CN104529424B - A kind of have two-phase exchange coupling and keep the composite permanet magnet ferrite of high-coercive force - Google Patents
A kind of have two-phase exchange coupling and keep the composite permanet magnet ferrite of high-coercive force Download PDFInfo
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- CN104529424B CN104529424B CN201510023278.5A CN201510023278A CN104529424B CN 104529424 B CN104529424 B CN 104529424B CN 201510023278 A CN201510023278 A CN 201510023278A CN 104529424 B CN104529424 B CN 104529424B
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Abstract
The invention discloses and a kind ofly there is two-phase exchange-coupling interaction and keep the composite permanet magnet ferrite of high-coercive force, belong to magnetic ferrites preparing technical field.This complex ferrite adopts hydro thermal method to prepare separately and through the SrFe of overpickling
12o
19and CoFe
2o
4ferrite nano powder is pressed into disk according to certain mass ratio, is then prepared from the temperature lower calcination 2h of 700 ~ 900 DEG C respectively, containing the ferrite i.e. externally display single-phase magnetic behavior of two-phase, namely there is exchange-coupling interaction.This complex ferrite is owing to adopting high saturation and magnetic intensity and coercitive CoFe
2o
4ferrite, as " soft magnetism phase ", is not only conducive to improving its saturation magnetization, and can ensure the high-coercive force still keeping minimum 152.5kA/m (about 1915Oe) after firing.
Description
Technical field
The invention belongs to the preparing technical field of magnetic ferrites, be specifically related to a kind ofly to there is two-phase exchange-coupling interaction but still keep the composite permanet magnet ferrite of high-coercive force.
Background technology
The M type SrFe of hexaplanar
12o
19(SrM) ferrite, due to its higher cost performance, cheap raw material and excellent chemical stability, is still widely used in electronics, household electrical appliances, automobile and other industries, is one of maximum magnetic material of Current production.But, regrettably, although China is the big country that SrM permanent-magnet ferrite is produced, and nonproductive power, current product is based on low and middle-grade, and production technology level still has big gap than American-European Japan etc.For this reason, be badly in need of seeking new SrM permanent-magnet ferrite preparation method, to improve its level of production.
Utilize high-coercive force (H
cbut) low saturation magnetization (M
s) permanent magnetism phase and high M
sbut low H
csoft magnetism mutually between exchange-coupling interaction remove the magnetic property improving permanent magnetic material, be widely used at present and study, particularly in rare earth permanent magnet.The such as patent No. is the preparation method that the patent of invention of ZL201010289049.5 discloses a kind of nanocrystalline two-phase coupling rare-earth permanent magnet; The patent No. is that the patent of invention of ZL201010524561.3 discloses a kind of exchange coupling biphase composite NdFeB paramagnetic particles and preparation method and application.But utilize exchange-coupling interaction to remove to improve the current rare report of magnetic property of permanent-magnet ferrite, many technological difficulties need to be captured.Patent of invention number is the patent of ZL200610048970.4, in permanent magnetism Sr ferrite, with the addition of a kind of special L expect to replace non magnetic additive, and the granularity that suitable control L expects, not only significantly improve density and the degree of orientation of product, and find wherein there is exchange-coupling interaction, thus improve magnetic property.But inventing the preparation method that uses is traditional conventional ceramic technique, and successively lower than 1270 DEG C with higher than the high temperature of 1270 DEG C under carried out two-step sintering and become phase, this generally can make ferritic crystal grain look very large.And micromagnetics research shows, when twice close to permanent magnetism phase domain wall thickness of the size of soft magnetism phase, soft, permanent magnetism mutually between exchange sclerosis not only very effective, but also avoid the coercitive decline caused by exchange coupling.Therefore, employing needs the conventional ceramic technique of high temperature sintering to be unfavorable for the formation of exchange coupling effect.The way that the powder that the patent ZL201310415239.0 that applicant oneself has obtained the authorization adopts hydro thermal method to prepare at high temperature sinters has prepared SrM/ (Ni, Zn) Fe
2o
4ferrite powder, result shows to there is good exchange-coupling interaction in sample, is conducive to improving the ferritic performance of SrM.And the another one patent ZL201310415623.0 that we have obtained the authorization ourselves, SrM/ (Ni, the Zn) Fe of similar nucleocapsid structure that directly utilized hydro thermal method to prepare
2o
4ferrite powder, Magnetic Measurement shows that it presents the behavior of single-phase magnetic, there is good exchange-coupling interaction.But method described in above-mentioned two patents, all can cause the coercitive very big decline of sample.
