Sumitomo Special Metals Co., Ltd.

Hitachi Metals, Ltd.

Neomax Co., Ltd.

Yasutaka Shigemoto

Satoshi Hirosawa

Hirokazu Kanekiyo

Toshio Miyoshi

Yusuke Shioya

Takeshi Nishiuchi

Noriyuki Nozawa

A sintered R-T-B based magnet composition includes: R: not less than 27 mass % and not more than 37 mass % (R is at least one rare-earth element which always includes at least one of Nd and Pr), B: not less than 0.75 mass % and not more than 0.97 mass %, Ga: not less than 0.1 mass % and not more than 1.0 mass %, Cu: not less than 0 mass % and not more than 1.0 mass %, and T: 61.03 mass % or more (where T is at least one selected from Fe, Co, Al, Mn and Si and always includes Fe, such that the Fe content is 80 mass % or more in the entire T). [T]/[B] is greater than 14.0. An R amount is greater in the surface than in the center, and a Ga amount is greater in the surface than in the center. [T]/[B] in the surface is higher than [T]/[B] in the center.

R-T-B sintered magnet and production method therefor

A nanocomposite magnet according to the present invention has a composition represented by the general formula: RQM(FeT), where R is at least one rare-earth element, Q is at least one element selected from the group consisting of B and C, M is at least one metal element that is selected from the group consisting of Al, Si, Ti, V, Cr, Mn, Cu, Zn, Ga, Zr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au and Pb and that always includes Ti, and T is at least one element selected from the group consisting of Co and Ni. The mole fractions x, y, z and m satisfy the inequalities of 6 at %&#x2266;x&#x3c;10 at %, 10 at %&#x2266;y&#x2266;17 at %, 0.5 at %&#x2266;z&#x2266;6 at % and 0&#x2266;m&#x2266;0.5, respectively. The nanocomposite magnet includes a hard magnetic phase and a soft magnetic phase that are magnetically coupled together. The hard magnetic phase is made of an RFeB-type compound, and the soft magnetic phase includes an &#x3b1;-Fe phase and a crystalline phase with a Curie temperature of 610&#xb0; C. to 700&#xb0; C. (&#x3c9; phase) as its main phases.

Nano-composite magnet, quenched alloy for nano-composite magnet, and method for producing them and method for distinguishing them

An iron-based rare earth alloy magnet has a composition represented by the general formula: (FeT)QRM, where T is at least one element selected from the group consisting of Co and Ni; Q is at least one element selected from the group consisting of B and C; R is at least one rare earth element substantially excluding La and Ce; and M is at least one metal element selected from the group consisting of Ti, Zr and Hf and always includes Ti. In this formula, the mole fractions x, y, z and m meet the inequalities of: 10 at %&#x3c;x&#x2266;20 at %; 6 at %&#x2266;y&#x3c;10 at %; 0.1 at %&#x2266;z&#x2266;12 at %; and 0&#x2266;m&#x2266;0.5, respectively.

Permanent magnet including multiple ferromagnetic phases and method for producing the magnet

An iron-based rare earth alloy magnet has a composition represented by the general formula: (Fe T ) Q R M , where T is at least one element selected from the group consisting of Co and Ni; Q is at least one element selected from the group consisting of B and C; R is at least one rare earth element substantially excluding La and Ce; and M is at least one metal element selected from the group consisting of Ti, Zr and Hf and always includes Ti. In this formula, the mole fractions x, y, z and m meet the inequalities of: 10 at %<x&lE;20 at %; 6 at %&lE;y<10 at %; 0.1 at %&lE;z&lE;12 at %; and 0&lE;m&lE;0.5, respectively.

Permanent magnet including multiple ferromagnetic phases and method of producing the magnet

A method of making an iron base magnetic material alloy powder includes the steps of: preparing an iron base magnetic material alloy containing at least 50% by mass of iron; and pulverizing the magnetic material alloy using a pin mill. A portion of the mill, which comes into contact with the magnetic material alloy, is made of a cemented carbide material at least partially.

Method of making iron base magnetic material alloy powder

The inventive method for preparing nanocomposite magnet powder includes the step of preparing material alloy powder for a nanocomposite magnet represented by a general formula Fe R B Co M where R is a rare-earth element of which 90-100 atomic percent is Pr and/or Nd while 0-10 atomic percent is another lanthanoid and/or Y, and the molar fractions x, y, z and u meet the inequalities of 2&lE;x&lE;6, 16&lE;y&lE;20, 0.2&lE;z&lE;7 and 0.01&lE;u&lE;7, respectively. The powder includes a metastable phase and an amorphous structure existing in a metal structure. Heat treatment is performed for the material alloy powder to crystallize Fe B and Fe&mdash;R&mdash;B compounds from the amorphous structure. An integral value of the difference between a temperature-time curve represented by the temperature of the material alloy powder as a function of the heat treatment time during the heat treatment and a reference temperature-time curve is in a range from 10&deg; C.&middot;sec to 10,000&deg; C.&middot;sec, the reference temperature-time curve being obtained when heat treatment similar to the above heat treatment is performed for an equivalent amount of alloy that has the same composition as the material alloy but does not include the amorphous structure.

Method for preparing nanocomposite magnet powder and method for producing nanocomposite magnet

An inventive material alloy for a nanocomposite magnet is represented by a general formula Fe,R,B,, Fe,R,B,Co,, Fe,R,B,M,or Fe,R,B,Co,M,. R is a rare-earth element. 90 atomic percent or more of R is Pr and/or Nd, while equal to or larger than 0 atomic percent and less than 10 atomic percent of R is another lanthanoid and/or Y. M is at least one element selected from the group consisting of Al, Si, Ti, V, Cr, Mn, Ni, Cu, Ga, Zr, Nb, Mo, Hf, Ta, W, Pt, Pb, Au and Ag. The molar fractions x, y, z and u meet the inequalities of 2&lE;x&lE;6, 16&lE;y&lE;20, 0.2&lE;z&lE;7 and 0.01&lE;u&lE;7, respectively. The alloy includes a metastable phase Z represented by at least one of a plurality of Bragg reflection peaks observable by X-ray diffraction analysis. The at least one peak corresponds to a lattice spacing of 0.179 nm&plusmn;0.005 nm. An intensity of the Bragg reflection peak represents 5 to 200 percent, both inclusive, of a maximum intensity of a halo pattern. An intensity of a (110) Bragg reflection peak of body-centered Fe represents less than 5 percent of the maximum intensity of the halo pattern.

Growing community of inventors

Ibaraki, Japan

Yasutaka Shigemoto