A rare earth permanent magnet material and a raw Material composition, a preparation method therefor and use thereof. The rare earth permanent magnet material comprises the following components in percentage by mass: 29.0-32.0 wt. % of R. where R comprises RH, and the content of RH is greater than 1 wt. %; 0.30-0.50 wt. % of Cu (not including 0.50 wt. %); 0.10-1.0 wt. % of Co; 0.05-0.20 wt. % of Ti; 0.92-0.98 wt. % of 13; and the remainder being Fe and unavoidable impurities; wherein R is a rare-earth element and at least comprises Nd; and RH is a heavy rare-earth element and at least comprises Tb. The R-T-B system permanent magnet material exhibits excellent performance, wherein Br≥14.30 kGs, and Hej≥24.1 kOe. The invention can synchronously improve Br and Hcj.

An application step of applying an adhesive agent to an application area of a surface of a sintered R-T-B based magnet work, an adhesion step of allowing a particle size-adjusted powder that is composed of a powder of an alloy or a compound of a Pr—Ga alloy which is at least one of Dy and Tb to the application area of the surface of the sintered R-T-B based magnet work, and a diffusing step of heating it at a temperature which is equal to or lower than a sintering temperature of the sintered R-T-B based magnet work to allow the Pr—Ga alloy contained in the particle size-adjusted powder to diffuse from the surface into the interior of the sintered R-T-B based magnet work are included. The particle size of the particle size-adjusted powder is set so that, when powder particles composing the particle size-adjusted powder are placed on the entire surface of the sintered R-T-B based magnet work to form a particle layer which is not less than one layer and not more than three layers, the amount of Ga contained in the particle size-adjusted powder is in a range from 0.10 to 1.0% with respect to the sintered R-T-B based magnet work by mass ratio.

A method for producing a bonded magnet, comprising: (i) low-shear compounding of a thermoplastic polymer and magnetic particles to form an initial homogeneous mixture thereof; (ii) feeding the initial homogeneous mixture into a plasticator comprising a low-shear single screw rotating unidirectionally toward a die orifice and housed within a heated barrel to result in heating of the initial homogeneous mixture until the thermoplastic polymer melts and forms a further homogeneous mixture, wherein said further homogeneous mixture is transported within threads of the single screw towards the die orifice and exits the die orifice as a solid pellet; (iii) conveying the solid pellet into a mold and compression molding the pellet in the mold, to form the bonded magnet, wherein the bonded magnet possesses a magnetic particle loading of at least 80 vol % and exhibits one or more magnetic properties varying by less than 5% throughout the bonded magnet.

A magnet structure includes columnar grains of rare earth permanent magnet phase aligned in a same direction and arranged to form bulk anisotropic rare earth alloy magnet having a boundary defined by opposite ends of the columnar grains and lacking triple junction regions, and rare earth alloy diffused onto opposite ends of the bulk anisotropic rare earth alloy magnet.

A method for preparing a metal powder includes preparing a mixture by mixing a fluoride of a group 1 element, a fluoride of a group 2 element or a transition metal fluoride, with neodymium oxide, boron, iron, and a reducing agent; and heating the mixture at a temperature of 800° C. to 1100° C.

An R—Fe—B base sintered magnet is provided consisting essentially of R (which is at least two rare earth elements and essentially contains Nd and Pr), M.sub.1 which is at least two of Si, Al, Mn, Ni, Cu, Zn, Ga, Ge, Pd, Ag, Cd, In, Sn, Sb, Pt, Au, Hg, Pb, and Bi, M.sub.2 which is at least one of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W, boron, and the balance of Fe, and containing an intermetallic compound R.sub.2(Fe,(Co)).sub.14B as a main phase. The magnet contains an R—Fe(Co)-M.sub.1 phase as a grain boundary phase, the R—Fe(Co)-M.sub.1 phase contains A phase which is crystalline with crystallites of at least 10 nm formed at grain boundary triple junctions, and B phase which is amorphous and/or nanocrystalline with crystallites of less than 10 nm formed at intergranular grain boundaries and optionally grain boundary triple junctions.

A rare earth-iron-nitrogen-based magnetic powder according to this invention contains, as main constituent components, a rare-earth element (R), iron (Fe), and nitrogen (N). Moreover, this magnetic powder has an average particle size of 1.0-10.0 μm, and contains 22.0-30.0 mass % of a rare-earth element (R) and 2.5-4.0 mass % of nitrogen (N). Further, this magnetic powder includes: a core part having any one crystal structure among a Th.sub.2Zn.sub.17 type, a Th.sub.2Ni.sub.17 type, and a TbCu.sub.7 type; and a shell layer provided on the surface of the core part and having a thickness of 1-30 nm. The shell layer contains a rare-earth element (R) and iron (Fe) so that the R/Fe atomic ratio is 0.3-5.0, and further contains 0-10 at % (exclusive of 0) of nitrogen (N). Furthermore, this magnetic powder contains compound particles composed of a rare-earth element (R) and phosphorus (P).

A method for preparing a NdFeB permanent magnetic material may include providing a covered NdFeB magnetic powder by depositing heavy rare earth particles or high-melting particles onto a NdFeB magnetic powder by physical vapor deposition; and performing orientation molding and sintering on the covered NdFeB magnetic powder to provide the NdFeB permanent magnetic material.

There are provided a method for producing a magnetic refrigeration material whose magnetic transition temperature can be adjusted with high accuracy, and a magnetic refrigeration material whose magnetic transition temperature has been adjusted with high accuracy. The magnetic refrigeration material production method of the present invention includes the steps of: preparing a first predetermined magnetic refrigeration material and a second predetermined magnetic refrigeration material which differs from the first magnetic refrigeration material; and mixing the first magnetic refrigeration material and the second magnetic refrigeration material to obtain a third magnetic refrigeration material. The content of the first magnetic refrigeration material and the content of the second magnetic refrigeration material in the third magnetic refrigeration material are determined by the magnetic transition temperatures of the first magnetic refrigeration material and the second magnetic refrigeration material and by a target magnetic transition temperature of the third magnetic refrigeration material. The magnetic refrigeration material of the present invention includes at least a first predetermined magnetic refrigeration material and a second predetermined magnetic refrigeration material which differs from the first magnetic refrigeration material. The absolute value of the difference between the magnetic transition temperature of the present magnetic refrigeration material and a target magnetic transition temperature is 0.7 K or less.

According to an embodiment, a composite permanent magnet includes a matrix of magnetically hard phase grains having an average grain size of 10 nm to 50 μm; and magnetically soft phase grains embedded within the matrix, and having an average grain size of at least 50 nm, each grain having an elongated shape with an aspect ratio of at least 2:1. According to another embodiment, a composite permanent magnet includes a matrix of magnetically hard phase grains having an average grain size of 10 nm to 50 μm; and magnetically soft phase grains embedded within the matrix, and having an average grain width of at least 50 nm, an average grain height of 20 to 500 nm, and an aspect ratio of at least 2:1. According to yet another embodiment, a method of forming a composite permanent magnet is also provided.