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Preparation method and product of high coercivity sintered NdFeB

A high coercive force, neodymium iron boron technology, applied in the direction of inductance/transformer/magnet manufacturing, magnetic materials, magnetic objects, etc., can solve the problems of limited diffusion distance of heavy rare earth, unsuitable for application market, unsuitable for actual production, etc. Achieve the effects of improving the fluidity of grain boundaries, inhibiting the nucleation of reverse magnetization, and realizing efficient utilization

Inactive Publication Date: 2018-07-17
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method has a complicated process and is not suitable for actual production. The diffusion distance of heavy rare earths is limited (<5μm), which makes the size of the magnet used for diffusion too small and not suitable for the actual application market.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0034] A kind of preparation method of low-cost sintered NdFeB with high coercive force, the main phase NdFeB alloy described in the atomic percentage, its composition is (Nd a PR 1-a ) b Fe 100-b-c-d B c m d , where Nd is neodymium, Pr is praseodymium, Fe is iron, B is boron, M is Dy, Tb, Ce, Co, Ni, V, Ti, Mo, Mn, Ga, Al, Cu, Zr, One or more of Ta, Ag, Si, Nb elements; a, b, c, d satisfy the following relationship: 0.7≦a≦1, 10≦b≦20, 5.5≦c≦6.5, 0≦d≦2 .

[0035] The grain boundary phase alloy is calculated in atomic percentage, and its composition is (R x R' 1-x ) y M' 100-y , R is one or more of La, Ce, Pr, Nd, R' is one or more of Tb, Dy, Ho, M' is Fe, Cr, Co, Ni, V, Ti, Mo , Mn, Ga, Al, Cu, Zr, Ta, Ag, Si, Ca, B, Mg, Zn, In, Sn or one or several elements; where x, y satisfy the following relationship: 0≦x<1 ,0

[0036] A method for preparing high-coercivity and low-cost sintered NdFeB alloys. The grain boundary heavy rare earth alloy has a melting point b...

Embodiment 1

[0046] 1) The main phase alloy is prepared by three kinds of alloy processes of rapid solidification casting, hydrogen explosion and jet milling to prepare the main alloy powder. The diameter of the powder particle is about 3.5 μm. The main alloy is expressed in atomic percentage, and its composition is (Pr 0.2 Nd 0.8 ) 13.62 Fe 78.82 m 1.58 B 5.98 , wherein Pr:Nd=1:4, M is Al=0.72, Co=0.49, Cu=0.14, Zr=0.14, Ga=0.09;

[0047] 2) The grain boundary phase alloy is smelted by electric arc, mechanically crushed, and ball milled with protective medium until the average grain size is about 0.85 μm. The auxiliary alloy is expressed in atomic percentage, and its composition is Pr 37 Dy 30 Cu 33 ;

[0048] 3) Fully mix the prepared grain boundary phase alloy powder and the main alloy powder in gasoline, petroleum ether or other organic protective media with a mixer protected by nitrogen or argon, wherein the mass fraction of the auxiliary alloy powder is 2.0 %;

[0049] 4) Ca...

Embodiment 2

[0053] 1) The main phase alloy is prepared by three kinds of alloy processes of rapid solidification casting, hydrogen explosion and jet milling to prepare the main alloy powder. The diameter of the powder particle is about 3.5 μm. The main alloy is expressed in atomic percentage, and its composition is (Pr 0.2 Nd 0.8 ) 13.05 Dy 0.12 Fe 80.81 Al 0.25 Nb 0.07 B 5.7

[0054] 2) The grain boundary phase alloy is smelted by electric arc, mechanically crushed, and ball milled with protective medium until the average grain size is about 1.5 μm. The auxiliary alloy is expressed in mass percentage, and its composition is Dy 32.5 Fe 62 Cu 5.5 .

[0055] 3) Fully mix the prepared grain boundary phase alloy powder and the main alloy powder in gasoline, petroleum ether or other organic protective media with a mixer protected by nitrogen or argon, and the mass fraction of the auxiliary alloy powder is 3.0 %:

[0056] 4) Carry out orientation pressing of the mixed alloy powder un...

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Abstract

The invention discloses a preparation method of high-coercivity sintered Nd-Fe-B. The preparation method comprises the following steps: preparing a main phase alloy powder and a grain boundary phase alloy powder; protecting the prepared main phase alloy powder and the grain boundary phase alloy powder by using nitrogen or argon in a protective medium, and uniformly mixing, wherein the mass percent of the added grain boundary phase alloy powder accounts for 0.1-10 percent; carrying out orientation profiling and cold isostatic pressing on the mixed alloy powder; in a vacuum sintering furnace, sintering a profiled magnet block for 2-4h at the temperature of 1000-1100 DEG C, then carrying out primary tempering for 2-4h at the temperature of 800-950 DEG C, and carrying out secondary tempering for 2-4h at the temperature of 450-650 DEG C to prepare the sintered Nd-Fe-B. The invention also discloses the high-coercivity sintered Nd-Fe-B. According to the preparation method disclosed by the invention, by virtue of low melting point auxiliary alloy, the wetting temperature between a grain boundary phase and a main phase is lowered, the wetting time is prolonged, the utilization ratio of heavy rare earth is increased, the used amount of rare earth is lowered, the process is simple, the cost is low, and the high-coercivity sintered Nd-Fe-B is suitable for mass production.

Description

technical field [0001] The invention belongs to the technical field of permanent magnet materials, and in particular relates to a preparation method and product of high coercivity sintered NdFeB. Background technique [0002] In 1983, on the basis of extensive research on RE-Fe-X ternary alloys, Sagawa Masato and others in Japan prepared a magnetic energy product as high as 290kJ / m by powder metallurgy. 3 The advanced neodymium iron boron (Nd-Fe-B) sintered magnets created the third generation of rare earth permanent magnet materials. Sintered Nd-Fe-B is widely used in military equipment, electroacoustic devices, motors, generators, computer hard disk drives (HDD), voice coil motors (VCM), human magnetic resonance imaging (MRI), microwave communication technology, controllers , instruments, magnetic separation equipment, magnetic chucks and other devices and equipment that require permanent magnetic fields. [0003] Sintered NdFeB magnets are based on Nd 2 Fe 14 Compound...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/057H01F1/08H01F41/02B22F3/16
Inventor 严密张玉晶王新华金佳莹
Owner ZHEJIANG UNIV
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