CN107689279A - One kind improves the coercitive method of sintered NdFeB built-up magnet - Google Patents

One kind improves the coercitive method of sintered NdFeB built-up magnet Download PDF

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Publication number
CN107689279A
CN107689279A CN201710823046.7A CN201710823046A CN107689279A CN 107689279 A CN107689279 A CN 107689279A CN 201710823046 A CN201710823046 A CN 201710823046A CN 107689279 A CN107689279 A CN 107689279A
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alloy
powder
rare earth
magnet
alloys
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李柱柏
王东山
张雪峰
张志新
刘飞
刘艳丽
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Inner Mongolia University of Science and Technology
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Inner Mongolia University of Science and Technology
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
    • H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/02—Making ferrous alloys by powder metallurgy
    • C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
    • C22C33/0278—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5%
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Power Engineering (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Hard Magnetic Materials (AREA)

Abstract

The present invention discloses a kind of raising coercitive method of sintered NdFeB built-up magnet, belongs to rare earth permanent-magnetic material preparation field.This method optimizes design to the composition of Nd Fe B alloys and Dy Fe B alloys, appropriate to reduce Nd contents in Nd Fe B alloys, improve Dy contents in Dy Fe B alloys.Because Nd constituent contents are relatively low in Nd Fe B alloys, the diffusion of Nd elements reduces in sintering process, thus the Dy in Dy Fe B alloys is reduced by the probability of Nd element substitutions, the high magnetocrystalline anisotropy field of Dy Fe B phases is maintained, and so addition Dy Fe B alloy powder magnet coercivitys can significantly improve on a small quantity.This method can also reduce the dosage of rare earth and Dy elements, and the cost of raw material is reduced while magnetic property is improved.

Description

One kind improves the coercitive method of sintered NdFeB built-up magnet
Technical field：
The present invention relates to one kind to improve the coercitive method of sintered NdFeB built-up magnet, belongs to rare earth permanent-magnetic material preparation Field.
Background technology：
Rare-earth permanent magnet neodymium iron boron Nd-Fe-B has high energy product, be widely used in traffic, the energy, computer, communication, The fields such as machinery, medical treatment, household electrical appliances and science and techniques of defence, have promoted the development of related industry, have been that modern science and technology are indispensable Critical material, its yield and dosage turned into weigh national overall national strength and the horizontal important symbol of the national economic development it One.At present, China is important as the maximum rare-earth Nd-Fe-B permanent magnet production base in the whole world, and Nd-Fe-B permanent magnet Application market.
Although Nd-Fe-B permanent magnet magnetic energy product is high, coercivity is relatively low.In order to further meet electric automobile, wind-power electricity generation Actual demand Deng field is, it is necessary to further improve the coercivity of rare-earth Nd-Fe-B permanent magnet.Dy2Fe14The saturated magnetization of B alloys Intensity is although low, but the magnetocrystalline anisotropy field with superelevation, and magnet coercivity is high.Therefore by melting by Nd elements and Dy is mixed and made into (Nd, Dy)-Fe-B alloys, and the coercivity of magnet is improved, but the remanent magnetism of the method magnet can reduce, and to be made Coercivity, which improves, to be needed to add more Dy elements, and the production cost of magnet also greatly increases.
Dy elements or Dy alloy powders are added in neodymium iron boron powder in batch mixing, the coercivity of magnet is improved, But the remanent magnetism of the method magnet can reduce, and coercivity raising degree is not too much notable.By Dy alloyed powders in annealing process End passes through the addition of the methods of coating can be diffused into inside in magnet surface, Dy elements from magnet surface；But using this method Dy members For element from magnet surface to the diffusion and uneven of inside, it is limited that magnet coercivity, which improves degree, and because of diffusion depth Limitation the method is only applicable to produce small size magnet, is not suitable for the production in enormous quantities of Sintered NdFeB magnet.
Chinese patent CN103219117A (application publication number) is closed Nd-Fe-B and Dy-Fe-B using the method for dual alloy Gold mixing, because Dy-Fe-B phases have the magnetocrystalline anisotropy field of superelevation, the coercivity of magnet can be improved in theory；But Nd elements can spread substitution Dy into Dy-Fe-B phases actually in high temperature sintering, so as to significantly reduce the magnetic of Dy-Fe-B phases Anisotropic crystalline field, magnet coercivity raising degree are simultaneously not bery notable.Chinese patent CN103794322A (application publication number) will High magnetocrystalline anisotropy field master alloying and low magnetocrystalline anisotropy field master alloying are mixed with magnet, but the patent has no clearly Method controls the diffusion of element between two kinds of alloys, needs to mix a certain amount of intergranular addition of addition to improve magnet coercivity Phase, this can increase the addition of heavy rare earth Dy elements, make the reduction of magnet remanent magnetism, while also be unfavorable for reducing being produced into for magnet This.
