Abstract: In sintering a metal powder after pressure molding into a given configuration, random amorphous flaky metal fine powders (10) are used as metal powder materials. In addition, spherical particulate metal powders 11 are used as main materials, and random amorphous flaky metal fine powders 10 having finer particle size than the metal powders 11 and produced by fracturing a metal fracture material by means of high-velocity gas swirling flow are used as sub-materials, and molding and sintering are performed in a state of dispersing the sub-materials (10) in the main materials (11). Thus, despite being a power metallurgical product, it is possible to obtain a metal product having a dense metallographic structure and excellent in properties such as mechanical strength.

Abstract: A rare earth sintered magnet includes a main phase that includes an R2T14B phase of crystal grain where R is one or more rare earth elements including Nd, T is one or more transition metal elements including Fe or Fe and Co, and B is B or B and C; a grain boundary phase in which a content of R is larger than a content of the R2T14B phase; and a grain boundary triple point that is surrounded by three or more main phases. The grain boundary triple point includes an R75 phase containing R of 60 at % to 90 at %, Co, and Cu. The relational expression 0.05?(Co+Cu)/R<0.5 is satisfied. An area where a Co-rich region overlaps with a Cu-rich region in a cross-sectional area of the grain boundary triple point is 60% or more.

Abstract: A permanent magnet motor includes: a rotor and a stator; and a plurality of permanent magnets placed on either the rotor or the stator. Each permanent magnet is an R—Fe—B based rare-earth sintered magnet including a light rare-earth element RL (at least one of Nd and Pr) as a major rare-earth element R, and partially includes a high coercivity portion in which a heavy rare-earth element RH (at least one element selected from the group consisting of Dy, Ho and Tb) is diffused in a relatively higher concentration than in the other portion.

Abstract: The present invention is aimed at providing a method for producing an NdFeB sintered magnet having a higher coercivity and higher squareness of the magnetization curve than ever before. A method for producing an NdFeB sintered magnet according to the present invention includes the steps of forming a layer containing Dy and/or Tb on the surface of an NdFeB sintered magnet base material and then performing a grain boundary diffusion process for diffusing Dy and/or Tb from the aforementioned layer through the crystal grain boundaries of the magnet base material into the magnet base material by heating the magnet base material to a temperature equal to or lower than the sintering temperature thereof, and this method is characterized in that a) the content of a rare earth in a metallic state in the magnet base material is equal to or higher than 12.

Abstract: Disclosed is a sintered magnet which is a rare-earth magnet using a less amount of a rare-earth element but having a higher maximum energy product and a higher coercivity. The sintered magnet includes a NdFeB crystal; and an FeCo crystal adjacent to the NdFeB crystal through the medium of a grain boundary. The FeCo crystal includes a core and a periphery and has a cobalt concentration decreasing from the core to the periphery. The FeCo crystal has a difference in cobalt concentration of 2 atomic percent or more between the core and the periphery. In the NdFeB crystal, cobalt and a heavy rare-earth element are unevenly distributed and enriched in the vicinity of the grain boundary.

Abstract: An anisotropic rare earth sintered magnet has a tetragonal R2Fe14B compound as a major magnetic phase, wherein R is Nd or a mixture of Nd with at least one rare earth element. Grains of the compound phase have two crystallographic axes, c and a-axes aligned. The biaxially aligned magnet exhibits a coercivity Hc of at least 1.6 MA/m.

Abstract: To mold a high-resistance magnet at low temperature, including room temperature, the magnet includes magnetic powders, metallic powders having a lower hardness than the magnetic powders and a high-resistance layer, wherein the magnetic powders occupy a larger volume than the metallic powders. In particular, the high-resistance layer contains a fluorine compound and is placed between the magnetic powder and the metallic powders.

Abstract: A method for preparing a rare earth permanent magnet material comprises the steps of: disposing a powder comprising one or more members selected from an oxide of R2, a fluoride of R3, and an oxyfluoride of R4 wherein R2, R3 and R4 each are one or more elements selected from among rare earth elements inclusive of Y and Sc on a sintered magnet form of a R1—Fe—B composition wherein R1 is one or more elements selected from among rare earth elements inclusive of Y and Sc, and then heat treating the magnet form and the powder at a temperature equal to or below the sintering temperature of the magnet in vacuum or in an inert gas. The result high performance, compact or thin permanent magnet has a high remanence and coercivity at a high productivity.

