A permanent magnet in which demagnetization adjustment can be easily performed and a method for manufacturing the same are provided. The permanent magnet contains 22 to 28 mass % of a rare-earth element R, 12 to 23 mass % of Fe, 3 to 9 mass % of Cu, 1 to 4 mass % of Zr, and a remainder consisting of Co and unavoidable impurities, in which, in a demagnetization curve in which the horizontal axis indicates a demagnetization field (kOe) and the vertical axis indicates the total amount of magnetic flux (×10.sup.−5 WbT) in the permanent magnet, the slope of an approximate straight line in demagnetization field ranges from 0 to −11 kOe is 1.2 or smaller.

The invention relates to high entropy alloy of rare earth elements (RE-HEAs) including at least four and up to twelve elements selected form rare earth elements R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8, R.sub.9, R.sub.10, R.sub.11, R.sub.12, which rare earth elements R.sub.1 to R.sub.12 each represents one of elements 57 to 60, 62 to 70, 39 and 40 of the periodic system and to high entropy alloy of transition elements (TM-HEAs) including at least 3 and up to 12 elements selected from transitional elements TM.sub.1, TM.sub.2, TM.sub.3, TM.sub.4, TM.sub.5, TM.sub.6, TM.sub.7, TM.sub.8, TM.sub.9, TM.sub.10, TM.sub.11, TM.sub.12, which transitional elements TM.sub.1 to TM.sub.12 each represent at least one of elements 21 to 30, 41 to 48 and 72 to 79 of the periodic system. Such RE-HEAs and/or TM-HEAs can be used as building blocks in magnetic high entropy composite alloys, e.g. of the type (RE-HEAs).sub.x(TM-HEAs).sub.yT.sub.z, for the manufacture of magnetic devices and permanent magnets.

An iron-based rare earth boron-based isotropic magnet alloy, which has an alloy composition represented by T.sub.100-x-y-z(B.sub.1-nC.sub.n).sub.xRE.sub.yM.sub.z (where T is a transition metal element containing at least Fe, RE contains at least Nd, and M is one or more metal elements selected from the group consisting of Al, Si, V, Cr, Ti, Mn, Cu, Zn, Ga, Zr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au, and Pb), 4.2 atom %≤x≤5.6 atom %, 11.5 atom %≤y≤13.0 atom %, 0.0 atom %≤z≤5.0 atom %, and 0.0≤n≤0.5, and the iron-based rare earth boron-based isotropic magnet alloy has an average crystal grain size of 10 nm to less than 70 nm as a main phase.

A platelet-shaped magnetic effect pigment is provided for use in a printing ink, and includes a layer construction with a magnetic layer and at least one optical functional layer, such that the magnetic layer is based on a magnetic material having a column-shaped nanostructure and the magnetic columns respectively have a largely uniform preferential magnetic direction deviating from the platelet plane.

A permanent magnet having excellent magnetic properties, and a device including such a permanent magnet are provided. A permanent magnet consists of a sintered compact having a composition consisting of, in a mass percentage composition, R: 23 to 27% (R is a rare-earth element including at least Sm); Fe: 22 to 27%; Mn: 0.01 to 2.5%; and a remainder consisting of Co and unavoidable impurities, in which the sintered compact contains a plurality of crystal grains and grain boundaries, an average crystal grain size (A. G.) of the crystal grains is equal to or larger than 100 μm, and a coefficient of variation (C. V.) of crystal grain sizes is equal to or smaller than 0.60.

Disclosed in the present invention are a heavy rare earth alloy, neodymium-iron-boron permanent magnet material, a raw material, and a preparation method. The heavy rare earth alloy comprises the following components: RH: 30-100 mas %, not including 100 mas %; X, 0-20 mas %, not including 0; B: 0-1.1 mas %; and Fe and/or Co: 15-69 mas %, RH comprising one or more heavy rare earth elements in Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc, and X being Ti and/or Zr. When the heavy rare earth alloy of the present invention is used as a sub-alloy to prepare the neodymium-iron-boron permanent magnet material, a high utilization rate of heavy rare earth is achieved, so that the coercivity can also be greatly improved while the neodymium-iron-boron permanent magnet material maintains high remanence.

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 grain boundary diffusion method for a bulk rare earth permanent magnetic material includes the following steps: (1) fabricating an initial magnet by a sintering, hot pressing, or hot deformation process; (2) loading a grain boundary diffusion alloy source on a surface of the magnet through electrodeposition, chemical vapor deposition (CVD), physical vapor deposition (PVD), direct physical contact, or adhesive bonding; and (3) placing the initial magnet loaded with the grain boundary diffusion alloy source in a SPS device, and heating to obtain a final magnet. The current, plasma, and pressure in an SPS process can be controlled to significantly improve elemental diffusion coefficient and enhance the diffusion depth. The bulk rare earth permanent magnetic material undergoing grain boundary diffusion fabricated in the present disclosure has a significant increase in magnetic properties that catering to commercial demands for industrial production.

A molding device for molding a magnet roll with a profiled cross-section comprises a heating and kneading unit that supplies, to a cylindrical metal mold, a kneaded material obtained by heating and kneading a raw mixture including ferromagnetic particles and thermoplastic resin, an extrusion molding unit that molds the supplied kneaded material by the metal mold, and a magnetic field generating unit disposed at an end portion of the metal mold in a lengthwise direction that generates a magnetic field inside the metal mold, and the metal mold has a profiled C-shaped cross-section at an inlet for the kneaded material and a profiled cross-section at an outlet for the kneaded material more complex than the inlet.