A sintered magnet contains Sm—Fe—N-based crystal grains and has high coercivity; and a magnetic powder is capable of forming a sintered magnet without lowering the coercivity even if heat is generated in association with the sintering. A sintered magnet comprises a crystal phase composed of a plurality of Sm—Fe—N-based crystal grains and a nonmagnetic metal phase present between the Sm—Fe—N crystal grains adjacent to each other, wherein a ratio of Fe peak intensity I.sub.Fe to SmFeN peak intensity I.sub.SmFeN measured by an X-ray diffraction method is 0.2 or less. A magnetic powder comprises Sm—Fe—N-based crystal particles and a nonmagnetic metal layer covering surfaces of the Sm—Fe—N crystal particles.

The present disclosure discloses an yttrium (Y)-added rare-earth permanent magnetic material and a preparation method thereof. A chemical formula of the material expressed in atomic percentage is (YxRE1-x)aFebalMbNc, wherein 0.05≤x≤0.4, 7≤a≤13, 0≤b≤3, 5≤c≤20, and the balance is Fe, namely, bal=100-a-b-c; RE represents a rare-earth element Sm, or a combination of the rare-earth element Sm and any one or more elements of Zr, Nd and Pr; M represents Co and/or Nb; and N represents nitrogen. In the preparation method, the rare-earth element Y is utilized to replace the element Sm of a samarium-iron-nitrogen material. By regulating a ratio of the element Sm to the element Y, viscosity of an alloy liquid can be reduced, and an amorphous forming ability of the material is enhanced.

A Sm—Fe—N-based rare earth magnet more resistant to demagnetization than ever before in an environment where an external magnetic field is applied, particularly at high temperatures, and a production method thereof are provided.

The present disclosure presents a production method of a rare earth magnet, including preparing a coated magnetic powder, compression-molding the coated magnetic powder in a magnetic field to obtain a magnetic-field molded body, pressure-sintering the magnetic-field molded body to obtain a sintered body, and heat-treating the sintered body, and a rare earth magnet obtained by the method. D.sub.50 of the magnetic powder in the coated magnetic powder is 1.50 μm or more and 3.00 μm or less, the content ratio of the zinc component in the coated magnetic powder is 3 mass % or more and 15 mass % or less, and the heat treatment temperature is 350° C. or more and 410° C. or less.

A magnet material is represented by a composition formula 1: R.sub.xNb.sub.yB.sub.xM.sub.100x-y-z, R is at least one element selected from the group consisting of rare-earth elements, M is at least one element selected from the group consisting of Fe and Co, x is a number satisfying 4≤x≤10 atomic %, y is a number satisfying 0.1≤y≤8 atomic %, and z is a number satisfying 0.1≤z≤12 atomic %. The magnet material includes: a main phase having a TbCu.sub.7 crystal phase; and a grain boundary phase. The magnet material satisfies a relation of n.sub.Nb2/n.sub.Nb1>5, where n.sub.Nb1 is an average Nb concentration in the TbCu.sub.7 crystal phase and n.sub.Nb2 is a maximum Nb concentration in the grain boundary phase.

A high-performance permanent magnet is provided. A permanent magnet expressed by a composition formula: R.sub.pFe.sub.qM.sub.rCu.sub.tCo.sub.100-p-q-r-t-. The magnet comprises a metal structure including a cell phase having a Th.sub.2Zn.sub.17 crystal phase, and a Cu-rich phase provided to divide the cell phase and having a Cu concentration higher than that of the Th.sub.2Zn.sub.17 crystal phase. An Fe concentration of the Th.sub.2Zn.sub.17 crystal phase is not less than 30 atomic % nor more than 45 atomic %. An average length of the Cu-rich phase is not less than 30 nm nor more than 250 nm.

A high-performance permanent magnet is provided. A permanent magnet expressed by a composition formula: (R.sub.1-xA.sub.x).sub.pFe.sub.qM.sub.rCu.sub.tCo.sub.100-p-r-t. The magnet comprises a metal structure including a plurality of crystal grains which constitutes a main phase having a Th.sub.2Zn.sub.17 crystal phase, An Fe concentration of each of the crystal grains is 28 atomic % or more. A concentration difference of the element A among the crystal grains is not less than 0.2 atomic % nor more than 3.0 atomic %.

The magnet material is represented by a composition formula 1: (R.sub.1-xY.sub.x).sub.aM.sub.bA.sub.c, where R is at least one element selected from the group consisting of rare-earth elements, M is at least one element selected from the group consisting of Fe and Co, A is at least one element selected from the group consisting of N, C, B, H and P, x is a number satisfying 0.01≤x≤0.8, a is a number satisfying 4≤a≤20 atomic %, b is a number satisfying b=100−a−c atomic %, and c is a number satisfying 0≤c≤18 atomic %), and includes a main phase having a Th.sub.2Ni.sub.17 crystal structure. A concentration of the element M in the main phase is 89.6 atomic % or more.

Included is a method of preparing a compound for bonded magnets, the method including: coating a magnetic material having an average particle size of 10 μm or less with a thermosetting resin and a curing agent at a ratio of the equivalent weight of the curing agent to the equivalent weight of the thermosetting resin of 2 or higher and 10 or lower to obtain a coated material; granulating the coated material by compression to obtain a granulated product; milling the granulated product to obtain a milled product; and surface treating the milled product with a silane coupling agent to obtain a compound for bonded magnets, the method either including, between the granulation and the milling, heat curing the granulated product to obtain a cured product, or including, between the milling and the surface treatment, heat curing the milled product to obtain a cured product.

There is provided a compact for a magnet which can produce a magnetic member having high coercive force. The compact for a magnet is produced by compression-molding a rare earth-iron-based alloy powder containing a plurality of particles of a rare earth-iron-based alloy containing a rare earth element and iron, wherein the rare earth-iron-based alloy satisfies configurations (a) to (c) below and has 5% by volume or more and 20% by volume or less of voids formed therein. (a) Having a structure containing 10% by mass or more and 30% by mass or less of Sm, 10% by mass or less of Mn, and the balance consisting of Fe and inevitable impurities. (b) A composition, Sm.sub.2MN.sub.xFe.sub.17-x (x=0.1 or more and 2.5 or less). (c) An average crystal grain diameter of 700 nm or less.

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).