Abstract: An R—Fe—B sintered magnet has a structure including main phase crystal grains and a grain boundary area surrounding the crystal grains. The sintered magnet includes fluorine and a specified metal element selected from elements belonging to Group 2 through Group 16 of periodic table excepting the rare earth element, carbon and boron. The fluorine has a higher concentration in a region closer to a magnet surface than in the center. The specified element also has a higher concentration in the region closer to the surface. The sintered magnet includes oxyfluoride containing carbon, Dy and the metal element in a grain boundary area region at a distance of 1 ?m or greater from the magnet surface, and the carbon has a higher concentration than the concentration of the metal element in a region at a distance of 1 ?m to 500 ?m from the magnet surface.

Abstract: The present invention relates to a permanent magnet manufactured by steps of: wet-pulverizing a high-melting metal element-containing organic compound or a precursor of a high-melting ceramic in a solvent together with a magnet raw material to pulverize the magnet raw material into fine particles having a grain size of 3 ?m or less and to coat a surface of the pulverized magnet raw material with the high-melting metal element-containing organic compound or the precursor of the high-melting ceramic; adding a resin binder to the magnet raw material coated with the high-melting metal element-containing organic compound or the precursor of the high-melting ceramic; producing a slurry by kneading the magnet raw material and the resin binder; molding the slurry into a sheet form to prepare a green sheet; and sintering the green sheet.

Abstract: Anisotropic rare earth-iron based resin bonded magnet comprises: [1] a continuous phase including: (1) a spherical Sm2Fe17N3 based magnetic material covered with epoxy oligomer where its average particle size is 1 to 10 ?m, its average aspect ratio ARave is 0.8 or more, and mechanical milling is not applied after Sm—Fe alloy is nitrided; (2) a linear polymer with active hydrogen group reacting to the oligomer; and (3) additive; and [2] a discontinuous phase being an Nd2Fe14B based magnetic material coated with the epoxy oligomer where its average particle size is 50 to 150 ?m, and its average aspect ratio ARave is 0.65 or more, further satisfying: [3] the air-gap ratio of a granular compound on the phases is 5% or less; and [4] a composition where crosslinking agent with 10 ?m or less is adhered on the granular compound is formed at 50 MPa or less.

Abstract: Crystal fractured surfaces of raw meal powder having more equal crystal orientation relationship in the magnetic field are arranged to be assembled together so that a method of manufacturing a permanent magnet which has an extremely high degree of orientation can be provided. In this invention, raw meal powder (P) is filled into a cavity, the raw meal powder (P) is oriented in the magnetic field while being pressed or urged by pressing means that has a smaller area than the cross-sectional area of the cavity. Semi-finished product thus oriented is compression-molded into a predetermined shape in the magnetic field.

Abstract: An R-T-B based sintered magnet according to the present invention has a composition including: 27.3 mass % to 29.5 mass % of R; 0.92 mass % to 1 mass % of B; 0.05 mass % to 0.3 mass % of Cu; 0.02 mass % to 0.5 mass % of M; and T as the balance, and has an oxygen content of 0.02 mass % to 0.2 mass %. The main phase of the sintered magnet is an R2T14B type compound. The crystal grain size of the main phase is represented by an equivalent circle diameter of 8 ?m or less. And crystal grains with equivalent circle diameters of 4 ?m or less account for at least 80% of the overall area of the main phase.

Abstract: In order to make a sintered R-T-B-M magnet so that R2T14B phases that include a lot of Dy in the surface region of the main phase are distributed over the entire magnet, a region including a heavy rare-earth element RH at a high concentration is formed continuously beforehand at an interface between the crystals of an R2T14B compound that is the main phase of the sintered R-T-B-M magnet and the other phases.

Abstract: A rare earth magnet having a composition represented by RTB wherein R denotes a rare earth element, T a transition metal and B boron, the magnet being composed of magnet powder constituted by crystalline particles. The particles of the magnetic powder have a ratio of a short diameter being 10 ?m or more to a long diameter is 0.5 or less. An element Rm having a magnetic anisotropy higher than that of the rare earth element is contained in the surface and inside of the magnet constituted by the magnet powder in an approximately constant concentration. An oxy-fluoride and carbon are present at boundaries of the particles of the magnet powder.

