Abstract: 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.

Abstract: 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.

Abstract: The present invention provides a rare earth based magnet that inhibits the high temperature demagnetization rate even when less or no heavy rare earth elements such as Dy, Tb and the like than before are used. The rare earth based magnet according to the present invention is a sintered magnet which includes R2T14B crystal grains as main phase and grain boundary phases between the R2T14B crystal grains. When the grain boundary phase surrounded by three or more main phase crystal grains is regarded as the grain boundary multi-point, the microstructure of the sintered body is controlled so that the ratio of the grain boundary triple-point surrounded by three main phase crystal grains in all grain boundary multi-points to be specified value or less.

Abstract: An R-T-B based sintered magnet including main phase particles having an R2T14B type crystal structure. R is at least one rare earth element essentially including a heavy rare-earth element RH. T is at least one transition metal element essentially including Fe or Fe and Co. B is boron. At least one of the main phase particles includes low RH crystal phases inside the main phase particle. The low RH crystal phases include the R2T14B type crystal structure, wherein an RH concentration in the low RH crystal phases is relatively lower than the RH concentration in the whole main phase particles. The R-T-B based sintered magnet may satisfy rs?rc?20% when an existence ratio of the main phase particles including the low RH crystal phases in a magnet surface layer part is rs (%) and the same in a magnet central part is rc (%).

Abstract: An R-T-B based sintered magnet including a main phase particle comprising an R2T14B type crystal structure. R is at least one rare earth element, T is at least one transition metal element essentially including Fe or Fe and Co, and B is boron. The R-T-B based sintered magnet includes a magnet surface layer part and a magnet central part existing inside the magnet surface layer part. A crystal orientation degree of the main phase particle in the magnet surface layer part having a magnetic pole surface is lower than the crystal orientation degree of the main phase particle in the magnet central part.

Abstract: The present invention provides a rare earth based magnet including R2T14B main-phase crystal grains, and two-grain boundary phases between adjacent two R2T14B main-phase crystal grains, the two-grain boundary phases are controlled such that the thickness thereof is 5 nm or more and 500 nm or less, and it is composed of a phase with a magnetism different from that of a ferromagnet.

Abstract: An R-T-B based sintered magnet including a plural number of main phase particles having an R2T14B type crystal structure. R is at least one rare earth element essentially including heavy rare earth elements RH, T is at least one transition metal element essentially including Fe or Fe and Co, and B is boron. At least one of the main phase particles is a reverse core-shell main phase particle including a core part and a shell part, in which CRC/CRS>1.0 is satisfied when a total RH concentration (at %) in the core part is defined as CRC and a total RH concentration (at %) in the shell part is defined as CRS. An existence ratio of the reverse core-shell main phase particles is larger in a surface layer part of the magnet than in a central part of the magnet.

Abstract: The present invention provides a rare earth based magnet in which the demagnetization rate at a high temperature can be inhibited even if the amount of heavy rare earth element(s) such as Dy and Tb is evidently decreased compared to the past or no such heavy rare earth element is used. The rare earth based magnet of the present invention is a sintered magnet which comprises R2T14B crystal grains as the major phases and the crystal boundary phases among the R2T14B crystal grains. The microstructure of the sintered body is controlled by including crystal boundary phases containing at least R, T and M in the crystal boundary phases, wherein the relative atomic ratios of R, T and M are as follows, i.e., 60 to 80% for R, 15 to 35% for T and 1 to 20% for M.

Abstract: The present invention provides a rare earth based magnet in which the demagnetization rate at a high temperature can be inhibited even if the amount of heavy rare earth element(s) such as Dy and Tb is evidently decreased compared to the past or no such heavy rare earth element is used. The rare earth based magnet of the present invention is a sintered magnet which comprises R2T14B crystal grains as the main phases and the crystal boundary phases among R2T14B crystal grains. The microstructure of the sintered body is controlled by at least containing the first crystal boundary phases and the second crystal boundary phases, wherein the first crystal boundary phases contain at least R-T-M in the ranges of 20 to 40 atomic % for R, 60 to 75 atomic % for T and 1 to 10 atomic % for M, and the second crystal boundary phases contains at least R-T-M in the ranges of 50 to 70 atomic % for R, 10 to 30 atomic % for T and 1 to 20 atomic % for M.

