CN101320609B - Grain boundary phase-reconstructed high-corrosion resistance sintered NdFeB magnet and preparation method thereof - Google Patents
Grain boundary phase-reconstructed high-corrosion resistance sintered NdFeB magnet and preparation method thereof Download PDFInfo
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- 238000005260 corrosion Methods 0.000 title claims abstract description 53
- 229910001172 neodymium magnet Inorganic materials 0.000 title claims abstract description 48
- 238000002360 preparation method Methods 0.000 title claims abstract description 8
- RZJQYRCNDBMIAG-UHFFFAOYSA-N [Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Zn].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn] Chemical class [Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Zn].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn] RZJQYRCNDBMIAG-UHFFFAOYSA-N 0.000 claims abstract description 56
- 238000000034 method Methods 0.000 claims abstract description 46
- 239000000843 powder Substances 0.000 claims abstract description 44
- 239000000203 mixture Substances 0.000 claims abstract description 27
- 238000005245 sintering Methods 0.000 claims abstract description 23
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 13
- 239000000956 alloy Substances 0.000 claims abstract description 13
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 9
- 229910052802 copper Inorganic materials 0.000 claims abstract description 9
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 8
- 229910052692 Dysprosium Inorganic materials 0.000 claims abstract description 7
- 229910052777 Praseodymium Inorganic materials 0.000 claims abstract description 7
- 229910052771 Terbium Inorganic materials 0.000 claims abstract description 7
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 7
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 6
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 6
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 6
- 229910052718 tin Inorganic materials 0.000 claims abstract description 6
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 6
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 6
- 229910052772 Samarium Inorganic materials 0.000 claims abstract description 5
- 229910052769 Ytterbium Inorganic materials 0.000 claims abstract description 5
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 5
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 5
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 5
- 229910052715 tantalum Inorganic materials 0.000 claims abstract description 5
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 5
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 5
- 238000002844 melting Methods 0.000 claims abstract description 4
- 229910052746 lanthanum Inorganic materials 0.000 claims abstract description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 20
- 238000005496 tempering Methods 0.000 claims description 20
- 238000005516 engineering process Methods 0.000 claims description 17
- 239000011812 mixed powder Substances 0.000 claims description 14
- QJVKUMXDEUEQLH-UHFFFAOYSA-N [B].[Fe].[Nd] Chemical compound [B].[Fe].[Nd] QJVKUMXDEUEQLH-UHFFFAOYSA-N 0.000 claims description 12
- 229910052739 hydrogen Inorganic materials 0.000 claims description 10
- 239000001257 hydrogen Substances 0.000 claims description 10
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 8
- 238000000137 annealing Methods 0.000 claims description 8
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- 230000000171 quenching effect Effects 0.000 claims description 4
- 229910052733 gallium Inorganic materials 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 230000007797 corrosion Effects 0.000 abstract description 42
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- 238000010923 batch production Methods 0.000 abstract 1
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- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
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- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 6
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- 239000010931 gold Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
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- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 4
- 239000000696 magnetic material Substances 0.000 description 4
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- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 3
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- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
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- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention discloses a sintered Nd-Fe-B magnet with high corrosion resistance and the grain boundary reconstruction and a preparation method thereof. The composition of the invention is that: NdeFe100-e-f-gBfMg, wherein, e is greater than or equal to 6 and equal to or less than 24, f is greater than or equal to 5. 6 and equal to or less than 7, g is greater than or equal to 0.03 and equal to or less than 8, M is one or some of elements Dy, Tb, Pr, Sm, Yb, La, Co, Ni, Cr, Nb, Ta, Zr, Si, Ti, Mo, W, V, Ca, Mg, Cu, Al, Zn, Ga, Bi, Sn and In; The method is that: main phrase alloy and reconstructed grain boundary phase alloy are respectively pulverized and mixed uniformly; the powder mixture is pressed to a mould in the magnetic field, and fabricated into a sintering magnet in a high vacuumsintering furnace. By the reconstruction of the grain boundary phase composition, the invention can obtain the grain boundary phase alloy with low melting point and high electrode potential, decreasethe potential difference between the main phase and the grain boundary phase on the basis of ensuring the magnetic properties, promote the intrinsic corrosion resistance of magnet, and has the advantages of simple process, low cost and being suitable for the batch production. Therefore, by combining the grain boundary reconstruction and double alloy method, the sintered Nd-Fe-B magnet with high intrinsic corrosion resistance can be prepared.