The content of the invention：
The present invention needs to solve the problems, such as to be to overcome Nd-Fe-B alloy rare earth elements Nd diffusions to cause Dy-Fe-B to close Deficiency substituted Dy in gold, there is provided one kind improves the coercitive method of sintered NdFeB built-up magnet.It moderately reduces Nd- The content of Fe-B alloy middle rare earth Nd elements, improve Dy-Fe-B alloy middle rare earth Dy constituent contents.Due in Nd-Fe-B alloys Content of rare earth is low, close to RE2Fe14B phases just divide content, therefore structure is very stable, and in high temperature sintering, Nd elements are to intergranular liquid Mutually the possibility of diffusion reduces, it is difficult to which into Dy-Fe-B alloys, diffusion substitutes Dy, thus the superelevation magnetocrystalline that Dy-Fe-B phases have Anisotropy field is maintained.Simultaneously because Dy-Fe-B alloy Rare Earth Element Contents are of a relatively high, Dy elements can be to intergranular liquid Mutually spread, also may replace Nd-Fe-B phases grain boundary Nd elements, improve the magnetocrystalline anisotropy field of Nd-Fe-B phases grain boundary. Comprehensive both above factor, the high magnetocrystalline anisotropy field of Dy-Fe-B phases are maintained, Nd-Fe-B phase Grain Surface magnetocrystallines Different in nature field is improved, and magnet coercivity can significantly increase.
For achieving the above object, the invention provides following technical scheme：
1) Nd-Fe-B alloy powders and Dy-Fe-B alloy powders are mixed with permanent-magnet material, Nd-Fe-B alloys Formula is RE ' by atomic percenta1Fe100-a1-b-cBbMc, Dy-Fe-B alloys formula is RE " by atomic percenta2Fe100-a2-b- cBbMc, wherein 10.5≤a1≤13,15≤a2≤20,5≤b≤9,0≤c≤10, and a2-a1 >=3.
2) in above-mentioned chemical formula RE ' and RE " be selected from rare earth element La and Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, One or more in Er, Tm, Yb, Lu, Y, Sc, wherein, RE ', which should comprise at least Pr or Nd, RE ", should comprise at least Dy；It is above-mentioned M is addition element in chemical formula, be Co, Ni, Cu, Zn, Al, Ga, Nb, Mo, Ti, Zr, V, Cr, Mn, C, Si, P, S, Ge, Se, One or more in Sn, Ta, Pb.
3) alloy RE 'a1Fe100-a1-b-cBbMcMain components of the rare earth elements RE ' using Nd or Pr as rare earth, Nd or Pr are total Weight is more than RE 'a1Fe100-a1-b-cBbMcThe 70% of alloy middle rare earth gross weight, and alloy principal phase is RE '2Fe14B structure；Close Golden RE "a2Fe100-a2-b-cBbMcMain components of the rare earth elements RE " using Dy as rare earth, Dy gross weights are more than RE "a2Fe100-a2-b- cBbMcThe 50% of alloy middle rare earth gross weight, and alloy principal phase is RE "2Fe14B structure.
4) Nd-Fe-B alloy powders and Dy-Fe-B alloy powders are mixed by a certain percentage, wherein Nd-Fe-B alloyed powders End is not less than the 70wt% of powder gross weight after mixing, and Dy-Fe-B alloy powders are no more than powder gross weight after mixing 30wt%.
5) when mixing Nd-Fe-B alloy powders and Dy-Fe-B alloy powders, other alloys or metal powder can also be added End, but the addition of other alloys or metal dust is not higher than the 30wt% of powder gross weight after mixing.Other alloys or metal Powder, include rare earth elements RE, Fe, B, M one or more；RE be selected from rare earth element La and Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Sc one or more；M be Co, Ni, Cu, Zn, Al, Ga, Nb, Mo, Ti, Zr, V, Cr, One or more in Mn, C, Si, P, S, Ge, Se, Sn, Ta, Pb；Powder can by melting, hydrogen is broken and then airflow milling or ball Mill method obtains.
