A permanent magnet of an embodiment includes: a composition represented by a composition formula: R(Fe.sub.pM.sub.qCu.sub.rCo.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 Zr, Ti, and Hf, and relations of 0.3≦p≦0.4, 0.01≦q≦0.05, 0.01≦r≦0.1, and 7≦z≦8.5 (atomic ratio) are satisfied; and a structure including a cell phase having a Th.sub.2Zn.sub.17 crystal phase, and a cell wall phase existing to surround the cell phase. An average magnetization of the cell wall phase is 0.2 T or less.

In one embodiment, a permanent magnet has a composition expressed by a composition formula: RN.sub.x(Cr.sub.pSi.sub.qM.sub.1-p-q).sub.z (R is at least one element selected from Y and rare-earth elements, M is at least one element selected from Fe and Co, and x, p, q, and z are atomic ratios satisfying 0.5≦x≦2.0, 0.005≦p≦0.2, 0.005≦q≦0.2, and 4≦z≦13, respectively). The permanent magnet has a density of 6.5 g/cm.sup.3 or more and satisfies the relationship of I(110)/{I(110)+I(303)}≦0.05, in which I(303) represents a diffraction peak intensity from a (303) plane of a Th.sub.2Zn.sub.17 phase obtained through powder X-ray diffraction of the permanent magnet, and I(110) represents a diffraction peak intensity from a (110) plane of an α-Fe phase obtained through the powder X-ray diffraction.

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 permanent magnet of an embodiment includes a sintered compact, the sintered compact including: a composition expressed by R.sub.pFe.sub.qM.sub.rCu.sub.sCo.sub.100-p-q-r-s, (R is at least one element selected from rare earth elements, M is at least one element selected from Zr, Ti, and Hf, 10.5≦p≦12.5 atomic %, 24≦q≦40 atomic %, 0.88≦r≦4.5 atomic %, and 3.5≦s≦10.7 atomic %); and a structure having crystal grains each composed of a main phase including a Th.sub.2Zn.sub.17 crystal phase, and a crystal grain boundary of the crystal grains. An average crystal grain diameter of the crystal grains is 50 μm or more and 100 μm or less, and a ratio of the crystal grains having a crystal grain diameter of 50 μm or more is 75% or more.

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 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, a Cu-rich phase having a Cu concentration higher than the cell phase, and a plurality of M-rich platelet phases extending in a direction intersecting with a c-axis of the Th.sub.2Zn.sub.17 crystal phase in a section including the c-axis and having a M element concentration higher than the cell phase. In the section, the cell phase has a 200 nm diameter or more, and a gap between the M-rich platelet phases is 80 nm or less.

A method for producing a sintered R-T-B based magnet of this disclosure includes the steps of preparing a plurality of sintered R-T-B based magnet bodies (R is at least one of rare earth elements and necessarily contains Nd and/or Pr; and T is at least one of transition metals and necessarily contains Fe); preparing a plurality of alloy powder particles having a size of 90 μm or less and containing a heavy rare earth element RH (the heavy rare earth RH is Tb and/or Dy) at a content of 20 mass % or greater and 80 mass % or less; loading the plurality of sintered R-T-B based magnet bodies and the plurality of alloy powder particles of a ratio of 2% by weight or greater and 15% by weight or less with respect to the plurality of sintered R-T-B based magnet bodies into a process chamber; and heating, while rotating and/or swinging, the process chamber to move the sintered R-T-B based magnet bodies and the alloy powder particles continuously or intermittently to perform an RH supply and diffusion process.

A permanent magnet includes R and T (R essentially includes Sm one or more of rare earth elements in addition to Sm, and T essentially includes Fe, or Fe and Co, one or more of transition metal elements in addition to Fe, or Fe and Co). A composition ratio of R in the permanent magnet is 20 at % or more and 40 at % or less. A remaining part is substantially only T, or only T and C. T amount is more than 1.5 times of R amount and less than 4.0 times of the R amount. Main phase grains included in the permanent magnet have an Nd5Fe17 type crystal structure. An average crystal grain size of the main phase grains of the permanent magnet is greater than 1 μm. A number ratio of main phase grains having a crystal grain size of less than 0.4 μm is less than 20%.

The present invention relates to a Ce-containing sintered rare earth permanent magnet with high toughness and high coercivity and a method of preparing the magnet, belonging to the technical field of rare earth permanent magnetic materials. The magnet is prepared by steps of raw material batching, strip casting, hydrogen decrepitation and jet milling, powder orientating and forming, sintering and heat treatment. The materials of the permanent magnet comprise the main phase alloy powders and the Ce added phase alloy powders, wherein the Ce added phase alloy is a magnetic phase or a non-magnetic liquid-phase alloy; and the Ce added phase alloy accounts for 5% to 30% of the total weight of the permanent magnet, and the remainder is the main phase alloy. During the jet milling stage, a certain concentration of oxygen is added into the inert gas, so that the final magnet has an oxygen content of 1500 to 2500 ppm. The Ce-containing dual-alloy magnet prepared in accordance with the present invention has high coercivity, and the intrinsic coercivity (H.sub.cj) is up to 17 to 28.73 kOe. The magnet of the present invention has good fracture toughness which is increased by 10% to 30% as compared with the conventional Nd—Fe—B sintered magnet. The magnet of the present invention can meet needs of high-end applications such as wind power generation, new energy vehicles, and the like, and greatly expands the application fields of Ce-containing magnets.

The present disclosure is directed to methods of preparing substantially spherical metallic alloyed particles, having micron and sub-micron (i.e., nanometer)-scaled dimensions, and the powders so prepared, as well as articles derived from these powders. In particular embodiments, these metallic alloyed particles, complising rare earth metals, can be prepared in sizes as small 80 nm in diameter with size variances as low as 2-5%.

One embodiment of the present invention includes single-crystal particles of a TbCu.sub.7 type samarium-iron-nitrogen based alloy in an anisotropic magnet powder.