CN105448444A - Method for preparing rare-earth permanent magnetic material with improved performance and rare-earth permanent magnetic material - Google Patents

Method for preparing rare-earth permanent magnetic material with improved performance and rare-earth permanent magnetic material Download PDF

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CN105448444A
CN105448444A CN201410729369.6A CN201410729369A CN105448444A CN 105448444 A CN105448444 A CN 105448444A CN 201410729369 A CN201410729369 A CN 201410729369A CN 105448444 A CN105448444 A CN 105448444A
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rare earth
earth metal
magnet
rare
magnetic material
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CN105448444B (en
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赵玉刚
陈国安
张瑾
钮萼
王浩颉
陈治安
叶选涨
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Beijing Zhong Ke San Huan High Tech Co Ltd
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Beijing Zhong Ke San Huan High Tech Co Ltd
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Priority to PCT/CN2015/095280 priority patent/WO2016086777A1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/06—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H01F1/08—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets

Abstract

The invention discloses a method for preparing a rare-earth permanent magnetic material and the rare-earth permanent magnetic material. The method comprises the step as follows: after a blank pressing procedure and before an isostatic pressing procedure, rare-earth source powder is arranged on the surface, vertical to a magnetic field orientation direction, of the pressed blank on the condition that the weight percentage of a heavy rare-earth element in the rare-earth source powder is not lower than those of other rare-earth elements. Due to the rare-earth element adding step after the blank is pressed, products with various shapes and sizes can be fabricated; the method is simple in technological process; improvement of Hcj is achieved under the premise of not changing a traditional process route; and distribution of the Hcj is uniform.

Description

The method of the rare earth permanent-magnetic material that a kind of processability is improved and rare earth permanent-magnetic material
Technical field
The present invention generally relates to the production method of rare earth permanent-magnetic material, more specifically, relates to preparation method and the rare earth permanent-magnetic material of the agglomeration permanent magnetic material that a kind of magnetic property improves.
Background technology
Because automobile and electronic application field are to the demand of energy-saving motor, the sintered NdFeB of being used widely in the fields such as VCM, motor, signal generator, mobile phone and MRI is further expanded in the application in motor market.The raising of the magnetic property such as remanent magnetism and coercive force promotes the quick growth of sintered magnet in motor market.
How giving full play to the intrinsic characteristic of neodymium iron boron principal phase, improve the HCJ (Hcj, hereinafter also referred to as coercive force) of sintered NdFeB, is the problem of current hotspot research.In fusion process, adding the heavy rare earth elements such as Dy, Tb, make the Nd in its aliquot replacement magnet to improve the coercive force of sintered NdFeB magnet, is a kind of well-known effective ways.Because Dy 2fe 14b or Tb 2fe 14b has and compares Nd 2fe 14the magnetocrystalline anisotropy field that B is higher, namely has larger theoretical HCJ.Dy, Tb part replaces principal phase Nd 2fe 14the solid solution phase (Nd, Dy) generated after Nd in B 2fe 14b or (Nd, Tb) 2fe 14the magnetocrystalline anisotropy field of B compares Nd 2fe 14b is large, thus can significantly improve the coercive force of sintered magnet.But this element replaces the negative consequence brought, be exactly the saturation magnetization significantly reducing magnet, therefore the remanent magnetism of magnet and maximum magnetic energy product all can obviously reduce.Because at Nd 2fe 14in B principal phase, the magnetic moment forward of Nd and Fe is arranged in parallel, and both magnetic moments are enhancement superpositions; And Dy/Tb and Fe is antiferromagnetic coupling, the magnetic moment of Dy/Tb and Fe magnetic moment antiparallel arrangements, total magnetic moment of partial offset principal phase.In addition, rare and distribution is very uneven containing the mineral reserve reserves of Dy, Tb for Nd, Dy, Tb unit price is far above Nd, and this replacement can cause magnet cost to increase.
In recent years, some new techniques were used to the HCJ improving Sintered NdFeB magnet.First methods such as passing through coating, deposition, plating, sputter, cover makes magnet outside cover containing heavy rare earth element, as metal dust or the compound of Dy or Tb, makes heavy rare earth element through grain boundary decision in sintered magnet principal phase by heat treatment.In heat treatment process, crystal boundary rich-Nd phase liquefies because of heating, and the diffusion velocity of the Dy/Tb in crystal boundary is faster compared with the diffusion velocity of principal phase inside particles with from crystal boundary.Utilize this diffusion velocity poor, adjustment heat treatment temperature and time, very thin, continuous print, rich heavy rare earth element a shell will be produced between sintered body principal phase and Nd-rich phase.Because the anisotropy of NdFeB sintered magnet coercive force by principal phase particle determines, therefore the NdFeB sintered magnet of principal phase outer cladding high concentration heavy rare earth element shell has high-coercive force.And the higher region of this concentration is only limitted to the surf zone of each principal phase particle, then as principal phase particle, generally heavy rare-earth element content is lower, and therefore remanent magnetism (Br) does not reduce substantially.
Such as, the open No.CN1898757A of the patent application of KCC of Japanese SHIN-ETSU HANTOTAI gives a kind of plating technology of magnet surface.Sintering blank is processed into little and thin magnet, with being scattered in the slurries dip-coating magnet formed in water or organic solvent by heavy rare earth micron order fine powder, then under vacuum or inert gas atmosphere, higher than under sintering temperature, magnet is not being heat-treated.Result makes coercive force have more raising, and remanent magnetism does not reduce substantially.This method had both saved the use of heavy rare earth, inhibit again the decline of remanent magnetism.
But the data display that the website as Hitachi Metals is announced, adopt grain boundary decision method, in magnet, the distribution of HCJ is even not, and comparatively mid portion is high for the coercive force namely near each limit place of material.
In the large-scale production of visible grain boundary decision legal system for NdFeB sintered magnet, some problems demand are still had to solve.The standby NdFeB magnet product size of grain boundary decision legal system is relatively little, and thickness of sample requires to be approximately 5mm and following, which has limited the application of this technology in large-scale production.Coercitive skewness in the magnet of grain boundary decision method process.From the angle of technique, grain boundary decision technology belongs to post-processing approach, being the method by heat-treating again after magnet surface covers heavy rare earth after having prepared sintered magnet, there is treatment process long, high in cost of production defect.
Therefore still have that development technology is more simple, cost reduces, be suitable for processing the permanent magnetic material of all size shape, reduce the interpolation of heavy rare earth and improve the method for magnet combination property.
Summary of the invention
For problems of the prior art, the present invention aims to provide a kind of preparation method of new R-T-B type rare-earth permanent magnet.The method does not change traditional handicraft substantially, also without the need to the aftertreatment technology step of complexity, improves the HCJ of magnet under the prerequisite of substantially not losing remanent magnetism, thus simplifies technique, reduces cost.
According to a first aspect of the invention, a kind of method preparing rare earth permanent-magnetic material is provided, the method comprises: after slug press operation, and before isostatic pressed operation, rare earth source power is arranged in the face of suppressed blank perpendicular to magnetic field orientating direction, and prerequisite is the percentage by weight that the percentage by weight of heavy rare earth element in described rare earth source power is not less than other rare earth elements.
Arrange the blank after rare earth source power carry out isostatic pressed compacting by described, and carry out sintering circuit.Described rare earth source can be by least one in the nitrate hydrate of the oxide of the fluoride of the hydride of the alloy of rare earth metal, rare earth metal, rare earth metal, rare earth metal, rare earth metal, the oxyfluoride of rare earth metal and rare earth metal.
