Abstract: 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]?72.3([B]?0.45[Ti])>0??(1) ([T]?72.3([B]?0.45[Ti]))/55.85<13[Ga]/69.72??(2) [Ga]?[Cu]??(3).

Abstract: To provide an R-T-B based sintered magnet having high Br and high HcJ while 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?x?1.0, 0.07?y?1.0, 0.05?z?0.5, 0?q?0.1, and 0.100?y/(x+y)?0.340; v=u?(6?+10?+8?), where the amount of oxygen (% by mass) is ?, the amount of nitrogen (% by mass) is ?, and the amount of carbon (% by mass) is ?; and v and w satisfy the following inequality expressions: v?32.0, 0.84?w?0.93, and ?12.5w+38.75?v??62.5w+86.125.

Abstract: 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?x?0.70, 0.07?y?0.2, 0.05?z?0.5, 0?q?0.1; when 0.40?x?0.70, v and w satisfy the following inequality expressions: 50w?18.5?v?50w?14, and ?12.5w+38.75?v??62.5w+86.125; and, when 0.20?x?0.40, v and w satisfy the following inequality expressions: 50w?18.5?v?50w?15.5 and ?12.5w+39.125?v??62.5w+86.125, and x satisfy the following inequality expression: ?(62.5w+v ?81.625)/15+0.5?x??(62.5w+v?81.625)/15+0.8; a high-temperature heat treatment step of heating the magnet to a temperature of 730° C. or higher and 1,020° C. or lower, and then cooling to 300° C. at a cooling rate of 20° C./min; and a low-temperature heat treatment step of heating the magnet to a temperature of 440° C. or higher and 550° C. or lower.

Abstract: 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° C. to 1,020° C. and then cooling the sintered magnet material to 300° C. at a cooling rate of 5° 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° C. to 550° C.: [T]?72.3[B]>0??(1) ([T]?72.3[B])/55.85<13[Ga]/69.72??(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.

Abstract: To provide an R-T-B based sintered magnet having high Br and high HcJ while 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?x?0.70, 0.07?y?0.2, 0.05?z?0.5, 0?q?0.1; v=u?(6?+10?+8?), where the amount of oxygen (% by mass) is ?, the amount of nitrogen (% by mass) is ?, and the amount of carbon (% by mass) is ?; when 0.40?x?0.70, v and w satisfy the following inequality expressions: 50w?18.5?v?50w?14, and ?12.5w+38.75?v??62.5w+86.125; and, when 0.20?x?0.40, v and w satisfy the following inequality expressions: 50w?18.5?v?50w?15.5 and ?12.5w+39.125?v??62.5w+86.125, and x satisfy the following inequality expression: ?(62.5w+v?81.625)/15+0.5?x??(62.5w+v?81.625)/15+0.8.

Abstract: 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° C. or higher and 1,100° C. or lower, and then performing (a) temperature dropping to 500° C. at 10° C./min or less, or (b) temperature dropping to 500° C. at 10° C./min or less after performing a first heat treatment of holding at a first heat treatment temperature of 800° C. or higher and 950° 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° C. or higher and 750° C. or lower, and then cooling the R-T-B based sintered magnet material to 400° C. at 5° C./min or more.

Abstract: 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]?72.3([B]?0.45[Ti])>0??(1) ([T]?72.3([B]?0.45[Ti]))/55.85<13[Ga]/69.

Abstract: 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° C. or higher and 1,100° C. or lower, and then performing (a) temperature dropping to 500° C. at 10° C./min or less, or (b) temperature dropping to 500° C. at 10° C./min or less after performing a first heat treatment of holding at a first heat treatment temperature of 800° C. or higher and 950° 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° C. or higher and 750° C. or lower, and then cooling the R-T-B based sintered magnet material to 400° C. at 5° C./min or more.

Abstract: 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° C. to 1,020° C. and then cooling the sintered magnet material to 300° C. at a cooling rate of 5° 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° C. to 550° C.: [T]?72.3[B]>0??(1) ([T]?72.3[B])/55.85<13[Ga]/69.72??(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.

Abstract: 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?x?0.70, 0.07?y?0.2, 0.05?z?0.5, 0?q?0.1; when 0.40?x?0.70, v and w satisfy the following inequality expressions: 50w?18.5?v?50w?14, and ?12.5w+38.75?v??62.5w+86.125; and, when 0.20?x?0.40, v and w satisfy the following inequality expressions: 50w?18.5?v?50w?15.5 and ?12.5w+39.125?v??62.5w+86.125, and x satisfy the following inequality expression: ?(62.5w+v ?81.625)/15+0.5?x??(62.5w+v?81.625)/15+0.8; a high-temperature heat treatment step of heating the magnet to a temperature of 730° C. or higher and 1,020° C. or lower, and then cooling to 300° C. at a cooling rate of 20° C./min; and a low-temperature heat treatment step of heating the magnet to a temperature of 440° C. or higher and 550° C. or lower.

Abstract: To provide an R-T-B based sintered magnet having high Br and high HcJ while 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?x?1.0, 0.07?y?1.0, 0.05?z?0.5, 0?q?0.1, and 0.100?y/(x+y)?0.340; v=u?(6?+10?+8?), where the amount of oxygen (% by mass) is ?, the amount of nitrogen (% by mass) is ?, and the amount of carbon (% by mass) is ?; and v and w satisfy the following inequality expressions: v?32.0, 0.84?w?0.93, and ?12.5w+38.75?v??62.5w+86.125.

Abstract: To provide an R-T-B based sintered magnet having high Br and high HcJ while 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?x?0.70, 0.07?y?0.2, 0.05?z?0.5, 0?q?0.1; v=u?(6?+10?+8?), where the amount of oxygen (% by mass) is ?, the amount of nitrogen (% by mass) is ?, and the amount of carbon (% by mass) is ?; when 0.40?x?0.70, v and w satisfy the following inequality expressions: 50w?18.5?v?50w?14, and ?12.5w+38.75?v??62.5w+86.125; and, when 0.20?x<0.40, v and w satisfy the following inequality expressions: 50w?18.5?v?50w?15.5 and ?12.5w+39.125?v??62.5w+86.125, and x satisfy the following inequality expression: ?(62.5w+v?81.625)/15+0.5?x??(62.5w+v?81.625)/15+0.8.

Abstract: The invention provides a method for preparing a soft magnetic material which meets demands for low iron loss, high density, high strength and high productivity. The method comprises a surface oxidation step of forming oxide films on the surfaces of a soft magnetic powder, a step of preparing a molding compound of the soft magnetic powder by mixing a soft magnetic powder and a binder with a predetermined blending ratio, a press molding step of press-molding the molding compound of the soft magnetic powder into a predetermined shape, and a sintering step of sintering the press-molded soft magnetic powder to produce a soft magnetic material, wherein a millimeter wave sintering apparatus or a discharge plasma sintering apparatus is used as a heating means in the surface oxidation step or in the sintering step.

Abstract: The invention provides a method for preparing a soft magnetic material which meets demands for low iron loss, high density, high strength and high productivity. The method comprises a surface oxidation step of forming oxide films on the surfaces of a soft magnetic powder, a step of preparing a molding compound of the soft magnetic powder by mixing a soft magnetic powder and a binder with a predetermined blending ratio, a press molding step of press-molding the molding compound of the soft magnetic powder into a predetermined shape, and a sintering step of sintering the press-molded soft magnetic powder to produce a soft magnetic material, wherein a millimeter wave sintering apparatus or a discharge plasma sintering apparatus is used as a heating means in the surface oxidation step or in the sintering step.