CN101499346A

CN101499346A - Sintered NdFeB permanent magnet with high working temperature and high corrosion resistance

Info

Publication number: CN101499346A
Application number: CNA2008100332552A
Authority: CN
Inventors: 严密; 周向志; 马天宇; 罗伟; 樊熊飞; 任强民
Original assignee: Zhejiang University ZJU; Zhejiang Innuovo Magnetics Industry Co Ltd
Current assignee: Zhejiang University ZJU; Zhejiang Innuovo Magnetics Industry Co Ltd
Priority date: 2008-01-30
Filing date: 2008-01-30
Publication date: 2009-08-05

Abstract

The invention provides a sintered Nd-Fe-B (neodymium iron boron) permanent magnet combination with high working temperature and high corrosion resistance; the composition of the magnet comprises 80-95% of main phase alloy powder and 5-20% of nano-modified grain-boundary-phase alloy powder, taking the total weight of the permanent magnet combination in calculation; the main phase alloy powder is calculated by atomic percentage, and the composition comprises NdaFe100-a-b-cBbMc, wherein a is no less than 11 but no more than 16, b is no less than 5.4 but no more than 6.6, and c is no less than 0 but no more than 6, and M is one or more types of elements Dy, Tb, Nb, Co, Ga, Zr, and Al; and the average particle diameter of the main phase alloy powder is 3-8 mu m. The invention also provides a sintered Nd-Fe-B permanent magnet which simultaneously has high working temperature and high corrosion resistance.

Description

A kind of elevated operating temperature and high-corrosion resistance Sintered NdFeB permanent magnet

Technical field

The present invention relates to a kind of thermal endurance and corrosion resistance Nd-Fe-B permanent magnet composition, relate to particularly based on pairing gold process crystal boundary phase nano modification technology prepare elevated operating temperature and high corrosion-resistant neodymium iron boron magnetic body composition.

Background technology

Sintered Nd-Fe-B permanent magnetic material is the strongest permanent magnet of present magnetic, has high energy product, excellent specific properties such as high performance-price ratio, since day nineteen eighty-three neodymium iron boron base of the present invention rare earth permanent magnet, Gross World Product from then less than 1 ton of nearly 50,000 ton of rising to 2006, it is most important permanent magnetic material in a period of time at present and in the future, such as computer technology, information technology, aeronautical and space technology, communication and traffic technique, play the part of more and more important role in the field such as Automated Technology in Office and health care technology, become the important substance basis of modern science and technology and people's lives.

The basic mechanical design feature index of NdFeB material is remanent magnetism B _r, coercive force H _c(HCJ H _CjWith magnetic strength coercive force H _Cb), magnetic energy product (BH) _MaxWith Curie temperature T _cThe researcher of permanent magnetic material and the producer's main task are exactly the potentiality of excavated material to greatest extent, improve the B of permanent magnetic material _r, H _c, (BH) _MaxAnd T _cThrough the development in 24 years, the maximum magnetic energy product of Sintered NdFeB magnet was promoted to 474kJ/m (59.5MGOe) by the 279kJ/m (35MGOe) at the beginning of coming out, reached theoretical value 512kJ/m (64MGOe) 93%; Remanent magnetism also is promoted to 1.555T from 1.23T, has reached more than 96% of theoretical value 1.6T, and this appearance and technological progress for new industry provides important material guarantee.But the HCJ of above-mentioned magnet has only 653kA/m, less than 12% of theoretical value, when in parts such as motor, using, magnet performance is because of heating or ambient temperature raising reduction greatly, even cause component failure, add that the lower resistance to corrosion of NdFeB (neodymium iron boron) rare-earth permanent magnet has become two big bottlenecks of restriction extrahigh energy density Nd-Fe-B rare-earth permanent magnet range of application.Scientist has all over the world done a large amount of work for this reason in recent years, but is not still making a breakthrough aspect heat-resisting quantity and the corrosion resistance two so far.

(1) heat-resisting quantity

The parameter of describing magnet temperature stability mainly contains: total losses h _T, irreversible flux loss h _Irr, reversible loss h _Rev, reversible temperature coefficient (comprising magnetic strength temperature coefficient α and coercive force temperature coefficient β).The maximum operating temperature of magnet commonly used improves the neodymium iron boron magnetic body working temperature and mainly concentrates on following three aspects as one of module of magnet temperature characteristic in actual the use, improves the Curie temperature T of magnet _c, the HCJ H of raising magnet _CjWith the temperature coefficient that reduces magnet, and the main method of reduction temperature coefficient is to improve Curie temperature T _cOr HCJ H _CjSo that wherein the most key is the H that improves magnet _Cj, H _CjLimiting value be magnetocrystalline anisotropy field H _A, it depends on the magnetocrystalline anisotropy constant K of material ₁And K ₂According to Theoretical Calculation, Nd ₂Fe ₁₄The anisotropy field of B compound, promptly coercitive limiting value is 80kOe, however the actual coercive force of the sintered Nd-Fe-B alloy that obtains at present only is the 1/3-1/30 of its theoretical value, thereby the coercive force of raising Sintered NdFeB magnet also has a lot of work to do.

The coercive force H of neodymium iron boron magnetic body is described _cThe following empirical equation of general employing,

H _c＝αH _k—N _effM _s

Hk represents that magnetic moment is consistent and rotates needed anisotropy field that α represents that the grainiess defective is to the coercitive minimizing factor, N _EffThe coupling of expression crystal grain self-heating demagnetizing effect and intergranule interacts and effective demagnetizing factor of formation, M _sExpression magnet saturation magnetization.This shows that coercitive reduction mainly is that (relative orientation that comprises intergranule) causes because grainiess defective and crystal grain interact, coercive force is a structure sensitive parameter.Everybody generally admits, and the microstructure model with high-coercive force sintered neodymium iron boron material should be: the uniform crystal boundary of thickness is wrapped in Nd mutually ₂Fe ₁₄B crystal grain and do not have the existence of epitaxial loayer, Nd ₂Fe ₁₄B crystal grain is tiny, size is even, grain shape rule almost spherical, Nd ₂Fe ₁₄The chemical composition of B crystal grain is consistent with even structure.

In order to improve the shortcoming that NdFeB is a RE permanent magnetic alloy, people have adopted the method for alloying based on above-mentioned thinking, the researcher has studied multiple element widely to ternary NdFeB permanent-magnet alloy Effect on Performance, but present result of study shows, can partly improve magnetic property raising coercive force though add element, will be cost to sacrifice other performances all basically.

The method of above-mentioned alloying comprises two alloyages.Two alloyages are to improve the coercitive effective way of magnet, nearly Nd ₂Fe ₁₄The B just main-phase alloy of branch ratio and the crystal-boundary phase alloy of rich rare earth prepares respectively; mix by certain proportioning; make crystal boundary be dispersed in around the principal phase mutually; principal phase is formed good coating; improve the magnet microstructure; hinder the exchange-coupling interaction between the hard magnetic phase; add the nano modification particle mutually or handle at crystal boundary and make crystal boundary separate out spontaneous nano particle in mutually by subsequent techniques such as tempering; play the pinning point effect; the obstruction neticdomain wall moves; improve the coercive force of magnet, and then improved the working temperature of magnet.And can make principal phase more reasonable with crystal boundary composition mutually, the composition of principal phase can be more near Nd simultaneously ₂Fe ₁₄B is just dividing ratio, and therefore two alloyages can guarantee that alloy has high H when hanging down neodymium content _CjBut at present two alloyages only are suitable for ball milling powder process, the production Nd-Fe-B series permanent magnet of small lot, and the technology of two alloyage large-scale production Nd-Fe-B (also the being neodymium iron boron) permanent magnets of utilization is also immature.

In sum, this area lacks a kind of Nd-Fe-B that works (also being neodymium iron boron) permanent magnet under elevated operating temperature.