Invention also provides a kind of described Nd-Fe-B alloy powders and Dy-Fe-B alloy powders to be mixed with burning Tie the preparation method of neodymium iron boron built-up magnet：
Weighing and burden is carried out to raw material according to composition design requirement, prepares at least two alloys, the i.e. relatively low Nd- of content of rare earth Fe-B alloys and the Dy-Fe-B alloys with superelevation magnetocrystalline anisotropy field, its rare earth elements press excessive 5wt% dispensings, with Supplement the volatilization of subsequent technique rare earth element.The raw material prepared is put into Medium frequency induction rapid hardening furnace crucible, is filled with after vacuumizing High-purity argon gas, then power transmission heating, fused solution is poured into the water-cooled copper roller that linear velocity is 1~3m/s when melting is liquid On, obtain the rapid casting that average thickness is 0.1~2.0mm；Also original can be made by the way of sensing heating under vacuum Material is molten into liquid, and ensures that alloying component is uniform, is then cooled to alloy cast ingot.Obtained quick setting belt or alloy are put into hydrogen Crushed in broken stove, obtain just broken powder；Then by hydrogen break pulverized powder add high pressure nitrogen carry out airflow milling, can also protect The oxidation and reunion of a small amount of antioxidant prevention powder are added under atmosphere in hydrogen breaks pulverized powder, antioxidant and hydrogen crush powder The ratio at end is 2~6ml/kg, and alloy powder is prepared into the magnetic of 1~6 μm of particle mean size by airflow milling；Wherein Dy-Fe- B alloy powders further can make powder particle average-size drop to less than 3.5 μm by ball milling., will according to component design requirement The alloy powder of acquisition is well mixed according to a certain percentage, wherein must include Nd-Fe-B alloy powders and Dy-Fe-B alloyed powders End；70wt% of the Nd-Fe-B alloy powders not less than powder gross weight after mixing；Dy-Fe-B alloy powders content is not higher than mixed The 30wt% of powder gross weight after conjunction；The other alloys or metal dust added are not higher than powder gross weight after mixing 30wt%.Also directly mixed after can crushing the quick setting belt of acquisition and ingot casting hydrogen by component requirements, then carry out airflow milling, gas again The oxidation and reunion of a small amount of antioxidant prevention powder can be added during stream mill under protective atmosphere, antioxidant and hydrogen crush powder Ratio be 2~6ml/kg, mixed alloy powder is prepared into the magnetic of 1~6 μm of particle mean size by airflow milling.Will be mixed Close uniform powder and be orientated in 1~3T magnetic field compressing, it is 3~5g/cm that density is made in cold isostatic press3Hair Base, improve the density and intensity of blank.Blank is put into sintering furnace, high vacuum will be evacuated in stove and is then charged with argon gas, then Temperature is raised into 990~1100 DEG C to be sintered, insulation is cooled to normal temperature and obtains sintered magnet after 1~6 hour.Can be by acquisition Sintered magnet is heat-treated 1~4 hour at 700~980 DEG C and 400~700 DEG C respectively.
The rare earth element contents such as the Nd in Nd-Fe-B alloys of the present invention are low；Dy-Fe-B alloy rare earth elements Dy content Height, and superelevation magnetocrystalline anisotropy field is provided.In sintering annealing process rare earth elements mainly from the high alloy of content of rare earth Spread in the low alloy phase of opposite content, Nd elements spread into Dy-Fe-B phases in the low Nd-Fe-B phases of content of rare earth substitutes Dy Weaken, the magnetocrystalline anisotropy field of Dy-Fe-B phase superelevation is maintained, and magnet can keep high coercivity.
The present invention has the Dy-Fe-B alloy rare earth elements Dy contents of superelevation magnetocrystalline anisotropy field high, is moved back in sintering Dy elements spread more notable to intergranular during fire, further spread, improve to the low Nd-Fe-B phases Grain Surface of content of rare earth The magnetocrystalline anisotropy field of Nd-Fe-B alloy phase Grain Surfaces, so also can promote the coercivity of magnet to be improved.
For the present invention using Nd-Fe-B alloys as principal phase, the content of rare earth of principal phase is low, therefore the total content of rare earth of magnet compares Low, Fe content is big, and the saturation magnetization of magnet is high, and remanent magnetism is high, can obtain good comprehensive magnetic energy.
Compared with prior art, the beneficial effects of the present invention are：
1) diffusion of the element such as Nd-Fe-B alloys phase middle rare earth Nd of the present invention weakens, in Nd element substitution Dy-Fe-B phases Dy elements are suppressed, and the superelevation magnetocrystalline anisotropy field that Dy-Fe-B phases have is maintained, and magnet thus has higher coercive Power.
2) diffusion of the element such as Nd-Fe-B alloys phase middle rare earth Nd of the present invention is suppressed, it is only necessary to adds a small amount of Dy-Fe-B Powder magnet coercivity with regard to that can significantly improve, thus Nd-Fe-B alloy powders account for mixing after the amount of powder can increase, price is high Dy elements dosage reduce, the cost of raw material of magnet is lower.
