CN103903826A - Corrosion-resistant neodymium, iron and boron permanent magnet - Google Patents

Corrosion-resistant neodymium, iron and boron permanent magnet Download PDF

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Publication number
CN103903826A
CN103903826A CN201410135610.2A CN201410135610A CN103903826A CN 103903826 A CN103903826 A CN 103903826A CN 201410135610 A CN201410135610 A CN 201410135610A CN 103903826 A CN103903826 A CN 103903826A
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China
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permanent magnet
iron
neodymium
corrosion
corrosion resistance
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王波
张子龙
严辉
李超
张铭
王如志
宋雪梅
侯育冬
朱满康
刘晶冰
汪浩
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Beijing University of Technology
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Beijing University of Technology
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Abstract

The invention discloses a corrosion-resistant neodymium, iron and boron permanent magnet, and belongs to the field of rare earth magnetic materials. A coating layer with high corrosion resistance and magnetic permeability grows on the surface of neodymium, iron and boron powder by the aid of a chemical plating or vapor deposition method, the particle size of the neodymium, iron and boron powder ranges from 10 micrometers to 120 micrometers, the coating layer is made of nickel or zinc or chromium or the like, and then the coated neodymium, iron and boron powder is oriented, compressed and sintered to obtain the novel corrosion-resistant neodymium, iron and boron permanent magnet. A ratio of the particle size of the neodymium, iron and boron powder to the thickness of the corrosion-resistant coating layer is 10-60:1. The corrosion-resistant neodymium, iron and boron permanent magnet has the advantages that the neodymium, iron and boron permanent magnet is high in corrosion resistance, residual magnetism Br, coercivity Hc and magnetic energy product BH, and the integral corrosion resistance of the neodymium, iron and boron permanent magnet is unaffected by damage to a surface layer of the neodymium, iron and boron permanent magnet.