(2) corrosion resistance

On the other hand; the means of protective finish are mainly taked in the corrosion protection of permanent magnet Nd-Fe-B material at present to Nd-Fe-B (also being neodymium iron boron); with plating, chemical plating or physical vaporous deposition with metal such as Ni, Zn, Al, Ni-P, Ni-Fe, Ni-Co-P, Cu, Cd, Cr, TiN, ZrN or compound plating in magnet surface, comparatively effectively typical method is electroplated Ni and ion plating Al at present.In addition, alloying also is the effective way that improves corrosion resistance, adds the decay resistance that trace element can improve magnet in neodymium iron boron magnetic body, studies show that elements such as Cu, Al, Nb, Ga, Co, V, Mo can improve the corrosion resistance of alloy effectively; But, damage the magnetic property of magnet sometimes, and alloying also will improve the cost of material, and can not fundamentally solve the inherent shortcoming of Nd-Fe-B (neodymium iron boron) magnet, these factors are all limiting the application of this anti-corrosion method.In a word, researched and developed out the corrosion protection method of many Nd-Fe-B (neodymium iron boron) magnet at present, also obtained anti-corrosion preferably effect, further applying of Nd-Fe-B (neodymium iron boron) magnet played very big facilitation.Do not solve but the anticorrosion problem of magnet is also basic, various means of defences have different defectives, and applying organic coating as magnet surface has requirement to operational environment, and the anti-corrosion time is not long; When the aqueous solution was electroplated, neodymium was very easily oxidized and have hydrogen to be present in to cause hydrogen embrittlement etc. in the coating.

At the problem that exists above, research from now on should focus on a kind of method that can thoroughly improve corrosion resistance that finds.

A lot of bibliographical informations Cu, Ti, Ti﹠amp; C and TiC in the sintered NdFeB of single alloy technique preparation the behavior of separating out and to the influence of magnetic property, the bibliographical information that also has the coercitive influence of heavy rare earth salt pair sintered NdFeB powder, relevant interpolation heavy rare earth salt magnetic hardening principal phase boundary layer technology has been applied for patent.But the weak point of above-mentioned patent is to improve the coercitive while of magnet, and the remanent magnetism of magnet or magnetic energy product are descended to some extent, and the corrosive nature of magnet is not well improved yet.

In sum, this area lacks a kind of have simultaneously elevated operating temperature and high-corrosion resistance Sintered NdFeB permanent magnet.

Summary of the invention

First purpose of the present invention is to obtain a kind of elevated operating temperature and high-corrosion resistance Sintered NdFeB set of permanent magnets compound.

Second purpose of the present invention is to obtain to also have a kind of elevated operating temperature and high-corrosion resistance Sintered NdFeB set of permanent magnets compound.

The 3rd purpose of the present invention is to obtain the permanent magnet that a kind of composition of the present invention makes,

The 4th purpose of the present invention is to obtain the preparation method of a kind of elevated operating temperature and high-corrosion resistance Sintered NdFeB permanent magnet.

The 5th purpose of the present invention is to obtain a kind of purposes of modified Nano powder.

In a first aspect of the present invention, a kind of elevated operating temperature and high-corrosion resistance Sintered NdFeB set of permanent magnets compound, the composition of described magnet comprises the nano modification crystal-boundary phase alloy powder of 80-95% main-phase alloy powder and 5-20%, in described permanent magnet composition total weight;

Described main-phase alloy powder is in atomic percent, and its composition is Nd _aFe _100-a-b-cB _bM _c, 11≤a≤16,5.4≤b≤6.6,0≤c≤6 wherein, M is one or more in Dy, Tb, Nb, Co, Ga, Zr, the Al element; The average particulate diameter of described main-phase alloy powder is 3-8 μ m;

Described nano modification crystal-boundary phase alloy powder comprises the modified Nano powder of 87-98% crystal-boundary phase alloy powder and surplus, in nano modification crystal-boundary phase alloy powder total weight;

Described crystal-boundary phase alloy is in atomic percent, and its composition is Nd _dFe _100-d-e-fB _eR _f, 13.5≤d≤30,4≤e≤7,0≤f≤15 wherein, R is one or more in Dy, Tb, Nb, Co, Ga, Zr, C, Al, the Si element; Its average particulate diameter is 1-4 μ m;

The average particulate diameter of described modified Nano powder is 2-40nm, fusing point 1000-3000 ℃, and electrode potential-0.2-0.4V.

In a specific embodiment of the present invention, described modified Nano powder is nanometer titanium, nanometer copper, Nano titanium nitride or its combination.

In a specific embodiment of the present invention, described modification crystal-boundary phase alloy modified powder is prepared by following method:

Adopt casting technique to make alloy of ingot crystal-boundary phase alloy of the present invention or rapid hardening thin slice technology makes the rapid hardening thin slice or rapid quenching technique is made rapid tempering belt, adopt mechanical ball milling or airflow milling powder process, making average particulate diameter is the crystal-boundary phase alloy powder of 1-4 μ m

Described crystal-boundary phase alloy powder and modified Nano powder are evenly mixed the crystal-boundary phase alloy powder that obtains the nanometer powder modification in ratio of the present invention.

Particularly, described crystal-boundary phase alloy powder can add optional processing aid with the modified Nano powder when mixing; More specifically, the consumption of described optional processing aid is: in the crystal-boundary phase alloy powder and modified Nano mixture of powders of 100 weight portions, add the combination of 1-10 weight portion antioxidant and 2-5 weight portion lubricant.

Second aspect present invention provides a kind of elevated operating temperature and high-corrosion resistance Sintered NdFeB set of permanent magnets compound, the composition of described magnet comprises the nano modification crystal-boundary phase alloy powder of 80-95% main-phase alloy powder and 5-20%, in described permanent magnet composition total weight;

Described nano modification crystal-boundary phase alloy particles of powder diameter is 1-4 μ m, and it comprises the modified metal titanium of 87-98% crystal-boundary phase alloy component and surplus, in nano modification crystal-boundary phase alloy powder total weight;

Described crystal-boundary phase alloy is in atomic percent, and its composition is Nd _dFe _100-d-e-fB _eR _f, 13.5≤d≤30,4≤e≤7,0≤f≤15 wherein, R is one or more in Dy, Tb, Nb, Co, Ga, Zr, C, Al, the Si element.

The mixture of crystal-boundary phase alloy and Titanium is provided, described crystal-boundary phase alloy accounts for the 87-98 weight % of described mixture total weight amount, surplus is described Titanium, described mixture carries out mixed smelting, the employing casting technique makes alloy of ingot or rapid hardening thin slice technology makes the rapid hardening thin slice or rapid quenching technique is made rapid tempering belt, and adopt mechanical ball milling or airflow milling powder process, making average particulate diameter is the modification crystal-boundary phase alloy powder of 1-4 μ m

In a specific embodiment of the present invention, described main-phase alloy powder is made by ingot casting crush method, rapid hardening thin slice crush method or rapid tempering belt crush method;

Particularly, in the described ingot casting crush method, adopt casting technique that main-phase alloy is made the neodymium iron boron alloy of ingot, by the quick-fried method of hydrogen or disintegrating machine with described alloy of ingot fragmentation, fragmentation is after the airflow milling abrasive material, and making average particulate diameter is the described main-phase alloy powder of 3-8 μ m;

Particularly, in the described rapid hardening thin slice crush method, adopt rapid hardening technology that main-phase alloy is made neodymium iron boron rapid hardening thin slice, by the quick-fried method of hydrogen or disintegrating machine with the fragmentation of described rapid hardening thin slice, fragmentation is after the airflow milling abrasive material, and making average particulate diameter is the described main-phase alloy powder of 3-8 μ m;

Particularly, in the described rapid tempering belt crush method, adopt rapid quenching technique that main-phase alloy is made the neodymium iron boron rapid tempering belt, by the quick-fried method of hydrogen or disintegrating machine with described rapid tempering belt fragmentation, fragmentation is after the airflow milling abrasive material, and making average particulate diameter is the described main-phase alloy powder of 3-8 μ m.

