Provided is an Sm—Fe—N rare earth magnet comprising Sm—Fe—N crystal grains. An oxygen content in the Sm—Fe—N rare earth magnet is 0.5% by mass or less on the basis of a total amount of the Sm—Fe—N rare earth magnet, and an average grain size of the Sm—Fe—N crystal grains is 1 μm or less.

There is provided a manufacturing method for a rare earth magnet, including forming a zinc-containing coating film on a surface of a particle of a samarium-iron-nitrogen-based magnetic powder to obtain a coated powder, subjecting the coated powder to compression molding to obtain a compacted powder body, and subjecting the compacted powder body to pressure sintering, in which a coating rate of the coating film with respect to an entire surface of the particle of the coated powder is 96% or more, and the formation of the coating film and the pressure sintering of the compacted powder body is carried out in a vacuum or an inert gas atmosphere, and the compression molding of the coated powder is carried out in the atmospheric air.

The permanent magnet includes: a main phase expressed by a composition formula: RM.sub.ZN.sub.X and having at least one crystal structure selected from the group consisting of a Th.sub.2Ni.sub.17 crystal structure, a Th.sub.2Zn.sub.17 crystal structure, and a TbCu.sub.7 crystal structure; and a sub phase having a phosphorus compound phase containing a phosphorus compound excluding a phosphoric acid compound.

A samarium-iron-nitrogen-based magnetic material containing Sm, Fe, N, Ti, and Co at a content of 2.5 at % or less. A content of the Sm may be 7 at % to 10 at %, a content of the Fe may be 65 at % to 80 at %, a content of the N may be 13 at % to 16 at %, and a content of the Ti may be 0.5 at % to 1.5 at %.

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.

The production method of a rare earth magnet of the present disclosure includes a coated magnetic powder preparation step, a mixed powder preparation step, and a pressure sintering step. In the coated magnetic preparation step, a zinc-containing coating 12 is formed on the particle surface of a samarium-iron-nitrogen-based magnetic powder to obtain a coated magnetic powder 14. In the mixed powder preparation step, a binder powder 20 having a melting point not higher than the melting point of the coating 12 and the coated magnetic powder 14 are mixed to obtain a mixed powder. In the pressure sintering step, denoting as T.sub.1° C. the temperature at which the peak disappears in an X-ray diffraction pattern of the binder powder 20 and as T.sub.2° C. the temperature at which the magnetic phase in the samarium-iron-nitrogen-based magnetic powder 10 decomposes, the mixed powder is pressure-sintered at T.sub.1° C. or more and (T.sub.2−50)° C. or less.

A permanent magnet is 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 main phase having a Th.sub.2Zn.sub.17 crystal phase and a grain boundary phase. The main phase includes a cell phase having the Th.sub.2Zn.sub.17 crystal phase and a Cu-rich phase. A section including a c-axis of the Th.sub.2Zn.sub.17 crystal phase has a first region in the crystal grain and a second region in the crystal grain, the first region is provided in the cell phase divided by the Cu-rich phase, the second region is provided within a range of not less than 50 nm nor more than 200 nm from the grain boundary phase in a direction perpendicular to an extension direction of the grain boundary phase, and a difference between a Cu concentration of the first region and a Cu concentration of the second region is 0.5 atomic percent or less.

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 %.

A method of manufacturing a permanent magnet comprises a solution heat treatment. The solution heat treatment includes: performing a heat treatment at a temperature T.sub.ST; placing a cooling member including a first layer and a second layer on the first layer between the heater and the treatment object so that the first layer faces the treatment object; and transferring the treatment object together with the cooling member to the outside of a heating chamber, and cooling the treatment object until a temperature of the treatment object becomes a temperature lower than a temperature T.sub.ST200 C. In the step of cooling the treatment object, a cooling rate until the temperature of the treatment object becomes the temperature T.sub.ST200 C. is 5 C./s or more.

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 0.05x0.4, 7a13, 0b3, 5c20, 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.