We open, patent in a review (publication number CN104211387A) with the relatively little CoFe of coercive force
2o
4for parent, find the SrM ferrite adding only 2%-10% mass ratio, high-coercive force, significantly can promote CoFe
2o
4coercive force, secondly even can reach the technique effect of lifting more than 90%, first its know-why is that ferritic pinning effect is closely related with SrM, and we propose SrM-CoFe
2o
4although between exchange-coupling interaction significantly may reduce the coercive force of " Hard Magnetic phase " SrM, also can increase substantially " soft magnetism phase " CoFe
2o
4coercive force.The patent of this application, just as background, with " Hard Magnetic phase " SrM for parent, mixes " soft magnetism phase " CoFe according to the mass ratio of 3 ~ 2:1
2o
4, substantially reduce the number expensive CoFe
2o
4use, but while ensureing to realize exchange-coupling interaction in SrM, very high coercive force can also be kept simultaneously, improve exchange-coupling interaction with this and " Hard Magnetic phase " coercive force can be caused to decline larger contradiction.
Summary of the invention
The technical problem to be solved in the present invention is to prepare a kind of having two-phase exchange-coupling interaction and keeping the composite permanet magnet ferrite of high-coercive force newly.SrM/CoFe prepared by the present invention
2o
4ferrite, although by two phase compositions, but externally presents the magnetic behavior of single-phase, has good exchange-coupling interaction, and pure SrM ferrite of comparing, and still can keep higher coercive force.
In order to solve above technical problem, the present invention is achieved by the following technical programs.
The present invention prepares and a kind ofly has exchange coupling and keep the two-phase composite permanet magnet ferrite of high-coercive force, and described ferrite is SrM ferrite permanent-magnet phase and CoFe
2o
4the compound that ferrite " soft magnetism phase " forms.Its concrete preparation process is as follows:
(1) SrM phase is prepared: to analyze pure Sr (NO
3)
2, Fe (NO
3)
3and NaOH is raw material, consider a large amount of losses of Sr element in preparation process, in raw material, Fe and Sr mol ratio is according to 4:1 proportioning, OH
-and NO
- 3mol ratio is according to 3:1 proportioning.After nitrate and NaOH are dissolved in deionized water respectively, stir and in mixed nitrate solution, drip NaOH make precipitation by metallic ion, precipitated liquid and sediment are moved into hydrothermal reaction kettle and carries out hydro-thermal reaction.Control hydrothermal reaction kettle compactedness is 80% simultaneously, and reaction condition is 220 DEG C × 5h.For ensureing the purity of phase, gained nanometer powder product is carried out pickling.
(2) CoFe is prepared
2o
4phase: to analyze pure Co (NO
3)
2with Fe (NO
3)
3for raw material, according to CoFe in raw material
2o
4in molecular formula, elemental mole ratios batching, is dissolved in deionized water respectively by nitrate and NaOH, then stirs and in mixed nitrate solution, drips NaOH make precipitation by metallic ion, until stop during pH=9.Then, precipitated liquid and sediment are moved into hydrothermal reaction kettle and carries out hydro-thermal reaction, control hydrothermal reaction kettle compactedness is 80% simultaneously, and reaction condition is 200 DEG C × 8h.For ensureing the purity of phase, gained nanometer powder product is carried out pickling.
