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.

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 method of manufacturing a bead assembly for a sphincter augmentation device includes initiating 3D printing of a unibody housing such that the unibody housing defines a first opening, a chamber, and a magnet chamber. The method further includes pausing the 3D printing process, inserting a magnet within the magnetic chamber, and then resuming 3D printing of the unibody housing to form a hermetic seal between the magnet chamber and an external surface of the unibody housing.

A magnetic core includes a metal magnetic powder, which has a large size powder, an intermediate size powder, and a small size powder. A particle size of the large size powder is 10 μm or more and 60 μm or less. A particle size of the intermediate size powder is 2.0 μm or more and less than 10 μm. A particle size of the small size powder is 0.1 μm or more and less than 2.0 μm. The large size powder, the intermediate size powder, and the small size powder have an insulation coating. When A1 represents an average insulation coating thickness of the large size powder, A2 represents an average insulation coating thickness of the intermediate size powder, A3 represents an average insulation coating thickness of the small size powder, A3 is 30 nm or more and 100 nm or less, A3/A1≥1.3, and A3/A2≥1.0.

Disclosed are a rare-earth permanent magnet having improved magnetic properties and a method of manufacturing the same. A method of manufacturing a rare-earth permanent magnet may include: preparing a mixed powder including i) a first alloy represented by R1.sub.aR2.sub.bB.sub.cM.sub.dFe.sub.bal and ii) a second alloy represented by R2.sub.bB.sub.cM.sub.dFe.sub.bal where R1 is one or two or more of La, Ce, and Y; R2 is a rare-earth element except for La, Ce, and Y; and M is a metal element; press-forming and sintering the prepared mixed powder in a magnetic field to prepare a sintered body; and performing a heat treatment based on diffusion temperature conditions of an R1 component and an R2 component contained in the prepared sintered body.

The present invention relates to an additive manufacturing powder material including Fe alloy particles each having an oxide film on a surface thereof, in which the Fe alloy particles satisfy d≤15 and I/d≤0.025, where d [nm] represents a thickness of the oxide film, and a peak intensity ratio I represents an intensity ratio IB/IA of a peak B in a region B of a Raman shift of 1,309 to 1,329 cm.sup.−1 to a peak A in a region A of a Raman shift of 657.5 to 677.5 cm.sup.−1 in a Raman spectrum.

A rare earth permanent magnet includes a main phase containing: a rare earth element R of one or more types including Nd; an element L of one or more types selected from a group consisting of Co, Be, Li, Al, and Si; B; and Fe, wherein crystals which form the main phase belong to P4.sub.2/mnm; some of B atoms occupying a 4f site of the crystals are substituted with atoms of the element L; each distribution of Nd atoms and the atoms of the element L appears along a C-axis direction of the crystals in a plurality of cycles; and the rare earth permanent magnet includes an area where a cycle of the atoms of the element L matches a cycle of the Nd atoms.

A method for producing a radially anisotropic sintered ring magnet by continuously repeating a step of supplying magnetic powder to a die comprising a columnar magnetic core, and a cylindrical outer die having axially connected magnetic member and non-magnetic member, with a cavity between the core and the cylindrical outer die, and a step of compression-molding the magnetic powder in a radial magnetic field applied between the magnetic core and the magnetic member of the outer die, plural times in one die, to form a final green body composed of pluralities of integrally connected green bodies; and sintering the final green body; the magnetic field being applied in a state where an upper end of the magnetic member of the cylindrical outer die is higher than an upper surface of the magnetic powder supplied.

An RFeB system sintered magnet which does not contain a heavy rare-earth element R.sup.H (Dy, Tb and Ho) in a practically effective amount and yet is suited for applications in which the magnet undergoes a temperature increase during its use. The RFeB system sintered magnet contains at least one element selected from the group consisting of Nd and Pr as a rare-earth element R in addition to Fe and B while containing none of Dy, Tb and Ho, the magnet having a temperature characteristic value t.sub.(100-23) which satisfies −0.58<t.sub.(100-23)<0, where t.sub.(100-23) is defined by the following equation:

[00001]$t_{\left(100-23\right)}=\frac{H_{\mathrm{cj}}\left(100\right)-H_{\mathrm{cj}}\left(23\right)}{\left(100-23\right)\times H_{\mathrm{cj}}\left(23\right)}\times 100$

using H.sub.cj(23) which is the value of the coercivity at a temperature of 23° C. and H.sub.cj(100) which is the value of the coercivity at a temperature of 100° C.

An R-T-B based permanent magnet includes R-T-B based compounds as main-phase crystal grains. R is a rare earth element. T is iron group element(s) essentially including Fe or Fe and Co. B is boron. A two-grain boundary is contained between the two adjacent main-phase crystal grains. An average grain size of the main-phase crystal grains is 0.9 μm or more and 2.8 μm or less. A thickness of the two-grain boundary is 5 nm or more and 200 nm or less.