Described rare earth metal is at least one be selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, is preferably at least one in Pr, Nd, Tb and Dy.
Described heavy rare earth metal is at least one be selected from Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.Be preferably Tb, Dy and/or Ho.
The alloy of rare earth metal can be expressed as R 1 a-M 1 b, wherein R 1be selected from least one in rare earth metal, M 1be be selected from Al, Si, C, P, Ti, V, Cr, Mn, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, Hf, Ta, W, Pb and Bi Zhi Shao ー kind element, " a " and " b " represents atomic percentage, and scope is: 15<b≤99, surplus is a.
The alloy of described rare earth metal also can be expressed as R 1 xt 1 ym 1 z, wherein R 1be selected from least one in rare earth metal, T 1be be selected from Fe and Co Zhi Shao ー kind element, M 1be be selected from Al, Si, C, P, Ti, V, Cr, Mn, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, Hf, Ta, W, Pb and Bi Zhi Shao ー kind element, x, y and z represent atomic percentage, and scope is: 5≤X≤85,15<Z≤95, surplus is y and y is greater than 0.
Preferably, R 1at least containing a kind of heavy rare earth metal.
The alloy of above-mentioned rare earth metal preferably comprises intermetallic compound or the 2:14:1 phase structure rare earth compound of at least 70 volume %.
For example, rare earth intermetallic compound comprises and has MgCu 2the intermetallic compound of type structure, R 1cu 2, as TbCu 2deng, but be not limited thereto.
The hydride of rare earth metal such as has DyH x, TbH xdeng, but be not limited thereto.
The granularity of described rare earth source power can be 2 ~ 100 μm, is preferably 3 ~ 20 μm.
Above-mentioned rare earth source power directly can be arranged in blank perpendicular on the surface of magnetic field orientating.
Above-mentioned rare earth source power also dispersibles and forms slurries in a suitable solvent, slurries is evenly coated in blank perpendicular on the surface of magnetic field orientating.Have various ways to apply, such as, spray, brushing etc.Solvent can be one or more in alcohols, ester class or alkane, as long as be beneficial to powder dispersion, be easy to coating, and this method or product is not produced to the solvent of ill-effect.
The layout of above-mentioned rare earth source power also can adopt and rare earth source power is pressed into certain thickness, such as, after the pressed compact of 0.5 ~ 1mm, covers blank perpendicular to the mode on the surface of magnetic field orientating.Overall compacting in isostatic pressed subsequently.
The blank direction of orientation of preferably suppressing has≤thickness of 20mm, and more preferably≤10mm, such as thickness is within the scope of 5 ~ 10mm.
Preferably, the heap(ed) capacity in rare earth source, with rare earth permanent-magnetic material prepared in the unit are being furnished with the surface of described rare earth source power with arrange described rare earth source power before the weight difference of slug press represent, be 0.1 ~ 50mg/cm 2, preferably 0.5 ~ 15mg/cm 2.Method of the present invention except described on the face of suppressed blank perpendicular to magnetic field orientating direction, arrange the operation of heavy rare earth source power except, other operations all can adopt normal process steps, typically comprise the operation of melting, coarse crushing, micro mist processed, die mould, isostatic pressed and sintering and tempering.
Certainly, one or more operation can be increased as required, as surface-treated operation can be comprised further after tempering process, such as remove the unnecessary rare earth active layer of arranging, as can machine-tooled method be adopted, by material surface, the surface being particularly furnished with rare earth source power processes, and obtains the magnet that smooth surface is smooth.Again such as, also the operation etc. magnetized can be comprised further.Certainly, also one or more operation can be reduced, such as, when obtaining melted material, can directly from coarse crushing operation.
According to a second aspect of the invention, a kind of sintered rare-earth permanent magnetic material is provided, described material by magnet surface along magnetic field orientating direction to magnet inner 500 μm of degree of depth, heavy rare-earth element content reduces gradually, and wherein main phase grain has the core-shell structure comprising shell portion and core, wherein the content of core heavy rare earth element is lower than the content of shell portion heavy rare earth element, and the two at least differs 1at.%.
Preferably, the content of core heavy rare earth element differs 1 ~ 4at.% with the content of shell portion heavy rare earth element.
According to a kind of execution mode, sintered rare-earth permanent magnetic material of the present invention by magnet surface along magnetic field orientating direction to magnet inner 500 μm of degree of depth, have at least the main phase grain of 50% to have described core-shell structure.Further, by magnet surface along magnetic field orientating direction to magnet inner 200 μm of degree of depth, have at least the main phase grain of 70% to have described core-shell structure.
According to a kind of execution mode, the remanent magnetism of sintered rare-earth permanent magnetic material of the present invention declines compared to the sintering system permanent magnetic material not adding heavy rare earth element and is no more than 0.010T, preferably more than 0.005T.In sintered rare-earth permanent magnetic material of the present invention, HCJ is no more than 20kAm in the value difference at edge of materials place and distance material surface same distance place, material middle part -1, preferably more than 10kAm -1.
Rare earth permanent-magnetic material prepared by method of the present invention is R-T-B type magnet material.Wherein R is rare earth element, comprises at least one heavy rare earth element and at least one other rare earth elements except heavy rare earth element.At least one of other rare earth elements preferably in Nd, Pr, La, Ce, Sm, Sc, Y and Eu except heavy rare earth element, is more preferably Nd or Pr.T is Fe and/or Co.Alternatively, T also can comprise at least one be selected from Al, Cu, Zn, In, Si, P, S, Ti, V, Cr, Mn, Ni, Ga, Ge, Zr, Nb, Mo, Pd, Ag, Cd, Sn, Sb, Hf, Ta and W.B is boron.Described material also contains micro-requisite impurity element, as carbon, nitrogen, oxygen etc.
According to preferred embodiment, B accounts for 3 ~ 15 atom % of whole alloy, particularly 4 ~ 8 atom %.R accounts for 10 ~ 15 atom % of whole alloy, particularly 12 ~ 15 atom %.T representative comprises the one or more of elements being selected from Al, Cu, Zn, In, Si, P, S, Ti, V, Cr, Mn, Ni, Ga, Ge, Zr, Nb, Mo, Pd, Ag, Cd, Sn, Sb, Hf, Ta and W of 0 ~ 11 atom %, particularly 0.1 ~ 5 atom %.Surplus is the incidental impurities of Fe and/or Co and such as C, N and O.Preferably, Fe accounts at least 50 atom % of whole alloy, particularly at least 65 atom %.Co can replace part Fe, 0 ~ 40 atom % of such as Fe, particularly 0 ~ 15 atom %.
According to the 3rd invention of the present invention, provide a kind of rare earth permanent-magnetic material prepared according to said method.
Method of the present invention can improve the magnetic property of sintered magnet, and at least the growth of 1kOe and Br just slightly decline to realize HCJ.Owing to carrying out the step of adding rare earth element when first pressing blank, therefore the use of the method does not limit scantling and shape, can be used for the magnet preparing all size and shape, and is not limited only to small-size materials.
The most important thing is the method reduce heavy rare earth addition and do not change conventional processing routes condition under, preparation process simply, realizes the raising of magnet HCJ, and being evenly distributed of HCJ.