Description

A kind of corrosion resistance Nd-Fe-B permanent magnet
Technical field
The invention belongs to rareearth magnetic material field, what be specifically related to is a kind of corrosion resistance Nd-Fe-B permanent magnet.
Background technology
As the neodymium iron boron NdFeB based permanent magnet of third generation permanent magnetic material, owing to thering is high remanent magnetism, high-coercive force and high energy product, be the best permanent magnetic material of current magnetic property.Be widely used in the numerous areas such as Aeronautics and Astronautics, short-wave communication tedhnology, motor, automobile, wind power generation.But this class magnet has an obvious defect, i.e. poor corrosion resistance (magnet weightlessness is larger), thus limit the further expansion of magnet applications scope.
The main cause of Nd-Fe-B permanent magnet corrosion is oxidation, i.e. chemical corrosion.NdFeB material mainly contains three phase compositions, principal phase matrix Nd2Fe14B, rich B phase and rich Nd phase.Wherein the oxidability of rich B phase and rich Nd phase is stronger.Rich B phase is distributed in each grain boundaries mutually with rich Nd, tends to because oxidation causes the weightlessness of NdFeB material.
In order to improve the decay resistance of NdFeB material, reduce material weightlessness, people have carried out a lot of research, protect by the method for plating on the neodymium iron boron block sintering.Effective method is a plating on the neodymium iron boron block sintering, thereby obtains all more satisfactory corrosion resistance NdFeB materials of magnetic property and decay resistance.But this protected mode has an obvious shortcoming, these protective layers are often not tight with the combination of neodymium iron boron matrix, once protective layer partly or entirely comes off, its decay resistance will decline rapidly.
Summary of the invention
The object of the present invention is to provide a kind of novel corrosion resistant Nd-Fe-B permanent magnet, this corrosion-resisting permanent magnet decay resistance is strong, is conducive to industrial production and people's life.The technical scheme adopting is:
A kind of novel corrosion resistant Nd-Fe-B permanent magnet, the coating layer such as nickel or zinc, chromium particle diameter with chemical plating or vapour deposition process growth one deck in the Nd-Fe-B powder surface of 10 ?120 μ m to high corrosion resistance energy and magnetic permeability energy, can obtain novel corrosion resistant Nd-Fe-B permanent magnet by the neodymium iron boron powder after coated through orientation, die mould, sintering.
The ratio of the thickness of described neodymium iron boron powder particle diameter and corrosion resistance coating layer is 10 ?60:1.
The coated corrosion resistance Nd-Fe-B permanent magnet of nickel described above can be adopted preparation with the following method:
(1) get the neodymium iron boron powder of particle diameter 10-120 μ m, use after distilled water cleans and put into oil removing under the ultrasonic effect of degreasing fluid at 40kHZ, 100W.Guarantee that temperature when oil removing is at 40-85 ℃, oil removing time 1-5min, pH 8-11.
(2) step (1) powder after treatment is cleaned up with distilled water, be placed in pickle pickling.Guarantee pickling temperature 10-40 ℃, pickling time 10-60s.
(3) step (2) powder after treatment is cleaned with distilled water, activated with activating solution.Temperature 10-40 ℃ when activation, soak time 10-60s.
(4) step (3) powder after treatment is added to NiSO 4, NaH 2pO 2, Na 3c 6h 5o 7, (NH 4) 2sO 4, Nd 2(SO 4) 3in the mixed solution of KI, chemical nickel plating under the condition stirring.Temperature 40-85 ℃ when nickel plating, plating time 5-20min.In nickel process, maintain pH 5-9.
(5) step (4) powder after treatment is cleaned through distilled water, in vacuum (or Ar gas protective atmosphere), dried, baking temperature is no more than 120 ℃.
(6), by the oriented moulding first pressing in 1.0-2.5T magnetic field of step (5) powder after treatment, pressed compact obtains pressed compact through static pressure processing such as 100-300MPa;
(7) by step (6) pressed compact after treatment at 1000 ℃ of-1600 ℃ of vacuum-sintering 3-6 hour, more tempered processing, makes magnet.
Preferably, in step (1), described degreasing fluid is NaOH, Na 2cO 3, Na 3pO 4, OP-10 composition mixed liquor.Wherein, the concentration of NaOH is 8-10gL -1, Na 2cO 3concentration be 40-60gL -1, Na 3pO 4concentration be 60-80gL -1, the concentration of OP-10 is 1-2gL -1.
In step (2), described pickle is HCl(or HNO 3) with the mixed liquor of thiocarbamide, in mixed liquor, the concentration of each component is preferably HCl and the 1gL of 1-5% -1thiocarbamide.
In step (3), in described activating solution, the concentration of each component is preferably 5-30gL -1citric acid, 10-15gL -1ammonium acid fluoride.
In step (4), described NiSO 4, NaH 2pO 2, Na 3c 6h 5o 7, (NH 4) 2sO 4, Nd 2(SO 4) 3be preferably 20-30gL with the concentration of each component in the mixed solution of KI -1niSO 4, 18-30gL -1naH 2pO 2, 30-40gL -1na 3c 6h 5o 7, 50-70gL -1(NH 4) 2sO 4, 0-5gL -1nd 2(SO 4) 3, 3mgL -1kI.
In step (7), when described temper prior to 850 ?950 ℃ of one-level tempering 2 ?4 hours, then in 450 ℃ ?600 ℃ of second annealings process 4 ?6 hours.
In like manner chromium and zinc coated also can adopt similar method.
The invention has the advantages that:
Nd-Fe-B permanent magnet decay resistance of the present invention is strong, and the breakage on top layer does not affect its overall corrosion resistance energy, and has very high remanent magnetism Br, coercivity H and very large magnetic energy product BH.
