An object of the present invention is to enhance a coercive force of magnetic particles by promoting formation of a continuous R-rich grain boundary phase in a crystal grain boundary of a magnetic phase of the particles, and to thereby obtain R-T-B-based rare earth magnet particles further having a high residual magnetic flux density. The present invention relates to production of R-T-B-based rare earth magnet particles capable of exhibiting a high coercive force even when a content of Al therein is reduced, and a high residual magnetic flux density, in which formation of an R-rich grain boundary phase therein can be promoted by heat-treating Al-containing R-T-B-based rare earth magnet particles obtained by HDDR treatment in vacuum or in an Ar atmosphere at a temperature of not lower than 670° C. and not higher than 820° C. for a period of not less than 30 min and not more than 300 min.

The present disclosure refers to a method of preparing a NdFeB magnet powder. The method includes a hydrogen treatment process including the steps of: a) charging NdFeB alloy flakes into a hydrogen treatment furnace, wherein the NdFeB alloy flakes include a neodymium-rich phase and a main phase; b) performing a hydrogen absorption by heating the hydrogen treatment furnace in a first stage to a temperature at which only the neodymium-rich phase undergoes a hydrogen absorption reaction, then introducing and maintaining hydrogen at a predetermined pressure until the hydrogen absorption of the neodymium-rich phase is finished, then stop heating of the hydrogen treatment furnace in a second stage, where the temperature falls to a temperature at which the main phase undergoes a hydrogen absorption reaction; and c) when the hydrogen absorption of step b) is finished, performing a vacuum dehydrogenation of the obtained coarse magnet powder.

The present invention relates to a Ce-containing sintered rare earth permanent magnet with high toughness and high coercivity and a method of preparing the magnet, belonging to the technical field of rare earth permanent magnetic materials. The magnet is prepared by steps of raw material batching, strip casting, hydrogen decrepitation and jet milling, powder orientating and forming, sintering and heat treatment. The materials of the permanent magnet comprise the main phase alloy powders and the Ce added phase alloy powders, wherein the Ce added phase alloy is a magnetic phase or a non-magnetic liquid-phase alloy; and the Ce added phase alloy accounts for 5% to 30% of the total weight of the permanent magnet, and the remainder is the main phase alloy. During the jet milling stage, a certain concentration of oxygen is added into the inert gas, so that the final magnet has an oxygen content of 1500 to 2500 ppm. The Ce-containing dual-alloy magnet prepared in accordance with the present invention has high coercivity, and the intrinsic coercivity (H.sub.cj) is up to 17 to 28.73 kOe. The magnet of the present invention has good fracture toughness which is increased by 10% to 30% as compared with the conventional Nd—Fe—B sintered magnet. The magnet of the present invention can meet needs of high-end applications such as wind power generation, new energy vehicles, and the like, and greatly expands the application fields of Ce-containing magnets.

A method for preparing a rare earth anisotropic bonded magnetic powder, comprises the following steps: (1) preparing raw powder with RTBH as the main component, wherein, R is Nd or Pr/Nd, and T is a transition metal containing Fe; (2) adding La/Ce hydride and copper powder to the raw powder to form a mixture; (3) subjecting the mixture to atmosphere diffusion heat treatment to give the rare earth anisotropic bonded magnetic powder. The invention selects high-abundance rare earth elements La, Ce to replace Dy, Tb, Nd, Pr and other medium and heavy rare earth elements, which can achieve the same coercivity improvement effect while also significantly reducing the cost, thereby achieving efficient application of low-cost and high-abundance rare earths.

The invention discloses an anisotropic bonded magnetic powder and a preparation method thereof. The anisotropic bonded magnetic powder has a general formula of R.sub.1R.sub.2TB, wherein R.sub.1 is a rare earth element containing Nd or PrNd, R.sub.2 is one or two of La and Ce, T is a transitional element, and B is boron. The preparation method includes the steps of smelting the master alloy to prepare ingot(s), preparing a rare earth hydride of formula R.sub.1TBH.sub.X, preparing a hydride diffusion source of formula R.sub.1R.sub.2TH.sub.X, mixing, heat treating, and high-vacuum dehydrogenating, to obtain the anisotropic bonded magnetic powder. The invention uses La and Ce hydrides as the diffusion source, can save cost, remove hydrogen from the diffusion source at a lower dehydrogenation temperature, avoid crystal grain growth at a high temperature, and ensure the quality of the product.

The present disclosure relates generally to a method for improving the performance of sintered NdFeB magnet. A method of preparing a sintered NdFeB magnet therefore comprises the steps of: a) preparing alloy flakes from a raw material of the NdFeB magnet by a strip casting process; and b) preparing a coarse alloy powder from the alloy flakes by a hydrogen decrepitation process, the hydrogen decrepitation process including treatment of the alloy flakes under a hydrogen pressure of 0.10 MPa to 0.25 MPa for a duration of 1 to 3.5 hours, then degassing the hydrogen at a predetermined temperature between 300° C. to 400° C. for a duration time of 0.5 to 5 hours, and then mixing the resulting coarse alloy powder with a lubricant.

A method includes mixing first and second alloys to form a mixture, pressing the mixture within a first magnetic field to form a magnet having anisotropic particles of the first alloy aligned with a magnetic moment of the magnet, and heat treating the magnet within a second magnetic field to form elongated grains from the second alloy and align the elongated grains with the moment.

Provided is a cleaning device for cleaning a magnet powder including: a flask provided to contain the magnet powder and a cleaning material used to clean the magnet powder; and a vacuum manifold provided to maintain the magnet powder and the cleaning material contained in the flask in an inert state during cleaning.

Provided is a method for cleaning a magnet powder including a loading operation for loading a magnet powder, a cleaning solution, and zeolite into a flask; a gas injecting operation for injecting an inert gas into the flask; and a vacuum drying operation for drying the magnet powder and the zeolite in a vacuum.

Provided is a method for manufacturing a magnet powder including: preparing a primary mixture by mixing neodymium (III) nitrate, boric acid, and iron (III) nitrate nonahydrate; preparing an oxide by heat-treating the primary mixture; removing a residual organic material of the oxide by heat-treating the oxide; preparing a hydrogen-reduced oxide by reacting the oxide, from which the residual organic material is removed, with hydrogen by heat treatment; preparing a secondary mixture by mixing the hydrogen-reduced oxide with calcium; obtaining a product by subjecting the secondary mixture to reduction-diffusion reaction by heat treatment; and obtaining Nd.sub.2Fe.sub.14B powder by pulverizing the product.

There is provided a method for manufacturing a rare earth sintered magnet by many times repetitively finely pulverizing a rare earth alloy on a jet mill by supplying high-pressure nitrogen gas to narrow grain size distribution to make an easy alignment in a magnetic field, and by micronizing crystal grains by using a hydrogenation-disproportionation-desorption-recombination (HDDR) process, to improve the coercivity and thermostability of the rare earth sintered magnet.

There is provided a production method and a production device for producing each of the rare earth sintered magnet sintered bodies without carrying a mold in a sintering furnace. The method includes feeding an alloy powder into a mold having side walls divided into two or more sections; filling the alloy powder into the mold to prepare a filled molded-body; orienting the alloy powder in the filled molded-body by applying a magnetic field to the filled molded-body to prepare an oriented filled-molded-body; detaching the side walls of the mold from the oriented filled-molded-body and retrieving the oriented filled-molded-body from the mold; and sintering the retrieved oriented filled-molded-body. The filling step and the orienting step are performed at different locations. A pulsed magnetic field can be applied in the orienting step and inside of the mold can be partitioned into a plurality of cavities by partitions.