Accompanying drawing explanation
Fig. 1 is for illustrating the uniform schematic diagram of inner coercivity profile in sintered rare-earth permanent magnetic material of the present invention;
Fig. 2 is the SEM photo of the nearly surface of sintered rare-earth permanent magnetic material section of the present invention;
Fig. 3 is the SEM photo of sintered rare-earth permanent magnetic material section of the present invention apart from 200 μm, surface place; With
Fig. 4 is the SEM photo of sintered rare-earth permanent magnetic material section of the present invention apart from 500 μm, surface place.
Embodiment
With reference to preferred implementation and the specific embodiment of accompanying drawing and following detailed description, various aspects of the present invention and above-mentioned and other advantage are described in further detail.It will be understood by those skilled in the art that these contents described below are to understand the present invention better, scope of the present invention is not limited to this.
Term definition:
The blank mentioned herein, refer to the blank for the preparation of R '-T-B type magnet material, wherein R ' is selected from least one in rare earth element, preferably at least comprises Nd or Pr.T is iron (Fe) and/or cobalt (Co).Alternatively, T also can comprise to be selected from by Al, Cu, Zn, In, Si, P, S, Ti, V, Cr, Mn, Ni, Ga, Ge, Zr, Nb, Mo, Pd, Ag, Cd, Sn, Sb, Hf, Ta and W form at least one in group.B is boron.In addition, also containing micro-requisite impurity element, as carbon, nitrogen, oxygen etc.
The R '-T-B type magnet mentioned herein refers to the rare-earth-iron/cobalt-B magnet that with the addition of heavy rare earth metal or do not add heavy rare earth metal.R ' and T as defined above.Described R '-T-B type magnet can adopt traditional sintering process preparation, also can adopt existing sintering-grain boundary diffusion process preparation.
R-T-B type magnet material herein refers to the permanent magnetic material that method according to the present invention prepares.Wherein R comprises at least one heavy rare earth element and at least one other rare earth elements except heavy rare earth element.Other rare earth elements except heavy rare earth element to be preferably selected from by Nd, Pr, La, Ce, Sm, Sc, Y and Eu form at least one in group, more preferably at least containing Nd or Pr.T is Fe and/or Co.Alternatively, T also can comprise to be selected from by Al, Cu, Zn, In, Si, P, S, Ti, V, Cr, Mn, Ni, Ga, Ge, Zr, Nb, Mo, Pd, Ag, Cd, Sn, Sb, Hf, Ta and W form at least one in group.B is boron.Described material also contains micro-requisite impurity element, as carbon, nitrogen, oxygen etc.
Coercive force herein, unless stated otherwise, refers to HCJ (H cj).
Routine (or tradition) sintering process (or method) herein refers to the technique (or method) at least comprising coarse crushing, micro mist processed, slug press, isostatic pressed and sintering circuit.
Not at other terms of this definition, its implication is the usual definition of association area.
In order to improve with Nd-Fe-B the coercive force of the R '-T-B type magnet being representative, conventional grain boundary decision method adheres to heavy rare earth metal on sintered magnet surface by the method such as coating, deposition, plating, sputtering at present, make heavy rare earth metal through grain boundary decision in sintered magnet principal phase by heat treatment again, thus on magnet, form the heavy rare earth metal shell that heavy rare earth metal density from outside to inside reduces gradually.The method can effectively improve magnet coercive force, and remanent magnetism declines not remarkable.
But this method also exists increases too much additional process, and the problem of the only sintered magnet that suitable dimensions is less.And coercivity profile is uneven.
The method with the sintering R-T-B type permanent magnet material of the HCJ of improvement provided by the invention is the improvement on the Process ba-sis of traditional sintered magnet.The technique of traditional sintered magnet generally includes melting, coarse crushing, micro mist processed, die mould, isostatic pressed and sintering circuit, and the present invention increases an operation between slug press operation and isostatic pressed operation: on the face of suppressed blank perpendicular to magnetic field orientating direction, arrange rare earth source power.
According to a kind of execution mode, method of the present invention comprises:
Raw material are prepared by melting: in proportion in proportion, melt in Strip casting stove (stripcasting), with the copper roller linear velocity of >=1m/s, carry out scale casting, finally obtain the bar strap of thickness 0.2 ~ 0.5mm.
The method of Strip casting also can be replaced by other methods with effects equivalent, such as, can pour into a mould in flat pattern mold (flatmold) or stack mould (bookmold), also can adopt (two or many) alloyage.
Coarse crushing: bar strap is carried out hydrogenation fragmentation (HD) process, obtain middle flour, be generally the size of the size of 0.05 ~ 3mm, particularly 0.05 ~ 1.5mm.Hydrogen content control range is 800 ~ 3000ppm.
Blang's pulverizer also can be used to carry out coarse crushing.But preferably adopt (hydrogenation) to pulverize for the alloy prepared by strip casting method
Micro mist processed: middle flour is carried out airflow milling powder, particle size scope D50 is 2 ~ 8 μm, particularly (3.5 ~ 7) μm, typically be D50=3 ~ 6 μm (particle size is obtained by laser diffraction measurement method, D50 to be weight accumulated value be 50% particle diameter).
Device for micro mist processed can also be ball mill or high energy ball mill.
Die mould: at pressue device, as being pressed in sealing vertical press (magnetic field intensity is >1.4T).Wherein blank is≤20mm along the thickness of magnetic direction.First percent consolidation (greendensity) can reach such as 3.6-4.2g/cm 3.(first percent consolidation <3.6g/cm 3time, blank cannot be effectively shaping; First percent consolidation >4.2g/cm 3time, heavy rare earth source cannot compound effective in matrix blank)
Arrange rare earth source power: on the face of suppressed blank perpendicular to magnetic field orientating direction, arrange heavy rare earth source power, particle size 2 ~ 100 μm, be preferably 3 ~ 20 μm.
Rare earth source power refers to the material that can provide rare earth metal in subsequent handling to magnet.Such as, rare earth source can be rare earth metal, or the alloy of rare earth metal, hydride, fluoride, oxide, oxyfluoride or nitrate hydrate.
The rare earth source power loaded can be the one in these materials above, also can be the mixture of two or more.Prerequisite is the percentage by weight that in loaded rare earth source power, the percentage by weight of heavy rare earth metal is no less than other rare earth metals except heavy rare earth metal.
The alloy of rare earth metal can be expressed as R 1 a-M 1 bor R 1 xt 1 ym 1 z.Wherein R 1rare earth metal, preferably at least containing a kind of heavy rare earth metal.That is, can containing a kind of, two or more rare earth metals in the alloy of rare earth metal, preferred at least one is heavy rare earth metal.M 1be be selected from by Al, Si, C, P, Ti, V, Cr, Mn, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, Hf, Ta, W, Pb and Bi form in group Zhi Shao ー kind element.T 1be be selected from Fe and Co Zhi Shao ー kind element.A and b; X, y and z represent atomic percentage.For R 1 a-M 1 btype alloy 15<b≤99, surplus is a.For R 1 xt 1 ym 1 ztype alloy 5≤x≤85,15<z≤95, surplus is y and y is greater than 0.
The alloy of rare earth metal preferably comprises the intermetallic compound of at least 70 volume % or the rare earth compound of 2:14:1 phase structure.
Such as, the alloy of rare earth metal can be the compound with 2:14:1 structure, R 1 2fe 14b, as Dy 2fe 14b etc.; Or there is MgCu 2the intermetallic compound of type structure, R 1cu 2, as TbCu 2deng.
