A samarium-iron-nitrogen alloy powder according to one embodiment of the present invention is characterized in that a value obtained by dividing the hydrogen content of the samarium-iron-nitrogen alloy powder by the BET specific surface area of the samarium-iron-nitrogen alloy powder is less than or equal to 400 ppm/(m.sup.2/g), and a value obtained by dividing the oxygen content of the samarium-iron-nitrogen alloy powder by the BET specific surface area of the samarium-iron-nitrogen alloy powder is less than or equal to 11,000 ppm/(m.sup.2/g).

This powder satisfies requirements 1 and 2.

Requirement 1: |dA(T)/dT| satisfies 10 ppm/° C. or more at at least one temperature Ti in a range of −200° C. to 1200° C. A is (a-axis (shorter axis) lattice constant) of a crystal in the powder)/(c-axis (longer axis) lattice constant of the crystal in the powder), and each of the lattice constants is obtained by X-ray diffractometry of the powder. Requirement 2: a particle diameter D50 at a cumulative frequency of 50%, a particle diameter D10 at a cumulative frequency of 10%, and a particle diameter D90 at a cumulative frequency of 90% in a volume-based cumulative particle diameter distribution curve obtained by a laser diffraction scattering method satisfy conditions (I) and (II): (I) D10/D50 is 0.05 or more and 0.45 or less; and (II) 190 is 0.5 μm or more and 70 μm or less.

A solid composition contains a first material and a powder and satisfies requirements 1 and 2. Requirement 1: |dA(T)/dT| satisfies 10 ppm/° C. or more at least at −200° C. to 1,200° C. A is (an a-axis lattice constant of a crystal in the powder)/(a c-axis lattice constant of a crystal in the powder), obtained from X-ray diffractometry of the powder. Requirement 2: C is 0.04 or more. C is (a log differential pore volume when a pore diameter of the solid composition is B in a pore distribution curve of the solid composition)/(a log differential pore volume corresponding to a maximum peak intensity in the pore distribution curve of the solid composition). B is (a pore diameter giving a maximum peak intensity in the pore distribution curve of the solid composition)/2. The pore distribution curve of the solid composition shows a relationship between the pore diameter and the log differential pore volume.

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.

[Problem] To provide a highly efficient manufacturing method including an RH supply-diffusion process by which the number of magnets processed at a time can be increased without allowing sintered R-T-B based magnets to stick to holding members. [Solution] A method for producing a sintered R-T-B based magnet including the steps of: forming a stack of RH diffusion sources and sintered R-T-B based magnet bodies by stacking the diffusion sources and the magnet bodies alternately with a holding member having openings interposed; and carrying out an RH supply-diffusion process by loading the stack into a process vessel and creating an atmosphere with a pressure of 0.1 Pa to 50 Pa and a temperature of 800° C. to 950° C. within the process vessel.

[Problem] To provide a highly efficient manufacturing method including an RH supply-diffusion process by which the number of magnets processed at a time can be increased without allowing sintered R-T-B based magnets to stick to holding members. [Solution] A method for producing a sintered R-T-B based magnet including the steps of: forming a stack of RH diffusion sources and sintered R-T-B based magnet bodies by stacking the diffusion sources and the magnet bodies alternately with a holding member having openings interposed; and carrying out an RH supply-diffusion process by loading the stack into a process vessel and creating an atmosphere with a pressure of 0.1 Pa to 50 Pa and a temperature of 800° C. to 950° C. within the process vessel.

The present invention provides for materials and methods of making metal and ceramic matrix composites reinforced with boron nitride nanomaterials for improved physical properties such as hardness, fracture toughness, and bend strength.

An article for magnetic heat exchange comprising a magnetocalorically active phase with a NaZn.sub.13-type crystal structure is provided by hydrogenating a bulk precursor article. The bulk precursor article is heated from a temperature of less than 50° C. to at least 300° C. in an inert atmosphere and hydrogen gas only introduced when a temperature of at least 300° C. is reached. The bulk precursor article is maintained in a hydrogen containing atmosphere at a temperature in the range 300° C. to 700° C. for a selected duration of time, and then cooled to a temperature of less than 50° C.

In an embodiment, a permanent magnet includes a composition represented by a composition formula: R(Fe.sub.pM.sub.qCu.sub.r(Co.sub.1-sA.sub.s).sub.1-p-q-r).sub.z, where, R is at least one element selected from rare earth elements, M is at least one element selected from Ti, Zr, and Hf, A is at least one element selected from Ni, V, Cr, Mn, Al, Si, Ga, Nb, Ta, and W, 0.05≦p≦0.6, 0.005≦q≦0.1, 0.01≦r≦0.15, 0≦s≦0.2, and 4≦z≦9, and a two-phase structure of a Th.sub.2Zn.sub.17 crystal phase and a copper-rich phase. In a cross-section of the permanent magnet containing a crystal c axis of the Th.sub.2Zn.sub.17 crystal phase, an average distance between the copper-rich phases is 120 nm or less.

In an embodiment, a permanent magnet includes a composition represented by a composition formula: R(Fe.sub.pM.sub.qCu.sub.r(Co.sub.1-sA.sub.s).sub.1-p-q-r).sub.z, where, R is at least one element selected from rare earth elements, M is at least one element selected from Ti, Zr, and Hf, A is at least one element selected from Ni, V, Cr, Mn, Al, Si, Ga, Nb, Ta, and W, 0.05≦p≦0.6, 0.005≦q≦0.1, 0.01≦r≦0.15, 0≦s≦0.2, and 4≦z≦9, and a two-phase structure of a Th.sub.2Zn.sub.17 crystal phase and a copper-rich phase. In a cross-section of the permanent magnet containing a crystal c axis of the Th.sub.2Zn.sub.17 crystal phase, an average distance between the copper-rich phases is 120 nm or less.