CN107077940A - Sintered magnet based on R FE B without heavy rare earth element and preparation method thereof - Google Patents
Sintered magnet based on R FE B without heavy rare earth element and preparation method thereof Download PDFInfo
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- CN107077940A CN107077940A CN201580043655.XA CN201580043655A CN107077940A CN 107077940 A CN107077940 A CN 107077940A CN 201580043655 A CN201580043655 A CN 201580043655A CN 107077940 A CN107077940 A CN 107077940A
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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
- H01F1/12—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 soft-magnetic materials
- H01F1/14—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 soft-magnetic materials metals or alloys
- H01F1/20—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 soft-magnetic materials metals or alloys in the form of particles, e.g. powder
- H01F1/22—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 soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
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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
- H01F1/12—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 soft-magnetic materials
- H01F1/14—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 soft-magnetic materials metals or alloys
- H01F1/147—Alloys characterised by their composition
- H01F1/153—Amorphous metallic alloys, e.g. glassy metals
- H01F1/15325—Amorphous metallic alloys, e.g. glassy metals containing rare earths
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- 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 present invention relates to a kind of sintered magnet based on R Fe B, wherein the sintered magnet is included：Principal phase, it is by the R containing LREE2Fe14B (R is La, Ce, Nd, Pr, Pm, Sm, Eu or Nb) crystal grain is formed；With the second phase, it is made up of such microstructure, and the rich R phases (R is La, Ce, Nd, Pr, Pm, Sm, Eu or Nb) in the microstructure containing LREE surround the crystal grain, and by the R2Fe14The crystal boundary of B crystal grain formation optionally includes refractory metal element, two adjacent R2Fe14Contact rate between B crystal grain is 50% or smaller.
Description
Technical field
The present invention relates to the R-Fe-B sintered magnets without heavy rare earth element (HREE), more particularly, to based on following
The R-Fe-B sintered magnets of manufacture：Liquid coating techniques, even if wherein using Gao Rong in the case of without heavy rare earth element
Point metal precursor obtains the improved magnetic characteristic of sintered magnet to prepare with controlled microstructural Nd-Fe-B powder；Burn
Knot technique, controlled microstructure effectively suppresses grain growth during sintering process, and the raising for obtaining sintered magnet is rectified
Stupid power；And to controlling the addition of a small amount of refractory metal and the selectively formed related technology of crystal boundary, so that sintered magnet
Remanent magnetism reduction minimize.The invention further relates to the method for manufacturing the sintered magnet.
Background technology
Maximum magnetic energy product (BH-max) value of Nd-Fe-B sintered magnets is 29MGOe to 53MGOe, higher than other permanent magnets
Such as Alnico (1MGOe to 7.5MGOe), ferrite (1.1MGOe to 4.5MGOe) and SmCo5
(18MGOe to 33MGOe).BH-max is the parameter for the magnetic characteristic for representing permanent magnet.Nd-Fe-B sintered magnets are presently believed to be
Permanent magnet most strong in existing permanent magnet.Due to so excellent magnetic characteristic, Nd-Fe-B sintered magnets have been widely used in machine
The miniature motor of bed and the motor, electronic information aid and automobile of industrial robot.Because Nd-Fe-B sintered magnets are near
To be applied to the motor of hybrid electric vehicle and electric car, therefore Nd-Fe-B sintered magnets are by global many passes
Note.However, the Curie temperature of Nd-Fe-B sintered magnets is only 350 DEG C, at such a temperature, Nd-Fe-B sintered magnets start to lose
Its magnetic characteristic, and there is its magnetic characteristic deterioration at elevated temperatures.Especially, in order to for exposed to extreme ring
The hybrid electric vehicle of (including being up to 200 DEG C of temperature) and the motor of electric car are, it is necessary to consider magnetic property under the conditions of border
Deterioration manufacture Nd-Fe-B sintered magnets.Generally, the deterioration of magnetic characteristic and coercivity are closely related.According on city
The report of the magnetic characteristic for the Nd-Fe-B sintered magnets sold, at room temperature its coercivity be 25kOe, and coercive force temperature coefficient for-
0.5%/DEG C.It is thus known that when commercially available Nd-Fe-B sintered magnets are exposed to 100 DEG C and 150 DEG C, its coercivity is lost respectively
About 50% and about 75%.Nd-Fe-B sintered magnets for the motor of hybrid electric vehicle need have high coercive at room temperature
Performance in the temperature range of operation of vehicular electric machine to keep its coercivity.
It is related to addition with high intrinsic for manufacturing the most common process of the Nd-Fe-B sintered magnets with high-coercive force
Coercitive element.By adding representational heavy rare earth element such as Dy and Tb, it is possible to increase the coercive of Nd-Fe-B sintered magnets
Power.Such heavy rare earth element formation intermetallic compound such as magnetic anisotropy constant be respectively 150kOe and 220kOe (at least
It is Nd2Fe14Twice of B (67kOe)) Dy2Fe14B and Tb2Fe14B.That is, the addition of heavy rare earth element is remarkably contributing to
Improve the coercivity of Nd-Fe-B sintered magnets.