(3) preparation of complex ferrite: by the SrFe of preparation in step (1) and (2)
12o
19and CoFe
2o
4after nanometer powder is pressed into disk according to mass ratio 3 ~ 2:1, at the temperature of 700 DEG C ~ 900 DEG C, sinter 2h respectively become compactness magnet, gained magnet is the composite permanet magnet ferrite with two-phase exchange coupling.
Two-phase complex ferrite provided by the present invention is primarily of permanent magnetism phase SrM ferrite and " soft magnetism phase " CoFe
2o
4ferrite two-phase is according to different quality ratio composition.SrM phase and CoFe
2o
4by hydro thermal method preparation, and ensure the purity of its phase through overpickling.The feature of hydro thermal method (about 200 DEG C) directly can form ferrite phase at a lower temperature, becomes phase without the need to high temperature sintering.Therefore, follow-up sintering block only needs the densification considering material, and without the need to being considered to phase problem, this is conducive to reducing sintering temperature, thus realizes controlling grain growth, is beneficial to the formation of exchange-coupling interaction.Precursor powder only need be sintered 2h by two-phase complex ferrite provided by the present invention under the low temperature of 700 DEG C to 900 DEG C can burn till compactness magnet, and average grain diameter still remains within 100nm.Gained two-phase complex ferrite externally presents the behavior of single-phase magnetic, there is good exchange-coupling interaction, and coercive force declines little than pure SrM ferrite, the minimum high-coercive force that still can keep 152.5kA/m (about 1915Oe).
Gained complex ferrite of the present invention still keeps the principle of high-coercive force to be after realizing exchange coupling:
1) " soft magnetism phase " CoFe adopted
2o
4the coercive force of nanometer powder is comparatively large, and the coercive force of ultra-soft magnetic ferrites far away is in fact also a kind of permanent magnetic material, but because coercive force, much smaller than SrM ferrite, is just called as " soft magnetism phase ".And its saturation magnetization is far above SrM ferrite, thus with SrM ferrite compound after, not only can significantly improve the saturation magnetization of sample, higher coercive force can also be kept.
2) CoFe for preparing of hydro thermal method
2o
4its average grain diameter of ferrite only about 20nm, sinters 2h at 700 DEG C, and within size can be controlled in 100nm, according to theory of magnetism, nanocrystal is easy to realize good exchange coupling and keeps high coercive force.
3) especially, it should be noted that, complex ferrite with SrM ferrite for parent, CoFe
2o
4content is relatively less.And the coercive force of SrM is far above CoFe
2o
4, thus can think magnetization time CoFe
2o
4there is not so-called pinning effect to SrM, the high-coercive force of complex ferrite and pinning effect have nothing to do.
Compared with prior art, the present invention has following technique effect:
1) CoFe
2o
4saturation magnetization is far above SrM ferrite, and during 700 DEG C of sintering, its coercive force also reaches about 123kA/m (about 1545Oe), is thus conducive to still keeping high coercive force while utilizing exchange-coupling interaction to improve sample saturation magnetization.
2) " soft magnetism phase " used CoFe of preparing for hydro thermal method
2o
4ferrite nano powder, more close with the ferritic production technology of SrM, be beneficial to and realize exchange-coupling interaction.
3) compared with us open, patent in a review (publication number CN104211387A), this patent take SrM as parent, substantially reduce the number expensive CoFe
2o
4use, be beneficial to cost-saving.
Accompanying drawing explanation
Fig. 1 is X-ray diffraction (XRD) collection of illustrative plates of complex ferrite prepared by embodiment 1.
Fig. 2 is the TEM photo of complex ferrite prepared by embodiment 1;
Fig. 3 is the pure SrM ferrite of embodiment 1 preparation and the magnetic hysteresis loop figure of complex ferrite.
Fig. 4 is the return curve figure of complex ferrite prepared by embodiment 1.
