Abstract: A rare-earth-iron-boron based alloy powder, in which a heavy rare-earth element such as Dy is present at a higher concentration in a main phase than in a grain boundary phase and which can be sintered easily, and a method of making such an alloy powder are provided. A rare-earth-iron-boron based magnet alloy according to the present invention includes, as a main phase, a plurality of R2Fe14B type crystals (where R is at least one element selected from the group consisting of the rare-earth elements and yttrium) in which rare-earth-rich phases are dispersed. The main phase includes Dy and/or Tb at a higher concentration than a grain boundary phase does.

Abstract: An R-T-B based sintered magnet with a reduced B concentration but with sufficiently high coercivity is provided. An R-T-B based sintered magnet according to the present invention has a composition including: 27.0 mass % to 32.0 mass % of R, which is at least one of Nd, Pr, Dy and Tb and which always includes either Nd or Pr; 63.0 mass % to 72.5 mass % of T, which always includes Fe and up to 50% of which is replaceable with Co; 0.01 mass % to 0.08 mass % of Ga; and 0.85 mass % to 0.98 mass % of B.

Abstract: A method of making a magnetically anisotropic magnet powder according to the present invention includes the steps of preparing a master alloy by cooling a rare-earth-iron-boron based molten alloy and subjecting the master alloy to an HDDR process. The step of preparing the master alloy includes the step of forming a solidified alloy layer, including a plurality of R2Fe14B-type crystals (where R is at least one element selected from the group consisting of the rare-earth elements and yttrium) in which rare-earth-rich phases are dispersed, by cooling the molten alloy through contact with a cooling member.

Abstract: Magnetic alloy powder for a permanent magnet contains: R of about 20 mass percent to about 40 mass percent (R is Y, or at least one type of rare earth element); T of about 60 mass percent to about 79 mass percent (T is a transition metal including Fe as a primary component); and Q of about 0.5 mass percent to about 2.0 mass percent (Q is an element including B (boron) and C (carbon)). The magnetic alloy powder is formed by an atomize method, and the shape of particles of the powder is substantially spherical. The magnetic alloy powder includes a compound phase having Nd2Fe14B tetragonal structure as a primary composition phase. A ratio of a content of C to a total content of B and C is about 0.05 to about 0.90.

Abstract: The step of preparing a rapidly solidified alloy by rapidly quenching a melt of an R-T-B-C based rare-earth alloy (where R is at least one of the rare-earth elements including Y, T is a transition metal including iron as its main ingredient, B is boron, and C is carbon) and the step of thermally treating and crystallizing the rapidly solidified alloy are included. The step of thermally treating results in producing a first compound phase with an R2Fe14B type crystal structure and a second compound phase having a diffraction peak at a site with an interplanar spacing d of 0.295 nm to 0.300 nm (i.e., where 2&thgr;=30 degrees). An intensity ratio of the diffraction peak of the second compound phase to that of R2Fe14B type crystals representing a (410) plane is at least 10%. The present invention provides an R-T-B-C based rare-earth alloy magnetic material, including carbon (C) as an indispensable element but exhibiting excellent magnetic properties, and makes it possible to recycle rare-earth magnets.

Abstract: The present invention is a production method of an R-T-B-C rare earth alloy (R is at least one element selected from the group consisting of rare earth elements and yttrium, T is a transition metal including iron as a main component, B is boron, and C is carbon). An R-T-B bonded magnet containing a resin component, or an R-T-B sintered magnet with a resin film formed on the surface thereof is prepared, and a solvent alloy containing a rare earth element R and a transition metal element T is prepared. Thereafter, the R-T-B bonded magnet is molten together with the solvent alloy. In this way, a rare earth alloy can be recovered from a spent bonded magnet or a defective one generated in a production process stage, and a rapidly quenched alloy magnet can be obtained. As a result, magnet powder is recovered from the R-T-B magnet, and the recycling of a magnet including a resin component can be realized.

Abstract: In a rare earth magnet, an added heavy rare earth element RH such as Dy is effectively used without any waste, so as to effectively improve the coercive force. First, a molten alloy of a material alloy for an R-T-Q rare earth magnet (R is a rare earth element, T is a transition metal element, and Q is at least one element selected from the group consisting of B, C, N, Al, Si, and P), the rare earth element R containing at least one kind of element RL selected from the group consisting of Nd and Pr and at least one kind of element RH selected from the group consisting of Dy Tb, and Ho is prepared. The molten alloy is quenched, so as to produce a solidified alloy. Thereafter, a thermal treatment in which the rapidly solidified alloy is held in a temperature range of 400° C. or higher and lower than 800° C. for a period of not shorter than 5 minutes nor longer than 12 hours is performed.

Abstract: Magnetic alloy powder for a permanent magnet contains: R of about 20 mass percent to about 40 mass percent (R is Y, or at least one type of rare earth element); T of about 60 mass percent to about 79 mass percent (T is a transition metal including Fe as a primary component); and Q of about 0.5 mass percent to about 2.0 mass percent (Q is an element including B (boron) and C (carbon)). The magnetic alloy powder is formed by an atomize method, and the shape of particles of the powder is substantially spherical. The magnetic alloy powder includes a compound phase having Nd2Fe14B tetragonal structure as a primary composition phase. A ratio of a content of C to a total content of B and C is about 0.05 to about 0.90.

Abstract: An anisotropic sintered permanent magnet consists essentially of 12 to 18 at % R, wherein R represents Pr, Nd, Dy, Tb and other rare earth element or elements contained as inevitable impurities provided that 0.8.ltoreq.(Pr+Nd+Dy+Tb)/R.ltoreq.1.0, 5 to 9.5 at % B, 2 to 5 at % Mo, 0.01 to 0.5 at % Cu, 0.1 to 3 at % Al, and balance being Fe. B(x) and Mo(y) are (x-4.5).ltoreq.y.ltoreq.(x-3.0), and part of Fe may be replaced by Co to be 3-7 at % Co. Up to 90 at % of Mo may be replaced by V. The magnet is characterized by main tetragonal R.sub.2 (Fe, Mo).sub.14 B or R.sub.2 (Fe, Co, Mo).sub.14 B phase and boundary phase of (Fe, Mo)-B, or (Fe, Co, Mo)-B and R.sub.m (Fe, Co, Mo).sub.n where m/n=1/2 to 3/1. B-rich phase Nd.sub.1+.epsilon. Fe.sub.4 B.sub.4 disappears. Dy and/or Tb linearly increase iHc. High coercivity and maximum energy product are obtained: iHc.gtoreq.15 kOe (or 21 kOe) and (BH)max.gtoreq.20 MGOe (or 28 MGOe) with high corrosion resistance and high pulverizability of alloy.