The hydride of rare earth metal can be R 1h x, such as DyH x, TbH x.
The fluoride of rare earth metal can be R 1f n, but be generally R 2f 3; Oxide can be R 1o n, but be generally R 1 2o 3; Oxyfluoride can be R 1o mf n, but be generally R 1oF.Wherein m and n is positive count respectively.
The nitrate hydrate of rare earth metal can be Dy (NO 3) 35H 2o etc.
Preferably, R 1at least containing a kind of heavy rare earth metal.
It is 2 ~ 100 μm that rare earth metal source can be made into granularity, is preferably the powder of 3-20 μm, to be arranged in blank equably perpendicular on the surface of magnetic field orientating.
Also above-mentioned rare earth source power dispersion can be formed slurries, in a suitable solvent to be evenly coated in blank perpendicular on the surface of magnetic field orientating.Have various ways to apply, such as, spray, brushing etc.Solvent can be one or more the combination in alcohols, ester class or alkane equal solvent.
Any other can certainly be adopted heavy rare earth metal source can be overlayed on process on blank.Such as, above-mentioned heavy rare earth metal source power is pressed into the pressed compact of 1mm, carries out compound with matrix pressed compact.
The heap(ed) capacity in rare earth source, to be furnished with in the unit are of described rare earth source power, prepared rare earth permanent-magnetic material with arrange that the weight difference of slug press represents before described rare earth source power, be 0.1 ~ 50mg/cm 2, preferably 0.5 ~ 15mg/cm 2.
Particularly, the heap(ed) capacity in rare earth source is weight by measuring slug press and the difference obtaining the two through the weight that following steps finally obtain rare earth permanent-magnetic material of the present invention, again divided by the gross area on surface being furnished with rare earth source power, the area namely perpendicular to the face (being generally upper and lower surfaces) in magnetic field orientating direction obtains.
Isostatic pressed: packed by blank with polybag or plastic sheet or rubber pattern, carry out isostatic pressed, the pressure of isostatic pressed is 170 ~ 210MPa.
Sintering and tempering: in vacuum sintering furnace, carry out vacuum-sintering, sintering temperature is 900 ~ 1150 DEG C, be preferably 1020 ~ 1100 DEG C, sintering time 1 ~ 6 hour, is then filled with Ar gas and is cooled to less than 100 DEG C; Again be warmed up to 800 ~ 1000 DEG C and be incubated 1 ~ 5 hour, then filling Ar gas and be cooled to less than 100 DEG C; Then, continue to be warmed up to 450 ~ 620 DEG C and be incubated 1 ~ 8 hour and fill Ar gas cool to room temperature.
Surface treatment: usually can comprise this operation, to obtain the smooth magnet of smooth surface.Such as adopt machine-tooled method, remove the unnecessary rare earth active layer of arranging.Surface treatment procedure is familiar with by those skilled in the art, thus repeats no more.
Method according to the present invention prepares R-T-B type magnet material.Wherein R is rare earth element, comprises at least one heavy rare earth element and at least one other rare earth elements except heavy rare earth element.Other rare earth elements except heavy rare earth element to be preferably selected from by Nd, Pr, La, Ce, Sm, Sc, Y and Eu form at least one in group, be more preferably Nd or Pr.T is Fe and/or Co.Alternatively, T also can comprise to be selected from by Al, Cu, Zn, In, Si, P, S, Ti, V, Cr, Mn, Ni, Ga, Ge, Zr, Nb, Mo, Pd, Ag, Cd, Sn, Sb, Hf, Ta and W form at least one in group.B is boron.Described material also contains micro-requisite impurity element, as carbon, nitrogen, oxygen etc.
According to preferred embodiment, B accounts for 3 ~ 15 atom % of whole alloy, particularly 4 ~ 8 atom %.R accounts for 10 ~ 15 atom % of whole alloy, particularly 12 ~ 15 atom %.T representative comprises the one or more of elements being selected from Al, Cu, Zn, In, Si, P, S, Ti, V, Cr, Mn, Ni, Ga, Ge, Zr, Nb, Mo, Pd, Ag, Cd, Sn, Sb, Hf, Ta and W of 0 ~ 11 atom %, particularly 0.1 ~ 5 atom %.Surplus is the incidental impurities of Fe and/or Co and such as C, N and O.Preferably, Fe accounts at least 50 atom % of whole alloy, particularly at least 65 atom %.Co can replace part Fe, 0 ~ 40 atom % of such as Fe, particularly 0 ~ 15 atom %.
In sintered rare-earth permanent magnetic material of the present invention, the distribution of heavy rare earth metal is by magnet surface inner shell-type distribution presenting concentration and reduce gradually along magnetic field orientating direction to magnet.Wherein getting over 500 μm of degree of depth apart from magnet surface, heavy rare earth metal content reduces gradually, and to distance magnet surface about 1000 μm place, the content of heavy rare earth metal is 0 substantially.
In addition, carry out analysis to the section of sintered magnet material of the present invention and find, the region distributed there being heavy rare earth metal, main phase grain has core-shell structure.With reference to figure 2, the electron scanning micrograph display of material section, crystal grain has obvious shell portion (color is more shallow) and core (color is darker).Pass through the elementary analysis to the crystal grain different parts in a large number with core shell structure, find the content of content lower than shell portion heavy rare earth metal of core heavy rare earth metal, the two at least differs 1at.%, most difference 1 ~ 4at.%.
In addition sintered rare-earth permanent magnetic material of the present invention by magnet surface along magnetic field orientating direction to magnet inner 500 μm of degree of depth, have at least the main phase grain of 50% to have described core-shell structure; And the inner 200 μm of degree of depth of the magnet that arrives, then have at least the main phase grain of 70% to have described core-shell structure.
According to the magnetic property analysis to sintered rare-earth permanent magnetic material of the present invention, prepare with employing conventional sintering technique but additionally do not add compared with the sintered magnet of heavy rare earth metal, the remanent magnetism of magnet material of the present invention declines and is no more than 0.010T, is no more than 0.005T according to preferred implementation.
Further the analysis of HCJ in sintered rare-earth permanent magnetic material of the present invention at material different parts is found, coercitively in magnet material of the present invention to distribute very evenly.Wherein the coercive force difference at edge of materials place and distance material surface same distance place, material middle part is no more than 20kAm -1, be no more than 10kAm according to preferred implementation -1.And the coercive force in magnet (pointed by Hitachi Metals) its bight adopting grain boundary decision legal system standby, edge and heart portion characterizes uneven.
The present invention utilizes the method for isostatic pressed that pressed compact matrix and rare earth powder are carried out close fit, and compared with grain boundary decision method, its bond strength improves, and applies effective, is conducive to uniformity and the consistency of follow-up diffusion process.Therefore, method of the present invention is operation simple (without the need to reprocessing) not only, and evenly can improve the magnetic property of magnet unexpectedly.In addition because introduce heavy rare earth metal after the slug press stage, therefore this method can prepare the finished product magnet of any shape, is also better than grain boundary decision method to the restriction aspect of size.
The present invention is further illustrated below by specific embodiment.