Fig. 5 is magnetic hysteresis loop figure (a) and return curve figure (b) of complex ferrite prepared by embodiment 2.
Fig. 6 is magnetic hysteresis loop figure (a) and return curve figure (b) of complex ferrite prepared by embodiment 3.
Fig. 7 is magnetic hysteresis loop figure (a) and return curve figure (b) of complex ferrite prepared by embodiment 4.
Embodiment
Below in conjunction with drawings and Examples in detail the present invention is described in detail, but the present invention is not limited to following embodiment.
Embodiment 1
Preparation SrFe
12o
19powder: to analyze pure nitrate Sr (NO
3)
2, Fe (NO
3)
3for the SrFe of 2mmol prepared by raw material
12o
19powder, in raw material, Fe and Sr mol ratio is according to 4:1 proportioning, needs Sr (NO
3)
22mmol, Fe (NO
3)
38mmol; According to mol ratio OH
-/ NO
- 3naOH needed for=3 proportionings, namely needs 84mmolNaOH.Nitrate raw material are dissolved in 45ml deionized water, NaOH are dissolved in 30ml deionized water.Then, stir and make precipitation by metallic ion to mixed nitrate solution dropping NaOH solution, precipitated liquid and sediment are moved into 100ml hydrothermal reaction kettle and carries out hydro-thermal reaction, control reactor compactedness is 80% simultaneously, and reaction condition is 220 DEG C × 5h.Gained powder deionized water after reaction and absolute ethyl alcohol are cleaned 3 times and 2 times respectively.For ensureing the purity of phase, gained Sr ferrite powder 2% watery hydrochloric acid cleans once, and then cleans 3 times and 1 time respectively with deionized water and absolute ethyl alcohol.
Preparation CoFe
2o
4powder: to prepare 7mmolCoFe
2o
4proportioning raw material, it is pure that raw material are all analysis.By 7mmolCo (NO
3)
2with 14mmolFe (NO
3)
3be dissolved in 45ml deionized water, 4gNaOH being dissolved in 50ml aqueous solution outfit concentration is the NaOH of 2mol/L.Then, stir and make precipitation by metallic ion to mixed nitrate solution dropping NaOH solution, until pH=9 stops.Precipitated liquid and sediment are moved into 100ml hydrothermal reaction kettle and carries out hydro-thermal reaction, control hydrothermal reaction kettle compactedness is 80% simultaneously, and reaction condition is 200 DEG C × 8h.Gained powder deionized water after reaction and absolute ethyl alcohol are cleaned 3 times and 2 times respectively.For ensureing the purity of phase, gained CoFe
2o
4powder 2% watery hydrochloric acid cleans once, and then cleans 3 times and 1 time respectively with deionized water and absolute ethyl alcohol.
The preparation of complex ferrite: by the SrFe of preparation
12o
19and CoFe
2o
4nanometer powder is pressed into the disk of diameter 1cm according to mass ratio 3:1, at the temperature of 700 DEG C, then sinters 2h become compactness magnet.Gained magnet is the two-phase composite permanet magnet ferrite having exchange coupling, keep high-coercive force.
Accompanying drawing 1 is X-ray diffraction (XRD) collection of illustrative plates of the final complex ferrite powder of gained in embodiment 1.As seen from the figure, only there is SrFe
12o
19and CoFe
2o
4the peak position of two-phase, illustrates that it comprises SrFe really
12o
19and CoFe
2o
4two-phase, and have no other impurity.Fig. 2 is that magnet after 700 DEG C of sintering is pulverized the TEM photo of last test, and can see that its average crystal grain size is within 100nm clearly, remain nanometer scale, this contributes to the formation of exchange coupling very much.Fig. 3 is the pure SrM samples of vibrating specimen magnetometer (VSM) test 700 DEG C sintering and the magnetic hysteresis loop of complex ferrite.As seen from the figure, containing SrFe
12o
19and CoFe
2o
4there is not the two-phase indicatrix of stepped ramp type or necking down type in the complex ferrite powder sample of two-phase, but presents good single-phase permanent magnetism indicatrix, there is good exchange coupling in this interpret sample.And compared with the ferritic coercive force 173.1kA/m (about 2174Oe) of pure SrM, the coercive force of complex ferrite declines very little, is 162.6kA/m (about 2042Oe); Its saturation magnetization is increased to 61.6emu/g from 59.2emu/g.In order to prove the existence of exchange coupling further, we are return curve to sample test, as shown in Figure 4.The return curve tilted further demonstrate that the existence of exchange-coupling interaction in sample.
