Tdk Corporation

Agilent Technologies, Inc.

Tetsuya Hidaka

Chikara Ishizaka

Makoto Iwasaki

Akira Fukuno

Takuma Hayakawa

Gouichi Nishizawa

Ayato Kakoki

Eiji Kato

Yoshinori Fujikawa

Hidetake Kitaoka

Kazuya Sakamoto

Haruna Nakajima

Tomomi Yamamoto

Kazuo Sato

Masashi Miwa

Jun Hagiwara

Tetsuhito Yoneyama

Nobuya Uchida

Ken-ichi Nishikawa

Hironari Okada

Takeshi Sakamoto

Takeshi Masuda

You Kondoh

Yuki Nagamine

Yawara Kaneko

Tsutomu Takenaka

Syota Goto

Koji Mitake

Fumitaka Baba

Mitsuchika Saito

Naoto Tsukamoto

Kent W Carey

Yasuyuki Nakayama

Shinya Fujito

Motohisa Murata

Motoaki Hosako

An R-T-B based sintered magnet containing a first heavy rare earth element, in which R includes Nd, T includes Co and Fe, the first heavy rare earth element includes Tb or Dy, the R-T-B based sintered magnet has a region in which a concentration of the first heavy rare earth element decreases from the surface toward the inside, a first grain boundary phase which contains the first heavy rare earth element and Nd but does not contain Co is present in one cross section including the region, and an area occupied by the first grain boundary phase in one cross section including the region is 1.8% or less.

R-T-B based sintered magnet

Provided is an alloy for R-T-B based rare earth magnet. 'R' is one or more of a rare earth element, 'T' is one or more of a transition metal element essentially including Fe or Fe and Co, and 'B' is boron. The alloy includes a single or a plural number of main phase (A), having a minimum length of 10 &#x3bc;m or more and a maximum length of 30 &#x3bc;m or more and 300 &#x3bc;m or less, in a cross section cut along a thickness direction of the alloy. The main phase (A) includes an RTB phase, and an area ratio of the main phase (A) to an entire cross section is 2% or more and 60% or less.

Alloy for R&#x2014;T&#x2014;B based rare earth sintered magnet and method for producing the R&#x2014;T&#x2014;B based rare earth sintered magnet

Provided is an R-T-B based permanent magnet including main phase grains including an RTB compound and a grain boundary. R is one or more rare earth elements essentially including Nd, T is Fe or Fe and Co and B is boron. the R-T-B based permanent magnet further includes X, Z and M. X is one or more selected from Ti, V, Zr, Nb, Hf and Ta, Z is one or more selected from C and N, M essentially includes Ga and further includes one or more selected from Al, Si, Ge, Cu, Bi and Sn. The grain boundary includes an XZ phase having a face-centered cubic structure.

R-T-B based permanent magnet

Provided is a motor including a permanent magnet, in which the permanent magnet includes a high temperature side permanent magnet part exposed to a high temperature inside the motor, and a low temperature side permanent magnet part exposed to a temperature lower than the high temperature inside the motor, and a coercive force of the high temperature side permanent magnet part is higher than the coercive force of the low temperature side permanent magnet part.

Motor containing a permanent magnet having high and low temperature side permanent magnet parts

Provided is an R-T-B based rare earth magnet. R is one or more rare earth elements, T is one or more transition metal elements essentially including Fe or Fe and Co, and B is boron. B content with respect to a total R-T-B based rare earth magnet is 0.80 mass % or more and 0.98 mass % or less. The R-T-B based rare earth magnet includes an RTBphase.

R-T-B based rare earth magnet

An R-T-B based sintered magnet includes 'R', 'T', and &#x201c;B&#x201d;. &#x201c;R&#x201d; represents a rare earth element. &#x201c;T&#x201d; represents a metal element other than rare earth elements including at least Fe, Cu, Mn, Al, Co, Ga, and Zr. &#x201c;B&#x201d; represents boron or boron and carbon. With respect to 100 mass % of a total mass of the R-T-B based sintered magnet, a content of &#x201c;R&#x201d; is 28.0 to 31.5 mass %, a content of Cu is 0.04 to 0.50 mass %, a content of Mn is 0.02 to 0.10 mass %, a content of Al is 0.15 to 0.30 mass %, a content of Co is 0.50 to 3.0 mass %, a content of Ga is 0.08 to 0.30 mass %, a content of Zr is 0.10 to 0.25 mass %, and a content of &#x201c;B&#x201d; is 0.85 to 1.0 mass %.