Abstract: A rare earth sintered magnet consists essentially of 26-36 wt % R, 0.5-1.5 wt % B, 0.1-2.0 wt % Ni, 0.1-3.0 wt % Si, 0.05-1.0 wt % Cu, 0.05-4.0 wt % M, and the balance of T and incidental impurities wherein R is a rare earth element, T is Fe or Fe and Co, M is selected from Ga, Zr, Nb, Hf, Ta, W, Mo, Al, V, Cr, Ti, Ag, Mn, Ge, Sn, Bi, Pb, and Zn. Simultaneous addition of Ni, Si, and Cu ensures magnetic properties and corrosion resistance.

Abstract: A method for producing a sintered R-T-B based magnet includes the steps of: providing R-T-B based alloy powders A and B so that the R-T-B based alloy powder B has a particle size D50 that is smaller by at least 1.0 ?m than that of the R-T-B based alloy powder A and that there is a difference ?RH of at least 4 mass % between the higher content of a heavy rare-earth element RH in the R-T-B based alloy powder B and the lower content of the heavy rare-earth element RH in the R-T-B based alloy powder A; mixing these two R-T-B based alloy powders A and B together; compacting the mixed R-T-B based alloy powder to obtain a compact with a predetermined shape; and sintering the compact.

Abstract: A rare earth magnet of the invention has a composition represented by the compositional formula RaHbFecCodBeMf, where: R is at least one rare earth element including Y; H is at least one heavy rare earth element from among Dy and Tb; M is at least one element from among Ga, Zn, Si, Al, Nb, Zr, Ni, Cu, Cr, Hf, Mo, P, C, Mg, and V; 13?a?20; 0?b?4; c=100?a?b?d?e?f; 0?d?30; 4?e?20; 0?f?3, and has a structure constituted by a main phase: a (RH)2(FeCo)14B phase, and a grain boundary phase: a (RH)(FeCo)4B4 phase and a RH phase, with a crystal grain size of the main phase of 10 nm to 200 nm.

Abstract: A rare earth permanent magnet is prepared by disposing a powdered metal alloy containing at least 70 vol % of an intermetallic compound phase on a sintered body of R—Fe—B system, and heating the sintered body having the powder disposed on its surface below the sintering temperature of the sintered body in vacuum or in an inert gas for diffusion treatment. The advantages include efficient productivity, excellent magnetic performance, a minimal or zero amount of Tb or Dy used, an increased coercive force, and a minimized decline of remanence.

Abstract: There is provided a method of manufacturing a permanent magnet which has an extremely high coercive force and high magnetic properties is manufactured at high productivity. There are executed: a first step of causing at least one of Dy and Tb to adhere to at least part of a surface of iron-boron-rare-earth based sintered magnet; and a second step of diffusing, through heat-treatment at a predetermined temperature, at least one of Dy and Tb adhered to the surface of the sintered magnet into grain boundary phase of the sintered magnet.

Abstract: One object of the present invention is to provide a method for manufacturing a permanent magnet which can effectively improving the magnetizing properties and coercive force with efficiently diffusing Dy into grain boundary phases without deteriorating a surface of sintered magnet of Nd—Fe—B family and does not require any subsequent working process. Sintered magnet S of Nd—Fe—B family and Dy are arranged in a processing chamber 20 apart from each other. Then Dy is evaporated by heating the processing chamber 20 under a reduced pressure condition to evaporate Dy with elevating the temperature of sintered magnet S to a predetermined temperature and to supply and deposit evaporated Dy atoms onto the surface of sintered magnet S. During which the supplying amount of Dy atoms onto the sintered magnet S is controlled so as to diffuse and homogeneously penetrate them into the grain boundary phases of sintered magnet before Dy layer is formed on the surface of sintered magnet.

Abstract: A rare earth permanent magnet is prepared by disposing a powdered metal alloy containing at least 70 vol % of an intermetallic compound phase on a sintered body of R—Fe—B system, and heating the sintered body having the powder disposed on its surface below the sintering temperature of the sintered body in vacuum or in an inert gas for diffusion treatment. The advantages include efficient productivity, excellent magnetic performance, a minimal or zero amount of Tb or Dy used, an increased coercive force, and a minimized decline of remanence.

