A sintered magnet and method of manufacturing the same are disclosed herein. According to an exemplary embodiment, a manufacturing method of a sintered magnet includes mixing the neodymium iron boron (NdFeB)-based powders and rare-earth hydride powders to prepare a mixture, heat-treating the mixture at a temperature of 600 to 850° C., and sintering the heat-treated mixture at a temperature of 1000 to 1100° C. to prepare the sintered magnet, wherein the rare earth hydride powders are neodymium hydride (NdH.sub.2) powders or mixed powers of NdH.sub.2 and praseodymium hydride (PrH.sub.2). In an embodiment, the NdFeB-based powders are prepared by a reduction-diffusion method.

Provided is a rare earth sintered magnet in which a multi-layer main phase particle having multiple layers including a layer 1 having R.sup.2 concentration, represented by at %, higher than that of a center of the particle, a layer 2 which is formed on the outside of the layer 1 and has R.sup.2 concentration lower than that of the layer 1, and a layer 3 which is formed on the outside of the layer 2 and has R.sup.2 concentration higher than that of the layer 2 is present at least in a portion in the vicinity of a surface of the main phase particle within at least 500 μm from a surface of the sintered magnet body.

The disclosure refers to a NdFeB alloy powder for forming high-coercivity sintered NdFeB magnets. The NdFeB alloy powder includes NdFeB alloy core particles with a multi-layered coating, wherein the multi-layered coating comprises:

a first metal layer directly disposed on the NdFeB alloy core particles, wherein the first metal layer consists of at least one of Tb and Dy;

a second metal layer directly disposed on the first metal layer, wherein the second metal layer consists of at least one of W, Mo, Ti, Zr, and Nb; and

a third metal layer directly disposed on the second metal layer, wherein the third metal layer consists of (i) at least one of Pr, Nd, La, and Ce; or (ii) a combination of one of the group consisting of Cu, Al, and Ga and at least one of the group consisting of Pr, Nd, La, and Ce.

The disclosure provides a novel NdFeB alloy powder for forming high-coercivity sintered NdFeB magnets. The NdFeB alloy powder includes NdFeB alloy core particles with a mixed metal coating. The mixed metal coating is formed by simultaneously vapor deposition of a) at least one high-melting metal M selected from the group consisting of Mo, W, Zr, Ti, and Nb; and b) at least one metal R, where R is selected from the group consisting of Pr, Nd, La, and Ce; or a metal alloy RX, where X is one selected from the group consisting of Cu, Al, and Ga and R is at least one selected from the group consisting of Pr, Nd, La, and Ce.

Disclosed are a method of manufacturing a rare-earth permanent magnet capable of offsetting a partially uneven demagnetization by varying the amount of heavy rare-earth element diffused to a grain boundary for each region and a Nd—Fe—B-based permanent magnet manufactured by the same.

The method includes: preparing a base material including a plurality of regions by using a sintered magnet including an Nd—Fe—B-based alloy; preparing a coating material including a heavy rare-earth element; applying the coating material to a surface of the base material; and diffusing the heavy rare-earth element to a grain boundary of the base material by heat-treating the base material to which the coating material is applied. In the applying the coating material, an amount of the coating material applied to each region of the base material may vary.

Provided is a permanent magnet including a rare-earth element R (such as Nd), a transition metal element T (such as Fe), B, Zr, and Cu. The permanent magnet contains a plurality of main phase grains including Nd, T, and B, and grain boundary multiple junctions, the one grain boundary multiple junction is a grain boundary surrounded by three or more of the main phase grains, one of the grain boundary multiple junctions contains a ZrB.sub.2 crystal and an R—Cu-rich phase including R and Cu, a concentration of B in the one grain boundary multiple junction containing both the ZrB.sub.2 crystal and the R—Cu-rich phase is from 5 to 20 atomic %, a concentration of Cu in the one grain boundary multiple junction containing both the ZrB.sub.2 crystal and the R—Cu-rich phase is from 5 to 25 atomic %, and a surface layer part of the main phase grain includes at least one kind of heavy rare-earth element among Tb and Dy.

A rotor of an electric machine includes a rotor core with one or more permanent magnets having opposing ends. The rotor core defining a magnet channel extending axially between opposing ends of the rotor core. The permanent magnet is disposed in the channel and extends axially through the rotor core. The magnet includes a planar layer of magnetically hard-phase material that includes rare-earth metal and includes a planar layer of magnetically soft-phase material that does not include rare-earth metal. Both of the hard and soft layers extend between the opposing ends. The soft-phase material has a major face disposed against a major face of the hard phase material.

A method for producing magnet-polymer pellets useful as a feedstock in an additive manufacturing process, comprising: (i) blending thermoplastic polymer and hard magnetic particles; (ii) feeding the blended magnet-polymer mixture into a pre-feed hopper that feeds directly into an inlet of a temperature-controlled barrel extruder; (iii) feeding the blended magnet-polymer mixture into the barrel extruder at a fixed feed rate of 5-20 kg/hour, wherein the temperature at the outlet is at least to no more than 10 C. above a glass transition temperature of the blended magnet-polymer mixture; (iv) feeding the blended magnet-polymer mixture directly into an extruding die; (v) passing the blended magnet-polymer mixture through the extruding die at a fixed speed; and (vi) cutting the magnet-polymer mixture at regular intervals as the mixture exits the extruding die at the fixed speed. The use of the pellets as feed material in an additive manufacturing process is also described.

To provide a rare earth magnet ensuring excellent magnetic anisotropy while reducing the amount of Nd, etc., and a manufacturing method thereof. A rare earth magnet comprising a crystal grain having an overall composition of (R2.sub.(1-x)R1.sub.x).sub.yFe.sub.100-y-w-z-vCo.sub.wB.sub.zTM.sub.v (wherein R2 is at least one of Nd, Pr, Dy and Tb, R1 is an alloy of at least one or two or more of Ce, La, Gd, Y and Sc, TM is at least one of Ga, Al, Cu, Au, Ag, Zn, In and Mn, 0<x<1, y=12 to 20, z=5.6 to 6.5, w=0 to 8, and v=0 to 2), wherein the average grain size of the crystal grain is 1,000 nm or less, the crystal grain consists of a core and an outer shell, the core has a composition of R1 that is richer than R2, and the outer shell has a composition of R2 that is richer than R1.

A responsive material having an elastomeric matrix in which ferromagnetic particles are dispersed so as to have a predetermined magnetization pattern which, when exposed to an external magnetic field, changes the shape of the responsive material from an initial shape to a predetermined transformed shape dictated by the magnetization pattern. An initial shape of the responsive material is formed by direct ink printing while applying magnetic fields to a dispensing nozzle to align the particles and gives rise to the desired magnetization pattern.