CN104028744A - Method for raising orientation degree of Nd-Fe-B powder particles - Google Patents
Method for raising orientation degree of Nd-Fe-B powder particles Download PDFInfo
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- CN104028744A CN104028744A CN201410244490.XA CN201410244490A CN104028744A CN 104028744 A CN104028744 A CN 104028744A CN 201410244490 A CN201410244490 A CN 201410244490A CN 104028744 A CN104028744 A CN 104028744A
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Abstract
The invention discloses a method for raising an orientation degree of Nd-Fe-B powder particles. The method comprises the steps of: loading a plurality of Nd-Fe-B powder particles in a mold cavity, applying an external magnetic field on the Nd-Fe-B powder particles in the mold cavity to allow the Nd-Fe-B powder particles to rotate by the action of a magnetostatic torque force and be subjected to a magnetostatic torque which is the same as a torque generated by mechanical resistance and friction among the Nd-Fe-B powder particles, applying vibration waves on the Nd-Fe-B powder particles on the basis of keeping the external magnetic field, allowing the Nd-Fe-B powder particles to be subjected to the action of the magnetostatic torque force of the external magnetic field only when the adjacent Nd-Fe-B powder particles are separated, and therefore, allowing the Nd-Fe-B powder particles to turn to the external magnetic field. According to the method, since the vibration waves are applied on the Nd-Fe-B powder particles, c axes of the Nd-Fe-B powder particle are turned to the external magnetic field more easily, and the orientation degree of magnetic steel is raised.
Description
Technical field
The present invention relates to rare earth permanent-magnetic material field, particularly a kind of method of the degree of orientation that improves Nd-Fe-B powder particle.
Background technology
At present, sintered Nd-Fe-B based magnet produces that the operations such as, powder process broken by melting, hydrogen, moulding, sintering form.The magnetic behavior of sintered Nd-Fe-B based magnet is mainly derived from the Nd with tetragonal
2fe
14b matrix phase (being commonly called as Nd-Fe-B powder particle).It is uniaxial crystal, and c-axis is easy magnetizing axis.If when the angle between the direction of magnetization and the c-axis of its easy magnetization is θ, the remanent magnetism of Nd-Fe-B powder particle is Br=u
0mscos θ, visible θ angle is less, and remanent magnetism is just larger, and, when along its easy magnetizing axis magnetization, Nd-Fe-B powder particle has maximum remanent magnetism Br=u
0ms.
But the degree of orientation Jr/Js that known sintered Nd-Fe-B based permanent magnet magnet steel obtains in molding procedure is only that 0.83～0.95 (degree of orientation is larger, magnet steel magnetic property is better), performance (remanent magnetism, coercivity, the magnetic energy product etc.) uniformity of product is poor, product second-rate.Therefore the degree of orientation that improves sintered Nd-Fe-B based permanent magnet magnet steel is one of key technology of manufacturing high-quality Sintered Nd-Fe-B Magnet.
But the c-axis degree of orientation of Nd-Fe-B powder particle is subject to the impact of many factors, as orientation external magnetic field intensity size, powder particle shape and the relative direction of distribution of sizes and surface state, molding mode, orientation field and briquetting pressure and the first dress density of orientation powder etc.In order to improve orientation external magnetic field, need huge current control device and high-performance permeability magnetic material, equipment manufacturing cost costliness, operation expense is suddenly high; In order to make the shape approximation of powder particle spherical, need in the process of powder process, add the corner angle of trace oxygen with oxide powder particle, thereby the yield of powder process operation is reduced; For the first dress density that ensures powder is apparent density, needing increases the frock of sieving and feed, and has increased manufacturing time.In a word, these factors have finally increased the manufacturing cost of product, are unfavorable for industrial-scale production.
The information that is disclosed in this background technology part is only intended to increase the understanding to general background of the present invention, and should not be regarded as admitting or imply that in any form this information structure has been the known prior art of persons skilled in the art.
Summary of the invention
The object of the present invention is to provide a kind of method of the degree of orientation of the Nd-Fe-B of raising powder particle, thereby it is high to overcome the low manufacturing cost of bringing of the degree of orientation of existing Sintered Nd-Fe-B Magnet, is unfavorable for the defect of industrial-scale production.
For achieving the above object, the invention provides a kind of method of the degree of orientation of the Nd-Fe-B of raising powder particle, method comprises: multiple Nd-Fe-B powder are contained in die cavity; Nd-Fe-B powder particle in die cavity is applied to external magnetic field, Nd-Fe-B powder particle is rotated under the effect of magnetostatic torque force, thus make mechanical resistance between magnetostatic running torque load moment and Nd-Fe-B powder particle that Nd-Fe-B powder particle is subject to and the common torque phase producing of frictional force with; On the basis that keeps external magnetic field, Nd-Fe-B powder particle is applied to vibration wave, in the time that adjacent Nd-Fe-B powder particle separates, Nd-Fe-B powder particle is only subject to the effect of the magnetostatic torque force of external magnetic field, thereby makes Nd-Fe-B powder particle turn to the direction of external magnetic field.