3) content of rare earth of Nd-Fe-B alloys of the present invention is low, and total content of rare earth is smaller in magnet, and magnet saturated magnetization is strong Degree is higher, and remanent magnetism is of a relatively high, and magnet is cost-effective.
Embodiment：
Embodiment 1
The Nd-Fe-B alloys formula of low content of rare earth is Nd by atomic percent12.5Fe81.5B6.Will by chemical formula requirement Rare earth Nd metal, Fe metals, Fe-B alloy weighing and burdens, are then placed in vacuum intermediate-frequency smelting furnace, by induction melting into Nd12.5Fe81.5B6Alloy cast ingot.Ingot casting is carried out to homogenization heat treatment 2 hours at 1100 DEG C, ensures that alloying component is more uniform, It is subsequently placed at progress hydrogen in the broken stove of hydrogen to crush, then wears into the Nd that particle mean size is 3.5 μm using airflow milling12.5Fe81.5B6Close Bronze end.
The Dy-Fe-B alloys formula of high rare-earth content is Dy by atomic percent17Fe75B8.Will be dilute by chemical formula requirement Native Dy metals, Fe metals, Fe-B alloy weighing and burdens, are then placed in vacuum intermediate-frequency smelting furnace, by induction melting into Dy17Fe75B8Alloy cast ingot.Ingot casting is carried out to homogenization heat treatment 2 hours at 1100 DEG C, ensures that alloying component is more uniform, with After be placed in hydrogen crush stove in carry out hydrogen crush, thinner Dy is then worn into alloy using ball milling17Fe75B8Alloy powder.
By 9 grams of Nd12.5Fe81.5B6Alloy powder and 1 gram of Dy17Fe75B8Alloy powder is well mixed, then by mixed powder It is compressing in magnetic field, then isostatic pressed is carried out into blank.Blank is put into sintering furnace and is sintered, wherein, sintering temperature For 1040 DEG C, 2 hours are incubated, after being cooled to room temperature, is then heat-treated 2 hours at 900 DEG C and 550 DEG C respectively.
Using the magnetic property of NIM-200C permanent magnetism measurement apparatus measurement magnet, magnet coercivity is 21.63kOe.
As a comparison case 1, by 10 grams of Nd12.5Fe81.5B6Alloy powder is compressing in magnetic field, then carry out isostatic pressed into Blank.Magnet is made by above-mentioned sintering, annealing process, uses NIM-200C permanent magnetism measurement apparatus to measure magnet coercivity as magnet Coercivity is 9.57kOe.There it can be seen that by by the Nd-Fe-B alloy powders of low content of rare earth and high rare-earth content Dy-Fe-B alloy powders mix, i.e. 9 grams of Nd12.5Fe81.5B6Alloy powder and 1 gram of Dy17Fe75B8The magnetic that alloy powder is mixed with Body, coercivity enhancing is notable, increases to 21.63kOe from 9.57kOe, adds 1.26 times.
Embodiment 2
The Nd-Fe-B alloys formula of low content of rare earth is Nd by atomic percent11.7Fe82.3B6.Will by chemical formula requirement Rare earth Nd metal, Fe metals, Fe-B alloy weighing and burdens, are then placed in vacuum intermediate-frequency smelting furnace, by induction melting into Nd11.7Fe82.3B6Alloy cast ingot.Ingot casting is carried out to homogenization heat treatment 2 hours at 1100 DEG C, ensures that alloying component is more uniform, It is subsequently placed at progress hydrogen in the broken stove of hydrogen to crush, then wears into the Nd that particle mean size is 3.5 μm using airflow milling11.7Fe82.3B6Close Bronze end.
The Dy-Fe-B alloys formula of high rare-earth content is Dy by atomic percent17Fe75B8.Will be dilute by chemical formula requirement Native Dy metals, Fe metals, Fe-B alloy weighing and burdens, are then placed in vacuum intermediate-frequency smelting furnace, by induction melting into Dy17Fe75B8Alloy cast ingot.Ingot casting is carried out to homogenization heat treatment 2 hours at 1100 DEG C, ensures that alloying component is more uniform, with After be placed in hydrogen crush stove in carry out hydrogen crush, thinner Dy is then worn into alloy using ball milling17Fe75B8Alloy powder.
By 9 grams of Nd11.7Fe82.3B6Alloy powder and 1 gram of Dy17Fe75B8Alloy powder is well mixed, then by mixed powder It is compressing in magnetic field, then isostatic pressed is carried out into blank.Blank is put into sintering furnace and is sintered, wherein, sintering temperature For 1050 DEG C, 2 hours are incubated, after being cooled to room temperature, is then heat-treated 2 hours at 900 DEG C and 550 DEG C respectively.