An R-T-B based sintered magnet includes 'R', 'T', and &#x201c;B&#x201d;. &#x201c;R&#x201d; represents a rare earth element including at least Tb. &#x201c;T&#x201d; represents a metal element except rare earth elements including at least Fe, Cu, Mn, Al, and Co. &#x201c;B&#x201d; represents boron or boron and carbon. With respect to 100 mass % of a total mass of the R-T-B based sintered magnet, a content of &#x201c;R&#x201d; is 28.0 to 32.0 mass %, a content of Cu is 0.04 to 0.50 mass %, a content of Mn is 0.02 to 0.10 mass %, a content of Al is 0.15 to 0.30 mass %, a content of Co is 0.50 to 3.0 mass %, and a content of &#x201c;B&#x201d; is 0.85 to 1.0 mass %. Tb2/Tb1 is 0.40 to less than 1.0, where Tb1 and Tb2 (mass %) denote a content of Tb at a surface portion and at a core portion, respectively.

A rare earth permanent magnet includes a main phase composed of a main phase particle and a grain boundary present among a plurality of the main phase particles. The grain boundary includes a region whose electric resistance is higher than that of the main phase.

Rare earth permanent magnet

Provided is a sintered magnet that is an R-T-B based sintered magnet having a region having a concentration of at least one heavy rare earth element decreasing from the surface toward the inside, in which the at least one heavy rare earth element includes at least either of Tb or Dy, R includes Nd, T includes Fe, Co, and Cu, there is a grain boundary phase containing at least either of Tb or Dy and Nd between two main phase particles, and a value obtained by subtracting a half value width of a concentration distribution curve of Cu from a half value width of a concentration distribution curve of Tb or Dy in a part including the grain boundary phase is from 10 to 20 nm.

Alloy for R-T-B based sintered magnet and R-T-B based sintered magnet

The present invention provides an R-T-B based sintered magnet including RTB crystal grains wherein; a grain boundary is formed by two or more adjacent RTB crystal grains, an R&#x2014;O&#x2014;C concentrated part, in which concentrations of R, O and C are higher than those in the RTB crystal grains respectively, is in the grain boundary, and a ratio (O/R) of O atom to R atom in the R&#x2014;O&#x2014;C concentrated part satisfies the following formula (1):0.4&#x3c;(O/R)&#x3c;0.7.

The present invention provides an R-T-B based sintered magnet including RTB crystal grains wherein; a grain boundary is formed by two or more adjacent RTB crystal grains, an R&#x2014;O&#x2014;C concentrated part, in which concentrations of R, O and C are higher than those in the RTB crystal grains respectively, is in the grain boundary, and an area of the R&#x2014;O&#x2014;C concentrated part occupying in that of the grain boundary on a cut surface of the R-T-B based sintered magnet is within a range of 10% or more to 75% or less.

A sintered rare earth magnet rotating machine and method improve temperature properties and strength having an excellent corrosion resistance. The sintered rare earth magnet includes at least a main phase composed of RTB (R represents at least one rare earth element of Nd, Pr or both and T represents at least one transition metal element including Fe or Fe and Co) compound and a grain boundary phase containing a higher proportion of R than the main phase, wherein the main phase includes a heavy rare earth element (one of Dy, Tb or both), at least part of main phase grains of the main phase included in the sintered rare earth magnet includes at least the following regions, low, high and intermediate concentration regions. These regions exist in order of low, high, and intermediate concentration regions, from low concentration region towards the grain boundary phase in the main phase grains.

Sintered rare earth magnet, method of producing the same, and rotating machine

The present invention provides a method for producing a sintered magnet, which can have a sufficient sintered density even when the magnet has a low-R composition. The method is for producing a sintered magnet comprising R (R: one or more rare-earth elements), T (T: one or more transition metal elements essentially comprising Fe, or Fe and Co) and B (boron) as the main components, wherein a starting alloy prepared by strip casting is pulverized to a given particle size to form a fine powder, where the starting alloy comprises discolored depositon the surface and the area ratio of the discolored depositis 1.5% or less, the resulting fine powder is compacted in a magnetic field to prepare a compact, and the compact is sintered.

Method for producing sintered magnet and alloy for sintered magnet

An R-T-B system permanent magnetcomprises a magnet bodycomprising a sintered body comprising at least a main phase comprising RTB grains (wherein R represents one or more rare earth elements, and T represents one or more transition metal elements including Fe or Fe and Co essentially) and a grain boundary phase containing R in a larger amount than the main phase, the magnet bodyhaving a 300 &#x3bc;m or less thick (not inclusive of zero thick) hydrogen-rich layerhaving a hydrogen concentration of 300 ppm or more formed in the surface layer portion, and an overcoatcovering the surface of the magnet bodycan improve the corrosion resistance of the R-T-B system permanent magnetwith an overcoatformed thereon without degrading the magnetic properties thereof. The present invention can be applied to formation of the overcoatby electrolytic plating, can fully ensure the corrosion resistance as a primary target of the overcoatformation without substantially degrading the production efficiency, and can provide the R-T-B system permanent magnetwith a high dimensional precision by suppressing the partial collapse (detachment of grains) of the surface thereof.

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Tokyo, Japan

Tetsuya Hidaka