Preferably, in technique scheme, the magnetic induction intensity of external magnetic field is greater than 1.5T.
Compared with prior art, the present invention has following beneficial effect:
The present invention makes the c-axis of Nd-Fe-B powder particle more easily turn to the direction of external magnetic field by Nd-Fe-B powder particle being applied to vibration wave, thereby has improved the degree of orientation of magnet steel, and the cost that applies in addition vibration wave is lower, simple, is convenient to industrial-scale production; The external magnetic field that the present invention applies Nd-Fe-B powder particle is greater than 1.5T, thereby the magnetostatic agglomerating force between Nd-Fe-B powder particle is disappeared, and is easier to make the c-axis rotation of magnetic direction outward of Nd-Fe-B powder particle, has improved production efficiency.
Brief description of the drawings
Fig. 1 is according to the initial loose state of Nd-Fe-B powder particle A, B in an embodiment of the method for the degree of orientation of raising Nd-Fe-B powder particle of the present invention.
Fig. 2 is the poised state of Nd-Fe-B powder particle A, B while applying the external magnetic field that is greater than 1.5T.
Fig. 3 is applying the instantaneous state separately time of Nd-Fe-B powder particle A, B after the vibration wave basis of external magnetic field (keep on).
Fig. 4 is the end-state of Nd-Fe-B powder particle A, B.
Main description of reference numerals:
1-powder particle A, 2-powder particle B, the c-axis of 3-powder particle A, the c-axis of 4-powder particle B, 5-outer magnetic field direction H.
Detailed description of the invention
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in detail, but is to be understood that protection scope of the present invention is not subject to the restriction of detailed description of the invention.
Unless separately there is other clearly to represent, otherwise in whole description and claims, term " comprises " or its conversion was stated being understood to include as " comprising " or " including " etc. element or part, and do not get rid of other element or other part.
Under original state, multiple Nd-Fe-B powder particles are contained in die cavity, all Nd-Fe-B powder particle entirety externally show isotropism, their c-axis random distribution, Nd-Fe-B powder particle A shown in Fig. 1 and B are that wherein two represent particle, the angle of Nd-Fe-B powder particle A and external magnetic field H is α, Nd-Fe-B powder particle B consistent with the direction of external magnetic field H (angle is 0).
According to the method for the degree of orientation of the raising Nd-Fe-B powder particle of the specific embodiment of the invention, comprise the steps:
Nd-Fe-B powder particle in die cavity is applied to external magnetic field H, and the magnetic induction intensity of external magnetic field H is greater than 1.5T;
After Nd-Fe-B powder particle averages out in magnetic field, in the situation of maintenance external magnetic field H, Nd-Fe-B powder particle is applied to vibration wave.
In the time that Nd-Fe-B powder particle is in magnetic field, external magnetic field H is the motive force that the c-axis that promotes Nd-Fe-B powder particle turns to outer magnetic field direction to the magnetostatic torque force of Nd-Fe-B powder particle, and the resistance of the frictional force being in contact with one another between mechanical resistance between the irregular powder particle of magnetostatic agglomerating force, profile between Nd-Fe-B powder particle and powder particle to be the c-axis that hinders Nd-Fe-B powder particle turn to outer magnetic field direction.
In the time that the magnetic induction intensity of external magnetic field H is greater than 1.5T, the aggregating state of Nd-Fe-B powder particle will be broken, magnetostatic agglomerating force has also just disappeared, and therefore Nd-Fe-B powder particle is only subject to mechanical resistance and the frictional force between magnetostatic torque force and the Nd-Fe-B powder particle of external magnetic field H.
Taking two Nd-Fe-B powder particles in scheming as example, while just having applied external magnetic field H, the magnetostatic running torque load moment that Nd-Fe-B powder particle A is subject to is greater than mechanical resistance and the common torque producing of frictional force, the c-axis of Nd-Fe-B powder particle A rotates to outer magnetic field direction H under the effect of magnetostatic torque force, along with the angle α between c-axis and the external magnetic field H of rotation Nd-Fe-B powder particle A diminishes gradually, magnetostatic running torque load moment is also diminishing gradually, and the common torque producing of mechanical resistance and frictional force is constant, in the time that these two kinds of moments equate, Nd-Fe-B powder particle A stressed reaches balance and stops the rotation, now the c-axis of powder particle A and the direction of external magnetic field do not reach consistent, as shown in Figure 2.In addition, because Nd-Fe-B powder particle A has produced impact to Nd-Fe-B powder particle B when rotated, be subject to the torque of Nd-Fe-B powder particle A, the c-axis of Nd-Fe-B powder particle B also produces rotation, angle under the state stopping the rotation reaching balance between c-axis and the external magnetic field H of Nd-Fe-B powder particle B is β, as shown in Figure 2.