Embodiment 1
Raw material purity being greater than 99wt% prepare in proportion, and alloying component percentage by weight is (PrNd) 28.5d y2.5al 0.8co 1.0cu 0.1fe balb 0.97, melt in the Strip casting stove (stripcasting) of 600Kg/ time, with the linear velocity of the running roller of 1.5m/s per second, carry out scale casting, finally obtain the bar strap of thickness 0.3mm.Bar strap is carried out HD process, obtains middle flour, its hydrogen content is 2000ppm.By flour input air flow mill in obtaining, obtain the micro mist of D50=5.0 micron, by obtained micro mist mixed powder in mixed powder machine, mixed powder carries out following process again.
Adopt vertical pressure, orientation field intensity is 1.4T, and slug press is 30mm × 30mm × 10mm, and wherein 10mm is direction of orientation, measures slug press weight, and suppressed blank is evenly applied 60%DyF along the upper and lower end face of direction of orientation 3with the mixed-powder of 40% 5 nitric hydrate dysprosium, powder weight is 3g, particle size is 10um, then plastic bag packaging is used to carry out isostatic pressed, isostatic pressed pressure is 170MPa, blank after isostatic pressed is carried out vacuum-sintering, sinters in vacuum sintering furnace, be filled with Ar gas after sintering temperature 1070 DEG C × 2h to carry out being cooled to about 80 DEG C, be again warmed up to 900 DEG C and fill Ar gas after being incubated 1 hour and carry out being cooled to about 80 DEG C.Follow-up continuous be warmed up to 480 DEG C and be incubated 2 hours and fill after Ar is cooled to 80 DEG C come out of the stove, after the blank after coming out of the stove adopts mill processing mode to remove overlay, measurement products weight, the heap(ed) capacity calculating products obtained therefrom middle rare earth source is 0.1mg/cm 2, re-use Linear cut mode processed sample, sample size is D10mm × 7mm (7mm direction is direction of orientation), and magnetic property measured by gained sample.
Comparative example 1
Adopt method substantially the same manner as Example 1, directly carry out isostatic pressed operation after difference is only slug press, do not carry out rare earth source power working procedure of coating.
Blank wire cutting machine after coming out of the stove samples, and sample chi is D10mm × 7mm (7mm direction is direction of orientation), and magnetic property measured by gained sample.
The magnetic property of sample prepared by table 1 embodiment 1 and comparative example 1
Br(T)/(kGs) Hcj(kAm -1)/(kOe) (BH)max(kJm -3)/(MGOe)
Embodiment 1 1.205/12.05 1719.4/21.6 276.9/34.8
Comparative example 1 1.210/12.10 1615.9/20.3 279.3/35.1
Embodiment 2
Obtain bar strap according to embodiment 1 identical component alloy and technique, bar strap is carried out HD process, obtain middle flour, its hydrogen content is 3000ppm.By flour input air flow mill in obtaining, obtain the micro mist of D50=5.0 micron, by obtained micro mist mixed powder in mixed powder machine, mixed powder carries out following process again.
Adopt vertical pressure, orientation field intensity is 1.6T, and slug press is 30mm × 30mm × 10mm, wherein 10mm is direction of orientation, measure slug press weight, the upper and lower end face even coating powders of suppressed blank along direction of orientation, powder is that 40% terbium oxide, 40% has MgCu 2the intermetallic compound (its composition is 10wt%Nd-12wt%Pr-35wt%Dy-41wt%Fe-2wt%Co) of type structure and the mixed-powder of 20%DyHx, powder weight is 5g, rare earth powder granularity is 15um, then rubber pattern packaging is used to carry out isostatic pressed, isostatic pressed pressure is 210MPa, blank after isostatic pressed is carried out vacuum-sintering, sinter in vacuum sintering furnace, be filled with Ar gas after sintering temperature 1070 DEG C × 2h to carry out being cooled to about 80 DEG C, again be warmed up to 900 DEG C and fill Ar gas after being incubated 1 hour and carry out being cooled to about 80 DEG C. follow-up continuous be warmed up to 480 DEG C and be incubated 2 hours and fill after Ar is cooled to 80 DEG C come out of the stove, after blank after coming out of the stove adopts mill processing mode to remove overlay, measurement products weight, the heap(ed) capacity calculating products obtained therefrom middle rare earth source is 50mg/cm 2, re-use Linear cut mode processed sample, sample size is D10mm × 7mm (7mm direction is direction of orientation), and magnetic property measured by gained sample.
Comparative example 2
Adopt method substantially the same manner as Example 2, directly carry out isostatic pressed operation after difference is only slug press, do not carry out rare earth source power working procedure of coating.
Blank wire cutting machine after coming out of the stove samples, and sample chi is sample size is D10mm × 7mm (7mm represents direction of orientation), and magnetic property measured by gained sample.
The magnetic property of sample prepared by table 2 embodiment 2 and comparative example 2
Br(T)/(kGs) Hcj(kAm -1)/(kOe) (BH)max(kJm -3)/(MGOe)
Embodiment 2 1.206/12.06 1870.6/23.5 276.1/34.7
Comparative example 2 1.210/12.1 1615.9/20.3 279.3/35.1
Embodiment 3
Bar strap is obtained according to embodiment 1 identical component alloy and technique.Bar strap is carried out HD process, obtains middle flour, its hydrogen content is 800ppm.By flour input air flow mill in obtaining, obtain the micro mist of D50=3.0 micron, by obtained micro mist mixed powder in mixed powder machine, mixed powder carries out following process again.
Adopt vertical pressure, orientation field intensity is 1.5T, and slug press is 30mm × 30mm × 10mm, and wherein 10mm is direction of orientation, measure slug press weight, suppressed blank is evenly applied 60% dysprosia, 20% 5 water holmium nitrate and 20%DyH along the upper and lower end face of direction of orientation xmixed-powder, powder weight is 3g, heavy rare earth particle size is 20um, then plastic sheet packaging is used to carry out isostatic pressed, isostatic pressed pressure is 190MPa, blank after isostatic pressed is carried out vacuum-sintering, sinter in vacuum sintering furnace, be filled with Ar gas after sintering temperature 1050 DEG C × 2h to carry out being cooled to about 80 DEG C, again be warmed up to 900 DEG C and fill Ar gas after being incubated 1 hour and carry out being cooled to about 80 DEG C. follow-up continuous be warmed up to 480 DEG C and be incubated 2 hours and fill after Ar is cooled to 80 DEG C come out of the stove, after blank after coming out of the stove adopts mill processing mode to remove overlay, measurement products weight, the heap(ed) capacity calculating products obtained therefrom middle rare earth source is 0.5mg/cm 2, re-use Linear cut mode processed sample, sample size is D10mm × 7mm (7mm direction is direction of orientation), and magnetic property measured by gained sample.
Comparative example 3
Adopt method substantially the same manner as Example 3, directly carry out isostatic pressed operation after difference is only slug press, do not carry out rare earth source power working procedure of coating.
Blank wire cutting machine after coming out of the stove samples, and sample chi is sample size is D10mm × 7mm (7mm represents direction of orientation), and magnetic property measured by gained sample.
The magnetic property of sample prepared by table 3 embodiment 3 and comparative example 3
Br(T)/(kGs) Hcj(kAm -1)/(kOe) (BH)max(kJm -3)/(MGOe)
Embodiment 3 1.205/12.05 1765.3/21.8 276.9/34.8
Comparative example 3 1.210/12.1 1655.7/20.8 279.3/35.1
Embodiment 4
Bar strap is obtained according to embodiment 1 identical component alloy and technique.Bar strap is carried out HD process, obtains middle flour, its hydrogen content is 1600ppm.By flour input air flow mill in obtaining, obtain the micro mist of D50=5.0 micron, by obtained micro mist mixed powder in mixed powder machine, mixed powder carries out following process again.