Description
Technical field
The present invention relates to a kind of grain boundary phase-reconstructed high-corrosion resistance Sintered NdFeB magnet and preparation method thereof.
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, obtained development rapidly, 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 main magnetic technology performance index of Nd-Fe-B magnet are 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
cAs a kind of functional material, all the time, the researcher of permanent magnetic material and the producer are to be placed on how to improve on the magnetic property to its research emphasis, the potentiality of excavated material to greatest extent at aspects such as its crystal structure, microstructure, magnetic domain form, HCJ mechanism improve the B of permanent magnetic material
r, H
c, (BH)
MaxAnd T
cThrough the development in 24 years, obtained good achievement, the maximum magnetic energy product of sintered nd-fe-b magnet is 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.
Along with the obvious raising of magnet magnetic property, the corrosion resistance that the Nd-Fe-B sintered magnet is lower has become the bottleneck of restriction extrahigh energy density Nd-Fe-B sintered permanent magnet range of application.At present; the means of protective finish are mainly taked in the corrosion protection of Nd-Fe-B material; 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 Electroless Plating 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 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 magnets at present, also obtained anti-corrosion preferably effect, further applying of Nd-Fe-B 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.And adopt coating not only to increase operation but also improved cost as the method for corrosion protection, at the problem that exists above, present research concentrates on a kind of method that can thoroughly improve corrosion resistance of exploring.The corrosion of Nd-Fe-B magnet can be divided into two kinds of electrochemical corrosion and chemical corrosions, and wherein electrochemical corrosion is main forms of corrosion.Electrochemical corrosion 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 lower than principal phase electrode potential in the Sintered NdFeB magnet, becomes anode in primary cell, has quickened its corrosion.Corrosion rate can be expressed as
E
The φ phaseBe the process equilibrium potential of principal phase, E
The crystal boundary phaseBe the process equilibrium potential of crystal boundary phase, P
The φ phaseBe the polarizability of principal phase, P
φ crystal boundary phasePolarizability for the crystal boundary phase.As seen, E is more little for Δ, and crystal boundary corrodes slow more mutually.Therefore, the potential difference that reduces between crystal boundary phase and principal phase becomes the corrosion proof key of raising magnet.Improve the electrode potential of crystal boundary phase, reduce and principal phase between corrosion potential poor, just can avoid or weaken intercrystalline corrosion, the reduction corrosion electric current density.Two alloyages are that principal phase and crystal-boundary phase alloy are smelted respectively, help carrying out on the basis that guarantees magnetic property the redesign of crystal boundary phase constituent, and the electrode potential of crystal boundary phase and principal phase is more or less the same, thereby improve the intrinsic corrosion resistance of Sintered NdFeB magnet.
Summary of the invention
The objective of the invention is to develop a kind of grain boundary phase-reconstructed high-corrosion resistance Sintered NdFeB magnet and preparation method thereof.
