The present invention relates to an alloy with formula of RE-M-B—Fe as defined herein and oxygen content less than 0.9 wt %, wherein said RE is in the range of 29.0 weight % to 33.0 weight %; M is in the range of 0.25 weight % to 1.0 weight %; B is in the range of 0.8 weight % to 1.1 weight %; and Fe makes up the balance. The present invention also relates to a method for preparing a RE-M-Fe—B magnetic powder, as defined herein comprising the steps of: (a) melt spinning a RE-M-Fe—B alloy composition to obtain a melt-spun powder; (b) pressing the melt-spun powder of step (a) to obtain a compact body; (c) hot deforming the compact body of step (b) to obtain a die-upset magnet; (d) crushing the die-upset magnet of step (c) to obtain a powder; (e) milling and sieving the powder of step (d); and (f) passivating the powder of step (e) to obtain a magnetic powder; wherein: each of steps (d) to (f) is performed under a low oxygen environment and transfer between each of steps (d) to (f) is a sealed transfer; and wherein the oxygen content of the low oxygen environment and during each sealed transfer is below 0.5 weight %.

This invention is directed to a corrosion-resistant permanent magnet, to a method for producing a corrosion-resistant permanent magnet, and to an intravascular blood pump comprising the magnet. The magnet is surrounded by a composite coating, the composite coating comprising, in the order recited, a first metal oxide layer, a metal layer, a second metal oxide layer, a linker layer, and a layer formed from poly(2-chloro-p-xylylene). In an alternative embodiment, a further metal layer and, optionally, a further metal oxide layer may be provided between the second metal oxide layer and the linker layer. In a further alternative embodiment, the metal layer may be omitted, and a further layer structure comprising at least one metal oxide layer, a linker layer, and a layer formed from poly(2-chloro-p-xylylene) may be provided instead.

Provided is a permanent magnet including a rare-earth element R, a transition metal element T, B, Zr, and Cu. The permanent magnet contains main phase grains including Nd, T, and B, and grain boundary multiple junctions, the 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, a concentration of B in the 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 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 process for producing R-T-B-based rare earth magnet powder having excellent coercive force and high remanent flux density. A process for producing R-T-B-based rare earth magnet powder by HDDR treatment, in which a raw material alloy for the R-T-B-based rare earth magnet powder includes R (wherein R represents at least one rare earth element including Y), T (wherein T represents Fe, or Fe and Co) and B (wherein B represents boron), and has a composition including R in an amount of between 12.0 atom % and 17.0 atom %, and B in an amount of between 4.5 atom % and 7.5 atom %; the HDDR treatment includes a DR step including a preliminary evacuation step and a complete evacuation step; and a rate of pressure reduction caused by evacuation in the preliminary evacuation step is not less than 1 kPa/min and not more than 30 kPa/min.

A strip cast alloy containing Nd in excess of the stoichiometry of Nd.sub.2Fe.sub.14B is subjected to HDDR treatment and diffusion treatment, yielding microcrystalline alloy powder in which major phase crystal grains with a size of 0.1-1 μm are surrounded by Nd-rich grain boundary phase with a width of 2-10 nm. The powder is finely pulverized, compacted, and sintered, yielding a sintered magnet having a high coercivity.

A method for producing a magnet powder is provided in the present disclosure. The method includes synthesizing a R—Fe—B-based magnet powder by a reduction-diffusion process, coating an antioxidant film onto a surface of the R—Fe—B-based magnet powder, and immersing and cleaning the R—F—B-based magnet powder in an aqueous solvent or a non-aqueous solvent, wherein R is Nd, Pr, Dy or Tb, and wherein the antioxidant film includes a compound containing at least one amino group.

The present invention relates to a method for preparing a neodymium-iron-boron rare-earth permanent magnetic material, in particular to a hot press molding-based method for preparing a rare-earth permanent magnet. The problem that the residual magnetism and coercive force of a rare-earth permanent magnet prepared in the prior art cannot be both high is solved. An RTM alloy infiltrates same during an HD treatment. RTM sticks to the surface of coarse powder and infiltrates into the interior of the coarse powder along a grain boundary. The temperature of hot press sintering is relatively low, and grains barely grow. In the absence of Dy and Tb, a higher coercive force is obtained. If an alloy containing Dy and Tb is used for infiltration, these atoms diffuse into the surface layer of a main phase during preheating and heat treatment, achieving grain boundary hardening. Under the premise of a very small reduction in the residual magnetism, the coercive force is greatly improved.

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.

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 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.