Hitachi Metals, Ltd.

Sumitomo Special Metals Co., Ltd.

Neomax Co., Ltd.

Futoshi Kuniyoshi

Rintaro Ishii

Teppei Satoh

Hitoshi Morimoto

Ryouichi Yamagata

Takeshi Nishiuchi

Koki Tokuhara

Kunitoshi Kanno

Tomoiku Ohtani

Ryoji Ono

Tomoiku Otani

Yuji Kaneko

Hiroya Kobayashi

Hiroyuki Tomizawa

Tsunehiro Kawata

Kazuo Tanaka

Shuji Mino

Noriyuki Nozawa

Shizuo Mori

Akihito Tsujimoto

Kazunari Shimauchi

Shohji Nakayama

Kiyofumi Suzuki

Takayuki Kanda

A sintered R-T-B based magnet has remanence (B) of 1.47 T or greater and coercivity (H) of 1900 kA/m or greater and contains Tb at a content of 0.35 mass % or lower.

Sintered R-T-B based magnet

A sintered R-T-B based magnet work contains R: 27.5 to 35.0 mass % (R is at least one rare-earth element which always includes Nd), B: 0.80 to 0.99 mass %, Ga: 0 to 0.8 mass %, M: 0 to 2 mass % (M is at least one of Cu, Al, Nb and Zr), and a balance T (T is at least one transition metal element which always includes Fe, with 10% or less of Fe replaceable by Co). [T]/55.85&#x3e;14[B]/10.8 is satisfied where [T] is the T content (mass %) and [B] is the B content (mass %). At least a portion of a Pr&#x2014;Ga alloy is in contact with a portion of the sintered magnet work surface, and a first heat treatment is performed at a temperature between 600&#xb0; C. and 950&#xb0; C. A second heat treatment is performed at a temperature lower than the temperature of the first heat treatment and between 450&#xb0; C. and 750&#xb0; C.

Method for producing R-T-B system sintered magnet

A sintered R-T-B based magnet includes a main phase crystal grain and a grain boundary phase, in which R: not less than 27.5 mass % and not more than 35.0 mass % (R always includes at least Nd and Pr); B: not less than 0.80 mass % and not more than 1.05 mass %; Ga: not less than 0.05 mass % and not more than 1.0 mass %; M: not more than 2 mass % (where M is at least one of Cu, Al, Nb, and Zr); and a balance T (where T is Fe, or Fe and Co) and impurities. At 300-&#x3bc;m depth from the magnet surface, a Pr/Nd ratio in a central portion of a main phase crystal grain is lower than 1, and a Pr/Nd ratio in an intergranular grain boundary is higher than 1. The Ga concentration gradually decreases in a portion of the magnet from the surface toward the interior.

R-T-B sintered magnet

A method for producing a sintered R-T-B based magnet includes the steps of: providing a sintered R1-T-B based magnet work (where R1 is a rare-earth element; T is Fe, or Fe and Co); providing a powder of an alloy in which a rare-earth element R2 accounts for 40 mass % or more of the entire alloy, the rare-earth element R2 always including Dy and/or Tb; subjecting the powder to a heat treatment to obtain a diffusion source; and heating the sintered R1-T-B based magnet work with the diffusion source to allow the at least one of Dy and Tb contained in the diffusion source to diffuse from the surface into the interior of the sintered R1-T-B based magnet work. The alloy powder is a powder produced by atomization.

Method for producing sintered R-T-B based magnet and diffusion source

A method for producing a sintered R-T-B based magnet includes applying an adhesive agent to an application area of the magnet, adhering a particle size-adjusted powder of a heavy rare-earth element RH which is at least one of Dy and Tb to the application area, and heating at a temperature which is equal to or lower than a sintering temperature of the magnet to allow the element RH in the particle size-adjusted powder to diffuse from the surface into the interior of the magnet. The particle size of the particle size-adjusted powder is set so that, when powder particles are placed on the entire surface of the magnet to form a single particle layer, the amount of element RH in the particle size-adjusted powder is in a range from 0.6 to 1.5% with respect to the magnet by mass ratio.

Method of producing R-T-B sintered magnet

A method of producing a sintered R-T-B based magnet includes providing a sintered R-T-B based magnet work, an RH compound (at least one selected from RH fluorides, RH oxides, and RH oxyfluorides), and an RL-Ga alloy, where the sintered magnet work contains R: 27.5 to 35.0 mass %, B: 0.80 to 0.99 mass %, Ga: 0 to 0.8 mass %, M: 0 to 2 mass % (where M is at least one of Cu, Al, Nb and Zr), and T: 60 mass % or more; a diffusion step of, while keeping the RH compound and the RL-Ga alloy in contact with a surface of the sintered magnet work, performing a first heat treatment between 700&#xb0; C. and 950&#xb0; C. to increase the RH amount contained in the sintered magnet work by between 0.05 mass % and 0.40 mass %; and performing a second heat treatment between 450&#xb0; C. and 750&#xb0; C. but which is lower than the first heat treatment.