However, the yield of heavy rare earth element is less than the yield of LREE.Especially, heavy rare earth element is in the earth's crust
Reserves are smaller, and at least 10 times more expensive than LREE.For these reasons, have been carried out constantly making great efforts so that weight is dilute
The addition of earth elements is minimized.
It has been generally acknowledged that in the case of without heavy rare earth element, crystallite dimension is reduced to carrying by suppressing grain growth
The coercivity of high Nd-Fe-B sintered magnets is maximally effective.Therefore, many researchs have been had attempted to reduce the size of crystal grain.
One example is the crystal grain refinement by Grain boundary pinning effect, its by add refractory metal such as Mo, Nb and W with crystal boundary or
The brilliant point of intersection formation second of person three is mutually induced.By the refractory metal added is in principal phase Nd2Fe14Solubility in B is low,
It is formed such as (Mo, Fe)3B2, Nb-Fe-B and W-Fe-B precipitate.It is reported that because such precipitate is present in the second phase
In (be for example present in grain boundaries), it shows Grain boundary pinning effect so as to suppressing grain growth during sintering.However, at this
In the case of kind, in Nd2Fe14The precipitate existed in B crystal boundaries causes to form reverse magnetic domain, and Nd2Fe14Precipitation on B crystal boundaries
The size of thing causes coercivity to reduce as the amount of additive increases and increases.Principal phase (Nd2Fe14B the presence drop of precipitate in)
The relative scale of low principal phase, causes remanent magnetism to reduce [non-patent literature 1 and 2].
(non-patent literature 1) A.Yan, X.Song, M.Song, X.Wanget, J.Alloy.Compd, 257,273
(1997).
(non-patent literature 2) S.Hirosawa, H.Tomizawa, S.Mino, A.Hamamura, IEEE.Trans.Magn,
26,1960(1990).
The content of the invention
Problem to be solved by this invention
The present invention allows for above mentioned problem and made, and is directed to related to by following manufacture sintered magnet
Technology：The amount of the second phase is controlled with optionally in grain boundaries the second phase of formation；The size of the second phase is controlled so that the second phase
Finely it is evenly distributed, so that Grain boundary pinning effect is maximized；And crystal grain is suppressed by maximized Grain boundary pinning effect
Growth, obtains the coercivity improved and minimizes the reduction of remanent magnetism.
It is a further object to provide for the side by simplified sintered magnet of the technique manufacture without HREE
Method.
The method solved the problems, such as
Therefore, the present inventor attempts the table in the Nd-Fe-B powder without heavy rare earth element (HREE) by following steps
Face induced synthesis molybdenum：Five ethyoxyl molybdenum (Mo (OC of refractory metal precursor will be used as2H5)5) be dissolved in absolute alcohol, it will be free of
HREE Nd-Fe-B powder is immersed so that refractory metal precursor is coated on the surface of the powder in the solution, and make through
The powder of coating thermally decomposes to remove the impurity than molybdenum being included in precursor.Gained powder is included without HREE
Nd-Fe-B powder is used as shell as core and molybdenum.Thin second can be evenly distributed in the crystalline substance of whole sample during sintering
In boundary.In addition, the present inventor attempts to suppress by controlling the amount of the molybdenum of addition second mutually into principal phase Nd2Fe14Crystal grain in B
Between diffusion (intergrain diffusion) so that remanent magnetism change minimize.
One aspect of the present invention provides R-Fe-B (R=La, Ce, Nd, Pr, Pm, Sm, Eu or Nb) sintered magnet, institute
Sintered magnet is stated to include：Principal phase, it is by the R comprising LREE2Fe14B crystal grain is formed；With the second phase, it, which has, wherein wraps
Rich R phases containing LREE surround the microstructure of the crystal grain, and optionally by the R2Fe14B crystal grain is formed
Grain boundaries or three brilliant point of intersection include refractory metal element, two of which adjacent R2Fe14Contact rate between B crystal grain is
50% or smaller.
Second is mutually selected from Mo2FeB2And MoFe2。
R2Fe14The average diameter of B crystal grain is 5nm to 6.5nm.
The coercivity of sintered magnet is 10kOe to 20kOe, and remanent magnetism is 1T to 1.7T.
Another aspect provides the method for manufacturing R-Fe-B sintered magnets, including：
I) solution of the R-Fe-B powder with refractory metal precursor in absolute alcohol is mixed with by refractory metal precursor
On the surface for being coated in R-Fe-B powder；
II the R-Fe-B powder coated through refractory metal precursor) is dried, then is thermally decomposed to prepare core-shell structure copolymer raw material
Powder；And
III) material powder is sintered.
Core-shell structure copolymer material powder is included in the Mo of the 0.03 weight % to 0.20 weight % on R-Fe-B powder surface.
Refractory metal precursor is five ethyoxyl molybdenum (Mo (OC2H5)5)。
In step II) in, thermal decomposition is carried out at environmental pressure and 750 DEG C to 1000 DEG C.