The permanent magnet that a third aspect of the present invention provides a kind of described composition to make,

Particularly, the working temperature of described permanent magnet is up to 220-260 ℃; Autoclave test 100h mass loss is 8-65mg/cm ²Magnetic energy product is 46-50MGOe; Remanent magnetism reaches 13.2-14.2kGs.

Particularly, described permanent magnet is made by the method that comprises the steps:

Composition of the present invention and gasoline are uniformly mixed into mixed-powder, and wherein said composition accounts for the 95-99.5% of described mixed-powder total weight, and described gasoline accounts for the 0.5-5% of described mixed-powder total weight;

Described mixed-powder is compressed to moulded blank in the magnetic field of 1.2-2.0T;

With described moulded blank in 1050-1125 ℃, vacuum 10 ^-3～10 ^-4Sintering 2-4h makes sintered magnet under the Pa, passes through 500-650 ℃ of tempering 2-4h again, obtains described permanent magnet.

A fourth aspect of the present invention is to obtain the preparation method of a kind of elevated operating temperature and high-corrosion resistance Sintered NdFeB permanent magnet, and described method comprises the steps:

80-95% main-phase alloy powder is provided;

The nano modification crystal-boundary phase alloy powder of surplus is provided;

Be pressed after described main-phase alloy powder and nano modification crystal-boundary phase alloy powder evenly mixed, sintering, obtain described permanent magnet;

Particularly, described main-phase alloy powder is in atomic percent, and its composition is Nd _aFe _100-a-b-cB _bM _c, 11≤a≤16,5.4≤b≤6.6,0≤c≤6 wherein, M be in Dy, Tb, Nb, Co, Ga, Zr or the Al element one or more; Its average particulate diameter 3-8 μ m;

Particularly, described crystal-boundary phase alloy powder is in atomic percent, and its composition is Nd _dFe _100-d-e-fB _eR _f, 13.5≤d≤30,4≤e≤7,0≤f≤15 wherein, R be in Dy, Tb, Nb, Co, Ga, Zr, C, Al or the Si element one or more; Its average particulate diameter is 1-4 μ m;

Particularly, described modified Nano powder is nanometer titanium, nanometer copper, Nano titanium nitride or its combination.

In a specific embodiment of the present invention, described nano modification crystal-boundary phase alloy powder is obtained by the method that comprises following arbitrary step:

It is 2-40nm that average particulate diameter is provided, fusing point 1000-3000 ℃, and the modified Nano powder of electrode potential-0.2-0.4V;

Described crystal-boundary phase alloy powder and modified Nano powder are obtained nano modification crystal-boundary phase alloy powder in even the mixing of ratio of the present invention;

Perhaps, described nano modification crystal-boundary phase alloy powder is prepared by following method:

The mixture of crystal-boundary phase alloy and Titanium is provided, and described crystal-boundary phase alloy accounts for the 87-98 weight % of described mixture total weight amount, and surplus is described Titanium,

Described mixture carries out mixed smelting, the employing casting technique makes alloy of ingot or rapid hardening thin slice technology makes the rapid hardening thin slice or rapid quenching technique is made rapid tempering belt, and adopt mechanical ball milling or airflow milling powder process, making average particulate diameter is the nano modification crystal-boundary phase alloy powder of 1-4 μ m.

A fifth aspect of the present invention provides a kind of purposes of modified Nano powder, and described nanometer powder is used for the crystal-boundary phase alloy powder is carried out modification;

The average particulate diameter of wherein said modified Nano powder is 2-40nm, fusing point 1000-3000 ℃, and electrode potential-0.2-0.4V.

Embodiment

Extensive studies has obtained a kind of new permanent magnet by crystal boundary phase nano modification technology to the present inventor through going deep into, and finds that this permanent magnet has the permanent magnet of anti-elevated operating temperature and decay resistance.

Thermal endurance of the present invention is meant in elevated operating temperature magnetic deterioration not, particularly 220-260 ℃ of elevated operating temperature magnetic deterioration not for example.

Corrosion resistance of the present invention or corrosion resistance are meant: mass loss is little in required time; 100h mass loss 8-65 (mg/cm for example particularly ²).

The implication of " nano modification " of the present invention comprising: directly nanometer powder is dispersed in the crystal-boundary phase alloy powder and forms nanophase, also be included in the crystal-boundary phase alloy fusion process by adding specific metal and make crystal-boundary phase alloy in sintering and heat treatment, separate out nano-scale particle to form spontaneous nanophase, thereby crystal boundary is carried out nano modification mutually.

Below describe in detail to various aspects of the present invention:

To have thermal endurance and corrosion proof Nd-Fe-B permanent magnet in order preparing, at first to need to prepare a kind of mixed-powder with predetermined composition.

Mixed-powder of the present invention is made up of the pairing gold, comprises the main-phase alloy powder, and nano modification crystal-boundary phase alloy powder.

Particularly, Nd-Fe-B permanent magnet of the present invention comprises the main-phase alloy powder of 80-95 weight % and the nano modification crystal-boundary phase alloy powder of surplus.Also the unavoidable impurities element be may contain in the described magnet, rare earth element, nickel, manganese, calcium, magnesium, sulphur and phosphorus except that neodymium for example comprised.These impurity elements do not have special adverse influence to the performance of magnet alloy composition of the present invention, as long as its content is no more than for example about 0.05wt%.

Particularly, described main-phase alloy neodymium iron boron is in atomic percent, and its composition is Nd _aFe _100-a-b-cB _bM _c, 11≤a≤16,5.4≤b≤6.6,0≤c≤6 wherein, M be in Dy, Tb, Nb, Co, Ga, Zr, the Al element one or more; Its average particulate diameter 3-8 μ m.

Preferably, described main-phase alloy powder is made by the ingot casting crush method and/or rapid hardening thin slice crush method makes.

Particularly, in the described ingot casting crush method, adopt casting technique that main-phase alloy is made the neodymium iron boron alloy of ingot, by the quick-fried method of hydrogen or disintegrating machine with described alloy of ingot fragmentation, fragmentation is after the airflow milling abrasive material, and making average particulate diameter is the described main-phase alloy powder of 3-8 μ m.

Particularly, in the described rapid hardening thin slice crush method, adopt rapid hardening technology that main-phase alloy is made neodymium iron boron rapid hardening thin slice, by the quick-fried method of hydrogen or disintegrating machine with the fragmentation of described rapid hardening thin slice, fragmentation is after the airflow milling abrasive material, and making average particulate diameter is the described main-phase alloy powder of 3-8 μ m.

Described nano modification crystal-boundary phase alloy powder comprises: directly nanometer powder is dispersed in the crystal-boundary phase alloy powder and forms nanophase, also be included in the crystal-boundary phase alloy fusion process by adding specific metal and make crystal-boundary phase alloy in sintering and heat treatment, separate out nano-scale particle to form spontaneous nanophase, thereby crystal boundary is carried out nano modification mutually.

Particularly, a specific embodiment of described nano modification crystal-boundary phase alloy powder comprises the modified Nano powder of 87-98% crystal-boundary phase alloy powder and surplus, calculates with described nano modification crystal-boundary phase alloy total weight of powder;

Described crystal-boundary phase alloy powder is in atomic percent, and its composition is Nd _dFe _100-d-e-fB _eR _f, 13.5≤d≤30,4≤e≤7,0≤f≤15 wherein, R be in Dy, Tb, Nb, Co, Ga, Zr, C, Al or the Si element one or more; Its average particulate diameter is 1-4 μ m;

More specifically, described modified Nano powder is nanometer titanium, nanometer copper, Nano titanium nitride or its combination.