Abstract: The present invention provides a rare earth based magnet that inhibits the high temperature demagnetization rate even when less or no heavy rare earth elements such as Dy, Tb and the like than before are used. The rare earth based magnet according to the present invention is a sintered magnet which includes R2T14B crystal grains as main phase and grain boundary phases between the R2T14B crystal grains. when evaluating the cross-sectional area distribution of the main phase crystal grains by histogram in any cross-section of the rare earth based magnet, the crystal grains with large particle size and the crystal grains with small particle size are controlled so that the cross-sectional area distribution becomes the one which respectively has at least one peak at two sides of the average value of the cross-sectional area.

Abstract: A rare earth magnet includes main phase grains having an R2T14B type crystal structure. The main phase grains include B. A concentration ratio A (A=?B/?B) of the main phase grains is 1.05 or more, where ?B and ?B are respectively a highest concentration of B and a lowest concentration of B in one main phase grain.

Abstract: A rare earth magnet includes main phase grains having an R2T14B type crystal structure. The main phase grains include C. A concentration ratio A1 (A1=?C/?C) of the main phase grains is 1.50 or more, where ?C and ?C are respectively a highest concentration of C and a lowest concentration of C in one main phase grain.

Abstract: A rare earth magnet includes main phase grains having an R2T14B type crystal structure. The main phase grains include Ga. A concentration ratio A (A=?Ga/?Ga) of the main phase grains is 1.20 or more, where ?Ga and ?Ga are respectively a highest concentration of Ga and a lowest concentration of Ga in one main phase grain.

Abstract: 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.

Abstract: 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.

Abstract: The present invention provides a sintered magnet having superior residual magnetic flux density and coercive force. The sintered magnet of the present invention comprises a group of R-T-B based rare earth magnet crystal particles 2 having a core 4 and a shell 6 covering the core 4, the mass ratio of a heavy rare earth element in the shell 6 is higher than the mass ratio of a heavy rare earth element in the core 4, and the thickest part of the shell 6 in the crystal particles 2 faces a grain boundary triple junction 1. A lattice defect 3 is formed between the core 4 and the shell 6.

Abstract: An R-T-B based sintered magnet maintains high magnetic properties and decreases usage of heavy rare earth elements. The magnet includes main phase grains and grain boundary phases, the main phase grain containing a core portion and a shell portion. X in the main phase LR(2-x)HRxT14B of the core portion ranges from 0.00 to 0.07; x in the main phase LR(2-x)HRxT14B of the shell portion ranges from 0.02 to 0.40; and the maximum thickness of the shell portion ranges from 7 nm to 100 nm. LR contains Nd and one or more light rare earth elements consisting of Y, La, Ce, Pr and Sm; HR contains Dy or/and Tb and one or more heavy rare earth elements consisting of Gd, Ho, Er, Tm, Yb and Lu; T contains Fe or/and Co and one or two kinds of Mn and Ni; and B represents boron partly replaced by C (carbon).

Abstract: The present invention provides a rare earth based magnet having a microstructure in which in a section of the R2T14B main-phase crystal grains, the number density of the fine products in the interior of (inside) the crystal grains is larger than that in the periphery of (outside) the crystal grains. That is, the rare earth based magnet includes R2T14B main-phase crystal grains and grain boundary phases formed between the R2T14B main-phase crystal grains. The R2T14B main-phase crystal grains include a substance where fine products are formed in the crystal grains. In the section of the main-phase crystal grains, when the crystal grains are divided into the interior of the crystal grains and the periphery of the crystal grains with a specific ellipse, the fine products are formed such that the number density in the interior is larger than that in the periphery.

Abstract: The present invention provides a rare earth based magnet that inhibits the high temperature demagnetization rate even when less or no heavy rare earth elements such as Dy, Tb and the like than before are used. The rare earth based magnet according to the present invention is a sintered magnet which includes R2T14B crystal grains as main phase and grain boundary phases between the R2T14B crystal grains. when evaluating the cross-sectional area distribution of the main phase crystal grains by histogram in any cross-section of the rare earth based magnet, the crystal grains with large particle size and the crystal grains with small particle size are controlled so that the cross-sectional area distribution becomes the one which respectively has at least one peak at two sides of the average value of the cross-sectional area.

Abstract: The present invention provides a rare earth based magnet that inhibits the high temperature demagnetization rate even when less or no heavy rare earth elements such as Dy, Tb and the like than before are used. The rare earth based magnet according to the present invention is a sintered magnet which includes R2T14B crystal grains as main phase and grain boundary phases between the R2T14B crystal grains. When the grain boundary phase surrounded by three or more main phase crystal grains is regarded as the grain boundary multi-point, the microstructure of the sintered body is controlled so that the ratio of the grain boundary triple-point surrounded by three main phase crystal grains in all grain boundary multi-points to be specified value or less.