In step II) in, thermally decompose 10-3Carried out at a temperature of the decompression of support and 250 DEG C to 400 DEG C.
In step III) in, it is sintered at 900 DEG C to 1100 DEG C and carries out.
In step III) in, sinter and carried out with 5 DEG C/min to 15 DEG C/min of the rate of heat addition.
The refractory metal precursor used in this method is used as present invention also offers five ethyoxyl molybdenums.
Invention effect
In the R-Fe-B sintered magnets of the present invention, formation refractory metal causes on the surface of R-Fe-B material powders
Thin second is uniformly distributed in the grain boundaries of whole sample and three brilliant point of intersection.Because this is uniformly distributed, can effectively it control
The microstructure of sintered magnet processed.Therefore, sintered magnet of the invention can overcome the limited thing of existing R-Fe-B sintered magnets
Manage characteristic and magnetic characteristic.In addition, the problem of sintered magnet of the present invention is related not to the supply and demand of heavy rare earth element, and therefore
It can be obtained with reasonable prices.
Brief description of the drawings
Fig. 1 is to show the schematic diagram for being used to manufacture the method for sintered magnet according to the present invention.
Fig. 2 shows the Mo (OC as refractory metal precursor2H5)5TGA and DSC results.
Fig. 3 shows the XRD spectrum of the compacting sample containing Mo and the compacting sample without Mo.
Fig. 4 shows surface and cross sectional Scanning Electron MIcrosope image through the Mo Nd-Fe-B powder coated, and it is tested
Measure the influence for studying thermal decomposition to intermetallic compound formation in powder；Point A and B are respectively the shell of core-shell structure copolymer material powder
And core.
Fig. 5 is shown the Nd-Fe-B powder coated through Mo is sintered after by SEM (BSE) and EPMA observe it is aobvious
Microstructure change.
Fig. 6 shows the XRD spectrum of the sintered magnet containing Mo and the sintered magnet without Mo, and it is measured for accurately dividing
Analyse the second phase observed in SEM and EPMA images.
Fig. 7 shows SEM (BSE) image and light microscope (OM) image of following sample：(a) not
Powder (being free of HREE) containing Dy, (b) is free of Mo sintered magnet, and the magnet containing Mo of (c) sintering (adds 0.03 weight %'s
Mo), the magnet containing Mo (0.05 weight % of addition Mo) of (d) sintering, and the magnet containing Mo of (e) sintering (add 0.2 weight
Mo the average grain size and grain size distribution), and using image obtained.
Fig. 8 show sintered magnet without Mo and sintering magnet containing Mo (add 0.03 weight %, 0.05 weight % and
0.2 weight % Mo) coercitive change.
Preferred forms
The present invention will be described in further detail now.
Term " three brilliant point of intersection " used herein refers to that three crystal grain are in contact with each other to form the area of rich R phases in sintered magnet
Domain.
R-Fe-B sintered magnets have by R2Fe14The structure that the principal phase of B crystal grain formation is surrounded by rich R phases.Sintered magnet
Magnetic characteristic and other characteristics determine by various different parameters, the size of such as crystal grain and the thickness of isolation and richness R phases.Especially
Ground, the heavy rare earth metal (Dy or Tb) with high intrinsic magnetic anisotropy field is mainly used in improving the magnetic characteristic of sintered magnet.
However, the low reserves of heavy rare earth element and localization cause unbalanced supply-demand and price unstable, limit it and use.
Therefore, the present inventor is studied work to develop the high-performance magnetism that magnetic characteristic is better than existing R-Fe-B sintered magnets
Property material.As a result, the present inventor is concerned about the fact, when refractory metal is simply mixed, can be with production period
Limit the size of crystal grain but form precipitate, cause the coercivity and remanent magnetism of reduction.The present inventor attempts to find for above-mentioned
The solution of problem.Especially, the inventors discovered that when refractory metal precursor is dissolved in into absolute alcohol, by without HREE's
Nd-Fe-B powder is immersed to be coated in refractory metal on the Nd-Fe-B powder without HREE in the solution, and to coated
Powder when being sintered, can manufacture and wherein be present in the second phase selectivity comprising refractory metal crystal boundary or three brilliant hand over
Sintered magnet at point.The present invention is completed based on this discovery.
The present invention is intended to provide being different from the sintered magnet of existing R-Fe-B sintered magnets, difference is：Even if without
Heavy rare earth element is by R2Fe14The size and microstructure of the principal phase of B crystal grain formation also effectively undergo control to obtain improvement
Magnetic characteristic such as high coercivity and remanent magnetism.
One aspect of the present invention provides a kind of sintered magnet, and the sintered magnet is included：Principal phase, it is by containing light rare earth
The R of element2Fe14B crystal grain is formed；With the second phase, it surrounds the micro- knot of crystal grain with the rich R phases wherein containing LREE
Structure, and by R2Fe14The grain boundaries of B crystal grain formation or three brilliant point of intersection include refractory metal element.