Using the magnetic property of NIM-200C permanent magnetism measurement apparatus measurement magnet, magnet coercivity is 21.14kOe.
As a comparison case 2, by 10 grams of Nd11.7Fe82.3B6Alloy powder is compressing in magnetic field, then carry out isostatic pressed into Blank.Magnet is made by above-mentioned sintering, annealing process, uses NIM-200C permanent magnetism measurement apparatus to measure magnet coercivity as magnet Coercivity is 9.06kOe.There it can be seen that by by the Nd-Fe-B alloy powders of low content of rare earth and high rare-earth content Dy-Fe-B alloy powders mix, i.e. 9 grams of Nd11.7Fe82.3B6Alloy powder and 1 gram of Dy17Fe75B8The magnetic that alloy powder is mixed with Body, coercivity enhancing is notable, increases to 21.14kOe from 9.06kOe, adds 1.33 times.
Embodiment 3
The Nd-Fe-B alloys formula of low content of rare earth is Nd by atomic percent11.5Fe82.5B6.Will by chemical formula requirement Rare earth Nd metal, Fe metals, Fe-B alloy weighing and burdens, are then placed in vacuum intermediate-frequency smelting furnace, by induction melting into Nd11.5Fe82.5B6Alloy cast ingot.Ingot casting is carried out to homogenization heat treatment 2 hours at 1100 DEG C, ensures that alloying component is more uniform, It is subsequently placed at progress hydrogen in the broken stove of hydrogen to crush, then wears into the Nd that particle mean size is 3.5 μm using airflow milling11.5Fe82.5B6Close Bronze end.
The Dy-Fe-B alloys formula of high rare-earth content is Dy by atomic percent17Fe75B8.Will be dilute by chemical formula requirement Native Dy metals, Fe metals, Fe-B alloy weighing and burdens, are then placed in vacuum intermediate-frequency smelting furnace, by induction melting into Dy17Fe75B8Alloy cast ingot.Ingot casting is carried out to homogenization heat treatment 2 hours at 1100 DEG C, ensures that alloying component is more uniform, with After be placed in hydrogen crush stove in carry out hydrogen crush, thinner Dy is then worn into alloy using ball milling17Fe75B8Alloy powder.
By 9 grams of Nd11.5Fe82.5B6Alloy powder and 1 gram of Dy17Fe75B8Alloy powder is well mixed, then by mixed powder It is compressing in magnetic field, then isostatic pressed is carried out into blank.Blank is put into sintering furnace and is sintered, wherein, sintering temperature For 1040 DEG C, 2 hours are incubated, after being cooled to room temperature, is then heat-treated 2 hours at 900 DEG C and 550 DEG C respectively.
Using the magnetic property of NIM-200C permanent magnetism measurement apparatus measurement magnet, magnet coercivity is 21.02kOe.
As a comparison case 3, by 10 grams of Nd11.5Fe82.5B6Alloy powder is compressing in magnetic field, then carry out isostatic pressed into Blank.Magnet is made by above-mentioned sintering, annealing process, uses NIM-200C permanent magnetism measurement apparatus to measure magnet coercivity as magnet Coercivity is 7.61kOe.There it can be seen that by by the Nd-Fe-B alloy powders of low content of rare earth and high rare-earth content Dy-Fe-B alloy powders mix, i.e. 9 grams of Nd11.5Fe82.5B6Alloy powder and 1 gram of Dy17Fe75B8The magnetic that alloy powder is mixed with Body, coercivity enhancing is notable, increases to 21.02kOe from 7.61kOe, adds 1.76 times.
Embodiment 1 is by 9 grams of Nd12.5Fe82.5B6Alloy powder and 1 gram of Dy17Fe75B8The magnet that alloy powder is mixed with is rectified Stupid power is 21.63kOe, and embodiment 2 is by 9 grams of Nd11.7Fe82.3B6Alloy powder and 1 gram of Dy17Fe75B8What alloy powder was mixed with Magnet coercivity is 21.14kOe, and embodiment 3 is by 9 grams of Nd11.5Fe82.5B6Alloy powder and 1 gram of Dy17Fe75B8Alloy powder mixes The magnet coercivity of preparation is 21.02kOe.As can be seen that the magnet total rare earth content of embodiment 3 is than embodiment 1 and embodiment 2 Magnet it is low, but these magnet coercivitys are essentially identical, are maintained at 21kOe level.This explanation embodiment 3 is although magnet rare earth Total amount is relatively low, and because the content of rare earth difference of two kinds of alloy powders is bigger, magnet can also obtain high-coercive force.