Embodiment 2
The preparation method of complex ferrite is with embodiment 1, and the parameter of variation is: by the SrFe of preparation
12o
19and CoFe
2o
4nanometer powder is pressed into disk according to mass ratio 2:1.VSM magnetic hysteresis loop figure (a) of test is given in Fig. 5.As seen from the figure, there is not the two-phase indicatrix of stepped ramp type or necking down type in complex ferrite powder sample, but present good single-phase permanent magnetism indicatrix, there is good exchange-coupling interaction in this interpret sample.The coercive force of sample is 152.5kA/m (about 1915Oe), still keeps high level; Its saturation magnetization is 65.1emu/g, is significantly increased than embodiment 1.The return curve (b) tilted also further demonstrate that the existence of exchange-coupling interaction in sample.
Embodiment 3
The preparation method of complex ferrite is with embodiment 1, and the parameter of variation is: sintering temperature is 900 DEG C.From the magnetic hysteresis loop (a) Fig. 6, complex ferrite presents single-phase permanent magnetism indicatrix, there is good exchange-coupling interaction in this interpret sample.The coercive force of sample is 200.7kA/m (about 2521Oe), still keeps high level; Its saturation magnetization is 68.0emu/g, is significantly increased than embodiment 2.The return curve (b) tilted also further demonstrate that the existence of exchange-coupling interaction in sample.
Embodiment 4
The preparation method of complex ferrite is with embodiment 1, and the parameter of variation is: SrFe
12o
19and CoFe
2o
4nanometer powder is pressed into disk according to mass ratio 2:1, and sintering temperature is 900 DEG C.From the magnetic hysteresis loop (a) Fig. 7, complex ferrite presents single-phase permanent magnetism indicatrix, there is good exchange-coupling interaction in this interpret sample.The coercive force of sample is 193.9kA/m (about 2435Oe), still keeps high level; Its saturation magnetization is 68.6emu/g, increases to some extent than embodiment 3.The return curve (b) tilted also further demonstrate that the existence of exchange-coupling interaction in sample.
Claims (1)
1. have two-phase exchange coupling and keep the composite permanet magnet ferrite of high-coercive force, it is characterized in that, this ferrite is SrFe
12o
19ferrite nano powder and CoFe
2o
4the compound that ferrite nano is powder sintered, its concrete preparation process is as follows:
(1) SrM phase is prepared: to analyze pure Sr (NO
3)
2, Fe (NO
3)
3and NaOH is raw material, consider a large amount of losses of Sr element in preparation process, in raw material, Fe and Sr mol ratio is according to 4:1 proportioning, OH
-with
mol ratio is according to 3:1 proportioning; After nitrate and NaOH are dissolved in deionized water respectively, stir and in mixed nitrate solution, drip NaOH make precipitation by metallic ion, precipitated liquid and sediment are moved into hydrothermal reaction kettle and carries out hydro-thermal reaction; Control hydrothermal reaction kettle compactedness is 80% simultaneously, and reaction condition is 220 DEG C × 5h; For ensureing the purity of phase, gained nanometer powder product is carried out pickling;
(2) CoFe is prepared
2o
4phase: to analyze pure Co (NO
3)
2with Fe (NO
3)
3for raw material, according to CoFe in raw material
2o
4in molecular formula, elemental mole ratios batching, is dissolved in deionized water respectively by nitrate and NaOH, then stirs and in mixed nitrate solution, drips NaOH make precipitation by metallic ion, until stop during pH=9; Then, precipitated liquid and sediment are moved into hydrothermal reaction kettle and carries out hydro-thermal reaction, control hydrothermal reaction kettle compactedness is 80% simultaneously, and reaction condition is 200 DEG C × 8h; For ensureing the purity of phase, gained nanometer powder product is carried out pickling;
(3) preparation of complex ferrite: by the SrFe of preparation in step (1) and (2)
12o
19and CoFe
2o
4nanometer powder sinters 2h respectively and becomes compactness magnet at the temperature of 700 DEG C ~ 900 DEG C after being pressed into disk according to mass ratio 3 ~ 2:1, gained magnet is the composite permanet magnet ferrite with two-phase exchange coupling.