Adopt vertical pressure, orientation field intensity is 1.8T, and slug press is 30mm × 30mm × 10mm, and wherein 10mm is direction of orientation, measures slug press weight.Suppressed blank is respectively covered a slice by 2.5gTb along the upper and lower end face of direction of orientation 2fe 1430mm × 30mm × 1mm thick rare earth source pressed compact of B powder compaction, particle size is 8um, and then use plastic bag packaging to carry out isostatic pressed, isostatic pressed pressure is 200MPa.Blank after isostatic pressed is carried out vacuum-sintering.Be filled with Ar gas after sintering temperature 1070 DEG C × 2h to carry out being cooled to about 80 DEG C, be again warmed up to 900 DEG C and fill Ar gas after being incubated 1 hour, being cooled to about 80 DEG C.Follow-up continuous be warmed up to 480 DEG C and be incubated 2 hours and fill after Ar is cooled to 80 DEG C come out of the stove.After blank after coming out of the stove adopts mill processing mode to remove overlay, measurement products weight, the heap(ed) capacity calculating products obtained therefrom middle rare earth source is 25mg/cm 2, re-use Linear cut mode processed sample, sample size is D10mm × 7mm (7mm direction is direction of orientation), and magnetic property measured by gained sample.
Comparative example 4
Adopt method substantially the same manner as Example 4, directly carry out isostatic pressed operation after difference is only slug press, do not carry out rare earth source power working procedure of coating.
Blank wire cutting machine after coming out of the stove samples, and sample chi is sample size is D10mm × 7mm (7mm represents direction of orientation), and magnetic property measured by gained sample.
The magnetic property of sample prepared by table 4 embodiment 4 and comparative example 4
Br(T)/(kGs) Hcj(kAm -1)/(kOe) (BH)max(kJm -3)/(MGOe)
Embodiment 4 1.202/12.02 1974.1/24.8 271.4/34.1
Comparative example 4 1.210/12.1 1615.9/20.3 279.3/35.1
Embodiment 5
Bar strap is obtained according to embodiment 1 identical component alloy and technique.Bar strap is carried out HD process, obtains middle flour, its hydrogen content is 2500ppm.By flour input air flow mill in obtaining, obtain the micro mist of D50=6.0 micron, by obtained micro mist mixed powder in mixed powder machine, mixed powder carries out following process again.
Adopt vertical pressure, orientation field intensity is 1.4T, and slug press is 30mm × 30mm × 10mm, wherein 10mm is direction of orientation, measure slug press weight, the upper and lower end face coating slurries of suppressed blank along direction of orientation, slurries consist of 15g and contain 50% terbium oxide, 30% and have MgCu 2the intermetallic compound (its composition is 2%Ce-22%Nd-16%Dy-15%Tb-2%Ho-40.8%Fe-1%Co-0.1%Cu-0.5%Ni-0 .2%Ga-0.2%Cr-0.2%Ti) of type structure and the mixed-powder of 20% 6 water terbium nitrate are scattered in 45g ethanol, applied thickness is 1mm, carry out isostatic pressed subsequently, isostatic pressed pressure is 200MPa, blank after isostatic pressed is carried out vacuum-sintering, be filled with Ar gas after sintering temperature 1080 DEG C × 2h to carry out being cooled to about 80 DEG C, again be warmed up to 900 DEG C and fill Ar gas after being incubated 1 hour, being cooled to about 80 DEG C.Follow-up continuous be warmed up to 480 DEG C and be incubated 2 hours and fill after Ar is cooled to 80 DEG C come out of the stove.After blank after coming out of the stove adopts mill processing mode to remove overlay, measurement products weight, the heap(ed) capacity calculating products obtained therefrom middle rare earth source is 2mg/cm 2, re-use Linear cut mode processed sample, sample size is D10mm × 7mm (7mm direction is direction of orientation), and magnetic property measured by gained sample.
Comparative example 5
Adopt method substantially the same manner as Example 5, directly carry out isostatic pressed operation after difference is only slug press, do not carry out rare earth source power working procedure of coating.
Blank wire cutting machine after coming out of the stove samples, and sample chi is sample size is D10mm × 7mm (7mm represents direction of orientation), and magnetic property measured by gained sample.
The magnetic property of sample prepared by table 5 embodiment 5 and comparative example 5
Br(T)/(kGs) Hcj(kAm -1)/(kOe) (BH)max(kJm -3)/(MGOe)
Embodiment 5 1.205/12.05 1759.2/22.1 274.5/34.5
Comparative example 5 1.210/12.1 1576.1/19.8 279.3/35.1
Embodiment 6
Bar strap is obtained according to embodiment 1 identical component alloy and technique.Bar strap is carried out HD process, obtains middle flour, its hydrogen content is 1600ppm.By flour input air flow mill in obtaining, obtain the micro mist of D50=4.8 micron, by obtained micro mist mixed powder in mixed powder machine, mixed powder carries out following process again.
Adopt vertical pressure, orientation field intensity is 1.4T, and slug press is 30mm × 30mm × 10mm, and wherein 10mm is direction of orientation, measure slug press weight, suppressed blank is respectively covered a slice along the upper and lower end face of direction of orientation and contains 20% dysprosium nitrate powder and 80%DyH by 3g respectively xthe 1mm thick rare earth source pressed compact of mixed-powder compacting, then plastic bag packaging is used to carry out isostatic pressed, isostatic pressed pressure is 200MPa, blank after isostatic pressed is carried out vacuum-sintering, be filled with Ar gas after sintering temperature 1070 DEG C × 2h to carry out being cooled to about 80 DEG C, again be warmed up to 900 DEG C and fill Ar gas after being incubated 1 hour, being cooled to about 80 DEG C.Follow-up continuous be warmed up to 480 DEG C and be incubated 2 hours and fill after Ar is cooled to 80 DEG C come out of the stove.After blank after coming out of the stove adopts mill processing mode to remove overlay, measurement products weight, the heap(ed) capacity calculating products obtained therefrom middle rare earth source is 10mg/cm 2, re-use Linear cut mode processed sample, sample size is D10mm × 7mm (7mm direction is direction of orientation), and magnetic property measured by gained sample.
Comparative example 6
Adopt method substantially the same manner as Example 6, directly carry out isostatic pressed operation after difference is only slug press, do not carry out rare earth source power working procedure of coating.
Blank wire cutting machine after coming out of the stove samples, and sample size is D10mm × 7mm (7mm represents direction of orientation), and magnetic property measured by gained sample.
The magnetic property of sample prepared by table 6 embodiment 6 and comparative example 6
Br(T)/(kGs) Hcj(kAm -1)/(kOe) (BH)max(kJm -3)/(MGOe)
Embodiment 6 1.204/12.04 1838.8/23.1 273.0/34.3
Comparative example 6 1.210/12.1 1615.9/20.3 279.3/35.1
Embodiment 7
Bar strap is obtained according to embodiment 1 identical component alloy and technique.Bar strap is carried out HD process, obtains middle flour, its hydrogen content is 800ppm.By flour input air flow mill in obtaining, obtain the micro mist of D50=3.0 micron, by obtained micro mist mixed powder in mixed powder machine, mixed powder carries out following process again.