Embodiment 4
The Nd-Fe-B alloys formula of low content of rare earth is Nd by atomic percent12.5Fe81.5B6.Will by chemical formula requirement Rare earth Nd metal, Fe metals, Fe-B alloy weighing and burdens, are then placed in vacuum intermediate-frequency smelting furnace, by induction melting into Nd12.5Fe81.5B6Alloy cast ingot.Ingot casting is carried out to homogenization heat treatment 2 hours at 1100 DEG C, ensures that alloying component is more uniform, It is subsequently placed at progress hydrogen in the broken stove of hydrogen to crush, then wears into the Nd that particle mean size is 3.5 μm using airflow milling12.5Fe81.5B6Close Bronze end.
The Dy-Fe-B alloys formula of high rare-earth content is Dy by atomic percent17Fe75B8.Will be dilute by chemical formula requirement Native Dy metals, Fe metals, Fe-B alloy weighing and burdens, are then placed in vacuum intermediate-frequency smelting furnace, by induction melting into Dy17Fe75B8Alloy cast ingot.Ingot casting is carried out to homogenization heat treatment 2 hours at 1100 DEG C, ensures that alloying component is more uniform, with After be placed in hydrogen crush stove in carry out hydrogen crush, thinner Dy is then worn into alloy using ball milling17Fe75B8Alloy powder.
By 8.7 grams of Nd12.5Fe81.5B6Alloy powder and 1.3 grams of Dy17Fe75B8Alloy powder is well mixed, then will mixing Powder is compressing in magnetic field, then carries out isostatic pressed into blank.Blank is put into sintering furnace and is sintered, wherein, sintering Temperature is 1050 DEG C, is incubated 2 hours, after being cooled to room temperature, is then heat-treated 2 hours at 900 DEG C and 550 DEG C respectively.
Using the magnetic property of NIM-200C permanent magnetism measurement apparatus measurement magnet, magnet coercivity is 23.53kOe.
As a comparison case 4, by 8.4 grams of Nd13Fe81B6Alloy powder and 1.6 grams of Dy13Fe81B6Alloy powder mixes, then By mixed powder in magnetic field it is compressing, then carry out isostatic pressed into blank.Magnet is made by above-mentioned sintering, annealing process, adopts It is that magnet coercivity is 19.89kOe with NIM-200C permanent magnetism measurement apparatus measurement magnet coercivity.Embodiment 4 and comparative example 4 Magnet total amount of rare earth, Nd constituent contents, Dy constituent contents are consistent, but the magnet coercivity of embodiment 4 is 23.53kOe, this comparison The coercivity 19.89kOe of the magnet of ratio 4 will height.Embodiment 4 is further illustrated by by the Nd-Fe-B alloys of low content of rare earth The Dy-Fe-B alloy powders of powder and high rare-earth content mix, and can significantly improve magnet coercivity.
Finally it should be noted that：Obviously, above-described embodiment is only intended to clearly illustrate example of the present invention, and simultaneously The non-restriction to embodiment.For those of ordinary skill in the field, can also make on the basis of the above description Other various forms of changes or variation.There is no necessity and possibility to exhaust all the enbodiments.And thus amplified Among the obvious changes or variations gone out is still in protection scope of the present invention.

Claims (8)

1. one kind improves the coercitive method of sintered NdFeB built-up magnet, it is characterised in that：By Nd-Fe-B alloy powders and Dy-Fe-B alloy powders are mixed with agglomeration permanent magnetic material, and Nd-Fe-B alloys formula is RE ' by atomic percenta1Fe100-a1-b-cBbMc, Dy-Fe-B alloys formula is RE " by atomic percenta2Fe100-a2-b-cBbMc, wherein 10.5≤a1≤ 13,15≤a2≤20,5≤b≤9,0≤c≤10, Nd-Fe-B alloy middle rare earth atomic percentage conc are far below Dy-Fe-B alloys Middle rare earth atomic percentage conc；
RE ' and RE " is selected from rare earth element La and Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Sc One or more, RE ', which should comprise at least Pr or Nd, RE ", should comprise at least Dy；
Element M is addition element, be Co, Ni, Cu, Zn, Al, Ga, Nb, Mo, Ti, Zr, V, Cr, Mn, C, Si, P, S, Ge, Se, One or more in Sn, Ta, Pb.
