The present invention relates to a method for preparing a neodymium-iron-boron rare-earth permanent magnetic material, in particular to a hot press molding-based method for preparing a rare-earth permanent magnet. The problem that the residual magnetism and coercive force of a rare-earth permanent magnet prepared in the prior art cannot be both high is solved. An RTM alloy infiltrates same during an HD treatment. RTM sticks to the surface of coarse powder and infiltrates into the interior of the coarse powder along a grain boundary. The temperature of hot press sintering is relatively low, and grains barely grow. In the absence of Dy and Tb, a higher coercive force is obtained. If an alloy containing Dy and Tb is used for infiltration, these atoms diffuse into the surface layer of a main phase during preheating and heat treatment, achieving grain boundary hardening. Under the premise of a very small reduction in the residual magnetism, the coercive force is greatly improved.

The present invention relates to a method for preparing a neodymium-iron-boron rare-earth permanent magnetic material, in particular to a hot press molding-based method for preparing a rare-earth permanent magnet. The problem that the residual magnetism and coercive force of a rare-earth permanent magnet prepared in the prior art cannot be both high is solved. An RTM alloy infiltrates same during an HD treatment. RTM sticks to the surface of coarse powder and infiltrates into the interior of the coarse powder along a grain boundary. The temperature of hot press sintering is relatively low, and grains barely grow. In the absence of Dy and Tb, a higher coercive force is obtained. If an alloy containing Dy and Tb is used for infiltration, these atoms diffuse into the surface layer of a main phase during preheating and heat treatment, achieving grain boundary hardening. Under the premise of a very small reduction in the residual magnetism, the coercive force is greatly improved.

Provided herein is a soft magnetic alloy powder that can exhibit a high saturation flux density and desirable soft magnetic characteristics. A dust core using the soft magnetic alloy powder is also provided. The soft magnetic alloy powder is an Fe-based nanocrystalline soft magnetic alloy powder of a crystallized Fe-based amorphous soft magnetic alloy powder, and has a DSC curve with a first peak that is 15% or less of a first peak of the Fe-based amorphous soft magnetic alloy in terms of a maximum value.

Provided herein is a soft magnetic alloy powder that can exhibit a high saturation flux density and desirable soft magnetic characteristics. A dust core using the soft magnetic alloy powder is also provided. The soft magnetic alloy powder is an Fe-based nanocrystalline soft magnetic alloy powder of a crystallized Fe-based amorphous soft magnetic alloy powder, and has a DSC curve with a first peak that is 15% or less of a first peak of the Fe-based amorphous soft magnetic alloy in terms of a maximum value.

High ultraviolet transmittance and high blackness can be obtained, and also has high insulating property.

A zirconium nitride powder of the present invention has a volume resistivity of 10.sup.7 Ω.Math.cm or more in the state of the pressurized powder body hardened at a pressure of 5 MPa, and a particle size distribution D.sub.90 of 10 μm or less when ultrasonically dispersed for 5 minutes in a state of being diluted with water or an alcohol having a carbon number of which is in a range of 2 to 5. Also, the zirconium nitride powder is dispersed in an acrylic monomer or an epoxy monomer to prepare a monomer dispersion. Further, the zirconium nitride powder is dispersed in a dispersing medium as a black pigment and further a resin is mixed to prepare a black composition.

The disclosure refers to a preparation method for NdFeB permanent magnet including:

a) Preparing main alloy flakes consisting of (Pr.sub.2Nd.sub.8).sub.xFe.sub.100-x-y-zB.sub.yM.sub.z,where M is at least one of Al,Co,Cu,Ga,Ti and Zr, 28.5 wt. % ≤x≤31.0 wt. %,0.85 wt. %≤y≤0.98 wt. % and 0.5 wt. %≤z≤5.0 wt. %;

