The present invention discloses a rare earth permanent magnet and a method for preparing same. The material of the rare earth permanent magnet has a heavy rare earth element volume diffusion phenomenon at a depth of 5 μm to 100 μm from the surface of the magnet to the interior of the magnet along the magnetic field orientation direction, thereby forming a volume diffusion layer region; the volume diffusion layer region is divided into magnet units having a volume of 10*100*5 μm, and the concentration difference of the heavy rare earth elements of the magnet units at different positions in the volume diffusion layer is below 0.5 at %. The present invention provides a sintered NdFeB magnet of high intrinsic coercive force Hcj on the premise of not influencing the remanence Br and the maximum magnetic energy product (BH)max of products. In the method for preparing the rare earth permanent magnet, microwave heat treatment is performed on a blank magnet coated with heavy rare earth source slurry in a vacuum condition. This method can effectively improve the heating efficiency, reduce the heat treatment time, lower the energy consumption, and reduce the production cost of the magnet.

The present invention discloses a rare earth permanent magnet and a method for preparing same. The material of the rare earth permanent magnet has a heavy rare earth element volume diffusion phenomenon at a depth of 5 μm to 100 μm from the surface of the magnet to the interior of the magnet along the magnetic field orientation direction, thereby forming a volume diffusion layer region; the volume diffusion layer region is divided into magnet units having a volume of 10*100*5 μm, and the concentration difference of the heavy rare earth elements of the magnet units at different positions in the volume diffusion layer is below 0.5 at %. The present invention provides a sintered NdFeB magnet of high intrinsic coercive force Hcj on the premise of not influencing the remanence Br and the maximum magnetic energy product (BH)max of products. In the method for preparing the rare earth permanent magnet, microwave heat treatment is performed on a blank magnet coated with heavy rare earth source slurry in a vacuum condition. This method can effectively improve the heating efficiency, reduce the heat treatment time, lower the energy consumption, and reduce the production cost of the magnet.

Systems and methods for recovering neodymium and other related rare earth elements from permanent magnets and/or various ore compositions are presented herein. In one embodiment, a method of recovering a rare earth element (REE) from a permanent magnet material and/or a mined ore composition (collectively “work material”) is presented. The method includes converting the work material to a higher surface area form, treating the converted work material with an aqueous solution of alkaline carbonates to dissolve the REE, filtering the treated and converted work material to yield a filtrate, and treating the filtrate with at least one of a precipitating agent or a precipitating condition to form REE solids. The aqueous solution of alkaline carbonates comprises at least one of potassium carbonate, potassium bicarbonate, or dissolved carbon dioxide.

The present invention discloses a short process preparation technology of sintered NdFeB magnets from the NdFeB sludge, which relates to a field of recycle technology of NdFeB sludge. The present invention comprises the following steps: water bath distillation of organics in sludge, ultrasonic cleaning, calcium reduction and diffusion, ultrasonic rinsing in a magnetic field and drying, powders mixing and sintering. NdFeB sludge as raw materials was directly prepared from recycled sintered magnets with high magnetic properties. Most of the organics in the sludge could be removed by a vacuum distillation process with stepwise heating. The ultrasonic rinsing process in a magnetic field could effectively remove the remaining organics. The recycled sintered magnets exhibited good maximum energy product [(BH).sub.max] of 35.26 MGOe. The present invention has important features, such as the short processing time, efficient environmental protection, high recycling rate and effective utilization rate of rare earth metals.

Disclosed herein is a method for manufacturing an R-T-B permanent magnet and the magnet made with the method. The method may include preparation of strip pieces by melting and casting, preparing coarse powder by hydrogen decrepitation of the strip pieces; milling the powder into fine powder; pressing the fine powder is pressed to form a compact, pre-sintering the compact in vacuum or inert gas, machining the pre-sintered block to a desired shape; and dispersing the heavy rare earth compound powder into an organic solvent to prepare a slurry and a second sintering step.

A sintered R.sub.2M.sub.17 magnet is provided that comprises at least 70 Vol % of a Sm.sub.2M.sub.17 phase, wherein R is at least one of the group consisting of Ce, La, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yt, Lu and Y, and M comprises Co, Fe, Cu and Zr. In an area of the R.sub.2M.sub.17 sintered magnet of 200 by 200 μm viewed in a Kerr micrograph, an areal proportion of demagnetised regions after application of an internal opposing field of 1200 kA/m is less than 5% or less than 2%.

A method of operating an electro-permanent magnet may include switching the electro-permanent magnet from an on state wherein magnetic fields of switching and permanent magnets combine to generate a first magnetic field having a first magnitude and a first polarity to a reversed state having a second polarity wherein magnetic fields of the switching magnets and the permanent magnets combine to generate a second magnetic field having a second magnitude less than the first magnitude and a second polarity different than the first polarity. The electro-permanent magnet may be switched from the reversed state to an off state wherein magnetic fields of the switching and permanent magnets combine to generate a third magnetic field having a magnitude that is no more than 50 percent of the second magnitude. Related electro-permanent magnets are also discussed.

The present invention provides a rare earth thin film magnet having Nd, Fe, and B as essential components, wherein the rare earth thin film magnet has a texture in which an α-Fe phase and a Nd.sub.2Fe.sub.14B phase are alternately arranged three-dimensionally, and each phase has an average crystal grain size of 10 to 30 nm. An object of this invention is to provide a rare earth thin film magnet having superior mass productivity and reproducibility and favorable magnetic properties, as well as to provide the production method thereof and a target for producing the thin film.

The present invention provides a rare earth thin film magnet having Nd, Fe, and B as essential components, wherein the rare earth thin film magnet has a texture in which an α-Fe phase and a Nd.sub.2Fe.sub.14B phase are alternately arranged three-dimensionally, and each phase has an average crystal grain size of 10 to 30 nm. An object of this invention is to provide a rare earth thin film magnet having superior mass productivity and reproducibility and favorable magnetic properties, as well as to provide the production method thereof and a target for producing the thin film.

A permanent magnet of an embodiment includes: a composition represented by a composition formula: R(Fe.sub.pM.sub.qCu.sub.rCo.sub.1-p-q-r).sub.z, where R is at least one element selected from rare-earth elements, M is at least one element selected from Zr, Ti, and Hf, and relations of 0.3≦p≦0.4, 0.01≦q≦0.05, 0.01≦r≦0.1, and 7≦z≦8.5 (atomic ratio) are satisfied; and a structure including a cell phase having a Th.sub.2Zn.sub.17 crystal phase, and a cell wall phase existing to surround the cell phase. An average magnetization of the cell wall phase is 0.2 T or less.