Accompanying drawing explanation
Fig. 1 is neodymium iron boron powder covered effect schematic diagram.
In figure, core is neodymium iron boron powder 1, outer cladding layer 2.
In figure, neodymium iron boron powder diameter D 1, coating thickness D 2.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention will be further described in detail, but the present invention is not limited to following examples.
Preparation method: comprise the steps:
(8) get the neodymium iron boron powder of particle diameter 10-120 μ m, use after distilled water cleans and put into oil removing under the ultrasonic effect of degreasing fluid at 40kHZ, 100W.Guarantee that temperature when oil removing is at 40-85 ℃, oil removing time 1-5min, pH 8-11.
(9) step (1) powder after treatment is cleaned up with distilled water, be placed in pickle pickling.Guarantee pickling temperature 10-40 ℃, pickling time 10-60s.
(10) step (2) powder after treatment is cleaned with distilled water, activated with activating solution.Temperature 10-40 ℃ when activation, soak time 10-60s.
(11) step (3) powder after treatment is added to NiSO 4, NaH 2pO 2, Na 3c 6h 5o 7, (NH 4) 2sO 4, Nd 2(SO 4) 3in the mixed solution of KI, chemical nickel plating under the condition stirring.Temperature 40-85 ℃ when nickel plating, plating time 5-20min.In nickel process, maintain pH 5-9.
(12) step (4) powder after treatment is cleaned through distilled water, in vacuum (or Ar gas protective atmosphere), dried, baking temperature is no more than 120 ℃.
(13), by the oriented moulding first pressing in 1.0-2.5T magnetic field of step (5) powder after treatment, pressed compact obtains pressed compact through static pressure processing such as 100-300MPa;
(14) by step (6) pressed compact after treatment at 1000 ℃ of-1600 ℃ of vacuum-sintering 3-6 hour, more tempered processing, makes magnet.
In step (1), described degreasing fluid is NaOH, Na 2cO 3, Na 3pO 4, OP-10 composition mixed liquor.Wherein, the concentration of NaOH is 8-10gL -1, Na 2cO 3concentration be 40-60gL -1, Na 3pO 4concentration be 60-80gL -1, the concentration of OP-10 is 1-2gL -1.
In step (2), described pickle is HCl(or HNO 3) with the mixed liquor of thiocarbamide, in mixed liquor, the concentration of each component is preferably HCl and the 1gL of 1-5% -1thiocarbamide.
In step (3), in described activating solution, the concentration of each component is preferably 5-30gL -1citric acid, 10-15gL -1ammonium acid fluoride.
In step (4), described NiSO 4, NaH 2pO 2, Na 3c 6h 5o 7, (NH 4) 2sO 4, Nd 2(SO 4) 3be preferably 20-30gL with the concentration of each component in the mixed solution of KI -1niSO 4, 18-30gL -1naH 2pO 2, 30-40gL -1na 3c 6h 5o 7, 50-70gL -1(NH 4) 2sO 4, 0-5gL -1nd 2(SO 4) 3, 3mgL -1kI.
In step (7), when described temper prior to 850 ?950 ℃ of one-level tempering 2 ?4 hours, then in 450 ℃ ?600 ℃ of second annealings process 4 ?6 hours.
Embodiment 1:
This novel corrosion resistant Nd-Fe-B permanent magnet, as shown in Figure 1, with the coated particle diameter D of metallic nickel 1be the neodymium iron boron powder of 50 μ m, coating thickness D 2be 3 μ m, D1:D2=16.7:1.Neodymium iron boron powder after coated obtains corrosion-resistant Ne-Fe-B permanent magnet after orientation, die mould, sintering.Weight loss rate in the NaCl that magnet is 1% the concentration of 25 ℃ is 0.05gh -1m -2.There is good decay resistance.
Magnetism testing: the sample of sintering is made to the standard sample of φ 10 × 10mm, measured magnetic property, result is as follows:
Br(KG) Hci(KOe) Hcb(KOe) (BH)max(MGOe)
12.58 13.40 12.21 38.68
Comparative example 1:
Getting particle diameter is the neodymium iron boron powder of 50 μ m, the Nd-Fe-B permanent magnet obtaining after orientation, die mould, sintering.Weight loss rate in the NaCl that magnet is 1% the concentration of 25 ℃ is 1.2gh -1m -2.
Embodiment 2:
This novel corrosion resistant permanent magnet, as shown in Figure 1, with the coated neodymium iron boron powder of crome metal, neodymium iron boron powder particle diameter D 1be 10 μ m, chromium coating thickness D 2be 1 μ m, D1:D2=10:1.The coated neodymium iron boron powder of chromium obtains corrosion resistance Nd-Fe-B permanent magnet after orientation, die mould, sintering.Weight loss rate in the NaCl that magnet is 1% the concentration of 25 ℃ is 0.1gh -1m -2.
Magnetism testing: the sample of sintering is made to the standard sample of φ 10 × 10mm, measured magnetic property, result is as follows:
Br(KG) Hci(KOe) Hcb(KOe) (BH)max(MGOe)
13.21 13.98 12.84 42.35
Comparative example 2:
Getting particle diameter is the neodymium iron boron powder of 10 μ m, the Nd-Fe-B permanent magnet obtaining after orientation, die mould, sintering.Weight loss rate in the NaCl that magnet is 1% the concentration of 25 ℃ is 1.4gh -1m -2.
Embodiment 3:
This novel corrosion resistant permanent magnet, as shown in Figure 1, with the coated neodymium iron boron powder of nickel, neodymium iron boron powder particle diameter D 1be 120 μ m, zinc coating thickness D 2be 2 μ m, D1:D2=60:1.The coated neodymium iron boron powder of nickel obtains corrosion resistance Nd-Fe-B permanent magnet after orientation, die mould, sintering.Weight loss rate in the NaCl that magnet is 1% the concentration of 25 ℃ is 0.08gh -1m -2.Magnetism testing: the sample of sintering is made to the standard sample of φ 10 × 10mm, measured magnetic property, result is as follows:
Br(KG) Hci(KOe) Hcb(KOe) (BH)max(MGOe)
11.86 12.56 11.14 35.12
Comparative example 3
Getting particle diameter is the neodymium iron boron powder of 120 μ m, the Nd-Fe-B permanent magnet obtaining after orientation, die mould, sintering.Weight loss rate in the NaCl that magnet is 1% the concentration of 25 ℃ is 0.9gh -1m -2.