The composition of grain boundary phase-reconstructed high-corrosion resistance Sintered NdFeB magnet is: Nd
eFe
100-e-f-gB
fM
g, 6≤e≤24,5.6≤f≤7,0.03≤g≤8 wherein, M be in Dy, Tb, Pr, Sm, Yb, La, Co, Ni, Cr, Nb, Ta, Zr, Si, Ti, Mo, W, V, Ca, Mg, Cu, Al, Zn, Ga, Bi, Sn, the In element one or more;
Grain boundary phase-reconstructed high-corrosion resistance Sintered NdFeB magnet preparation method comprises the steps:
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 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;
2) adopt quick-fried method of hydrogen or Mechanical Crushing that the alloy of ingot of main-phase alloy or alloy of ingot, rapid hardening thin slice or the rapid tempering belt of rapid hardening thin slice and crystal-boundary phase alloy are carried out fragmentation, after the fragmentation, by airflow milling or ball milling powder process, obtaining average grain diameter respectively is the main-phase alloy powder of 2-10 μ m and the crystal-boundary phase alloy powder of 1-3 μ m again;
3) with main-phase alloy powder and crystal-boundary phase alloy powder, the part by weight that main-phase alloy is mixed with crystal-boundary phase alloy is 90: 10～97: 3, adds the gasoline of 0.5-5% then, evenly mixes in batch mixer;
4) with mixed powder compression moulding blank in the magnetic field of 1.2-2.0T;
5) parison spare is put into high vacuum sintering furnace,,, make sintered magnet at 890-920 ℃ of one-level tempering 2-3h and 500-650 ℃ of second annealing 2-4h at 1050-1125 ℃ of sintering 2-5h.
Described main-phase alloy is in atomic percent, and its composition is Nd
aFe
100-a-b-cB
bM
c, 7≤a≤16,5.4≤b≤6.6,0.01≤c≤6 wherein, M be in Pr, Dy, Tb, Nb, Co, Ga, Zr, Al, Cu, the Si element one or more.
Described crystal-boundary phase alloy is in atomic percent, and its composition is R
100-x-yM
xN
y1≤x≤50 wherein, 30≤y≤80, R is one or more in Nd, Dy, Tb, Pr, Sm, Yb, the La element, M is one or more in Fe, Co, Ni, Cr, Nb, Ta, Zr, Si, Ti, Mo, W, V, Ca, the B element, N be in low-melting Mg, Cu, Al, Zn, Ga, Bi, Sn, the In element one or more.
The present invention is by the reconstruct of crystal boundary phase constituent, obtain having the crystal-boundary phase alloy of low melting point and high electrode current potential, on the basis that guarantees magnetic property, principal phase and crystal boundary potential difference have mutually been reduced, improved the intrinsic corrosion resistance of magnet, and technical process is simple, cost is lower, is suitable for mass production.Therefore, can prepare Sintered NdFeB magnet in conjunction with crystal boundary reconstruct and two alloyage with high intrinsic corrosion resistance.
Embodiment
Embodiment 1:
1) design again of crystal-boundary phase alloy composition, composition is Nd
19Co
1Cu
13.4Al
66.6(at%);
2) crystal-boundary phase alloy with main-phase alloy and reconstruct prepares respectively.Main-phase alloy adopts casting technique to make the neodymium iron boron alloy of ingot, and its composition is Nd
13.12Fe
80.69B
5.73(Dy
0.22Ga
0.24) (at%), the crystal-boundary phase alloy Nd of reconstruct
19Co
1Cu
13.4Al
66.6(at%) adopt rapid quenching technique to make rapid tempering belt;
3) crystal-boundary phase alloy of main-phase alloy and reconstruct is distinguished powder process.Undertaken slightly breaking by jaw crusher, broken in being undertaken by middle disintegrating machine, under nitrogen protection, make the powder that average particulate diameter is 4 μ m and 2 μ m respectively then by airflow milling;
4) the crystal-boundary phase alloy powder with reconstruct evenly mixes with the main-phase alloy powder, and the crystal-boundary phase alloy powder weight accounts for 3% of total weight, adds 0.5% gasoline simultaneously, evenly mixes in batch mixer;
5) with mixed powder compression moulding blank in the magnetic field of 2T;
6) parison spare is put into high vacuum sintering furnace,,, make sintered magnet at 900 ℃ of one-level tempering 2h and 500 ℃ of second annealing 4h at 1060 ℃ of sintering 3h;
7) adopt the pairing gold process, add the not reconstruct crystal-boundary phase alloy Nd of weight ratio 3% as stated above
36.22Fe
57.78B
6(at%) form mixed-powder, adopt identical magnetic field orientating die mould and sintering, tempering process to be prepared into magnet.