Reach after balance at Nd-Fe-B powder particle, on the basis that keeps external magnetic field H, Nd-Fe-B powder particle is applied to vibration wave (to the parameter such as wavelength, frequency of vibration wave without particular/special requirement), while making Nd-Fe-B powder particle under the effect of vibration, timesharing is poly-.The moment (as shown in Figure 3) of dividing out at Nd-Fe-B powder particle A and B, Nd-Fe-B powder particle A and B are all only subject to the magnetostatic running torque load moment of external magnetic field H, therefore Nd-Fe-B powder particle A and B produce rotation separately, make their c-axis consistent with the direction of external magnetic field H, as shown in Figure 4.
Because the degree of orientation of Nd-Fe-B powder particle can not directly be measured, in order to prove the effect of method of the degree of orientation of raising of the present invention Nd-Fe-B powder particle, carry out indirect reaction by the degree of orientation of measuring the Nd-Fe-B magnet steel of sintering after complete:
Get the Nd-Fe-B powder particle of two parts of same lot numbers, in the identical situation of other process conditions, in molding procedure, first part of Nd-Fe-B powder particle applied vibration wave of the present invention in the time of orientation, and second part does not apply vibration wave.
Through measuring the degree of orientation of the Nd-Fe-B magnet steel after sintering completes, the degree of orientation Jr/Js scope that first part of Nd-Fe-B powder particle burns the magnet steel is between 0.93～0.96, and the degree of orientation Jr/Js scope that second part of Nd-Fe-B powder particle burns the magnet steel is between 0.82～0.87.
Above-mentioned measurement result has absolutely proved that Nd-Fe-B powder particle is applied to vibration wave has played important positive role to the degree of orientation of magnet steel.
The present invention makes the c-axis of Nd-Fe-B powder particle more easily turn to the direction of external magnetic field by Nd-Fe-B powder particle being applied to vibration wave, thereby has improved the degree of orientation of magnet steel, and the cost that applies in addition vibration wave is lower, simple, is convenient to industrial-scale production; The external magnetic field that the present invention applies Nd-Fe-B powder particle is greater than 1.5T, thereby the magnetostatic agglomerating force between Nd-Fe-B powder particle is disappeared, and is easier to make the c-axis rotation of magnetic direction outward of Nd-Fe-B powder particle, has improved production efficiency.
The aforementioned description to concrete exemplary of the present invention is in order to illustrate and the object of illustration.These descriptions not want the present invention to be defined as disclosed precise forms, and obviously, according to above-mentioned instruction, can much change and change.Exemplary embodiment is selected and the object described is to explain certain principles of the present invention and practical application thereof, thereby made those skilled in the art can realize and utilize various exemplary of the present invention and various selection and change.Scope of the present invention is intended to be limited by claims and equivalents thereof.
Claims (2)
1. a method that improves the degree of orientation of Nd-Fe-B powder particle, is characterized in that, described method comprises:
Multiple Nd-Fe-B powder are contained in die cavity;
Nd-Fe-B powder particle in described die cavity is applied to external magnetic field, described Nd-Fe-B powder particle is rotated under the effect of magnetostatic torque force, thus make mechanical resistance between magnetostatic running torque load moment and described Nd-Fe-B powder particle that described Nd-Fe-B powder particle is subject to and the common torque phase producing of frictional force with;
On the basis that keeps described external magnetic field, described Nd-Fe-B powder particle is applied to vibration wave, in the time that adjacent Nd-Fe-B powder particle separates, described Nd-Fe-B powder particle is only subject to the effect of the magnetostatic torque force of described external magnetic field, thereby makes described Nd-Fe-B powder particle turn to the direction of described external magnetic field.
2. the method for the degree of orientation of raising Nd-Fe-B powder particle according to claim 1, is characterized in that, the magnetic induction intensity of described external magnetic field is greater than 1.5T.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110732399A (en) * | 2019-09-30 | 2020-01-31 | 包头韵升强磁材料有限公司 | method for improving outturn percentage of sintered neodymium iron boron jet mill powder |
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| JP3307418B2 (en) * | 1992-02-21 | 2002-07-24 | ティーディーケイ株式会社 | Molding method and method for manufacturing sintered magnet |
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| JP2011216711A (en) * | 2010-03-31 | 2011-10-27 | Nitto Denko Corp | Apparatus and method for manufacturing rare earth magnet |
| CN102909369A (en) * | 2012-11-01 | 2013-02-06 | 山西京宇天成科技有限公司 | Neodymium iron boron vibration magnetic field molding press device |
| CN103093921A (en) * | 2013-01-29 | 2013-05-08 | 烟台首钢磁性材料股份有限公司 | R-T-B-M-C sintered magnet, manufacturing method thereof and special device |
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| JP3307418B2 (en) * | 1992-02-21 | 2002-07-24 | ティーディーケイ株式会社 | Molding method and method for manufacturing sintered magnet |
| CN1258919A (en) * | 1998-12-28 | 2000-07-05 | 北京市石景山区京磁技术公司 | Forming method of sintered anisotropic magnet |
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| CN110732399A (en) * | 2019-09-30 | 2020-01-31 | 包头韵升强磁材料有限公司 | method for improving outturn percentage of sintered neodymium iron boron jet mill powder |
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Application publication date: 20140910 |