Method for producing R-T-B sintered magnet

A method for producing a sintered R-T-B based magnet includes the steps of: providing a sintered R-T-B based magnet work; providing a Pr&#x2014;Ga alloy powder produced through atomization; subjecting the Pr&#x2014;Ga alloy powder to a heat treatment at a temperature which is not lower than a temperature that is 250&#xb0; C. below a melting point of the Pr&#x2014;Ga alloy powder and which is not higher than the melting point, to obtain a diffusion source from the Pr&#x2014;Ga alloy powder; and placing the sintered R-T-B based magnet work and the diffusion source in a process chamber, and heating the sintered R-T-B based magnet work and the diffusion source in a vacuum or an inert gas ambient, thereby allowing Pr and Ga to diffuse from the diffusion source into the interior of sintered R-T-B based magnet work.

Method for producing sintered R&#x2014;T&#x2014;B based magnet and diffusion source

To provide an R-T-B based sintered magnet including R: 27.5 to 34.0% by mass, RH: 2 to 10% by mass, B: 0.89 to 0.95% by mass, Ti: 0.1 to 0.2% by mass, Ga: 0.3 to 0.7% by mass, Cu: 0.07 to 0.50% by mass, Al: 0.05 to 0.50% by mass, M (M is Nb and/or Zr): 0 to 0.3% by mass, balance T, and inevitable impurities, the following inequality expressions (1), (2), and (3) being satisfied:[T]&#x2212;72.3([B]&#x2212;0.45[Ti])&#x3e;0&#x2003;&#x2003;(1)([T]&#x2212;72.3([B]&#x2212;0.45[Ti]))/55.85&#x3c;13[Ga]/69.72&#x2003;&#x2003;(2)[Ga]&#x2265;[Cu]&#x2003;&#x2003;(3).

R-T-B-based sintered magnet and method for producing same

To provide an R-T-B based sintered magnet having high Band high Hwhile suppressing the content of Dy. Disclosed is an R-T-B based sintered magnet represented by the formula: uRwBxGayCuzAlqM(balance)T, where R is composed of light rare-earth element(s) RL and heavy rare-earth element(s) RH, RL is Nd and/or Pr, RH is Dy and/or Tb, T is Fe, and 10% by mass or less of Fe is capable of being replaced with Co, M is Nb and/or Zr, inevitable impurities being included, and u, w, x, y, z and q are expressed in terms of % by mass; RH accounts for 5% by mass or less of the R-T-B based sintered magnet, 0.4&#x2264;x&#x2264;1.0, 0.07&#x2264;y&#x2264;1.0, 0.05&#x2264;z&#x2264;0.5, 0&#x2264;q&#x2264;0.1, and 0.100&#x2264;y/(x+y)&#x2264;0.340; v=u&#x2212;(6&#x3b1;+10&#x3b2;+8&#x3b3;), where the amount of oxygen (% by mass) is &#x3b1;, the amount of nitrogen (% by mass) is &#x3b2;, and the amount of carbon (% by mass) is &#x3b3;; and v and w satisfy the following inequality expressions: v&#x2264;32.0, 0.84&#x2264;w&#x2264;0.93, and &#x2212;12.5w+38.75&#x2264;v&#x2264;&#x2212;62.5w+86.125.

R-T-B based sintered magnet

Disclosed is a method for producing a magnet, including a step of preparing a magnet represented by the formula: uRwBxGayCuzAlqM(balance)T, where RH is 5% or less, 0.20&#x2264;x&#x2264;0.70, 0.07&#x2264;y&#x2264;0.2, 0.05&#x2264;z&#x2264;0.5, 0&#x2264;q&#x2264;0.1; when 0.40&#x2264;x&#x2264;0.70, v and w satisfy the following inequality expressions: 50w&#x2212;18.5&#x2264;v&#x2264;50w&#x2212;14, and &#x2212;12.5w+38.75&#x2264;v&#x2264;&#x2212;62.5w+86.125; and, when 0.20&#x2264;x&#x2264;0.40, v and w satisfy the following inequality expressions: 50w&#x2212;18.5&#x2264;v&#x2264;50w&#x2212;15.5 and &#x2212;12.5w+39.125&#x2264;v&#x2264;&#x2212;62.5w+86.125, and x satisfy the following inequality expression: &#x2212;(62.5w+v &#x2212;81.625)/15+0.5&#x2264;x&#x2264;&#x2212;(62.5w+v&#x2212;81.625)/15+0.8; a high-temperature heat treatment step of heating the magnet to a temperature of 730&#xb0; C. or higher and 1,020&#xb0; C. or lower, and then cooling to 300&#xb0; C. at a cooling rate of 20&#xb0; C./min; and a low-temperature heat treatment step of heating the magnet to a temperature of 440&#xb0; C. or higher and 550&#xb0; C. or lower.