The LREE for being present in the LREE in principal phase and being present in rich R phases is independent of one another.That is,
Two kinds of LREEs can be same to each other or different to each other.
R is La, Ce, Nd, Pr, Pm, Sm, Eu or Nb.Nd is used as R in following embodiment part.
Two adjacent Rs2Fe14Contact rate between B crystal grain is 50% or smaller, preferably 23% to 40%.Contact rate is
The parameter that crystal grain is almost isolated by rich R completely is numerically shown.Relatively low contact rate shows that the mutual contact of crystal grain is less.
Contact rate be defined as crystal boundary contact area between two phases of identical with respect to microstructure crystal boundary the gross area it
Than.That is, contact rate is defined as the ratio between the grain boundary area being in contact with each other and whole grain boundary areas, or refers to crystal boundary adjacent to each other
The ratio between relatively whole grain boundary areas [16A volumes, 1985 years 7 of METALLURGICAL TRANSACTIONS A, R.M.GERMAN, the
Month, 1247；METALLOGRAPHY, V.Srikanth, G.S.Upadhyaya, volume 19, on November 4th, 1986,437-445；
International Journal of Refractory Metals&Hard Materials,V.T.Golovchan,
N.V.Litoshenko,21,2003,241-244].It is more that higher contact rate shows that crystal grain is in contact with each other.Relatively low contact rate
Show that crystal grain is isolated from each other.
Second is mutually Mo2FeB2Or MoFe2.The average grain size of second phase is less than submicron order, and is evenly distributed on
R2Fe14The grain boundaries of B crystal grain formation or three brilliant point of intersection.Second mutually efficiently controls crystallite dimension, while preventing Mo to be dissolved into
In crystal grain, the coercivity and remanent magnetism of the raising of sintered magnet are obtained.
In initial Nd2Fe14There are a large amount of Nd and a small amount of Nd in B powder1.xFe4B4Can be by the micro- knot of the initial powder
Structure and XRD analysis are observed.Nd and Nd1.xFe4B4React to form new intermetallic compound with Mo, wherein Mo is in the sintering process phase
Between formed by refractory metal precursor.Based on standard Gibbs free energy of formation, Nd2Fe14B compares Nd1.xFe4B4More stable, this is carried
It is high to be formed in Nd2Fe14Mo and Nd on B powder surface1.xFe4B4Reaction formed intermetallic compound without with Nd2Fe14B is anti-
The possibility answered.In addition, it is contemplated that binary alloy phase diagram, Mo and Nd can not form change between metal by the reaction under relevant temperature
Compound, but Mo and Fe can be with.As a result, the R-Fe-B powder that the nucleocapsid structure to be formed is coated by using refractory metal can be with
The second phase is formed by following chemical reaction during sintering process：
(1)4Mo+Nd1.xFe4B4→2Mo2FeB2+2Fe+1.xNd
(2)xFe+Mo→MoFex
In sintering process, it is present in the Nd on Nd-Fe-B powder surface1.xFe4B4It can react to form Mo with Mo2FeB2
Phase, as described in reaction (1).However, after as completed by sintering determined by the XRD facies analyses of sample, MoFexMutually pass through
Mo and the Fe being present in rich-Nd phase form Mo2FeB2Remaining Fe reacts and formed after phase.
The use of the core-shell structure copolymer material powder coated in the present invention through Mo makes it possible to form second during sintering process
Phase.Second mutually effectively suppresses grain growth, and crystallite dimension deviation is limited into 1.5 μm or smaller.
The formation of second phase improves the wetability between rich R phases and crystal grain, and causes richness R phases preferably to penetrate into crystal boundary
Between.
R2Fe14The average diameter of B crystal grain is 5nm to 6.5nm, and this applies to the level of sintered magnet.If R2Fe14B
The diameter of crystal grain is not easy to be isolated more than 6.5nm, then crystal grain, and magnetic exchange coupling therefore occurs between crystal grain, causes low
Coercivity.
The coercivity of sintered magnet with said structure is 10kOe to 20kOe, and remanent magnetism is 1T to 1.7T, than existing
There is sintered magnet to be in higher level.
Another aspect provides the method for manufacturing the microstructural sintered magnet, such as institute in Fig. 1
Show.
The production of the material powder of nucleocapsid structure generally passes through dry-coating process such as physical vapour deposition (PVD), chemical vapor deposition
Or spray to realize.On the contrary, the present invention method use liquid coating processes with more rapidly and simply mode prepare thickness of the shell
Uniform nucleocapsid structure material powder.
Core-shell structure copolymer material powder is prepared using liquid coating processes, wherein refractory metal is coated in by band casting
On R-Fe-B powder prepared by (strip casting).First, R-Fe-B powder is immersed into refractory metal precursor in absolute alcohol
In solution in with refractory metal precursor coat R-Fe-B powder.
Then, it is dried and thermally decomposes so that the organic compound from coated R-Fe-B powder is decomposed.
