high melting point metal or a high specific-tenacity material through the solid phase diffusion bonding by the hot isostatic pressing treatment, and a monolithically bonded construct with an interposal of a thin layer of the high melting point metal between a rare-earth magnet,and an alloy material,that is a high specific-tenacity material. As a method for the bonding, there is used a hot isostatic pressing treatment method in which a rare-earth An magnet and a high melting-point metal are laminated together, thereby to prepare an object to be treated, then the object is put into a hermetic-type high pressure container having an inner wall portion equipped with a heater, then the object is uniformly pressurized in all directions by a synergistic effect caused by pressure and temperature, while the object is maintained for a certain period of time under a certain pressure and temperature condition in an atmosphere of an inert gas, thereby to monolithically bond the object. With this, it is possible to obtain a bonded construct in which a magnet can monolithically be bonded with another metal member with a high strength, without deteriorating magnetic characteristics, such that the rare-earth magnet's insufficiency in brittleness, rigidity, tenacity and the like is compensated.

Monolithically bonded construct of rare-earth magnet and metal material and method for bonding same

A case for hydrogen-pulverizing a rare earth metal-based magnetic material is disclosed. The case includes a case body which is formed of a material having a heat conductivity of 1 W/cm&middot;deg or more. At least one heat-transferring/releasing member is mounted in the case body and formed of a material having a heat conductivity of 1 W/cm&middot;deg or more. The magnetic material is accommodated in the case and subjected to a hydrogen pulverization with hydrogen occluded in the magnetic material. Thus, the heating and cooling of the magnetic material can be performed in a short time, thereby achieving the pulverization of the magnetic material with an extremely excellent

Process for hydrogen-pulverizing a rare earth metal-based magnetic material, and hydrogen-pulverizing case

It is an object of the present invention to provide R-Fe-B permanent magnet materials having a good oxidation resistance and magnetic characteristics, and a process of producing the same capable of pulverizing efficiently, whereby an R-Fe-B molten alloy having a specific composition is casted into a cast piece having a specific plate thickness and a structure, in which an R-rich phase is finely separated below 5 .mu.m, by a strip casting process, the cast piece is subjected to a Hydrogenation for spontaneous decay, and thereafter, an alloy powder is dehydrogenated and stabilized for pulverization so as to fractionize crystal grains of a main phase constituting an alloy ingot, thereby the powder having a uniform grain distribution can be produced at an efficiency of about twice as much as the conventional process, and the R-rich phase and an R.sub.2 Fe.sub.14 B phase are also fractionized at the time of pulverization, thus by magnetization by pressing after the orientation using a pulse magnetic field, a high performance R-Fe-B permanent magnet having, a good oxidation resistance and magnetic characteristics of the magnet alloy, particularly, a total value A+B of a maximum energy product value (BH) max (MGOe); A and a characteristic value; B of a coercive force iHc (kOe) of 59 or more and the squareness of demagnetization curve {(Br.sup.2 /4)/(BH) max} of 1.01 to 1.045 is obtained.

R-FE-B permanent magnet materials and process of producing the same

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.

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Hyogo, Japan

Koki Tokuhara