Method for producing R-T-B based sintered magnet

A diffusion treatment device includes: a treatment container including a cylindrical main body and first and second lids, the cylindrical main body having a treatment space which is capable of receiving sintered magnet pieces and RH diffusion sources, the first and second lids being capable of hermetically sealing first and second openings, respectively, at opposite ends of the cylindrical main body; a conveyor for conveying the treatment container by a predetermined distance in an x-axis direction while a longitudinal direction of the treatment container is located in a y-axis direction in a rectangular coordinate system xyz; a heating unit including a lower heating section provided under the treatment container and an upper heating section provided above the treatment container, and a first rotating unit for rotating the treatment container around a y-axis while the longitudinal direction of the treatment container is located in the y-axis direction.

Diffusion treatment device and method for manufacturing R-T-B system sintered magnet using same

A sintered R1-T-B based magnet work and an R2-Ga alloy are provided. The sintered magnet work contains R: 27.5 to 35.0 mass %, B: 0.80 to 0.99 mass %, Ga: 0 to 0.8 mass %, M: 0 to 2 mass % (where M is at least one of Cu, Al, Nb and Zr), and T: 60 mass % or more. A diffusion step of, while keeping at least a portion of the R2-Ga alloy in contact with at least a portion of a surface of the sintered magnet work, performing a first heat treatment at a temperature which is not lower than 700&#xb0; C. and not higher than 950&#xb0; C. to increase the RH amount contained in the sintered magnet work by not less than 0.05 mass % and not more than 0.40 mass %, is performed; and a second heat treatment is performed at a temperature which is not lower than 450&#xb0; C. and not higher than 750&#xb0; C. but which is lower than the temperature of the first heat treatment.

A method for manufacturing an R-T-B based sintered magnet includes: 1) a step of preparing an R-T-B based sintered magnet material by sintering a molded body, the sintered magnet material having a particular composition and satisfying inequality expressions (1) and (2); 2) a high-temperature heat treatment step of heating the sintered magnet material to a heating temperature of 730&#xb0; C. to 1,020&#xb0; C. and then cooling the sintered magnet material to 300&#xb0; C. at a cooling rate of 5&#xb0; C./min or more; and 3) a low-temperature heat treatment step of heating the sintered magnet material after the high-temperature heat treatment step to 440&#xb0; C. to 550&#xb0; C.:[T]&#x2212;72.3[B]&#x3e;0&#x2003;&#x2003;(1)([T]&#x2212;72.3[B])/55.85&#x3c;13[Ga]/69.72&#x2003;&#x2003;(2)where [T] is a T content in percent by mass, [B] is a B content in percent by mass, and [Ga] is a Ga content in percent by mass.

Method for manufacturing R-T-B based sintered magnet

To provide an R-T-B based sintered magnet having high Band high Hwhile suppressing the content of Dy, and a method for producing the same. Disclosed is an R-T-B based sintered magnet represented by the formula: uRwBxGayCuzAlqMT, where 0.20&#x2264;x&#x2264;0.70, 0.07&#x2264;y&#x2264;0.2, 0.05&#x2264;z&#x2264;0.5, 0&#x2264;q&#x2264;0.1; v=u&#x2212;(6&#x3b1;+10&#x3b2;+8&#x3b3;), where the amount of oxygen (% by mass) is &#x3b1;, the amount of nitrogen (% by mass) is &#x3b2;, and the amount of carbon (% by mass) is &#x3b3;; when 0.40&#x2264;x&#x2264;0.70, v and w satisfy the following inequality expressions: 50w&#x2212;18.5&#x2264;v&#x2264;50w&#x2212;14, and &#x2212;12.5w+38.75&#x2264;v&#x2264;&#x2212;62.5w+86.125; and, when 0.20&#x2264;x&#x2264;0.40, v and w satisfy the following inequality expressions: 50w&#x2212;18.5&#x2264;v&#x2264;50w&#x2212;15.5 and &#x2212;12.5w+39.125&#x2264;v&#x2264;&#x2212;62.5w+86.125, and x satisfy the following inequality expression: &#x2212;(62.5w+v&#x2212;81.625)/15+0.5&#x2264;x&#x2264;&#x2212;(62.5w+v&#x2212;81.625)/15+0.8.

R-T-B based sintered magnet and method for producing R-T-B based sintered magnet

A method for manufacturing an R-T-B based sintered magnet includes: 1) a step of preparing an R-T-B based sintered magnet material by sintering a molded body at a temperature of 1,000&#xb0; C. or higher and 1,100&#xb0; C. or lower, and then performing (a) temperature dropping to 500&#xb0; C. at 10&#xb0; C./min or less, or (b) temperature dropping to 500&#xb0; C. at 10&#xb0; C./min or less after performing a first heat treatment of holding at a first heat treatment temperature of 800&#xb0; C. or higher and 950&#xb0; C. or lower, the R-T-B based sintered magnet material satisfying compositional requirements; and 2) a heat treatment step of performing a second heat treatment by heating the R-T-B based sintered magnet material to a second heat treatment temperature of 650&#xb0; C. or higher and 750&#xb0; C. or lower, and then cooling the R-T-B based sintered magnet material to 400&#xb0; C. at 5&#xb0; C./min or more.

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Osaka, Japan

Futoshi Kuniyoshi