Thermal decomposition is carried out preferably at environmental pressure and 750 DEG C to 1000 DEG C, true by the TGA in Fig. 2 and dsc analysis result
Fixed this is optimum condition.
Thermal decomposition can be 10-3Carried out at a temperature of the decompression of support and 250 DEG C to 400 DEG C.
Most preferably, refractory metal precursor is five ethyoxyl molybdenum (Mo (OC2H5)5)。
The material powder of nucleocapsid structure is besieged before sintering, and this is effective for the isolation of crystal grain.
As it was previously stated, 0.03 weight % of the material powder of nucleocapsid structure on the surface of R-Fe-B powder is extremely
0.20 weight % Mo shells.Mo shells content is 0.03 weight % or more, preferably 0.03 weight % to 0.2 weight %.Work as Mo
When shell content is 0.2% weight, it can be ensured that coercivity maximum is improved.
If Mo shells content is less than lower limit defined above, it is difficult to the size for effectively limiting crystal grain.If in addition, Mo
Shell content exceedes the upper limit defined above, then refractory metal (Mo) excess diffusion, into crystal grain, makes the coercivity of sintered magnet
Deterioration.Therefore preferably Mo shell contents are adjusted to scope defined above.
As described above, the step of technique of material powder for preparing nucleocapsid structure is reduced, enabling quick to prepare
Nucleocapsid structure material powder, and be favourable in terms of coating efficiency compared with routinely dry technique.Especially, the technique is kept away
The demand to optional equipment such as sputtering system is exempted from, and in terms of cost benefit has been therefore favourable compared with routinely dry technique
's.
Finally, the material powder of nucleocapsid structure is sintered to manufacture desired R- at 900 DEG C to 1100 DEG C
Fe-B sintered magnets.
Especially, when sintering temperature reaches about 635 DEG C, rich R phases are begun to appear in liquid phase.
When temperature is further raised, around core comprising shell of the high-melting-point containing metal along grain boundary decision to richness R liquid phases
In and form around crystal grain the second phase.Second mutually further isolates crystal grain.
Shell comprising refractory metal is with being present in Nd2Fe14Nd on B core powder surface1.xFe4B4Reaction forms second
Phase.Grain growth during second phase effectively suppresses sintering process causes crystallite dimension to may remain in low-level.
The change of intercrystalline capillary force is caused to improve wetability in the formation of the phase of grain boundaries second.Improved profit
The moist isolation for promoting crystal grain so that rich R phases are preferably penetrated between crystal boundary.
Sintering process suppresses the size of sintered particles and makes uniform microstructure.The relative density of sintered magnet be 99% or
Person is higher, and coercivity is 10kOe to 20kOe, and remanent magnetism is 1T to 1.7T, and these are above existing sintered magnet.Even if in addition, not
Using any heavy rare earth element, sintering process also ensures that the high-performance of sintered magnet.High performance sintered magnet may be used as being used for
The substitute of HREE sintered magnets in the magnetic material of engine, generator and green energy resource and its application component.
Another aspect of the present invention is related to five ethyoxyl molybdenums as making in the method for manufacturing R-Fe-B sintered magnets
The purposes of refractory metal precursor.More particularly, to five ethyoxyl molybdenum (Mo (OC2H5)5) it is used as high-melting-point for improving
The purposes of coatings of the Mo of metal on particle such as R-Fe-B powder particle surfaces.
When by liquid coating processes with refractory metal (Mo) coated particle such as R-Fe-B powder particles, five ethyoxyls
Molybdenum (Mo (OC2H5)5) presence to form uniform and thin coating (shell) on R-Fe-B powder surface.
Preferred forms
The present invention will be clarified in more detail with reference to following examples.However, these embodiments should not be construed as limiting or limit
Determine the scope of the present invention and disclosure.It should be understood that based on the teachings of the present invention including following examples, people in the art
Member can easily implement other embodiments of the present invention (its experimental result is not explicitly depicted).It should also be understood that such repair
Change and change is intended to fall under in scope of the following claims.
Embodiment 1
(1) manufacture composition is Nd14Fe80B6(Nd:14、Fe:80、B:6 (atom %)) sample.First, at 1600 DEG C
Raw material is liquefied and alloy strip is prepared by band casting.Hydrogenation is carried out to alloy strip broken to form micro-crack in grain boundaries, entered
Row injecting type is ground, and is classified into average grain diameter (D50) it is 5.0 μm of powder.Particle diameter distribution is 2 μm to 10 μm, and standard deviation
For 0.94.
(2) five ethyoxyl Mo (Mo (OC are used2H5)5) it is used as refractory metal precursor.By refractory metal precursor dissolving
In anhydrous (second) alcohol.Powder is immersed in the solution, dried under an argon, and at 750 DEG C thermally decompose 30 minutes with except
Remove organic compound.Come from the R of powder2Fe14B formation cores, come from the Mo formation shells of refractory metal precursor.