(5-10psig, 100h) has tested sample (corrosion resistance of Φ 1 * 0.5cm), performance such as table 1 by 110-115 ℃ to adopt autoclave test.
As can be seen from the above table, adopt crystal boundary reconstruct to make the not magnet height of crystal boundary reconstruct of Sintered NdFeB magnet corrosion resistance ratio, therefore can prepare the Sintered NdFeB magnet of high intrinsic corrosion resistance by crystal boundary reconstruct.
Embodiment 2:
1) design again of crystal-boundary phase alloy composition, composition is Nd
12.84Dy
7.16Si
3Zr
1.5Cu
10.8Zn
34.2Ga
30.5(at%);
2) crystal-boundary phase alloy with main-phase alloy and reconstruct prepares respectively.Main-phase alloy adopts the rapid hardening belt-rejecting technology to make the neodymium iron boron thin slice, and its composition is Nd
12.2Fe
80.15B
5.9(Tb
0.31Co
1.24Nb
0.2) (at%), the crystal-boundary phase alloy Nd of reconstruct
12.84Dy
7.16Si
3Zr
1.5Cu
10.8Zn
34.2Ga
30.5(at%) adopt casting technique to make alloy of ingot;
3) crystal-boundary phase alloy of main-phase alloy and reconstruct is distinguished powder process.Undertaken slightly breaking by jaw crusher, broken in being undertaken by middle disintegrating machine, under the protection of benzinum, make the powder that average particulate diameter is 3.5 μ m and 1 μ m respectively then by ball milling;
4) the crystal-boundary phase alloy powder with reconstruct evenly mixes with the main-phase alloy powder, and the crystal-boundary phase alloy powder weight accounts for 10% of total weight, adds 1.2% gasoline simultaneously, evenly mixes in batch mixer;
5) with mixed powder compression moulding blank in the magnetic field of 1.8T;
6) parison spare is put into high vacuum sintering furnace,,, make sintered magnet at 890 ℃ of one-level tempering 3h and 560 ℃ of second annealing 2h at 1080 ℃ of sintering 2h;
7) adopt the pairing gold process, add the not reconstruct crystal-boundary phase alloy Nd of weight ratio 10% as stated above
36.22Fe
57.78B
6(at%) form mixed-powder, adopt identical magnetic field orientating die mould and sintering, tempering process to be prepared into magnet.
(5-10psig, 100h) has tested sample (corrosion resistance of Φ 1 * 0.5cm), performance such as table 2 by 110-115 ℃ to adopt autoclave test.
As can be seen from the above table, adopt crystal boundary reconstruct to make the not magnet height of crystal boundary reconstruct of Sintered NdFeB magnet corrosion resistance ratio, therefore can prepare the Sintered NdFeB magnet of high intrinsic corrosion resistance by crystal boundary reconstruct.