Described average particulate diameter is that the crystal-boundary phase alloy modified powder of 1-4 μ m can be obtained by the traditional breaking method in this area.

Particularly, described modification crystal-boundary phase alloy modified powder can be prepared by following method:

Crystal-boundary phase alloy powder and modified Nano powder are evenly mixed the crystal-boundary phase alloy powder that obtains the nanometer powder modification in following ratio: wherein said crystal-boundary phase alloy powder accounts for mixture total weight amount 87-98 weight %, and surplus is the modified Nano powder.

Described crystal-boundary phase alloy powder can add optional processing aid with the modified Nano powder when mixing.

Particularly, the consumption of described optional processing aid is: in the crystal-boundary phase alloy powder and modified Nano mixture of powders of 100 weight portions, add the combination of 1-10 weight portion antioxidant and 2-5 weight portion lubricant.

In the described optional processing aid, described antioxidant and lubricant can adopt the traditional antioxidant in this area.Particularly for example, described antioxidant is polyethylene oxide alkyl ethers, poly(ethylene oxide) mono fatty acid ester or poly(ethylene oxide) allyl ether.Described lubricant for example is oleic acid or other traditional lubricant.

In yet another embodiment of the present invention, described nano modification crystal-boundary phase alloy powder is to obtain in the following way: the mixture that crystal-boundary phase alloy and Titanium are provided, described crystal-boundary phase alloy accounts for the 87-98 weight % of described mixture total weight amount, surplus is described Titanium, described mixture carries out mixed smelting, the employing casting technique makes alloy of ingot or rapid hardening thin slice technology makes the rapid hardening thin slice or rapid quenching technique is made rapid tempering belt, and adopt mechanical ball milling or airflow milling powder process, making average particulate diameter is the modification crystal-boundary phase alloy powder of 1-4 μ m.

By the modified Nano powder crystal boundary is carried out nano modification mutually, the non magnetic crystal boundary that makes modification is at principal phase (Nd for example ₂Fe ₁₄B crystal grain) surface evenly distributes, and improves the magnet microstructure, realizes the coating effect good to principal phase, reduces crystallite dimension and hinders the exchange coupling of hard magnetic between mutually.When obtaining desirable microscopic structure and crystallite dimension, spontaneous nano particle or nanometer powder part be present in crystal grain inside, play the pinning point effect, hinder moving of neticdomain wall, improve the coercive force of magnet, and then improve the working temperature of magnet.Heavy rare earth element crystal boundary mutually in suitably enrichment, the even distribution of the high electrode current potential nano-powder particles of spontaneous in addition nano particle and interpolation obviously reduces crystal boundary and principal phase electrode potential difference, the corrosion resisting property of raising magnet.Thereby obtain the Sintered NdFeB magnet of high-coercive force, elevated operating temperature and high anti-corrosion capability.

On the other hand because the corrosion of NdFeB magnet shows as the not intercrystalline corrosion between the homophase, its corrosion motive power be principal phase and rich neodymium mutually, the chemical potential between the boron-rich phase is poor.The electrode potential of rich neodymium crystal boundary phase is-0.65V, become anode in primary cell, and the principal phase electrode potential is-0.515V, becomes the negative electrode of primary cell.Therefore, improve the electrode potential of crystal boundary phase, reduce that the corrosion potential between the homophase is not poor, just can avoid or weaken intercrystalline corrosion, the reduction corrosion electric current density.The magnet that utilizes of the present invention pair of alloyage to produce, crystal boundary itself is single-phase alloy mutually, the atmospheric corrosion that in melting, coarse crushing process, is subjected to relatively a little less than, and after adding specific modified metal, by handling, its crystal boundary is evenly distributed on around the principal phase mutually, improve the microstructure of crystal boundary phase, improve the electrode potential of crystal boundary phase simultaneously, and then improve the anti-corrosion capability of magnet.

The mixture of described main-phase alloy powder and nano modification crystal-boundary phase alloy powder can adopt that common method is pressed, sintering, obtains described permanent magnet.

In the powder process, can add gasoline to the mixture of described main-phase alloy powder and nano modification crystal-boundary phase alloy powder and evenly mix.

Particularly for example with nano modification crystal-boundary phase alloy powder and main-phase alloy powder, (be uniformly mixed into mixed-powder, wherein modification crystal-boundary phase alloy powder weight accounts for the 5-20% of total weight to gasoline, and gasoline accounts for the 0.5-5% of total weight;

Mixed-powder is the compression moulding blank in the magnetic field of 1.2-2.0T; Described magnetic field can also be other intensity, or pulsed magnetic field, as long as make particle with respect to its easy magnetizing axis orientation;

Moulded blank is put in the high vacuum sintering furnace,, made sintered magnet, pass through 500-650 ℃ of tempering 2-4h again, obtain described permanent magnet 1050-1125 ℃ of sintering 2-4h (for example put into and carry out sintering).

Casting technique of the present invention, rapid hardening thin slice technology, the quick-fried method technology of hydrogen particular content have disclosed at following document: Zhou Shouzeng, Dong Qingfei " superpower permanet magnetic body---rare-earth system permanent magnetic material " Beijing, metallurgical industry publishing house, 2004.2 second edition, p159-164, p498-504, p326-332, p508-511, p169-172.

In a specific embodiment of the present invention, concrete steps of the present invention are as follows:

1) main-phase alloy adopts casting technique to make the neodymium iron boron alloy of ingot or make neodymium iron boron rapid hardening thin slice with rapid hardening thin slice technology, and its composition is Nd _aFe _100-a-b-cB _bM _c(at%), 11≤a≤16,5.4≤b≤6.6,0≤c≤6 wherein, M be in Dy, Tb, Nb, Co, Ga, Zr, the Al element one or more.Undertaken slightly breaking by jaw crusher, broken in being undertaken by middle disintegrating machine then, perhaps adopt the quick-fried method of hydrogen directly broken, at room temperature saturated suction hydrogen is made the quick-fried powder of hydrogen at 400-600 ℃ of dehydrogenase 12-10h then.Broken back main-phase alloy is by airflow milling or mechanical ball milling abrasive material, and making average particulate diameter is 3-8 μ m powder.

2) two kinds of methods are adopted in the preparation of crystal-boundary phase alloy modified powder, and its composition is by molecular formula Nd _dFe _100-d-e-fB _eR _f(at%) preparation, wherein R be in Dy, Tb, Nb, Co, Ga, Zr, C, Al, the Si element one or more, 13.5≤d≤30,4≤e≤7,0≤f≤15 wherein.One is the crystal-boundary phase alloy interpolation 2-15 weight portion Titanium mixed smelting of 100 weight portions, the employing casting technique makes alloy of ingot or rapid hardening thin slice technology makes the rapid hardening thin slice or rapid quenching technique is made rapid tempering belt, and adopt mechanical ball milling or airflow milling powder process, making average particulate diameter is the crystal-boundary phase alloy powder of 1-4 μ m; Other method is that crystal-boundary phase alloy adopts casting technique to make alloy of ingot or rapid hardening thin slice technology makes the rapid hardening thin slice or rapid quenching technique is made rapid tempering belt, adopt mechanical ball milling or airflow milling powder process, making average particulate diameter is the crystal-boundary phase alloy powder of 1-4 μ m, the nanometer powder that in the crystal-boundary phase alloy powder of 100 weight portions, adds the 2-15 weight portion, the antioxidant of 1-10 weight portion, the evenly mixed crystal-boundary phase alloy powder that obtains the nanometer powder modification in batch mixer, wherein the modified Nano powder is a kind of in nano titanium powder or copper nanoparticle or the nano silicon nitride titanium valve, and antioxidant is a kind of in polyethylene oxide alkyl ethers or poly(ethylene oxide) mono fatty acid ester or the poly(ethylene oxide) allyl ether;

3) will mix with the main-phase alloy powder through the crystal-boundary phase alloy powder of modification, the crystal-boundary phase alloy powder weight accounts for the 5-20% of total weight, adds the gasoline of 0.5-5% simultaneously, is uniformly mixed into mixed-powder in batch mixer.Wherein the nanometer powder average particulate diameter is 2-40nm.