Abstract: A rare earth permanent magnet material is prepared by covering a sintered magnet body of R1—Fe—B composition wherein R1 is a rare earth element, with a powder comprising at least 30% by weight of an alloy of R2aTbMcAdHe wherein R2 is a rare earth element, T is Fe and/or Co, and M is Al, Cu or the like, and having an average particle size up to 100 ?m, and heat treating the powder-covered magnet body at a suitable temperature, for causing R2, T, M and A in the powder to be absorbed in the magnet body.

Abstract: A magnet comprising grains of a ferromagnetic material whose main component is iron and a fluorine compound layer or an oxy-fluorine compound layer of fluoride compound particles of alkali metals, alkaline earth metals and rare earth elements, present on the surface of the ferromagnetic material grains, wherein an amount of iron atoms in the fluorine compound particles is 1 to 50 atomic %.

Abstract: In a method for producing an R—Fe—B based rare-earth sintered magnet according to the present invention, first, provided is an R—Fe—B based rare-earth sintered magnet body including, as a main phase, crystal grains of an R2Fe14B type compound that includes a light rare-earth element RL, which is at least one of Nd and Pr, as a major rare-earth element R. Thereafter, the sintered magnet body is heated while a heavy rare-earth element RH, which is at least one element selected from the group consisting of Dy, Ho and Tb, is supplied to the surface of the sintered magnet body, thereby diffusing the heavy rare-earth element RH into the rare-earth sintered magnet body.

Abstract: In an R—Fe—B based rare-earth sintered magnet according to the present invention, at a depth of 20 ?m under the surface of its magnet body, crystal grains of an R2Fe14B type compound have an (RL1-xRHx)2Fe14B (where 0.2?x?0.75) layer with a thickness of 1 nm to 2 ?m in their outer periphery. In this case, the light rare-earth element RL is at least one of Nd and Pr, and the heavy rare-earth element RH is at least one element selected from the group consisting of Dy, Ho and Tb.

Abstract: A sintered rare-earth magnet includes an Nd2Fe14B type crystalline phase as its main phase and Al as an additive. The magnet includes at least one light rare-earth element LR selected from the group consisting of yttrium and the rare-earth elements other than Dy, Ho and Tb, and at least one heavy rare-earth element HR selected from the group consisting of Dy, Ho and Tb. The mole fractions ?1, ?2 and ? of the light and heavy rare-earth elements LR and HR and Al satisfy the inequalities 25??1+?2?40 mass %, 0<?2?40 mass %, ?>0.20 mass %, and 0.04??/?2?0.12.

Abstract: First, an R—Fe—B based rare-earth sintered magnet body including, as a main phase, crystal grains of an R2Fe14B type compound that includes a light rare-earth element RL, which is at least one of Nd and Pr, as a major rare-earth element R is provided. Next, an M layer, including a metallic element M that is at least one element selected from the group consisting of Al, Ga, In, Sn, Pb, Bi, Zn and Ag, is deposited on the surface of the sintered magnet body and then an RH layer, including a heavy rare-earth element RH that is at least one element selected from the group consisting of Dy, Ho and Tb, is deposited on the M layer. Thereafter, the sintered magnet body is heated, thereby diffusing the metallic element M and the heavy rare-earth element RH from the surface of the magnet body deeper inside the magnet.

Abstract: An R—Fe—B based anisotropic sintered magnet according to the present invention has, as a main phase, an R2Fe14B type compound that includes a light rare-earth element RL (which is at least one of Nd and Pr) as a major rare-earth element R, and also has a heavy rare-earth element RH (which is at least one element selected from the group consisting of Dy and Tb). In the crystal lattice of the main phase, the c-axis is oriented in a predetermined direction. The magnet includes a portion in which at least two peaks of diffraction are observed within a 2? range of 60.5 degrees to 61.5 degrees when an X-ray diffraction measurement is carried out using a CuK ? ray on a plane that is located at a depth of 500 ?m or less under a pole face of the magnet and that is parallel to the pole face.

Abstract: An R—Fe—B based rare-earth sintered magnet according to the present invention includes, as a main phase, crystal grains of an R2Fe14B type compound that includes Nd, which is a light rare-earth element, as a major rare-earth element R. The magnet includes a heavy rare-earth element RH (which is at least one of Dy and Tb) that has been introduced through the surface of the sintered magnet by diffusion. The magnet has a region in which the concentration of the heavy rare-earth element RH in a grain boundary R-rich phase is lower than at the surface of the crystal grains of the R2Fe14B type compound but higher than at the core of the crystal grains of the R2Fe14B type compound.

