Tdk Corporation

Showa Denko K.k.

Takashi Yamazaki

Kenichiro Nakajima

Akifumi Muraoka

An alloy for R-T-B-based rare earth sintered magnets which contains R which is a rare earth element; T which is a transition metal essentially containing Fe; a metallic element M containing one or more metals selected from Al, Ga and Cu; B and inevitable impurities, in which R accounts for 13 at % to 15 at %, B accounts for 4.5 at % to 6.2 at %, M accounts for 0.1 at % to 2.4 at %, T accounts for balance, a proportion of Dy in all rare earth elements is in a range of 0 at % to 65 at %, and the following Formula 1 is satisfied,0.0049Dy+0.34&#x2264;B/TRE&#x2264;0.0049Dy+0.36&#x2003;&#x2003;Formula 1wherein Dy represents a concentration (at %) of a Dy element, B represents a concentration (at %) of a boron element, and TRE represents a concentration (at %) of all the rare earth elements.

Alloy for R-T-B-based rare earth sintered magnet, process of producing alloy for R-T-B-based rare earth sintered magnet, alloy material for R-T-B-based rare earth sintered magnet, R-T-B-based rare earth sintered magnet, process of producing R-T-B-based rare earth sintered magnet, and motor

In an alloy for an R-T-B-based rare earth sintered magnet of the present invention formed of a rare earth element R, a transition metal T containing Fe as a main component, a metal element M containing one or more types of metals selected from Al, Ga, and Cu, and B and inevitable impurities, 13 at % to 16 at % of R is contained, 4.5 at % to 6.2 at % of B is contained, 0.1 at % to 2.4 at % of M is contained, the balance is T and the inevitable impurities, a proportion of Dy in the entire rare earth element is 0 at % to 65 at %, Formula 1 described below is satisfied, a main phase containing RFeB and an alloy grain boundary phase containing more R than the main phase are included, and a distance between the alloy grain boundary phases is greater than or equal to 3 &#x3bc;m and less than or equal to 11 &#x3bc;m.0.30&#x2264;B/TRE&#x2264;0.37&#x2003;&#x2003;(Formula 1)

Alloy for R-T-B-based rare earth sintered magnet and manufacturing method thereof, and manufacturing method of R-T-B-based rare earth sintered magnet

An R-T-B-based rare earth sintered magnet, comprising a rare earth element R, B, a metallic element M which includes one or more metals selected from Al, Ga and Cu, a transition metal T which includes Fe as a main component, and inevitable impurities, wherein the sintered magnet includes 13 atom % to 15.5 atom % of R, 5.0 atom % to 6.0 atom % of B, 0.1 atom % to 2.4 atom % of M, and T and the inevitable impurities as a balance, and wherein the sintered magnet includes 0.015 atom % to 0.10 atom % of Zr as the transition metal T.

R-T-B-based rare earth sintered magnet and alloy for R-T-B-based rare earth sintered magnet

A method of manufacturing an R-T-B rare earth sintered magnet includes a process of disposing and sintering a compact of a first alloy powder and an alloy material of a second alloy in a chamber of a sintering furnace. The first alloy consists of R which represents a rare earth element, T which represents a transition metal essentially containing Fe, a metal element M which represents Al and/or Ga, B, Cu, and inevitable impurities. The first alloy contains 11 at % to 17 at % of R, 4.5 at % to 6 at % of B, 0 at % to 1.6 at % of M, and T as the balance, and Dy content in all of the rare earth elements is 0 at % to 29 at %. The second alloy consists of R which represents a rare earth element, T which represents a transition metal essentially containing Fe, a metal element M which represents Al and/or Ga, B, Cu, and inevitable impurities. The second alloy contains 11 at % to 20 at % of R, 4.5 at % to 6 at % of B, and 0 at % to 1.6 at % of M, and T as the balance, and Dy content in all of the rare earth elements is 0 at % to 29 at %.

R-T-B rare earth sintered magnet and method of manufacturing the same

An alloy material for an R-T-B system rare earth permanent magnet having a high orientation rate and high coercivity (Hcj), and a method for producing an R-T-B system rare earth permanent magnet using the alloy material. The alloy material includes a plurality of R-T-B system alloys having different compositions and a metal powder. The respective R-T-B system alloys are formed of R which is composed of two or more kinds selected from rare earth elements, T which is composed of a transition metal essentially containing Fe, B, and unavoidable impurities. A first alloy having the greatest Dy content contains 17 mass % or greater of Dy, and a Dy concentration difference between the first alloy and a second alloy having the smallest Dy concentration difference with respect to the first alloy among the plurality of R-T-B system alloys is 5 mass % or greater.

Alloy material for R-T-B system rare earth permanent magnet, method for producing R-T-B system rare earth permanent magnet, and motor

An R-T-B rare earth sintered magnet contains R which represents a rare earth element; T which represents a transition metal essentially containing Fe; a metal element M which represents Al and/or Ga; B; Cu; and inevitable impurities the R-T-B rare earth sintered magnet including 13.4 to 17 at % of R, 4.5 to 5.5 at % of B, and 0.1 to 2.0 at % of M, and T as the balance; in which the R-T-B rare earth sintered magnet is formed of a sintered body which includes a main phase composed of RFeB and a grain boundary phase including a larger amount of R than the main phase; in which the magnetization direction of the main phase is a c-axis direction, in which crystal grains of the main phase have one of an elliptical shape and an oval shape extended in such a direction so as to cross the c-axis direction; and in which the grain boundary phase includes an R-rich phase in which the total atomic concentration of the rare earth elements is 70 at % or greater and a transition metal-rich phase in which the total atomic concentration of the rare earth elements is 25 to 35 at %.

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Chichibu, Japan

Takashi Yamazaki