4) mixed-powder is compressed to parison spare in the magnetic field orientating moulding press, and moulding alignment magnetic field 1.2-2.0T increases the degree of orientation that magnetic can be improved in magnetic field.And the compression moulding of parison spare is finished in the glove box of sealing fully, makes the magnetic air-isolation, has avoided on the one hand the danger of catching fire because of magnet oxidation heating, has reduced the oxygen content of final magnet on the other hand again.

5) parison spare is put into high vacuum sintering furnace,, make sintered magnet, pass through 500-650 ℃ of tempering 2-4h again, obtain the finished product magnet at 1050-1125 ℃ of sintering 2-4h.

The invention has the advantages that:

(1) the present invention adopts two alloyages, by directly nanometer powder is dispersed in crystal boundary mutually in or in crystal boundary phase fusion process by adding specific metal, and make it in sintering and heat treatment, separate out nano-scale particle to form spontaneous nanophase, crystal boundary is carried out nano modification mutually, and the non magnetic crystal boundary that makes modification simultaneously is at principal phase Nd ₂Fe ₁₄The B grain surface evenly distributes, and improves the magnet microstructure, realizes the coating effect good to principal phase, reduces crystallite dimension and hinders the exchange coupling of hard magnetic between mutually.When obtaining desirable microscopic structure and crystallite dimension, spontaneous nano particle or nanometer powder part be present in crystal grain inside, play the pinning point effect, hinder moving of neticdomain wall, improve the coercive force of magnet, and then improve the working temperature of magnet.Heavy rare earth element crystal boundary mutually in suitably enrichment, the even distribution of the high electrode current potential nano-powder particles of spontaneous in addition nano particle and interpolation obviously reduces crystal boundary and principal phase electrode potential difference, the corrosion resisting property of raising magnet.Thereby obtain the Sintered NdFeB magnet of high-coercive force, elevated operating temperature and high anti-corrosion capability.

(2) mutually unmodified magnet coercive force height, working temperature height, the resistance to corrosion that makes of crystal boundary is strong than adopting the pairing gold process for the magnet that makes of the present invention, and principal phase and crystal boundary powder mutually are difficult for oxidation, and technical process is suitable for mass production.

(3) in a preferred embodiment of the present invention, the invention provides a kind of pairing gold process new utilize method, prepare elevated operating temperature and high-corrosion resistance Sintered NdFeB magnet by crystal boundary phase nano modification technology, main-phase alloy and crystal-boundary phase alloy are adopted specific method (for example rapid hardening slice method etc.) preparation respectively, and crystal boundary directly added specific high-melting-point high electrode current potential nanometer powder when communicating and adding special metal in the fusion process and carry out alloying or powder process and carries out modification.In the crystal-boundary phase alloy powder of master alloying powder and modification, add optional lubricant, antioxidant, mix, obtain the better permanent magnet of heat-resisting quantity and corrosion resistance by ad hoc fashion.

Compound provided by the present invention can be synthetic by marketable material and traditional chemical transform mode.

Other aspects of the present invention are because the disclosure of this paper is conspicuous to those skilled in the art.

Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiment only to be used to the present invention is described and be not used in and limit the scope of the invention.The experimental technique of unreceipted actual conditions in the following example usually according to normal condition, or carries out according to the condition that manufacturer advises.Unless otherwise indicated, otherwise all umbers are weight portion, and all percentages are weight percentage.

Unless otherwise defined or explanation, same meanings of being familiar with of all specialties used herein and scientific words and those skilled in the art.Any in addition method similar or impartial to described content and material all can be applicable in the inventive method.

Embodiment 1a

1) main-phase alloy and crystal-boundary phase alloy are prepared respectively.Main-phase alloy adopts rapid hardening thin slice technology, and copper roller linear resonance surface velocity is 1.2m/s, and composition is Nd _13.12Fe _80.69B _5.73(Dy _0.22Al _0.24) (at%), crystal-boundary phase alloy adopts 18m/s fast quenching speed to be prepared into rapid tempering belt, composition is Nd _17.2Fe _75.58B _6.38Dy _0.64Ga _0.2(at%).

2) with main-phase alloy and crystal-boundary phase alloy powder process respectively.Carry out coarse crushing by jaw crusher, broken in being undertaken by middle disintegrating machine, under nitrogen protection, pass through airflow milling then, main-phase alloy is made the powder that average particulate diameter is 3 μ m, and crystal-boundary phase alloy is made the powder that average particulate diameter is 1 μ m.

3) in the crystal-boundary phase alloy powder, add the nanometer titanium (average particulate diameter is 40nm) that accounts for its weight 2.5% through dispersion treatment respectively, and 3% the antioxidant polyethylene oxide alkyl ethers that accounts for crystal boundary phase powder and modified Nano powder total weight (particularly points out as nothing, following examples antioxidant is weight ratio, and all be) with crystal boundary phase powder and modified Nano powder total weight, 2% the lubricant oleic acid that accounts for crystal boundary phase powder and modified Nano powder total weight (particularly points out as nothing, following examples lubricant is weight ratio, and all be with crystal boundary phase powder and modified Nano powder total weight) evenly mixed in batch mixer, obtain crystal-boundary phase alloy powder through the nanometer powder modification.

4) will mix with the main-phase alloy powder through the crystal-boundary phase alloy powder of nanometer powder modification, make weight account for 5% of total weight through the crystal-boundary phase alloy powder of nanometer powder modification, add the gasoline that accounts for total weight 1% simultaneously, in batch mixer, be uniformly mixed into mixed-powder.

5) mixed powder is compressed to parison spare by the magnetic field orientating moulding press, moulding alignment magnetic field 1.6T finishes in the glove box of sealing fully, makes the magnetic air-isolation.

6) parison spare is put into the high vacuum sintering furnace sintering, 1050 ℃ of sintering 3h, and 510 ℃ of tempering heat treatment 3h make sintered magnet again.The gained performance is seen comparative example 1.

Embodiment 1b

The method of embodiment 1b is identical with embodiment 1a, and difference is, adopts the copper nanoparticle end in the step 3).The gained performance is seen comparative example 1.

Embodiment 1c

The method of embodiment 1c is identical with embodiment 1a, and difference is, adopts the nano silicon nitride ti powder in the step 3).The gained performance is seen comparative example 1.

The comparative example 1:

Comparative example 1 preparation method is identical with embodiment 1, and difference is, does not form mixed-powder with adding nanometer powder modification crystal-boundary phase alloy, accounts for total weight 5%, adopts identical magnetic field orientating die mould and sintering, tempering process to be prepared into magnet.

Adopt autoclave test (5-10psig, 110-115 ℃, (Φ 1 * 0.5cm): also be the corrosion resistance of comparative example 1 and embodiment 1a, 1b, 1c sample, adopt the magnetic property of characteristic of magnetization automatic measuring instrument AMF measurement magnet, performance such as table one 100h) to have tested sample.

Table one, the magnet performance that adopts different process to prepare

Therefrom as can be seen, adopt the pairing gold process to add sintered NdFeB that nanometer titanium, nanometer copper or nano silicon nitride titanium valve make and do not add the magnet that the nano modification powder makes than adopting the pairing gold process higher coercive force, working temperature and corrosion resistance are arranged, therefore add the sintered NdFeB that nanometer titanium, nanometer copper or nano silicon nitride titanium valve can be prepared high-coercive force, elevated operating temperature and highly corrosion resistant ability by the pairing gold process.