2. a kind of as claimed in claim 1 improve the coercitive method of sintered NdFeB built-up magnet, it is characterised in that：a2-a1 ≥3。
3. a kind of as claimed in claim 2 improve the coercitive method of sintered NdFeB built-up magnet, it is characterised in that：Alloy RE’a1Fe100-a1-b-cBbMcRare earth elements RE ' main component using Nd and/or Pr as rare earth, Nd and/or Pr gross weights are more than RE’a1Fe100-a1-b-cBbMcThe 70% of alloy middle rare earth gross weight, and alloy principal phase is RE '2Fe14B structure.
4. a kind of as claimed in claim 2 improve the coercitive method of sintered NdFeB built-up magnet, it is characterised in that：Alloy RE”a2Fe100-a2-b-cBbMcMain component of the rare earth elements RE " using Dy as rare earth, Dy gross weights are more than RE "a2Fe100-a2-b-cBbMc The 50% of alloy middle rare earth gross weight, and alloy principal phase is RE "2Fe14B structure.
5. a kind of as described in claim 3 or 4 improve the coercitive method of sintered NdFeB built-up magnet, it is characterised in that：Will Nd-Fe-B alloy powders and Dy-Fe-B alloy powders mix by a certain percentage, and wherein Nd-Fe-B alloy powders are not less than mixing The 70wt% of powder gross weight afterwards, Dy-Fe-B alloy powder are no more than the 30wt% of powder gross weight after mixing.
6. a kind of as claimed in claim 5 improve the coercitive method of sintered NdFeB built-up magnet, it is characterised in that：By Nd- When Fe-B alloy powders and Dy-Fe-B alloy powders mix, other alloys or metal dust, but other alloys or gold can be also added Belong to 30wt% of the addition not higher than powder gross weight after mixing of powder.
7. a kind of as claimed in claim 6 improve the coercitive method of sintered NdFeB built-up magnet, it is characterised in that：It is described its Its alloy or metal dust include RE, Fe, B, M one or more, RE be selected from rare earth element La and Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Sc one or more, M Co, Ni, Cu, Zn, Al, Ga, Nb, Mo, Ti, Zr, V, One or more in Cr, Mn, C, Si, P, S, Ge, Se, Sn, Ta, Pb；Powder can be crushed by melting, hydrogen, then airflow milling Or ball grinding method obtains.
8. a kind of as claimed in claim 7 improve the coercitive method of sintered NdFeB built-up magnet, it is characterised in that：This method Include following processing step：
Step 1：Weighing and burden is carried out to raw material according to composition design requirement, at least two alloys are prepared, wherein Nd- must be included Fe-B alloys and Dy-Fe-B alloys；Nd-Fe-B alloys formula is RE ' by atomic percenta1Fe100-a1-b-cBbMc, Dy-Fe-B Alloy formula is RE " by atomic percenta2Fe100-a2-b-cBbMc；A1, a2, b, c are atom percentage content, 10.5≤a1≤ 13,15≤a2≤20,5≤b≤9,0≤c≤10, a2-a1 >=3；RE ' and RE " be selected from rare earth element La and Ce, Pr, Nd, Pm, One or more in Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Sc, RE ' should comprise at least Pr or Nd, RE " should be extremely Dy is included less；Alloy RE 'a1Fe100-a1-b-cBbMcMain components of the rare earth elements RE ' using Nd and/or Pr elements as rare earth, Nd It is more than RE ' with Pr gross weightsa1Fe100-a1-b-cBbMcThe 70% of alloy middle rare earth gross weight, and alloy principal phase is RE '2Fe14B is tied Structure；Alloy RE "a2Fe100-a2-b-cBbMcMain components of the rare earth elements RE " using Dy elements as rare earth, Dy gross weights are more than RE”a2Fe100-a2-b-cBbMcThe 50% of alloy middle rare earth gross weight, and alloy principal phase is RE "2Fe14B structure；M be Co, Ni, One or more in Cu, Zn, Al, Ga, Nb, Mo, Ti, Zr, V, Cr, Mn, C, Si, P, S, Ge, Se, Sn, Ta, Pb, it is alloy In addition element；
Step 2：The raw material that step 1 is prepared is respectively put into Medium frequency induction rapid hardening furnace crucible, and high-purity argon gas is filled with after vacuumizing, It is then electrified to heat, it is in 1~3m/s water-cooled copper roller that fused solution is poured into linear velocity when melting is liquid, is averaged Thickness is 0.1~2.0mm rapid casting；Also the mode of sensing heating can be used to make melting sources for liquid under vacuum Body, and ensure that alloying component is uniform, then it is cooled to alloy cast ingot；