(3) then, using Magnetic field press under 20kOe magnetostatic field by obtained nucleocapsid structure material powder compacting with
Manufacture size is 20 × 12 × 15mm3Compacting sample.Compaction pressure is 1.2 tons, and the relative density of compacting sample is 48%.
Then, vacuum (≤2.4 × 10 is being maintained-6Support) vacuum drying oven at 1070 DEG C will compacting sample sinter 4 hours
To manufacture Nd-Fe-B sintered magnets.Under the conditions of the temperature and time, sintering fully induces richness Nd liquid phases in Nd2Fe14B is brilliant
It is uniformly distributed in boundary.
Fig. 2 is shown as the Mo (OC of refractory metal precursor2H5)5TGA and DSC results.As shown in Figure 2, at two
The weight change of refractory metal precursor is observed at 290 DEG C and 750 DEG C of temperature.DSC curve display reaction is heat release.
These results show that the powder of embodiment 1 (1) is thermally decomposed into the optimal of the core-shell structure copolymer material powder of embodiment 1 (2)
Condition.
Fig. 3 shows the XRD spectrum of the compacting sample containing Mo and the compacting sample without Mo.In two samples, find
Corresponding to Nd2Fe14B and rich-Nd phase peak.It has also been found that corresponding to Nd1.xFe4B4The peak of phase.Known Nd1.xFe4B4It is attributed to preparation
During Nd-Fe-B powder compared with B amount relatively little of Fe presence and Nd1.xFe4B4It is present in the surface of Nd-Fe-B powder.
However, in the compacting sample containing Mo, it was observed that corresponding to the low intensity peak centered of Mo phases.
Fig. 4 shows surface and cross sectional Scanning Electron MIcrosope image through the Mo Nd-Fe-B powder coated.In Fig. 4
In, point A and point B is respectively the shell and core of core-shell structure copolymer material powder.
As shown in Figure 4, EDS analysis shows only exist Nd, Fe and O in Nd-Fe-B powder, in Nd-Fe-B powder tables
There is Mo and Nd, Fe and O on face.
These results indicate that refractory metal elements Mo is only partly coated on the surface of Nd-Fe-B powder.
Fig. 5 shows the Nd-Fe-B powder coated through Mo is sintered after observed by SEM (BSE) and EPMA
Microstructure changes.SEM (BSE) analysis shows, except corresponding to Nd2Fe14B(Hard Magnetic body phase) dark space and corresponding to richness
Outside the clear zone of Nd phases, there is contrast second phase different from the contrast of rich-Nd phase (non-magnetic body phase) in grain boundaries.Carry out
EPMA imagings are with the element of the second phase observed by analyzing.Second phase is determined by BSE imagings.As a result it is shown in the second phase
There is substantial amounts of Mo atoms.It is less than 1 μm (sub-micron) in the size of three brilliant point of intersection and the phase of grain boundaries second, and equably divides
Cloth is on whole sintered sample.Think that being uniformly distributed for the second phase is because will by the liquid coating processes prepared for powder
Mo elements have been evenly distributed on Nd-Fe-B surfaces.It is formed uniformly during sintering process in crystal boundary and three brilliant point of intersection
Second phase may suppress crystal boundary movement.Also analyze the element containing Mo second is mutually not present in Nd2Fe14In B phases.Think that addition is non-
Chang Shaoliang Mo is induction of the formation of the second phase, and this restrained effectively Mo in Nd2Fe14Dissolving in B phases.Furthermore, it is possible to see
Observe display Nd2Fe14The microstructure change that B is isolated, because rich-Nd phase is very continuous.It is expected that with micro- knot
The sintered magnet of the rich-Nd phase of structure by the exchange between the ferromagnet in nucleation coercivity mechanism as can effectively be controlled
The microstructure of coercivity reduction processed.
Fig. 6 shows the XRD spectrum of the sintered magnet containing Mo and the sintered magnet without Mo, and it is measured for accurately dividing
Analyse the second phase observed in SEM and EPMA images.The XRD analysis of sintered sample show, in the situation of sample containing Mo of sintering
Under, except Nd2Fe14Outside B phases and rich-Nd phase, also there is the Mo of large volume2FeB2Mutually with the MoFe of small size2Phase.Substantial amounts of Nd
With a small amount of Nd1.xFe4B4It mutually may adhere to initial Nd2Fe14On the surface of B powder and may be anti-with the Mo on powder surface
Intermetallic compound phase should be formed.Based on standard Gibbs free energy of formation, Nd2Fe14B compares Nd1.xFe4B4It is more stable.In addition, examining
Consider binary alloy phase diagram, Mo and Nd can not form compound, but Mo and Fe can be with.As a result, there is core (Nd2Fe14B powder
End)-shell (Mo elements) structure powder can during sintering process by it is following chemical reaction form intermetallic compound phase
The possibility of (the second phase)：
(1)4Mo+Nd2Fe14B→2Mo2FeB2+2Fe+1.xNd
(2)XFe+Mo→MoFex
During sintering process, it is present in the Nd on Nd-Fe-B powder surface1.xFe4B4It can react to be formed with Mo
Mo2FeB2Phase, as shown in reaction (1).However, to be examined determined by the XRD facies analyses of sample after as completed by sintering
Consider MoFexThe many possibilities mutually formed.For example, MoFexMutually can by Mo and a small amount of Fe being present on rich-Nd phase or
Mo2FeB2Remaining Fe reaction is formed after mutually being formed.Herein it was observed that mutually be MoFe2Phase (is based on Mo-Fe compounds
One of).