Embodiment 3:
1) design again of crystal-boundary phase alloy composition, composition is Nd
16Yb
1Tb
3Fe
18.7Co
31.3Mg
9.7Sn
4.4A1
15.9(at%);
2) crystal-boundary phase alloy with main-phase alloy and reconstruct prepares respectively.Both all adopt the rapid hardening belt-rejecting technology to make the neodymium iron boron thin slice, and its composition is respectively Nd
14.33Fe
78.91B
6(Ga
0.36Cu
0.2Zr
0.2) (at%) and Nd
16Yb
1Tb
3Fe
18.7Co
31.3Mg
9.7Sn
4.4Al
15.9(at%);
3) crystal-boundary phase alloy of main-phase alloy and reconstruct is distinguished powder process.Directly broken by the quick-fried method of hydrogen, at room temperature saturated suction hydrogen is made the quick-fried powder of hydrogen at 520 ℃ of dehydrogenation 8h then, makes the powder that average particulate diameter is 4.3 μ m and 2 μ m respectively by airflow milling at last under nitrogen protection;
4) the crystal-boundary phase alloy powder with reconstruct evenly mixes with the main-phase alloy powder, and the crystal-boundary phase alloy powder weight accounts for 6% of total weight, adds 5% gasoline simultaneously, evenly mixes in batch mixer;
5) with mixed powder compression moulding blank in the magnetic field of 1.2T;
6) parison spare is put into high vacuum sintering furnace,,, make sintered magnet at 920 ℃ of one-level tempering 2h and 650 ℃ of second annealing 2.5h at 1050 ℃ of sintering 5h;
7) adopt the pairing gold process, add the not reconstruct crystal-boundary phase alloy Nd of weight ratio 6% as stated above
36.22Fe
57.78B
6(at%) form mixed-powder, adopt identical magnetic field orientating die mould and sintering, tempering process to be prepared into magnet.
(5-10psig, 100h) has tested sample (corrosion resistance of Φ 1 * 0.5cm), performance such as table 3 by 110-115 ℃ to adopt autoclave test.
As can be seen from the above table, adopt crystal boundary reconstruct to make the not magnet height of crystal boundary reconstruct of Sintered NdFeB magnet corrosion resistance ratio, therefore can prepare the Sintered NdFeB magnet of high intrinsic corrosion resistance by crystal boundary reconstruct.
Embodiment 4:
1) design again of crystal-boundary phase alloy composition, composition is Nd
7.9Pr
5.2La
1.71Sm
2.19Nb
6.63Ta
10Cu
8.1Mg
5.76Al
30.12In
20.31Bi
2.08(at%);
2) crystal-boundary phase alloy with main-phase alloy and reconstruct prepares respectively.Both all adopt the rapid hardening belt-rejecting technology to make the neodymium iron boron thin slice, and its composition is respectively Nd
11.88Fe
78.95B
5.7(Dy
2.6Al
0.5Cu
0.15Zr
0.11Nb
0.11) (at%) and Nd
7.9Pr
5.2La
1.71Sm
2.19Nb
6.63Ta
10Cu
8.1Mg
5.76Al
30.12In
20.31Bi
2.08(at%);
3) crystal-boundary phase alloy of main-phase alloy and reconstruct is distinguished powder process.Undertaken slightly breaking by jaw crusher, broken in being undertaken by middle disintegrating machine, under the protection of benzinum, make the powder that average particulate diameter is 3.3 μ m and 1.8 μ m respectively then by ball milling;
4) the crystal-boundary phase alloy powder with reconstruct evenly mixes with the main-phase alloy powder, and the crystal-boundary phase alloy powder weight accounts for 8% of total weight, adds 2% gasoline simultaneously, evenly mixes in batch mixer;
5) with mixed powder compression moulding blank in the magnetic field of 1.6T;
6) parison spare is put into high vacuum sintering furnace,,, make sintered magnet at 910 ℃ of one-level tempering 2h and 580 ℃ of second annealing 3h at 1125 ℃ of sintering 2h;
7) adopt the pairing gold process, add the not reconstruct crystal-boundary phase alloy Nd of weight ratio 8% as stated above
36.22Fe
57.78B
6(at%) form mixed-powder, adopt identical magnetic field orientating die mould and sintering, tempering process to be prepared into magnet.
(5-10psig, 100h) has tested sample (corrosion resistance of Φ 1 * 0.5cm), performance such as table 4 by 110-115 ℃ to adopt autoclave test.
As can be seen from the above table, adopt crystal boundary reconstruct to make the not magnet height of crystal boundary reconstruct of Sintered NdFeB magnet corrosion resistance ratio, therefore can prepare the Sintered NdFeB magnet of high intrinsic corrosion resistance by crystal boundary reconstruct.