b) Preparing auxiliary alloy flakes consisting of L.sub.uFe.sub.100-u-v-wB.sub.vM.sub.w,where L is at least one ofPr and Nd,M is at least one of Al,Co,Cu,Ga,Ti and Zr, 35.0 wt. %≤u≤45.0 wt. %,0 wt. %≤v≤5.0 wt. % and 2.0 wt. %≤w≤10.0 wt. %;

c) Mixing the main alloy flakes and the auxiliary alloy flakes in predetermined rate, then performing hydrogen decrepitation to produce alloy pieces,and then crushing the alloy pieces to alloy powder by jet milling;

d) Preparing a powder mixture including the alloy powder and added heavy rare earth powder consisting of at least one of Dy and Tb;

e) Pressing the powder mixture to a green compact while applying a magnetic field, and thermal treatment of the green compact in a vacuum furnace to obtain the NdFeB permanent magnet.

A rare earth permanent magnet material and a raw Material composition, a preparation method therefor and use thereof. The rare earth permanent magnet material comprises the following components in percentage by mass: 29.0-32.0 wt. % of R. where R comprises RH, and the content of RH is greater than 1 wt. %; 0.30-0.50 wt. % of Cu (not including 0.50 wt. %); 0.10-1.0 wt. % of Co; 0.05-0.20 wt. % of Ti; 0.92-0.98 wt. % of 13; and the remainder being Fe and unavoidable impurities; wherein R is a rare-earth element and at least comprises Nd; and RH is a heavy rare-earth element and at least comprises Tb. The R-T-B system permanent magnet material exhibits excellent performance, wherein Br≥14.30 kGs, and Hej≥24.1 kOe. The invention can synchronously improve Br and Hcj.

A rare earth permanent magnet material and a raw Material composition, a preparation method therefor and use thereof. The rare earth permanent magnet material comprises the following components in percentage by mass: 29.0-32.0 wt. % of R. where R comprises RH, and the content of RH is greater than 1 wt. %; 0.30-0.50 wt. % of Cu (not including 0.50 wt. %); 0.10-1.0 wt. % of Co; 0.05-0.20 wt. % of Ti; 0.92-0.98 wt. % of 13; and the remainder being Fe and unavoidable impurities; wherein R is a rare-earth element and at least comprises Nd; and RH is a heavy rare-earth element and at least comprises Tb. The R-T-B system permanent magnet material exhibits excellent performance, wherein Br≥14.30 kGs, and Hej≥24.1 kOe. The invention can synchronously improve Br and Hcj.

A method for producing a powdered starting material, which is provided for production of rare earth magnets, including the following steps: pulverizing an alloy, including at least one rare earth metal, wherein a powdered intermediate product is formed from the alloy including at least one rare earth metal, and carrying out at least one classification aimed at particle size and/or density for the powdered intermediate product, wherein a fraction of the powdered intermediate product, which is formed by means of the at least one classification, for fabrication of rare earth magnets. Furthermore, at least one dynamic classifier is provided, implementing at least one classification directed at particle size and/or density for the powdered intermediate product and thereby separates the fraction from the powdered intermediate product, which forms the starting material provided for manufacturing rare earth magnets.

A preparation method of improved sintered neodymium-iron-boron (Nd—Fe—B) casting strips includes the following steps: firstly nucleation assisted alloy particles used for sintered Nd—Fe—B casting strips are prepared, all elements are weighted as follows: 26.68-28% of Pr—Nd, 70-72.5% of Fe and 0.90-1% of B, and a Pr element in two elements of Pr—Nd accounts for 0-30 wt %; the compounded materials are smelted and poured to obtain alloy strips, then the alloy strips are crushed into particles with diameter of 1-10 mm; secondly, Nd—Fe—B casting strips are prepared: the prepared intermediate materials are smelted and melted into molten steel, and then are refined; after the intermediate materials are fully melted, the nucleation assisted alloy particles are added; and after the nucleation assisted alloy particles are added, smelting is performed for 3-15 minutes pouring is performed, and final Nd—Fe—B alloy casting strips are obtained.