Claims (2)

1. a corrosion resistance Nd-Fe-B permanent magnet, it is characterized in that, nickel, zinc or the chromium coating layer particle diameter with chemical plating or vapour deposition process growth one deck in the Nd-Fe-B powder surface of 10-120 μ m to high corrosion resistance energy and magnetic permeability energy, can obtain novel corrosion resistant Nd-Fe-B permanent magnet by the neodymium iron boron powder after coated through orientation, die mould, sintering.
2. according to a kind of corrosion resistance Nd-Fe-B permanent magnet of claim 1, it is characterized in that, the ratio of the thickness of described neodymium iron boron powder particle diameter and corrosion resistance coating layer is 10-60:1.
CN201410135610.2A 2014-04-04 2014-04-04 Corrosion-resistant neodymium, iron and boron permanent magnet Pending CN103903826A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104952582A (en) * 2015-04-17 2015-09-30 南通万宝实业有限公司 Novel permanently-magnetic material
CN109692963A (en) * 2018-12-18 2019-04-30 宁波中杭磁材有限公司 A kind of preparation method of the neodymium iron boron magnetic body of surface with corrosion-resistant finishes
CN110197752A (en) * 2019-06-13 2019-09-03 深圳市麦捷微电子科技股份有限公司 A kind of magnetic powder for the insulating powder technique and its preparation being passivated magnetic powder for hardly possible
CN113539665A (en) * 2021-07-28 2021-10-22 中国科学院宁波材料技术与工程研究所 Method for regulating and controlling coarse crystal growth of neodymium iron boron magnet

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JPH08250356A (en) * 1995-03-13 1996-09-27 Daido Steel Co Ltd Alloy powder for anisotropic magnet, anisotropic permanent magnet using the same and manufacture thereof
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CN103632833A (en) * 2013-12-03 2014-03-12 江苏大学 Preparation method of high-performance high-corrosion-resistance sintered Nd-Fe-B magnetic body

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104952582A (en) * 2015-04-17 2015-09-30 南通万宝实业有限公司 Novel permanently-magnetic material
CN109692963A (en) * 2018-12-18 2019-04-30 宁波中杭磁材有限公司 A kind of preparation method of the neodymium iron boron magnetic body of surface with corrosion-resistant finishes
CN110197752A (en) * 2019-06-13 2019-09-03 深圳市麦捷微电子科技股份有限公司 A kind of magnetic powder for the insulating powder technique and its preparation being passivated magnetic powder for hardly possible
CN110197752B (en) * 2019-06-13 2021-07-27 深圳市麦捷微电子科技股份有限公司 Insulating powder process for hard-to-passivate magnetic powder and magnetic powder prepared by using insulating powder process
CN113539665A (en) * 2021-07-28 2021-10-22 中国科学院宁波材料技术与工程研究所 Method for regulating and controlling coarse crystal growth of neodymium iron boron magnet
CN113539665B (en) * 2021-07-28 2023-08-22 中国科学院宁波材料技术与工程研究所 Method for regulating and controlling coarse grain growth of neodymium-iron-boron magnet

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Application publication date: 20140702