Fig. 7 shows SEM (BSE) image and light microscope (OM) image of following sample：(a) not
Powder (being free of HREE) containing Dy, (b) is free of Mo sintered magnet, and the magnet containing Mo of (c) sintering (adds 0.03 weight %'s
Mo), the magnet containing Mo (0.05 weight % of addition Mo) of (d) sintering, and the magnet containing Mo of (e) sintering (add 0.2 weight %
Mo), and obtain average grain size and grain size distribution using image.500 × multiplication factor under measure about 1,
000 to 1,100 Nd2Fe14The average grain size and grain size distribution of B phases.Imaging results show containing 0.03 weight %,
The average grain size of 0.05 weight % and 0.20 weight % Mo sintered sample is respectively 6.07 ± 0.13 μm, 5.88 ±
0.11 μm and 5.60 ± 0.11 μm, these are smaller about 1.33 μm to 1.8 μm than the sample (7.4 ± 0.22 μm) without Mo.In order to divide
Grain size distribution is analysed, the standard deviation of measured crystal grain is calculated.For 0.03 weight % of addition, 0.05 weight % and 0.20
Weight % Mo, the standard deviation of the sample containing Mo is respectively 1.53 μm, 1.42 μm and 1.3 μm, and the mark of the sample without Mo
Quasi- deviation is 2.5 μm.That is, standard deviation reduces with the increase of the Mo of addition amount.These results can be drawn
Such as draw a conclusion：With Mo addition increase, crystallite dimension becomes uniform.Even if when adding a small amount of Mo, crystallite dimension also subtracts
Small the reason for is：Mo is evenly distributed in the surface of Nd-Fe-B powder by using the liquid coating processes of Mo organic compounds
On.
Fig. 8 show sintered magnet without Mo and sintering magnet containing Mo (add 0.03 weight %, 0.05 weight % and
0.2 weight % Mo) coercitive change.
As shown in Figure 8, the coercivity of the sample without Mo is 11.88kOe (remanent magnetism：1.37T), and containing 0.03 weight
Amount %, the coercivity of 0.05 weight % and 0.20 weight % Mo sample be respectively 12.83kOe, 13.1kOe and
13.95kOe.Especially, the coercivity of the sample of the Mo containing 0.20 weight % is higher than the coercivity of the sample without Mo
2.07kOe.Especially, even if when Mo amounts increase, the remanent magnetism of the sample containing Mo also keeps constant or only slightly reduced
(1.35T to 1.37T).
From these results it can be concluded, the addition of refractory metal (Mo) restrained effectively crystal grain formation and raw
It is long so that even grain size, as shown in Figure 7.
In addition, will be used to manufacture sintered magnet of the invention using the improvement liquid coating processes of refractory metal precursor
Using enabling thin second to be uniformly distributed in sintered magnet, and induce small and uniform grain growth.Especially,
It is also very effective that very small amount of refractory metal precursor, which is only added, in terms of grain growth is controlled.
In summary, it is believed that the coercivity of raising is explained by adding very small amount of refractory metal precursor, it is lured
Second is led in the selectively formed of grain boundaries with crystallite dimension during effectively limiting sintering to increase.Especially, it is described micro-
Structure effectively suppresses Mo in Nd2Fe14Dissolved in B, minimize the reduction of remanent magnetism.
Industrial usability
In the R-Fe-B sintered magnets of the present invention, formation refractory metal causes carefully on R-Fe-B material powders surface
Second be uniformly distributed in the grain boundaries of whole sample and three brilliant point of intersection.Be uniformly distributed due to this, sintered magnet it is aobvious
Micro-structural can be effectively controlled.Therefore, sintered magnet of the invention can overcome the limited thing of existing R-Fe-B sintered magnets
Manage characteristic and magnetic characteristic.In addition, the problem of sintered magnet of the present invention is related not to the supply and demand of heavy rare earth element, and therefore
It can be obtained with reasonable prices.
Claims (11)
1. a kind of R-Fe-B (R=La, Ce, Nd, Pr, Pm, Sm, Eu or Nb) sintered magnet, comprising：Principal phase, the principal phase is by wrapping
R containing LREE2Fe14B crystal grain is formed；Mutually there is the rich R phases for wherein including LREE with the second phase, described second
The microstructure of the crystal grain is surrounded, and by the R2Fe14The grain boundaries of B crystal grain formation or three brilliant point of intersection include Gao Rong
Point metallic element, two of which adjacent R2Fe14Contact rate between B crystal grain is 50% or smaller.