Embodiment 2a:

1) main-phase alloy and crystal-boundary phase alloy are prepared respectively.Main-phase alloy adopts rapid hardening thin slice technology, and copper roller linear resonance surface velocity is 2.0m/s, and composition is Nd _14.2Fe _77.15B _5.82(Tb _0.31Al _0.24Co ₂Nb _0.28) (at%), crystal-boundary phase alloy adopts 18m/s fast quenching speed to be prepared into rapid tempering belt, composition is Nd _16.7Fe _75.27B _6.31(Dy _1.2Ga _0.2Al _0.32) (at%).

2) with main-phase alloy and crystal-boundary phase alloy powder process respectively.Directly broken by the quick-fried method of hydrogen; at room temperature saturated suction hydrogen is made the quick-fried powder of hydrogen at 500 ℃ of dehydrogenation 8h then, passes through airflow milling then under nitrogen protection; main-phase alloy is made the powder that average particulate diameter is 4 μ m, and crystal-boundary phase alloy is made the powder that average particulate diameter is 2 μ m.

3) in the crystal-boundary phase alloy powder, add the nanometer titanium (average particulate diameter is 30nm) that accounts for its weight 5% through dispersion treatment respectively, and 4% antioxidant poly(ethylene oxide) mono fatty acid ester, 3% lubricant polyethylene glycol, evenly mixed in batch mixer.

4) will mix with the main-phase alloy powder through the crystal-boundary phase alloy powder of nanometer powder modification, make weight account for 8% of total weight through the crystal-boundary phase alloy powder of nanometer powder modification, add the gasoline that accounts for total weight 1.2% simultaneously, in batch mixer, be uniformly mixed into mixed-powder.

6) parison spare is put into the high vacuum sintering furnace sintering, 1065 ℃ of sintering 3h, and 530 ℃ of tempering heat treatment 2.5h make sintered magnet again.

Embodiment 2b

The method of embodiment 2b is identical with embodiment 2a, and difference is, adopts the copper nanoparticle end in the step 3).The gained performance is seen comparative example 2.

Embodiment 2c

The method of embodiment 2c is identical with embodiment 2a, and difference is, adopts the nano silicon nitride ti powder in the step 3).The gained performance is seen comparative example 2.

The comparative example 2

Comparative example 2 preparation method is identical with embodiment 2, difference is, adopts the pairing gold process, does not form mixed-powder with adding nanometer powder modification crystal-boundary phase alloy as stated above, account for 8% of total amount, adopt identical magnetic field orientating die mould and sintering, tempering process to be prepared into magnet.

(5-10psig, 110-115 ℃, (corrosion resistance of Φ 1 * 0.5cm) adopts characteristic of magnetization automatic measuring instrument AMF to measure the magnetic property of magnet, performance such as table two 100h) to have tested the sample of comparative example 2 and embodiment 2a, 2b, 2c to adopt autoclave test.

Table two, the magnet performance that adopts different process to prepare

Embodiment 3a:

1) main-phase alloy and crystal-boundary phase alloy are prepared respectively.Main-phase alloy adopts rapid hardening thin slice technology, and copper roller linear resonance surface velocity is 2.2m/s, and composition is Nd _11.56Fe _81.55B _5.9Dy _0.99(at%), adopt the fast quenching technology, with crystal-boundary phase alloy Nd _27.83Fe _56.2B _6.68Dy _2.47Co _6.82(at%) be prepared into rapid tempering belt, fast quenching speed 18m/s.

2) with main-phase alloy and crystal-boundary phase alloy powder process respectively.Carry out coarse crushing by jaw crusher, broken in being undertaken by middle disintegrating machine, under nitrogen protection, pass through airflow milling then, main-phase alloy is made the powder that average particulate diameter is 5 μ m, and crystal-boundary phase alloy is made the powder that average particulate diameter is 3 μ m.

3) in the crystal-boundary phase alloy powder, add the nanometer titanium (average particulate diameter is 25nm) that accounts for its weight 6% through dispersion treatment respectively, and 4% antioxidant polyethylene oxide alkyl ethers, 4% anhydro sorbitol, evenly mixed in batch mixer.

4) will mix with the main-phase alloy powder through the crystal-boundary phase alloy powder of nanometer powder modification, make its weight account for 10% of alloy total weight, add 2% gasoline simultaneously, in batch mixer, be uniformly mixed into mixed-powder.

6) parison spare is put into the high vacuum sintering furnace sintering, 1085 ℃ of sintering 4.5h, and 560 ℃ of tempering heat treatment 3h make sintered magnet again.

Embodiment 3b

The method of embodiment 3b is identical with embodiment 3a, and difference is, adopts the copper nanoparticle end in the step 3).The gained performance is seen comparative example 3.

Embodiment 3c

The method of embodiment 3c is identical with embodiment 3a, and difference is, adopts the nano silicon nitride ti powder in the step 3).The gained performance is seen comparative example 3.

The comparative example 3:

Comparative example 3 preparation method is identical with embodiment 3, and difference is, does not form mixed-powder with adding nanometer powder modification crystal-boundary phase alloy, accounts for total weight 10%, adopts identical magnetic field orientating die mould and sintering, tempering process to be prepared into magnet.

Adopt autoclave test (5-10psig, 110-115 ℃, (Φ 1 * 0.5cm): also be the corrosion resistance of comparative example 3 and embodiment 3a, 3b, 3c sample, adopt the magnetic property of characteristic of magnetization automatic measuring instrument AMF measurement magnet, performance such as table three 100h) to have tested sample.

Table three, the magnet performance that adopts different process to prepare

Embodiment 4a:

1) main-phase alloy and crystal-boundary phase alloy are prepared respectively.Main-phase alloy adopts rapid hardening thin slice technology, and copper roller linear resonance surface velocity is 1.5m/s, and composition is Nd _12.69Fe _80.21B _5.7Dy _1.4(at%), crystal-boundary phase alloy adopts 18m/s fast quenching speed to be prepared into rapid tempering belt, and composition is Nd _23.74Fe _64.78B _6.88(Dy _0.92Co _1.27C _0.35Nb _0.4Al _1.66) (at%).

2) with main-phase alloy and crystal-boundary phase alloy powder process respectively.Directly broken by the quick-fried method of hydrogen; at room temperature saturated suction hydrogen is made the quick-fried powder of hydrogen at 500 ℃ of dehydrogenation 8h then, passes through airflow milling then under nitrogen protection; main-phase alloy is made the powder that average particulate diameter is 6 μ m, and crystal-boundary phase alloy is made the powder that average particulate diameter is 4 μ m.

3) in the crystal-boundary phase alloy powder, add the nanometer titanium (average particulate diameter is 20nm) that accounts for its weight 8% through dispersion treatment respectively, and 8% antioxidant poly(ethylene oxide) allyl ether, 3% lubricant oleic acid, evenly mixed in batch mixer.

4) will mix with the main-phase alloy powder through the crystal-boundary phase alloy powder of nanometer powder modification, make its weight account for 14% of total weight, add 3.4% gasoline simultaneously, in batch mixer, be uniformly mixed into mixed-powder.

5) mixed powder is compressed to parison spare by the magnetic field orientating moulding press, moulding alignment magnetic field 1.8T finishes in the glove box of sealing fully, makes the magnetic air-isolation.

6) parison spare is put into the high vacuum sintering furnace sintering, 1080 ℃ of sintering 3h, and 580 ℃ of tempering heat treatment 3h make sintered magnet again.

Embodiment 4b

The method of embodiment 4b is identical with embodiment 4a, and difference is, adopts the copper nanoparticle end in the step 3).The gained performance is seen comparative example 4.

Embodiment 4c

The method of embodiment 4c is identical with embodiment 4a, and difference is, adopts the nano silicon nitride ti powder in the step 3).The gained performance is seen comparative example 4.