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| CN104973859A (en) * | 2015-06-29 | 2015-10-14 | 安徽工业大学 | Preparation method for composite ferrite powder with exchange coupling effect |
| CN105006325B (en) * | 2015-06-30 | 2017-02-01 | 安徽工业大学 | Method for preparing composite ferrite powder with exchange coupling effect through grinding |
| CN106630992B (en) * | 2016-09-29 | 2020-05-22 | 安徽理工大学 | High-performance SrFe12O19/CoFe2O4Composite ferrite material and preparation method thereof |
| CN106567123A (en) * | 2016-11-15 | 2017-04-19 | 彭晓领 | Preparation method of high-coercivity strontium ferrite |
| CN107591542A (en) * | 2017-08-23 | 2018-01-16 | 太原科技大学 | A kind of preparation method of iron cobalt nano-complex base lithium air battery positive electrode material |
| CN108172356A (en) | 2018-01-30 | 2018-06-15 | 广州新莱福磁电有限公司 | A kind of double property magnetic materials and preparation method thereof |
| TWI693206B (en) * | 2019-03-08 | 2020-05-11 | 中國鋼鐵股份有限公司 | Method of fabricating modified ferrite magnetic powder and method of fabricating ferrite magnet |
| CN111892393B (en) * | 2020-07-30 | 2022-02-22 | 安徽鑫磁源磁业有限公司 | Preparation method of M-type strontium ferrite based multi-phase composite permanent magnetic material |
| CN112898004A (en) * | 2021-02-02 | 2021-06-04 | 安徽工业大学 | Biphase composite permanent magnetic ferrite with exchange coupling effect and preparation method thereof |
| CN114835484A (en) * | 2022-04-13 | 2022-08-02 | 四川高鑫磁性材料有限公司 | Permanent magnet composite material and preparation method thereof |
| CN115286377A (en) * | 2022-08-19 | 2022-11-04 | 安徽工业大学 | Hexagonal SrFe 12 O 19 Preparation method of ferrite-based composite permanent magnetic ferrite |
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| CN103449808B (en) * | 2013-09-12 | 2014-09-10 | 安徽工业大学 | Preparation method of biphase composite hard magnetic ferrite nano-powder with exchange coupling |
| CN103449807B (en) * | 2013-09-12 | 2014-09-03 | 安徽工业大学 | Preparation method of biphase composite hard magnetic ferrite with exchange coupling |
| CN104211388B (en) * | 2014-09-03 | 2016-01-20 | 安徽工业大学 | One is suitable for low sintering M-type strontium ferrite SrFe 12o 19preparation method |
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Effective date of registration: 20210121 Address after: 5 / F, building B, Zhigu building, 186 Yangzijiang Middle Road, Yangzhou Economic Development Zone, Jiangsu 225000 Patentee after: Yangzhou Huadan Power Electronic Technology Co.,Ltd. Address before: 201600 room 104, 43 Lane 1505, meijiabang Road, Songjiang District, Shanghai Patentee before: Yang Kuntang |
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| TR01 | Transfer of patent right |