Adopt vertical pressure, orientation field intensity is 1.4T, slug press is 30mm × 30mm × 10mm, wherein 10mm is direction of orientation, measure slug press weight, suppressed blank evenly to be applied the mixed-powder by 60% dysprosia and 40% neodymia along the upper and lower end face of direction of orientation, mixed-powder weight is 4.5g, particle size is 20um, then plastic sheet packaging is used to carry out isostatic pressed, isostatic pressed pressure is 190MPa, blank after isostatic pressed is carried out vacuum-sintering, sinter in vacuum sintering furnace, be filled with Ar gas after sintering temperature 1050 DEG C × 2h to carry out being cooled to about 80 DEG C, again be warmed up to 900 DEG C and fill Ar gas after being incubated 1 hour, be cooled to about 80 DEG C.Follow-up continuous be warmed up to 480 DEG C and be incubated 2 hours and fill after Ar is cooled to 80 DEG C come out of the stove.After blank after coming out of the stove adopts mill processing mode to remove overlay, measurement products weight, the heap(ed) capacity calculating products obtained therefrom middle rare earth source is 2mg/cm 2, re-use Linear cut mode processed sample, sample size is D10mm × 7mm (7mm direction is direction of orientation), and magnetic property measured by gained sample.
Comparative example 7
Adopt method substantially the same manner as Example 7, directly carry out isostatic pressed operation after difference is only slug press, do not carry out rare earth source power working procedure of coating.
Blank wire cutting machine after coming out of the stove samples, and sample chi is sample size is D10mm × 7mm (7mm represents direction of orientation), and magnetic property measured by gained sample.
The magnetic property of sample prepared by table 7 embodiment 7 and comparative example 7
Br(T)/(kGs) Hcj(kAm -1)/(kOe) (BH)max(kJm -3)/(MGOe)
Embodiment 7 1.208/12.08 1743.2/21.9 277.7/34.9
Comparative example 7 1.210/12.1 1655.7/20.8 279.3/35.1
Embodiment 8
Bar strap is obtained according to embodiment 1 identical component alloy and technique.Bar strap is carried out HD process, obtains middle flour, its hydrogen content is 800ppm.By flour input air flow mill in obtaining, obtain the micro mist of D50=3.0 micron, by obtained micro mist mixed powder in mixed powder machine, mixed powder carries out following process again.
Adopt vertical pressure, orientation field intensity is 1.4T, slug press is 30mm × 30mm × 10mm, wherein 10mm is direction of orientation, measure slug press weight, suppressed blank is evenly applied DyGa powder along the upper and lower end face of direction of orientation, powder weight is 4g, particle size is 10um, then plastic sheet packaging is used to carry out isostatic pressed, isostatic pressed pressure is 200MPa, blank after isostatic pressed is carried out vacuum-sintering, sinter in vacuum sintering furnace, be filled with Ar gas after sintering temperature 1050 DEG C × 2h to carry out being cooled to about 80 DEG C, again be warmed up to 900 DEG C and fill Ar gas after being incubated 1 hour, be cooled to about 80 DEG C.Follow-up continuous be warmed up to 480 DEG C and be incubated 2 hours and fill after Ar is cooled to 80 DEG C come out of the stove.After blank after coming out of the stove adopts mill processing mode to remove overlay, measurement products weight, the heap(ed) capacity calculating products obtained therefrom middle rare earth source is 5mg/cm 2, re-use Linear cut mode processed sample, sample size is D10mm × 7mm (7mm direction is direction of orientation), and magnetic property measured by gained sample.
Comparative example 8
Adopt method substantially the same manner as Example 8, directly carry out isostatic pressed operation after difference is only slug press, do not carry out rare earth source power working procedure of coating.
Blank wire cutting machine after coming out of the stove samples, and sample chi is D10 × 10 (10 represent direction of orientation), and magnetic property measured by gained sample.
The magnetic property of sample prepared by table 8 embodiment 8 and comparative example 8
Br(T)/(kGs) Hcj(kAm -1)/(kOe) (BH)max(kJm -3)/(MGOe)
Embodiment 8 1.206/12.06 1814.9/22.8 276.1/34.7
Comparative example 8 1.210/12.1 1655.7/20.8 279.3/35.1
Embodiment 9
Bar strap is obtained according to embodiment 1 identical component alloy and technique.Bar strap is carried out HD process, obtains middle flour, its hydrogen content is 800ppm.By flour input air flow mill in obtaining, obtain the micro mist of D50=3.0 micron, by obtained micro mist mixed powder in mixed powder machine, mixed powder carries out following process again.
Adopt vertical pressure, orientation field intensity is 1.4T, slug press is 30mm × 30mm × 10mm, wherein 10mm is direction of orientation, measure slug press weight, suppressed blank is evenly applied by the mixed-powder of 60%DyFe and 40%PrNdHx along the upper and lower end face of direction of orientation, mixed-powder weight is 5g, particle size is 5 μm, then plastic sheet packaging is used to carry out isostatic pressed, isostatic pressed pressure is 180MPa, blank after isostatic pressed is carried out vacuum-sintering, sinter in vacuum sintering furnace, be filled with Ar gas after sintering temperature 1050 DEG C × 2h to carry out being cooled to about 80 DEG C, again be warmed up to 900 DEG C and fill Ar gas after being incubated 1 hour, be cooled to about 80 DEG C.Follow-up continuous be warmed up to 480 DEG C and be incubated 2 hours and fill after Ar is cooled to 80 DEG C come out of the stove.After blank after coming out of the stove adopts mill processing mode to remove overlay, measurement products weight, the heap(ed) capacity calculating products obtained therefrom middle rare earth source is 1mg/cm 2, re-use Linear cut mode processed sample, sample size is D10mm × 7mm (7mm direction is direction of orientation), and magnetic property measured by gained sample.
Comparative example 9
Adopt method substantially the same manner as Example 9, directly carry out isostatic pressed operation after difference is only slug press, do not carry out rare earth source power working procedure of coating.
Blank wire cutting machine after coming out of the stove samples, and sample chi is sample size is D10mm × 7mm (7mm represents direction of orientation), and magnetic property measured by gained sample.
The magnetic property of sample prepared by table 9 embodiment 9 and comparative example 9
Br(T)/(kGs) Hcj(kAm -1)/(kOe) (BH)max(kJm -3)/(MGOe)
Embodiment 9 1.207/12.07 1735.8/21.8 276.9/34.8
Comparative example 9 1.210/12.1 1655.7/20.8 279.3/35.1
Embodiment 10
Bar strap is obtained according to embodiment 1 identical component alloy and technique.Bar strap is carried out HD process, obtains middle flour, its hydrogen content is 1600ppm.By flour input air flow mill in obtaining, obtain the micro mist of D50=5.0 micron, by obtained micro mist mixed powder in mixed powder machine, mixed powder carries out following process again.