The comparative example 4:

Comparative example 4 preparation method is identical with embodiment 4, and difference is, does not form mixed-powder with adding nanometer powder modification crystal-boundary phase alloy, accounts for total weight 14%, adopts identical magnetic field orientating die mould and sintering, tempering process to be prepared into magnet.

Adopt autoclave test (5-10psig, 110-115 ℃, (Φ 1 * 0.5cm): also be the corrosion resistance of comparative example 4 and embodiment 4a, 4b, 4c sample, adopt the magnetic property of characteristic of magnetization automatic measuring instrument AMF measurement magnet, performance such as table four 100h) to have tested sample.

Table four, the magnet performance that adopts different process to prepare

Embodiment 5a:

1) main-phase alloy and crystal-boundary phase alloy are prepared respectively.Main-phase alloy adopts rapid hardening thin slice technology, and copper roller linear resonance surface velocity is 2.0m/s, and composition is Nd _12.69Fe _80.21B _5.9Dy _1.2(at%), crystal-boundary phase alloy adopts 18m/s fast quenching speed to be prepared into rapid tempering belt, and composition is Nd _23.74Fe _64.78B _6.89(Dy _0.92Co _1.27Nb _0.6Al _1.8) (at%).

2) with main-phase alloy and crystal-boundary phase alloy powder process respectively.Directly broken by the quick-fried method of hydrogen; at room temperature saturated suction hydrogen is made the quick-fried powder of hydrogen at 500 ℃ of dehydrogenation 8h then, passes through airflow milling then under nitrogen protection; main-phase alloy is made the powder that average particulate diameter is 7 μ m, and crystal-boundary phase alloy is made the powder that average particulate diameter is 4 μ m.

3) in the crystal-boundary phase alloy powder, add the nanometer titanium (average particulate diameter is 5nm) that accounts for its weight 10% through dispersion treatment respectively, and 8% antioxidant poly(ethylene oxide) allyl ether, 4% lubricant stearic acid, evenly mixed in batch mixer.

4) will mix with the main-phase alloy powder through the crystal-boundary phase alloy powder of nanometer powder modification, make weight account for 16% of total weight through the crystal-boundary phase alloy powder of nanometer powder modification, add the gasoline that accounts for mixture total weight amount 3.0% simultaneously, in batch mixer, be uniformly mixed into mixed-powder.

6) parison spare is put into the high vacuum sintering furnace sintering, 1100 ℃ of sintering 3h, and 600 ℃ of tempering heat treatment 3h make sintered magnet again.

Embodiment 5b

The method of embodiment 5b is identical with embodiment 5a, and difference is, adopts the copper nanoparticle end in the step 3).The gained performance is seen comparative example 5.

Embodiment 5c

The method of embodiment 5c is identical with embodiment 5a, and difference is, adopts the nano silicon nitride ti powder in the step 3).The gained performance is seen comparative example 5.

The comparative example 5:

Comparative example 5 preparation method is identical with embodiment 5, and difference is, does not form mixed-powder with adding nanometer powder modification crystal-boundary phase alloy, accounts for total weight 16%, adopts identical magnetic field orientating die mould and sintering, tempering process to be prepared into magnet.

Adopt autoclave test (5-10psig, 110-115 ℃, (Φ 1 * 0.5cm): also be the corrosion resistance of comparative example 5 and embodiment 5a, 5b, 5c sample, adopt the magnetic property of characteristic of magnetization automatic measuring instrument AMF measurement magnet, performance such as table five 100h) to have tested sample.

Table five, the magnet performance that adopts different process to prepare

Embodiment 6a:

1) main-phase alloy and crystal-boundary phase alloy are prepared respectively.Main-phase alloy adopts rapid hardening thin slice technology, and copper roller linear resonance surface velocity is 2.0m/s, and composition is Nd _12.48Fe _80.42B _5.7Zr _1.0Dy _0.4(at%); Crystal-boundary phase alloy adopts 18m/s fast quenching speed to be prepared into rapid tempering belt, and composition is Nd _17.1Fe _75.58B _6.28Dy _0.64Ga _0.2Si _0.2(at%).

3) in the crystal-boundary phase alloy powder, add the DyF that accounts for its weight 12% through dispersion treatment respectively ₃Salt (average particulate diameter is 5nm), and 8% antioxidant poly(ethylene oxide) allyl ether, 5% lubricant oleic acid, evenly mixed in batch mixer.

4) will mix with the main-phase alloy powder through the crystal-boundary phase alloy powder of nanometer powder modification, make its weight account for 18% of total weight, add 4.2% gasoline simultaneously, in batch mixer, be uniformly mixed into mixed-powder.

6) parison spare is put into the high vacuum sintering furnace sintering, 1120 ℃ of sintering 3h, and 630 ℃ of tempering heat treatment 3h make sintered magnet again.

Embodiment 6b

The method of embodiment 6b is identical with embodiment 6a, and difference is, adopts the nano titanium powder end in the step 3).The gained performance is seen comparative example 6.

Embodiment 6c

The method of embodiment 6c is identical with embodiment 6a, and difference is, adopts the copper nanoparticle end in the step 3).The gained performance is seen comparative example 6.

Embodiment 6d

The method of embodiment 6d is identical with embodiment 6a, and difference is, adopts the nano silicon nitride ti powder in the step 3).The gained performance is seen comparative example 6.

The comparative example 6:

Comparative example 6 preparation method is identical with embodiment 6, and difference is, as stated above with not adding nanometer powder and DyF ₃Salt modification crystal-boundary phase alloy is formed mixed-powder, accounts for 18% of total amount, adopts identical magnetic field orientating die mould and sintering, tempering process to be prepared into magnet.

Adopt autoclave test (5-10psig, 110-115 ℃, (Φ 1 * 0.5cm): also be the corrosion resistance of comparative example 6 and embodiment 6a, 6b, 6c and 6d sample, adopt the magnetic property of characteristic of magnetization automatic measuring instrument AMF measurement magnet, performance such as table six 100h) to have tested sample.

Table six, the magnet performance that adopts different process to prepare

Therefrom as can be seen, adopt the pairing gold process to add the sintered NdFeB ratio interpolation DyF that nanometer titanium, nanometer copper or nano silicon nitride titanium valve make ₃The sintered NdFeB that salt obtains has higher coercive force, working temperature and corrosion resistance, therefore adds the sintered NdFeB that nanometer titanium, nanometer copper or nano silicon nitride titanium valve can be prepared high-coercive force, elevated operating temperature and highly corrosion resistant ability by the pairing gold process.

Embodiment 7:

1) main-phase alloy and crystal-boundary phase alloy are prepared respectively.Main-phase alloy adopts rapid hardening thin slice technology, and copper roller linear resonance surface velocity is 2.0m/s, and composition is Nd _12.48Fe _80.42B _5.7Zr _0.8Dy _0.4Tb _0.2(at%);

2) crystal-boundary phase alloy adopts two kinds of compositions, (a) is Nd _17.1Fe _75.18B _6.38Dy _0.64Ga _0.3C _0.2Si _0.2(at%); (b) be the titanium (powder particle) that before melting, adds 10% weight on this basis, adopt 18m/s fast quenching speed to be prepared into rapid tempering belt.

3) with main-phase alloy and crystal-boundary phase alloy powder process respectively.Directly broken by the quick-fried method of hydrogen; at room temperature saturated suction hydrogen is made the quick-fried powder of hydrogen at 500 ℃ of dehydrogenation 8h then, passes through airflow milling then under nitrogen protection; main-phase alloy is made the powder that average particulate diameter is 4 μ m, and crystal-boundary phase alloy is made the powder that average particulate diameter is 1 μ m.

4) in not adding the crystal-boundary phase alloy powder of titanium mixed smelting, add the nano titanium powder end (average particulate diameter is 5nm) that accounts for its weight 10% through dispersion treatment, and 6% antioxidant poly(ethylene oxide) allyl ether, 4% lubricant polyethylene glycol, evenly mixed in batch mixer.