Embodiment 5:
1) design again of crystal-boundary phase alloy composition, composition is Nd
9.9Sm
3.2Yb
1.7Dy
2.2Mo
9Ni
4W
3.33Cu
18.4Mg
7.84Al
30.31Zn
10.12(at%);
2) crystal-boundary phase alloy with main-phase alloy and reconstruct prepares respectively.Both all adopt the rapid hardening belt-rejecting technology to make the neodymium iron boron thin slice, and its composition is respectively Nd
16Fe
77.39B
6.6Cu
0.01(at%) and Nd
9.9Sm
3.2Yb
1.7Dy
2.2Mo
9Ni
4W
3.33Cu
18.4Mg
7.84Al
30.31Zn
10.12(at%);
3) crystal-boundary phase alloy of main-phase alloy and reconstruct is distinguished powder process.Undertaken slightly breaking by jaw crusher, broken in being undertaken by middle disintegrating machine, under the protection of benzinum, make the powder that average particulate diameter is 10 μ m and 3 μ m respectively then by ball milling;
4) the crystal-boundary phase alloy powder with reconstruct evenly mixes with the main-phase alloy powder, and the crystal-boundary phase alloy powder weight accounts for 9% of total weight, adds 3% gasoline simultaneously, evenly mixes in batch mixer;
5) with mixed powder compression moulding blank in the magnetic field of 1.6T;
6) parison spare is put into high vacuum sintering furnace,,, make sintered magnet at 900 ℃ of one-level tempering 2h and 540 ℃ of second annealing 3h at 1070 ℃ of sintering 3h;
7) adopt the pairing gold process, add the not reconstruct crystal-boundary phase alloy Nd of weight ratio 9% as stated above
36.22Fe
57.78B
6(at%) form mixed-powder, adopt identical magnetic field orientating die mould and sintering, tempering process to be prepared into magnet.
(5-10psig, 100h) has tested sample (corrosion resistance of Φ 1 * 0.5cm), performance such as table 5 by 110-115 ℃ to adopt autoclave test.
As can be seen from the above table, adopt crystal boundary reconstruct to make the not magnet height of crystal boundary reconstruct of Sintered NdFeB magnet corrosion resistance ratio, therefore can prepare the Sintered NdFeB magnet of high intrinsic corrosion resistance by crystal boundary reconstruct.
Embodiment 6:
1) design again of crystal-boundary phase alloy composition, composition is Nd
13.75Dy
5.1Cr
6.69V
3Ca
4Nb
2.1Ti
1.7B
5.6Cu
11.23Ga
10.63Al
24.12Zn
12.08(at%);
2) crystal-boundary phase alloy with main-phase alloy and reconstruct prepares respectively.Main-phase alloy adopts the rapid hardening belt-rejecting technology to make the neodymium iron boron thin slice, and its composition is respectively Nd
7Fe
81.6B
5.4(Pr
5.25Ga
0.25Cu
0.1Zr
0.1Nb
0.1Si
0.2) (at%), the crystal-boundary phase alloy Nd of reconstruct
13.75Dy
5.1Cr
6.69V
3Ca
4Nb
2.1Ti
1.7B
5.6Cu
11.23Ga
10.63Al
24.12Zn
12.08(at%) adopt rapid quenching technique to make rapid tempering belt;
3) crystal-boundary phase alloy of main-phase alloy and reconstruct is distinguished powder process.Main-phase alloy is directly broken by the quick-fried method of hydrogen, and at room temperature saturated suction hydrogen is made the quick-fried powder of hydrogen at 520 ℃ of dehydrogenation 8h then, makes the powder that average particulate diameter is 2 μ m respectively by airflow milling at last under nitrogen protection; Crystal-boundary phase alloy is undertaken slightly broken by jaw crusher, broken in being undertaken by middle disintegrating machine, makes the powder that average particulate diameter is 1.5 μ m by ball milling then under the protection of benzinum;
4) the crystal-boundary phase alloy powder with reconstruct evenly mixes with the main-phase alloy powder, and the crystal-boundary phase alloy powder weight accounts for 7% of total weight, adds 2.5% gasoline simultaneously, evenly mixes in batch mixer;
5) with mixed powder compression moulding blank in the magnetic field of 1.5T;
6) parison spare is put into high vacuum sintering furnace,,, make sintered magnet at 890 ℃ of one-level tempering 3h and 600 ℃ of second annealing 3.5h at 1067 ℃ of sintering 4h;
7) adopt the pairing gold process, add the not reconstruct crystal-boundary phase alloy Nd of weight ratio 7% as stated above
36.22Fe
57.78B
6(at%) form mixed-powder, adopt identical magnetic field orientating die mould and sintering, tempering process to be prepared into magnet.