Abstract: An R—Fe—B sinlered magnet having on the surface thereof a vapor deposited film of aluminum or an alloy thereof and a method for producing the same. The vapor deposited film of aluminum or an alloy thereof comprises a columnar crystalline structure grown broader from the surface of the R—Fe—B sintered magnet body outward to the outer surface, which has a part within a region defined in the thickness direction of the film as taken from the surface of the R—Fe—B sintered magnet to ? of the film thickness, 5 to 30 intercrystalline gaps of 0.01 ?m to 1 ?m in width as counted per 10 ?m length in the lateral direction of the film. The method comprises controlling the average film formation rate such that it is slower up to a predetermined point and then is speeded up later thereon.

Abstract: There is provided a method of manufacturing a permanent magnet in which Dy and/or Tb adhered to the surface of a sintered magnet containing a lubricant can be efficiently diffused and in which the permanent magnet having high magnetic properties can be manufactured at good productivity. The permanent magnet is manufactured by executing a first step of adhering at least one of Dy and Tb to at least a part of a surface of a sintered magnet made by sintering iron-boron-rare earth based alloy raw meal powder containing a lubricant; and a second step of heat-treating the sintered magnet at a predetermined temperature to thereby disperse at least one of Dy and Tb adhered to the surface of the sintered magnet into grain boundary phase of the sintered magnet. At this time, as the sintered magnet, there is used one manufactured in an average grain size within a range of 4 ?m˜8 ?m.

Abstract: There is provided a rare earth magnet with excellent Br and HcJ values. The rare earth magnet according to a preferred embodiment of the invention is characterized by being composed mainly of R (where R is at least one element selected from among rare earth elements including Y), B, Al, Cu, Zr, Co, O, C and Fe, wherein the content of each element is R: 25-34 wt %, B: 0.85-0.98 wt %, Al: 0.03-0.3 wt %, Cu: 0.01-0.15 wt %, Zr: 0.03-0.25 wt %, Co: ?3 wt % (but not 0 wt %), O: ?0.2 wt %, C: 0.03-0.15 wt % and Fe: remainder.

Abstract: An R-T-B based sintered magnet includes both a light rare-earth element RL (which is at least one of Nd and Pr) and a heavy rare-earth element RH (which is at least one of Dy and Tb) and Nd2Fe14B type crystals as a main phase. The magnet has a first region, which includes either the heavy rare-earth element RH in a relatively low concentration or no heavy rare-earth elements RH at all, and a second region, which includes the heavy rare-earth element RH in a relatively high concentration. The first and second regions are combined together by going through a sintering process.

Abstract: An R—Fe—B based rare-earth alloy powder with a mean particle size of less than about 20 ?m is provided and compacted to make a powder compact. Next, the powder compact is subjected to a heat treatment at a temperature of about 550° C. to less than about 1,000° C. within hydrogen gas, thereby producing hydrogenation and disproportionation reactions (HD processes). Then, the powder compact is subjected to another heat treatment at a temperature of about 550° C. to less than about 1,000° C. within either a vacuum or an inert atmosphere, thereby producing desorption and recombination reactions and obtaining a porous material including fine crystal grains, of which the density is about 60% to about 90% of their true density and which have an average crystal grain size of about 0.01 ?m to about 2 ?m (DR processes). Thereafter, the porous material is subjected to yet another heat treatment at a temperature of about 750° C. to less than about 1,000° C.

Abstract: By eliminating the necessity of a prior step for cleaning a sintered magnet before adhering Dy and/or Tb to the surface of the sintered magnet S, the productivity of a permanent magnet having diffused Dy and/or Tb into grain boundary phase is improved. Iron-boron-rare earth based sintered magnet (S) disposed in a processing chamber (20) is heated to a predetermined temperature. An evaporating material (V) which is made of a hydride containing at least one of Dy and Tb is disposed in the same or in another processing chamber and is evaporated to cause the evaporated evaporating material to the surface of the sintered magnet. Metal atoms of Dy and/or Tb are diffused into grain boundary phase of the sintered magnet.