5) two kinds of crystal-boundary phase alloy powder are mixed with the main-phase alloy powder respectively, make the crystal-boundary phase alloy powder weight account for 20% of mixture total weight amount separately, add the gasoline that accounts for mixture total weight amount 5% simultaneously separately, in batch mixer, be uniformly mixed into mixed-powder.

6) mixed powder is compressed to parison spare by the magnetic field orientating moulding press, moulding alignment magnetic field 1.8T finishes in the glove box of sealing fully, makes the magnetic air-isolation.

7) parison spare is put into the high vacuum sintering furnace sintering, 1150 ℃ of sintering 3h, and 640 ℃ of tempering heat treatment 3h make sintered magnet 7a and 7b again.

The comparative example 7:

Comparative example 7 preparation method is identical with embodiment 7, difference is, step 2) in, adopt the pairing gold process, interpolation accounts for total weight 20% and does not add titanium melting crystal-boundary phase alloy, and do not add the modified Nano powder, adopt identical magnetic field orientating die mould and sintering, tempering process to be prepared into magnet.

(5-10psig, 110-115 ℃, (corrosion resistance of Φ 1 * 0.5cm), employing characteristic of magnetization automatic measuring instrument AMF measures the magnetic property of magnet, performance such as table seven 100h) to have tested sample to adopt autoclave test.

Table seven, the magnet performance that adopts different process to prepare

Therefrom as can be seen, adopt pairing gold process crystal-boundary phase alloy add titanium melting and crystal-boundary phase alloy powder add sintered NdFeB that nano titanium powder obtains than adopting the pairing gold process crystal-boundary phase alloy do not add the titanium melting and do not add the magnet that the nano modification powder makes yet higher coercive force, working temperature and corrosion resistance are arranged, therefore add the titanium melting and the crystal-boundary phase alloy powder adds the sintered NdFeB that modifying nano titanium powder can be prepared high-coercive force, elevated operating temperature and highly corrosion resistant ability by pairing gold process crystal-boundary phase alloy.

Embodiment 8:

1) main-phase alloy and crystal-boundary phase alloy are prepared respectively.Main-phase alloy adopts rapid hardening thin slice technology, and copper roller linear resonance surface velocity is 1.8m/s, and composition is Nd _12.49Fe _80.21B _5.7Zr _1.0Dy _0.2Tb _0.2Al _0.2(at%);

2) crystal-boundary phase alloy adopts two kinds of compositions, and one is Nd _17.1Fe _75.18B _6.38Dy _0.64Ga _0.3C _0.4(at%), another kind is the titanium (titanium sheet) that adds 5% weight on this basis before melting, adopts 20m/s fast quenching speed to be prepared into rapid tempering belt.

3) with main-phase alloy and crystal-boundary phase alloy powder process respectively.Directly broken by the quick-fried method of hydrogen; at room temperature saturated suction hydrogen is made the quick-fried powder of hydrogen at 500 ℃ of dehydrogenation 8h then, passes through airflow milling then under nitrogen protection; main-phase alloy is made the powder that average particulate diameter is 5 μ m, and crystal-boundary phase alloy is made the powder that average particulate diameter is 3 μ m.

4) in not adding the crystal-boundary phase alloy powder of titanium mixed smelting, add the nano titanium powder end (average particulate diameter is 10nm) that accounts for its weight 5% through dispersion treatment, and 5% antioxidant poly(ethylene oxide) allyl ether, 2% lubricant polyethylene glycol, evenly mixed in batch mixer.

5) two kinds of crystal-boundary phase alloy powder are mixed with the main-phase alloy powder respectively, make its weight account for 10% of total weight, add 3% gasoline simultaneously, in batch mixer, be uniformly mixed into mixed-powder.

7) parison spare is put into the high vacuum sintering furnace sintering, 1150 ℃ of sintering 3h, and 640 ℃ of tempering heat treatment 3h make sintered magnet again.

8) adopt the pairing gold process, add accounting for total weight 10% and do not add titanium melting crystal-boundary phase alloy as stated above, and do not add the modified Nano powder, adopt identical magnetic field orientating die mould and sintering, tempering process to be prepared into magnet.

Table seven, the magnet performance that adopts different process to prepare

All quote in this application as a reference at all documents that the present invention mentions, just quoted as a reference separately as each piece document.Should be understood that in addition those skilled in the art can make various changes or modifications the present invention after having read above-mentioned instruction content of the present invention, these equivalent form of values fall within the application's appended claims institute restricted portion equally.

Claims

1. elevated operating temperature and high-corrosion resistance Sintered NdFeB set of permanent magnets compound, the composition of described magnet comprises the nano modification crystal-boundary phase alloy powder of 80-95% main-phase alloy powder and 5-20%, in described permanent magnet composition total weight;

2, composition as claimed in claim 1 is characterized in that, described modified Nano powder is nanometer titanium, nanometer copper, Nano titanium nitride or its combination.

3, composition as claimed in claim 1 is characterized in that, described modification crystal-boundary phase alloy modified powder is prepared by following method:

Adopt casting technique to make alloy of ingot crystal-boundary phase alloy as claimed in claim 1 or rapid hardening thin slice technology makes the rapid hardening thin slice or rapid quenching technique is made rapid tempering belt, adopt mechanical ball milling or airflow milling powder process, making average particulate diameter is the crystal-boundary phase alloy powder of 1-4 μ m

Described crystal-boundary phase alloy powder and modified Nano powder are evenly mixed the crystal-boundary phase alloy powder that obtains the nanometer powder modification in the described ratio of claim 1.

4. elevated operating temperature and high-corrosion resistance Sintered NdFeB set of permanent magnets compound, the composition of described magnet comprises the nano modification crystal-boundary phase alloy powder of 80-95% main-phase alloy powder and 5-20%, in described permanent magnet composition total weight;

5, composition as claimed in claim 4 is characterized in that,

Described modification crystal-boundary phase alloy modified powder is prepared by following method:

The mixture of crystal-boundary phase alloy and Titanium is provided, described crystal-boundary phase alloy accounts for the 87-98 weight % of described mixture total weight amount, surplus is described Titanium, described mixture carries out mixed smelting, the employing casting technique makes alloy of ingot or rapid hardening thin slice technology makes the rapid hardening thin slice or rapid quenching technique is made rapid tempering belt, and adopt mechanical ball milling or airflow milling powder process, making average particulate diameter is the modification crystal-boundary phase alloy powder of 1-4 μ m.

As each described composition of claim 1～5, it is characterized in that 6, described main-phase alloy powder is made by ingot casting crush method, rapid hardening thin slice crush method or rapid tempering belt crush method;

7, a kind of permanent magnet that makes by each described composition of claim 1～5,

Particularly, the working temperature of described permanent magnet is up to 220-260 ℃; Autoclave test 100h mass loss is 8-65mg/cm ²Magnetic energy product is 46-50MGOe; Remanent magnetism reaches 13.2-14.2kGs;

Composition as claimed in claim 1 and gasoline are uniformly mixed into mixed-powder, and wherein said composition accounts for the 95-99.5% of described mixed-powder total weight, and described gasoline accounts for the 0.5-5% of described mixed-powder total weight;

8, the preparation method of a kind of elevated operating temperature and high-corrosion resistance Sintered NdFeB permanent magnet, described method comprises the steps:

80-95% main-phase alloy powder is provided;

9, method as claimed in claim 8 is characterized in that, described nano modification crystal-boundary phase alloy powder is obtained by the method that comprises following arbitrary step:

Described crystal-boundary phase alloy powder and modified Nano powder are obtained nano modification crystal-boundary phase alloy powder in even the mixing of the described ratio of claim 1;

10, a kind of purposes of modified Nano powder is characterized in that, described nanometer powder is used for the crystal-boundary phase alloy powder is carried out modification;