The present application relates to a preparation method of neodymium iron boron products and the neodymium iron boron product prepared by using the same. The preparation method of neodymium iron boron products includes the following steps: Step S1: preparing blank magnet; Step S2: obtaining preprocessed sheets; Step S3: surface treating; Step S4: heavy rare earth coating; Step S5: stacking: stacking a plurality of preprocessed sheets to give stacked magnets; and Step S6: grain boundary diffusion: successively subjecting the stacked magnets to a primary heat treatment for 2-40 min, a secondary heat treatment at 700-1000° C. for 4-40 h, and then tempering at 450-700° C., in which the primary heat treatment is induction heat treatment or electric spark sintering.

The present invention provides a manufacturing method for obtaining a compression-bonded magnet with which it is possible to achieve, at a high level, both a residual magnetic flux density (Br) and the magnitude of a reverse magnetic field (Hk) that reduces Br by 10%. The manufacturing method of the present invention includes a molding step of compressing a bonded magnet raw material composed of a compound or the like of magnetic powder and a binder resin in a heated and oriented magnetic field. The bonded magnet raw material has a mass ratio of the magnet powder of 90 to 95.7 mass% to a total of the magnet powder and the binder resin. The magnet powder includes coarse powder having an average particle diameter of 40 to 200 .Math.m and fine powder having an average particle diameter of 1 to 10 .Math.m. The coarse powder has a mass ratio of 60 to 90 mass% to a total of the coarse powder and the fine powder. The coarse powder includes rare earth anisotropic magnet powder subjected to hydrogen treatment. The binder resin includes a thermosetting resin. The molding step is carried out with a compressing force of 8 to 70 MPa and a heating temperature of 120° C. to 200° C.

To provide a rare earth magnet having excellent coercive force and a production method thereof. A rare earth magnet, wherein the rare earth magnet comprises a magnetic phase containing Sm, Fe, and N, a Zn phase present around the magnetic phase, and an intermediate phase present between the magnetic phase and the Zn phase, wherein the intermediate phase contains Zn and the oxygen content of the intermediate phase is higher than the oxygen content of the Zn phase; and a method for producing a rare earth magnet, including mixing a magnetic raw material powder having an oxygen content of 1.0 mass % or less and an improving agent powder containing metallic Zn and/or a Zn alloy, and heat-treating the mixed powder.

R—Fe—B sintered magnet has a main phase containing R.sub.2(Fe,(Co)).sub.14B intermetallic compound and a grain boundary phase. The inter-particle grain boundary includes an expanded width part that is surrounded by a narrow width part at which the inter-particle width is 10 nm or less and that has a structure distended in the inter-particle width direction as compared with the grain boundary width of the narrow width part; the inter-particle width at the expanded width part is at least 30 nm; Fe/R ratio in the expanded width part is 0.01-2.5; the main phase includes, in the surface part thereof, an HR-rich phase represented by (R′,HR).sub.2(Fe,(Co)).sub.14B (R′ represents rare-earth elements excluding Dy, Tb, and Ho, and that essentially include Nd; and HR represents Dy, Tb, and Ho); the contained amount of HR in the HR-rich phase is higher than that in the central part of the main phase.

Disclosed are a device and method for continuously performing grain boundary diffusion and heat treatment, characterized in that the alloy workpiece or the metal workpiece are arranged in a relatively independent processing box together with a diffusion source; the device comprises, in successive arrangement, a grain boundary diffusion chamber, a first cooling chamber, a heat treatment chamber, and a second cooling chamber, and a transfer system provided between various chambers for delivering the processing box; each of the first cooling chamber and the second cooling chamber uses an air cooling system, and the cooling air temperature of the first cooling chamber is above 25° C. and at least differs by 550° C. from the grain boundary diffusion temperature of the grain boundary diffusion chamber; the cooling air temperature of the second cooling chamber is above 25° C. and at least differs by 300° C. from the heat treatment temperature of the heat treatment chamber; and the cooling chamber has a pressure of 50 kPa to 100 kPa. The device provided by the present invention can increase the cooling rate and production efficiency, and improve product consistency.

Provided is a permanent magnet including a rare-earth element R, a transition metal element T, B, Zr, and Cu. The permanent magnet contains main phase grains including Nd, T, and B, and grain boundary multiple junctions, the grain boundary multiple junction is a grain boundary surrounded by three or more of the main phase grains, one of the grain boundary multiple junctions contains a ZrB.sub.2 crystal and an R—Cu-rich phase, a concentration of B in the grain boundary multiple junction containing both the ZrB.sub.2 crystal and the R—Cu-rich phase is from 5 to 20 atomic %, a concentration of Cu in the grain boundary multiple junction containing both the ZrB.sub.2 crystal and the R—Cu-rich phase is from 5 to 25 atomic %, and a surface layer part of the main phase grain includes at least one kind of heavy rare-earth element among Tb and Dy.

An RIB-based permanent magnet material, a preparation method thereof, and an application thereof. The RIB-based permanent magnet material comprises the following components: R′: 29.5 to 33.5 wt. %, wherein R′ comprises Pr, and the content of Pr is ≥8.85 wt. %; C:0.106 to 0.26 wt. %; O: ≤0.07 wt. %; X: 0 to 5.0 wt. %, wherein X is one or more of Cu, Al, Ga, Co, Zr, Ti, Nb and Mn; B:0.90 to 1.2 wt. %; and Fe:61.4 to 69.5 wt. %. The RIB-based permanent magnet material can improve the performance of a permanent magnet material without employing heavy rare earths. There is no need to control the content of carbon introduced in the process, and the magnet exhibits excellent performance even with a high carbon content.

Disclosed are a neodymium-iron-boron magnet material, a raw material composition, a preparation method therefor and a use thereof. The raw material composition of the neodymium-iron-boron magnet material comprises the following components by mass percentage: 29.5-32% of R′, wherein R′ is a rare earth element and includes Pr and Nd; and Pr≥17.15%; 0.25-1.05% of Ga; 0.9-1.2% of B; and 64-69% of Fe. Without adding a heavy rare earth element to the neodymium-iron-boron magnet material, the remanence and coercive force of the resulting neodymium-iron-boron magnet material are both relatively high.

The present disclosure provides neodymium-iron-boron magnetic body having gradient distribution, comprising an ease-to-demagnetize zone and a hard-to-demagnetize zone, wherein in a direction perpendicular to magnetization direction, remanence of the ease-to-demagnetize zone is less than remanence of the hard-to-demagnetize zone, and coercivity of the ease-to-demagnetize zone is greater than coercivity of the hard-to-demagnetize zone; and along the direction perpendicular to magnetization direction, the remanence and the coercivity of the ease-to-demagnetize zone are respectively a constant value, and the remanence and the coercivity of the hard-to-demagnetize zone are respectively a constant value. Due to the gradient distribution of remanence and coercivity of the neodymium-iron-boron magnetic body provided by the present application, the remanence, coercivity, magnetic flux and surface magnetic field of the neodymium-iron-boron magnetic body are optimized.

A rare earth sintered magnet is produced by depositing a coating of rare earth-containing particles on the surface of a rare earth magnet body, and heat treating the magnet body for causing absorption and diffusion of rare earth element in the magnet body. The depositing step utilizes a particle impingement phenomenon.