Abstract: By causing at least one of Dy and Tb to be adhered to the surface of an iron-boron-rare earth based sintered magnet of a predetermined shape, and is then to be diffused into grain boundary phase, a permanent magnet can be manufactured at high workability and low cost. An iron-boron-rare earth based sintered magnet is disposed in a processing chamber and is heated to a predetermined temperature. Also, an evaporating material made up of a fluoride containing at least one of Dy and Tb disposed in the same or another processing chamber is evaporated, and the evaporated evaporating material is caused to be adhered to the surface of the sintered magnet. The Dy and/or Tb metal atoms of the adhered evaporating material are diffused into the grain particle phase of the sintered magnet before a thin film made of the evaporated material is formed on the surface of the sintered magnet.

Abstract: HfC particles having an average particle size of 5 to 100 nm are dispersed in an R—Fe—B type alloy in an amount of 0.2 to 3.0 atom %. Crystal grains are refined avoiding decreasing an amount of magnet components by containing carbide and coercive force can be improved, avoiding degradation of saturated magnetization by refining the crystal grains.

Abstract: An R-T-B system sintered magnet is provided which achieves both a high residual magnetic flux density and a high coercive force. The R-T-B system sintered magnet comprises main-phase grains 1 each having a core-shell structure comprising an inner shell part 2 and an outer shell part 3 surrounding the inner shell part 2, wherein the concentration of the heavy rare earth element in the inner shell part 2 is lower by 10% or more than the concentration of the heavy rare earth element in the periphery of the outer shell part 3, and (L/r)ave falls within a range from 0.03 to 0.40 in the main-phase grains 1 each comprising the inner shell part 2 and the outer shell part 3, wherein L represents the shortest distance from the periphery of the main phase grain 1 to the inner shell part 2, r represents the equivalent diameter of the main phase grain 1, and (L/r)ave represents the average value of L/r for the main-phase grains 1 present in the sintered body and having the core-shell structure.

Abstract: A rare earth sintered magnet includes a main phase that includes an R2T14B phase of crystal grain where R is one or more rare earth elements including Nd, T is one or more transition metal elements including Fe or Fe and Co, and B is B or B and C; a grain boundary phase in which a content of R is larger than a content of the R2T14B phase; and a grain boundary triple point that is surrounded by three or more main phases. The grain boundary triple point includes an R75 phase containing R of 60 at % to 90 at %, Co, and Cu. The relational expression 0.05?(Co+Cu)/R<0.5 is satisfied. An area where a Co-rich region overlaps with a Cu-rich region in a cross-sectional area of the grain boundary triple point is 60% or more.

Abstract: A method for the production of pressed permanent magnets comprises the following steps: A mixture of at least one magnetic powder and a thermosetting binder is provided and pressed to produce a moulded body. In order to obtain a permanent and particularly reliable protection against oxidation and corrosion, the moulded body is impregnated with an acid and solvent mixture in an impregnating bath before the cure of the thermosetting binder, whereby the entire surface of the permanent magnet is coated with a reaction layer [FIG. 1].

Abstract: Disclosed are a method for producing alloy flakes for rare earth sintered magnets, which makes uniform the intervals, size, orientation, and shape of the R-rich region and the dendrites of the 2-14-1 phase, and alloy flakes for a rare earth sintered magnet obtained by the method. A rare earth sintered magnet employing the alloy flakes is also disclosed.

Abstract: A process for producing a highly anticorrosive rare earth permanent magnet, characterized by sequentially subjecting an R—Fe—B sintered magnet to surface finishing involving cutting and/or polishing, plating pretreatment, nickel electroplating to a given plating thickness, immersion in an aqueous solution containing a phosphoric salt, washing with water and heat treatment at 150° to 400° C. for 1 to 24 hr in an atmosphere of 1.3×103 Pa or higher oxygen partial pressure so as to form a thin nickel oxide layer at the surface layer portion.

Abstract: An R-T-Cu—Mn—B based sintered magnet includes: 12.0 at % to 15.0 at % of R, which is at least one of the rare-earth elements that include Y and of which at least 50 at % is Pr and/or Nd; 5.5 at % to 6.5 at % of B; 0.08 at % to 0.35 at % of Cu; 0.04 at % to less than 0.2 at % of Mn; at most 2 at % (including 0 at %) of M, which is one, two, or more elements that are selected from the group consisting of Al, Ti, V, Cr, Ni, Zn, Ga, Zr, Nb, Mo, Ag, In, Sn, Hf, Ta, W, Au, Pb and Bi; and T as the balance, which is either Fe alone or Fe and Co and of which at most 20 at % is Co if T includes both Fe and Co.