(5-10psig, 100h) has tested sample (corrosion resistance of Φ 1 * 0.5cm), performance such as table 6 by 110-115 ℃ to adopt autoclave test.
As can be seen from the above table, adopt crystal boundary reconstruct to make the not magnet height of crystal boundary reconstruct of Sintered NdFeB magnet corrosion resistance ratio, therefore can prepare the Sintered NdFeB magnet of high intrinsic corrosion resistance by crystal boundary reconstruct.
Claims (2)
1. a grain boundary phase-reconstructed high-corrosion resistance Sintered NdFeB magnet preparation method is characterized in that comprising the steps:
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 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;
2) adopt quick-fried method of hydrogen or Mechanical Crushing that the alloy of ingot of main-phase alloy or alloy of ingot, rapid hardening thin slice or the rapid tempering belt of rapid hardening thin slice and crystal-boundary phase alloy are carried out fragmentation, after the fragmentation, by airflow milling or ball milling powder process, obtaining average grain diameter respectively is the main-phase alloy powder of 2-10 μ m and the crystal-boundary phase alloy powder of 1-3 μ m again;
3) with main-phase alloy powder and crystal-boundary phase alloy powder, the part by weight that main-phase alloy is mixed with crystal-boundary phase alloy is 90: 10～97: 3, adds the gasoline of 0.5-5% then, evenly mixes in batch mixer;
4) with mixed powder compression moulding blank in the magnetic field of 1.2-2.0T;
5) parison spare is put into high vacuum sintering furnace,,, make Sintered NdFeB magnet at 890-920 ℃ of one-level tempering 2-3h and 500-650 ℃ of second annealing 2-4h at 1050-1125 ℃ of sintering 2-5h;
Described Sintered NdFeB magnet composition is: Nd
eFe
100-e-f-gB
fM
g, 6≤e≤24,5.6≤f≤7,0.03≤g≤8 wherein, M be in Dy, Tb, Pr, Sm, Yb, La, Co, Ni, Cr, Nb, Ta, Zr, Si, Ti, Mo, W, V, Ca, Mg, Cu, Al, Zn, Ga, Bi, Sn, the In element one or more;
Described crystal-boundary phase alloy is in atomic percent, and its composition is R
100-x-yM
xN
y1≤x≤50 wherein, 30≤y≤80, R is one or more in Nd, Dy, Tb, Pr, Sm, Yb, the La element, M is one or more in Fe, Co, Ni, Cr, Nb, Ta, Zr, Si, Ti, Mo, W, V, Ca, the B element, N be in low-melting Mg, Cu, Al, Zn, Ga, Bi, Sn, the In element one or more.
2. a kind of grain boundary phase-reconstructed high-corrosion resistance Sintered NdFeB magnet preparation method according to claim 1 is characterized in that described main-phase alloy in atomic percent, and its composition is Nd
aFe
100-a-b-cB
bM
c, 7≤a≤16,5.4≤b≤6.6,0.01≤c≤6 wherein, M be in Pr, Dy, Tb, Nb, Co, Ga, Zr, Al, Cu, the Si element one or more.
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