The present invention provides a producing method of R-T-B-based sintered magnets in which, the recovery chamber 40 includes inert gas introducing means 42, evacuating means 43, a carry-in port, a discharge port 40a, and a recovery container 60. The recovery step includes a carrying-in step of conveying a processing container 50 into the recovery chamber 40, a discharging step of discharging coarsely pulverized powder in the processing container 50 into the recovery chamber 40, a gas introducing step of introducing inert gas into the recovery chamber 40, and an alloy accommodating step of recovering the coarsely pulverized powder into the recovery container 60. Addition of pulverization aid is carried out in the alloy accommodating step. A remaining amount of coarsely pulverized powder in the recovery chamber 40, an oxygen-containing amount of the R-T-B-based sintered magnet is reduced, and magnetic properties are enhanced.

The invention discloses a low-neodymium, non-heavy-rare-earth and high-performance magnet and its preparing method, and belongs to technical field of rare earth permanent magnetic material. The magnet has a chemical formula of [(Nd, Pr).sub.100-x(Ce.sub.100-yLa.sub.y).sub.x].sub.aFe.sub.100-a-b-cB.sub.bTM.sub.c, wherein x, y, a, b and c represent mass percents of corresponding elements respectively, 0x40%, 0y15%, 29a30%, 0.5b5%, 0.5c5%; and TM is one or more selected from Ga, Co, Cu, Nb and Al elements. A series of grades of magnets can be prepared with rapidly solidified strips of only three components. Component proportioning of magnet can also be directly performed by using mixed rare earth, so that the cost increased by further separation and purification of the rare earth is reduced. During the preparation of magnetic powder with a jet mill, an antioxidant lubricant which is composed of alcohol, gasoline and basic synthetic oil is added. A low-temperature sintering technology is adopted; and the sintering temperature is 1,010-1,050 C. and the annealing temperature is 450-550 C. The magnetic energy product (BH).sub.m is more than 40 MGOe; and the coercive force H.sub.cj is more than 10 kOe. The production time and the energy loss can be significantly reduced.

Disclosed are an R-T-B magnet and a preparation method therefor. The R-T-B magnet comprises the following components: R29 wt. %, R being a rare earth element and containing Nd, wherein Nd is 22 wt. %; 0.2-0.75 wt. % of Ti+Nb; 0.05-0.45 wt. % of Cu; 0.955-1.15 wt. % of B; and 58-69 wt. % of Fe, wherein wt. % is the ratio of the mass of each component to the total mass of the components; and the mass ratio of Ti to Nb is (1-5):1. According to the present invention, the matching relationship among the added elements in the R-T-B magnet is further optimized, and an R-T-B magnet with better magnetic properties such as relatively high residual magnetization, coercivity, and squareness can be prepared by using the formula.

A process is provided for the production of rare earth magnets comprising the steps of exposing a rare earth alloy to hydrogen gas at an elevated temperature so as to effect hydrogenation and disproportionation of the alloy, mechanically processing the disproportionated alloy, and degassing the processed alloy so as to effect hydrogen desorption and recombination of the alloy. The process of the invention finds use in the production and shaping of rare earth magnets, and may be particularly applicable to the production of thin magnetic sheets.

A process for producing Co, Al alloyed NdFeB nanoparticles, by a microwave assisted combustion process, followed by a reduction diffusion process, includes the steps of: preparing a first solution of boric acid dissolved in 4 N HNO.sub.3, dissolving iron nitrate nonahydrate, neodymium nitrate hexahydrate, cobalt nitrate hexahydrate, aluminium nitrate, the first solution in deionized water to form a second solution, adding glycine to the second solution in a molar ratio of 1:1 to form a third solution, subjecting the third solution to microwave radiation, thereby forming an first powder of NdFeCoAlB oxides, mixing the first powder with calcium hydride in a mass ratio of 1:1.1 (NdFeCoAlB oxides:CaH.sub.2) to form a second powder, compacted into a powder block, annealing the second powder in a vacuum furnace, washing the annealed second powder with a solution of ethylenediaminetetraacetic acid; and vacuum drying the second powder.