Abstract: The object of the present invention is to provide a rare earth magnet which enables to achieve a good balance between high coercive force and high residual magnetic flux density, and its manufacturing method. The present invention provides a rare earth magnet in which a layered grain boundary phase is formed on a surface or a portion of a grain boundary of Nd2Fe14B which is a main phase of an R—Fe—B (R is a rare-earth element) based magnet, and wherein the grain boundary phase contains a fluoride compound, and wherein a thickness of the fluoride compound is 10 ?m or less, or a thickness of the fluoride compound is from 0.1 ?m to 10 ?m, and wherein the coverage of the fluoride compound over a main phase particle is 50% or more on average.

Abstract: A method for preparing a rare earth permanent magnet material comprises the steps of disposing a powder on a surface of a sintered magnet body of R1aTbAcMd composition wherein R1 is a rare earth element inclusive of Sc and Y, T is Fe and/or Co, A is boron (B) and/or carbon (C), M is Al, Cu, Zn, In, Si, P, S, Ti, V, Cr, Mn, Ni, Ga, Ge, Zr, Nb, Mo, Pd, Ag, Cd, Sn, Sb, Hf, Ta, or W, said powder comprising an oxide of R2, a fluoride of R3 or an oxyfluoride of R4 wherein R2, R3, and R4 are rare earth elements inclusive of Sc and Y and having an average particle size equal to or less than 100 ?m, heat treating the magnet body and the powder at a temperature equal to or below the sintering temperature of the magnet body for absorption treatment for causing R2, R3, and R4 in the powder to be absorbed in the magnet body, and repeating the absorption treatment at least two times.

Abstract: First, an R—Fe—B based rare-earth sintered magnet body including, as a main phase, crystal grains of an R2Fe14B type compound that includes a light rare-earth element RL, which is at least one of Nd and Pr, as a major rare-earth element R is provided. Next, an M layer, including a metallic element M that is at least one element selected from the group consisting of Al, Ga, In, Sn, Pb, Bi, Zn and Ag, is deposited on the surface of the sintered magnet body and then an RH layer, including a heavy rare-earth element RH that is at least one element selected from the group consisting of Dy, Ho and Tb, is deposited on the M layer. Thereafter, the sintered magnet body is heated, thereby diffusing the metallic element M and the heavy rare-earth element RH from the surface of the magnet body deeper inside the magnet.

Abstract: A rare earth permanent magnet is prepared by disposing a powdered metal alloy containing at least 70 vol % of an intermetallic compound phase on a sintered body of R—Fe—B system, and heating the sintered body having the powder disposed on its surface below the sintering temperature of the sintered body in vacuum or in an inert gas for diffusion treatment. The advantages include efficient productivity, excellent magnetic performance, a minimal or zero amount of Tb or Dy used, an increased coercive force, and a minimized decline of remanence.

Abstract: A rare earth permanent magnet material is based on an R—Fe—Co—B—Al—Cu system wherein R is at least one element selected from Nd, Pr, Dy, Tb, and Ho, 15 to 33% by weight of Nd being contained. At least two compounds selected from M-B, M-B—Cu and M-C compounds (wherein M is Ti, Zr or Hf) and an R oxide have precipitated within the alloy structure as grains having an average grain size of up to 5 ?m which are uniformly distributed in the alloy structure at intervals of up to 50 ?m.

Abstract: The present invention provides a rare earth magnet, which is formed through at least hot molding, the rare earth magnet containing grains including an R2X14B phase as a main phase, and a grain boundary phase surrounding peripheries of the grains, in which R is at least one element selected from the group consisting of Nd, Pr, Dy, Tb and Ho, and X is Fe or Fe with a part being substituted by Co; in which an element RH is more concentrated in the grain boundary phase than in the grains, in which the element RH is at least one element selected from the group consisting of Dy, Tb and Ho; and the element RH is present with a substantially constant concentration distribution from the surface part of the magnet to the central part of the magnet.