2. R-Fe-B sintered magnets according to claim 1, wherein described second is mutually Mo2FeB2Or MoFe2。
3. R-Fe-B sintered magnets according to claim 1, wherein the R2Fe14The average diameter of B crystal grain be 5nm extremely
6.5nm。
4. R-Fe-B sintered magnets according to claim 1, wherein the coercivity of the sintered magnet be 10kOe extremely
20kOe, remanent magnetism is 1T to 1.7T.
5. a kind of method for manufacturing R-Fe-B sintered magnets, including I) by R-Fe-B powder and refractory metal precursor in nothing
Solution in water alcohol is mixed so that the refractory metal precursor is coated on the surface of the R-Fe-B powder, II) dry warp
The R-Fe-B powder of the refractory metal precursor coating, then is thermally decomposed to prepare core-shell structure copolymer material powder, and III)
The material powder is sintered.
6. method according to claim 5, wherein the refractory metal precursor is five ethyoxyl molybdenum (Mo (OC2H5)5)。
7. method according to claim 5, wherein, in step II) in, the thermal decomposition in environmental pressure and 750 DEG C extremely
Carried out at 1000 DEG C.
8. method according to claim 5, wherein, in step II) in, the thermal decomposition is 10-3The decompression of support and 250 DEG C
To carrying out at a temperature of 400 DEG C.
9. method according to claim 5, wherein, in step III) in, it is described to be sintered at 900 DEG C to 1100 DEG C
OK.
10. method according to claim 5, wherein, in step III) in, the sintering is with 5 DEG C/min to 15 DEG C/minute
The rate of heat addition of clock is carried out.
11. five ethyoxyl molybdenums are used as the refractory metal precursor used in method according to claim 5.
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| KR10-2014-0088349 | 2014-07-14 | ||
| KR1020140088349A KR101719871B1 (en) | 2014-07-14 | 2014-07-14 | HREE free sintered R-Fe-B magnets and manufacturing method thereof |
| PCT/KR2015/007314 WO2016010348A1 (en) | 2014-07-14 | 2015-07-14 | R-fe-b-based sintered magnet containing no heavy rare earth elements, and preparation method therefor |
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| CN114223044A (en) * | 2019-10-07 | 2022-03-22 | 株式会社Lg化学 | Method for producing sintered magnet |
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| KR102356630B1 (en) * | 2018-01-10 | 2022-01-26 | 주식회사 엘지화학 | Rare-earth magnet |
| CN109825754B (en) * | 2019-02-11 | 2021-05-28 | 西安交通大学 | Modified Mo2FeB2Base cermet and method for preparing same |
Citations (3)
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|---|---|---|---|---|
| CN1529367A (en) * | 1996-12-27 | 2004-09-15 | ������������ʽ���� | Powdered material, electrode components and their manufacturing method and secondary cells |
| JP2011216725A (en) * | 2010-03-31 | 2011-10-27 | Nitto Denko Corp | Permanent magnet and method for manufacturing the same |
| CN102511071A (en) * | 2010-03-31 | 2012-06-20 | 日东电工株式会社 | Permanent magnet and manufacturing method for permanent magnet |
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| JP4533216B2 (en) * | 1996-12-27 | 2010-09-01 | キヤノン株式会社 | Powder material, electrode structure, manufacturing method thereof, and secondary battery |
| JP2005286174A (en) * | 2004-03-30 | 2005-10-13 | Tdk Corp | R-t-b-based sintered magnet |
| JP5093485B2 (en) * | 2007-03-16 | 2012-12-12 | 信越化学工業株式会社 | Rare earth permanent magnet and manufacturing method thereof |
| JP5130270B2 (en) | 2009-09-30 | 2013-01-30 | 株式会社日立製作所 | Magnetic material and motor using the same |
| JP5501829B2 (en) * | 2010-03-31 | 2014-05-28 | 日東電工株式会社 | Rare earth permanent magnet manufacturing method |
| KR101707239B1 (en) * | 2010-08-23 | 2017-02-17 | 한양대학교 산학협력단 | R-Fe-B Sintered magnet having -phase and fabrication method thereof |
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| CN1529367A (en) * | 1996-12-27 | 2004-09-15 | ������������ʽ���� | Powdered material, electrode components and their manufacturing method and secondary cells |
| JP2011216725A (en) * | 2010-03-31 | 2011-10-27 | Nitto Denko Corp | Permanent magnet and method for manufacturing the same |
| CN102511071A (en) * | 2010-03-31 | 2012-06-20 | 日东电工株式会社 | Permanent magnet and manufacturing method for permanent magnet |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114223044A (en) * | 2019-10-07 | 2022-03-22 | 株式会社Lg化学 | Method for producing sintered magnet |
| CN114223044B (en) * | 2019-10-07 | 2024-03-08 | 株式会社Lg化学 | Method for producing sintered magnet |
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| WO2016010348A9 (en) | 2016-03-24 |
| KR101719871B1 (en) | 2017-03-24 |
| WO2016010348A1 (en) | 2016-01-21 |
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