Adopt vertical pressure, orientation field intensity is 1.4T, slug press is 30mm × 30mm × 10mm, wherein 10mm is direction of orientation, measure slug press weight, suppressed blank respectively to be covered a slice contains 30% dysprosium nitrate powder and 70%DyHx powder compaction respectively 1mm thick rare earth source pressed compact by 2.5g along the upper and lower end face of direction of orientation, then plastic bag packaging is used to carry out isostatic pressed, isostatic pressed pressure is 200MPa, blank after isostatic pressed is carried out vacuum-sintering, be filled with Ar gas after sintering temperature 1070 DEG C × 2h to carry out being cooled to about 80 DEG C, again be warmed up to 900 DEG C and fill Ar gas after being incubated 1 hour, be cooled to about 80 DEG C.Follow-up continuous be warmed up to 480 DEG C and be incubated 2 hours and fill after Ar is cooled to 80 DEG C come out of the stove.After blank after coming out of the stove adopts mill processing mode to remove overlay, measurement products weight, the heap(ed) capacity calculating products obtained therefrom middle rare earth source is 10mg/cm 2, re-use Linear cut mode processed sample, sample size is D10mm × 7mm (7mm direction is direction of orientation), and HCJ measured by gained sample.
Comparative example 10
Adopt method substantially the same manner as Example 10, directly carry out isostatic pressed operation after difference is only slug press, do not carry out rare earth source power working procedure of coating.
Blank after coming out of the stove adopts grain boundary decision method to carry out oozing Dy process, 30% dysprosium nitrate powder and 70%DyHx mixed-powder 20g are scattered in 60g ethanol and form slurries and be coated on blank surface, enter vacuum sintering furnace subsequently and heat-treat diffusion, temperature is 920 DEG C × 3 hours+480 DEG C × 5 hours.After blank after heat treatment diffusion adopts mill processing mode to remove overlay, measurement products weight, the heap(ed) capacity calculating products obtained therefrom middle rare earth source is 15mg/cm 2, use wire cutting machine to sample at each position identical with embodiment 10, sample size is D10mm × 7mm (7mm represents direction of orientation), and HCJ measured by gained sample.
As can be seen from Table 10, although the coercive force of embodiment improves high less than comparative example, embodiment is more more even than the sample interior coercivity profile of comparative example.
The HCJ of sample each several part prepared by table 10 embodiment 10 and comparative example 10
Embodiment 11
Sintered magnet product embodiment 4 prepared carries out fractograph analysis.The situation with magnet surface different distance place in magnet section is observed respectively by scanning electron microscopy (SEM, TESCANVEGA3LMH).See accompanying drawing 2 ~ 4, wherein respectively illustrate the SEM photo of nearly magnet surface (Fig. 2), distance magnet surface 200 μm (Fig. 3) and the section apart from magnet surface 500 μm (Fig. 4).
Can clearly be seen that from photo, the main phase grain of material demonstrates core-shell structure.And the closer to the position on surface, the crystal grain with core-shell structure is more intensive, and it is fewer to have the crystal grain of typical core-shell structure away from the place on surface on the contrary.The crystal grain (picture does not show) with core-shell structure seldom can be being observed apart from 1000 μm of places, surface.
Further employing EDS carries out Elemental redistribution mensuration, the element composition analyzing crystal grain diverse location finds, the content with the crystal grain heavy rare earth element Tb of core-shell structure presents the trend reduced gradually from outside to inside, and meanwhile, the trend (seeing table 11) that light rare earth element increases gradually as the content of Pr and Nd then presents from outside to inside.
The results of elemental analyses of crystal grain diverse location shown in table 11 Fig. 2
Heavy rare-earth element content analysis and comparison is carried out respectively to apart from the shell portion of great number of grains (at least 10, each position) at magnet surface different distance place and core.Further discovery, be apart from magnet surface 500 μm place in the degree of depth, in crystal grain, heavy rare earth element Tb still presents core-shell structure, and the overall content of heavy rare earth element in crystal grain, no matter be core or shell portion, all in downward trend (seeing table 12) gradually.
Table 12 is apart from element T b content in material surface diverse location place crystal grain
Note: in table, numerical value is the mean value to carrying out energy-spectrum scanning apart from the border (shell) of more than 10 crystal grain in surperficial same distance place and center (core).

Claims (10)

1. prepare the method for rare earth permanent-magnetic material for one kind, the method comprises: after slug press operation, and before isostatic pressed operation, rare earth source power is arranged in the face of suppressed blank perpendicular to magnetic field orientating direction, and prerequisite is the percentage by weight that the percentage by weight of heavy rare earth element in described rare earth source power is not less than other rare earth elements.
2. method according to claim 1, wherein said rare earth source to be selected from by the nitrate hydrate of the oxide of the fluoride of the hydride of the alloy of rare earth metal, rare earth metal, rare earth metal, rare earth metal, rare earth metal, the oxyfluoride of rare earth metal and rare earth metal form at least one in group.
3. method according to claim 2, the alloy of wherein said rare earth metal is expressed as R 1 a-M 1 bor be expressed as R 1 xt 1 ym 1 z,
Wherein R 1be selected from least one in rare earth metal, M 1be be selected from Al, Si, C, P, Ti, V, Cr, Mn, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, Hf, Ta, W, Pb and Bi Zhi Shao ー kind element, T 1be be selected from Fe and Co Zhi Shao ー kind element, M 1be be selected from Al, Si, C, P, Ti, V, Cr, Mn, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, Hf, Ta, W, Pb and Bi Zhi Shao ー kind element, a and b; X, y and z represent atomic percentage respectively, and scope is: 15<b≤99, and surplus is a; 5≤X≤85,15<Z≤95, surplus is y and y is greater than 0,
Preferably, R 1at least containing a kind of heavy rare earth metal,
More preferably, the alloy of described rare earth metal comprises intermetallic compound or the 2:14:1 phase structure rare earth compound of at least 70 volume %.
4. method according to claim 1 and 2, the granularity of wherein said rare earth source power is 2 ~ 100 μm, is preferably 3 ~ 20 μm.
5. method according to claim 2, comprising before the described rare earth source power of layout, forms the operation of slurries in a suitable solvent by described rare earth source power dispersion.
6. method according to claim 1, wherein suppressed blank direction of orientation has≤20mm, preferably≤10mm, the thickness more preferably within the scope of 5 ~ 10mm.
7. method according to claim 1 and 2, the heap(ed) capacity in its middle rare earth source, to be furnished with in the unit are of described rare earth source power, prepared rare earth permanent-magnetic material with arrange that the weight difference of slug press represents before described rare earth source power, be 0.1 ~ 50mg/cm 2, preferably 0.5 ~ 15mg/cm 2.
8. a sintered rare-earth permanent magnetic material, described material by magnet surface along magnetic field orientating direction to magnet inner 500 μm of degree of depth, heavy rare earth metal content reduces gradually, and wherein main phase grain has the core-shell structure comprising shell portion and core, the content of wherein said core heavy rare earth metal is lower than the content of described shell portion heavy rare earth metal, the two at least differs 1at.%, preferably differs 1 ~ 4at.%.
9. sintered rare-earth permanent magnetic material according to claim 8, wherein said material by magnet surface along magnetic field orientating direction to magnet inner 500 μm of degree of depth, have at least the main phase grain of 50% to have described core-shell structure; Preferably, by magnet surface along magnetic field orientating direction to magnet inner 200 μm of degree of depth, have at least the main phase grain of 70% to have described core-shell structure.
10. sintered rare-earth permanent magnetic material according to claim 8 or claim 9, the remanent magnetism of wherein said material declines compared to the sintering system permanent magnetic material not adding heavy rare earth metal and is no more than 0.010T, preferably more than 0.005T; Preferably, in described material, HCJ is no more than 20kAm in the value difference at edge of materials place and distance material surface same distance place, material middle part -1, preferably more than 10kAm -1.
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