The invention provides an RFeB sintered magnet consisting essentially of 12-17 at % of R, 0.1-3 at % of M.sub.1, 0.05-0.5 at % of M.sub.2, 4.8+2*m to 5.9+2*m at % of B, and the balance of Fe, containing R.sub.2(Fe,(Co)).sub.14B intermetallic compound as a main phase, and having a core/shell structure that the main phase is covered with a HR-rich layer and a (R,HR)Fe(Co)-M.sub.1 phase wherein HR is Tb, Dy or Ho. The sintered magnet exhibits a coercivity 10 kOe despite a low content of Dy, Tb, and Ho.

A high-coercivity NdFeB sintered magnet and a preparation method and use thereof are provided. The sintered magnet contains the following components in percentage by a mass: 100%: 26-37 wt % of R, R being at least one rare earth element including Nd; 0.07-0.23 wt % of Mn; 0.8-1 wt % of B; 0.5-4 wt % of M, M comprising Cu and/or Al, and at least one selected from Co, Ti, Ni, Zr and Ga; and the remaining being Fe. A Mn-containing auxiliary alloy powder is mixed with a Mn-free neodymium-iron-boron main alloy powder to prepare the NdFeB sintered magnet. The Mn-containing auxiliary alloy powder, also contains at least one of metals Cu and Al. Mn can replace a part of Fe in the main phase, so that the amount of solid solution of beneficial elements in grain boundaries in the main phase is reduced, and the coercivity is improved.

The present invention provides a method for producing an R-T-B-M sintered magnet having an oxygen content of less than 0.07 wt. % from R-T-B-M raw materials. The composition of R-T-B-M includes R being at least one element selected from a rare earth metal including Sc and Y. The composition also includes T being at least one element selected from Fe and Co. B in the composition is defined as Boron. The composition further includes M being at least one element selected from Ti, Ni, Nb, Al, V, Mn, Sn, Ca, Mg, Pb, Sb, Zn, Si, Zr, Cr, Cu, Ga, Mo, W, and Ta. The present invention provides for a step of creating an inert gas environment in the steps of casting, milling, mixing, molding, heating, and aging to prevent the powder from reacting with the oxygen in anyone of the above mentioned steps.

The invention discloses a neodymium-iron-boron magnet material, a preparation method, and use thereof. The neodymium-iron-boron magnet material comprises following components of: R: 28.00-32.00 wt %, wherein the R is a rare earth element; Al: 0.00-1.00 wt %; Cu: 0.12-0.50 wt %; B: 0.85-1.10 wt %; and a balance of Fe, wherein wt % refers to a weight percentage of respective elements in the neodymium-iron-boron magnet material; a volume percentage of a NdO phase having a FCC type crystal structure in an intergranular triangular zone of the neodymium-iron-boron magnet material in a grain boundary phase of the neodymium-iron-boron magnet material is equal to or less than 20%. By reducing the proportion of the NdO phase having the FCC type crystal structure, the present invention enhances the demagnetizing coupling ability of the grain boundary phase and improves the consistency of the intrinsic coercivity of the magnet.

The present invention discloses a method for recovering rare earth particulate material from an assembly comprising a rare earth magnet and comprises the steps of exposing the assembly to hydrogen gas to effect hydrogen decrepitation of the rare earth magnet to produce a rare earth particulate material, and separating the rare earth particulate material from the rest of the assembly. The invention also resides in an apparatus for separating rare earth particulate material from an assembly comprising a rare earth magnet. The apparatus comprises a reaction vessel having an opening which can be closed to form a gas-tight seal, a separator for separating the rare earth particulate material from the assembly, and a collector for collecting the rare earth particulate material. The reaction vessel is connected to a vacuum pump and a gas control system, and the gas control system controls the supply of hydrogen gas to the reaction vessel.