Step 3：Obtained quick setting belt or alloy cast ingot in step 2 are put into the broken stove of hydrogen and crushed, obtains just broken powder；With Hydrogen is broken into the pulverized powder nitrogen that adds high pressure afterwards and carries out airflow milling, can also be added under protective atmosphere in hydrogen breaks pulverized powder a small amount of Antioxidant, prevent the oxidation and reunion of powder, the ratio that antioxidant and hydrogen crush powder is 2~6ml/kg, passes through air-flow Alloy powder is prepared into the magnetic of 1~6 μm of particle mean size by mill；Wherein Dy-Fe-B alloy powders further make powder by ball milling Last particle mean size drops to less than 3.5 μm；
Step 4：According to component design requirement, the alloy powder that step 3 is obtained is well mixed according to a certain percentage, wherein necessary Including Nd-Fe-B alloy powders and Dy-Fe-B alloy powders, Nd-Fe-B alloy powders are not less than powder gross weight after mixing 70wt%, Dy-Fe-B alloy powder are no more than the 30wt% of powder gross weight after mixing；Other alloys or metal powder can also be added End, but the addition of other alloys or metal dust is not higher than the 30wt% of powder gross weight after mixing；Also can be incited somebody to action by this requirement Directly mixing after quick setting belt and ingot casting hydrogen that step 2 obtains are broken, then carries out airflow milling again, can be in protective atmosphere during airflow milling It is lower to add a small amount of antioxidant, prevent the oxidation and reunion of powder, the ratio that antioxidant and hydrogen crush powder is 2~6ml/ Kg, mixed alloy powder is prepared into the magnetic of 1~6 μm of particle mean size by airflow milling；
Step 5：The powder that step 4 is well mixed is orientated compressing in 1~3T magnetic field, is made in cold isostatic press Density is 3~5g/cm3Blank, improve the density and intensity of blank；
Step 6：Blank is put into sintering furnace, high vacuum will be evacuated in stove and is then charged with argon gas, temperature is then raised to 990~ 1100 DEG C are sintered, and insulation is cooled to normal temperature and obtains sintered magnet after 1~6 hour；
Step 7：The sintered magnet that step 6 is obtained is heat-treated 1~4 hour at 700~980 DEG C and 400~700 DEG C respectively.
CN201710823046.7A 2017-09-13 2017-09-13 One kind improves the coercitive method of sintered NdFeB built-up magnet Pending CN107689279A (en)

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CN111430091A (en) * 2020-04-28 2020-07-17 宁德市星宇科技有限公司 High-coercivity sintered neodymium-iron-boron magnet and preparation method thereof
CN113539600A (en) * 2021-07-12 2021-10-22 内蒙古科技大学 Dy-containing rare earth permanent magnet with high magnetic energy product and high coercivity and preparation method thereof
CN113724954A (en) * 2021-08-27 2021-11-30 安徽吉华新材料有限公司 Heavy rare earth-free high-coercivity permanent magnet and preparation process thereof
US20220148801A1 (en) * 2020-11-12 2022-05-12 Shin-Etsu Chemical Co., Ltd. Method for Manufacturing Rare Earth Sintered Magnet
WO2023001189A1 (en) * 2021-07-20 2023-01-26 烟台正海磁性材料股份有限公司 High-performance sintered neodymium-iron-boron magnet and preparation method therefor

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CN101615461A (en) * 2009-05-14 2009-12-30 浙江大学 Nanometer Zn crystal boundary modified high-corrosion resistance Sintered NdFeB magnet and preparation method thereof
CN103794322A (en) * 2014-01-18 2014-05-14 浙江大学 Ultrahigh-coercivity sintered neodymium-iron-boron magnet and preparation method thereof
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109440182A (en) * 2018-11-28 2019-03-08 北京工业大学 The method that the monocrystalline neodymium iron boron particles and hydrogen of a kind of reduction-diffusion process manufacture size adjustable abolish calcium
CN111430091A (en) * 2020-04-28 2020-07-17 宁德市星宇科技有限公司 High-coercivity sintered neodymium-iron-boron magnet and preparation method thereof
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CN113539600A (en) * 2021-07-12 2021-10-22 内蒙古科技大学 Dy-containing rare earth permanent magnet with high magnetic energy product and high coercivity and preparation method thereof
WO2023001189A1 (en) * 2021-07-20 2023-01-26 烟台正海磁性材料股份有限公司 High-performance sintered neodymium-iron-boron magnet and preparation method therefor
CN113724954A (en) * 2021-08-27 2021-11-30 安徽吉华新材料有限公司 Heavy rare earth-free high-coercivity permanent magnet and preparation process thereof
CN113724954B (en) * 2021-08-27 2024-01-19 安徽吉华新材料有限公司 High-coercivity permanent magnet without heavy rare earth and preparation process thereof

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Application publication date: 20180213