CN108682550A - A kind of raising Sintered NdFeB magnet corrosion resistance and coercitive method - Google Patents
A kind of raising Sintered NdFeB magnet corrosion resistance and coercitive method Download PDFInfo
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- CN108682550A CN108682550A CN201810435836.2A CN201810435836A CN108682550A CN 108682550 A CN108682550 A CN 108682550A CN 201810435836 A CN201810435836 A CN 201810435836A CN 108682550 A CN108682550 A CN 108682550A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
- H01F41/026—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets protecting methods against environmental influences, e.g. oxygen, by surface treatment
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
- C23C10/18—Solid state diffusion of only metal elements or silicon into metallic material surfaces using liquids, e.g. salt baths, liquid suspensions
- C23C10/20—Solid state diffusion of only metal elements or silicon into metallic material surfaces using liquids, e.g. salt baths, liquid suspensions only one element being diffused
- C23C10/22—Metal melt containing the element to be diffused
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
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- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- Hard Magnetic Materials (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
Abstract
A kind of raising Sintered NdFeB magnet corrosion resistance and coercitive method, belong to technical field of magnetic materials.The present invention improves the performance of magnet by using Sintered NdFeB magnet is immersed in the method in liquid Ga solution at a certain temperature.The present invention the specific steps are：It will pass through pretreated Sintered NdFeB magnet first and solid-state Ga takes and is placed in crucible in right amount, then crucible is placed in vacuum heat treatment furnace and is heat-treated, temperature is 400 600 DEG C, time is 0.5 1h, heat treatment terminates to take out in crucible, it is heated to 30 DEG C in air, magnet is taken out from the Ga of melting.The corrosion resistance of magnet and coercivity improve after present invention processing.
Description
Technical field
The present invention relates to a kind of raising Sintered NdFeB magnet corrosion resistance and coercitive methods, belong to magnetic material technology
Field.
Background technology
Nd-Fe-B permanent magnet material since self-discovery, has been referred to as by its excellent magnetic property as third generation permanent-magnet material
" magnetic king " adds its cost-effective advantage, is widely used in communication, medical treatment, automobile, electronics, wind-power electricity generation, aviation boat
The numerous areas such as it.But the expansion that its poor corrosion resistance and temperature stability seriously limit its scope of application, with
The development of science and technology, requirement of the every field to neodymium iron boron magnetic body comprehensive performance is higher and higher, therefore, develops the neodymium of high combination property
Iron boron magnet becomes a kind of inexorable trend.
By constantly exploring, it has been found that the corrosion of neodymium iron boron magnetic body occurs mainly on crystal boundary, if in magnet
In Grain-Boundary Phase (rich-Nd phase, richness B phases), increase the content of the elements such as Ga, Cu, Al, Zn, so that it may with improve magnet corrosion resistance and
Coercivity, but these elements are added in melting, can be evenly distributed on main phase grain Nd2Fe14In B and rich-Nd phase, and
They are all non-magnetic atoms, into main phase after can reduce molecular magnetic moment, to substantially reduce the remanent magnetism and magnetic energy product of magnet.
In this regard, patent 201710130288.8 proposes a kind of side preparing high-coercive force neodymium iron boron magnetic body by grain boundary decision
Method.The patent is taken out by immersing magnet in liquid low-melting-point metal or low-melting alloy after progress surface immersion, passes through two
Grade heat treatment makes low-melting-point metal or low-melting alloy enter Grain-Boundary Phase, and the ingredient and structure for improving Grain-Boundary Phase improve magnet
Coercivity.In order to improve the corrosion resistance of Sintered NdFeB magnet, while improving coercivity, at an efficient Ga
Reason method plays similar Sintered NdFeB magnet overlay coating anti-corrosion its essence is one layer of Ga enriched layer is formed in magnet surface
The effect of erosion.Compared with patent 201710130288.8, there are three features for present invention tool.First, patent 201710130288.8
Middle hot dipping process coats a thin layer Ga in magnet surface, therefore the Ga contents of magnet surface are less, and in follow-up heat treatment process
In only a small amount of Ga participate in reaction.And the present invention is carried out at the same time heat by the way that neodymium iron boron magnetic body and solid-state Ga to be placed in same container
Processing, sintered NdFeB is in the encirclement of a large amount of liquid Ga solution during heat treatment, has a large amount of Ga to participate in reaction；Its
Secondary, the Ga contents for remaining in magnet surface in patent 201710130288.8 during hot dipping are less, special according to the diffusion of Ga
Property and neodymium iron boron magnetic body structure feature, this part Ga preferentially diffuses into Grain-Boundary Phase by high-temperature heat treatment, and passing through improves magnetic
The border structure and crystal boundary distributed mutually of body obtain high-coercive force neodymium iron boron magnetic body, without being uniformly enriched on magnet surface layer.And this
Magnet is to be immersed in Ga solution, therefore Ga not only preferentially diffuses into Grain-Boundary Phase, a large amount of Ga to patent during heat treatment
It is enriched on magnet surface layer, magnet and environment has been isolated to a certain extent, therefore the technique can improve the corrosion resistance of magnet simultaneously
And coercivity；Third, for Sintered NdFeB magnet, in order to keep high-coercive force after temperature grain is spread, it usually needs
It is nearby made annealing treatment in rich 500 DEG C of neodymium phase fusing point, therefore patent 201710130288.8 is used and is heat-treated twice.This hair
It is bright diffusion temperature to be made to be reduced near rich-Nd phase fusing point since diffusion reaction is in a large amount of Ga solution, therefore at heat
Science and engineering skill can be heat-treated from two-stage and be reduced to level-one heat treatment, and heat treatment time is also reduced, and simplifies process, reduce at
This.Additionally due to the content of Ga is different in two reactions, the controllable range bigger of diffusing capacities of the Ga in magnet in the present invention.
Invention content
A kind of raising sintered Nd-Fe-B permanent magnet corrosion resistance and coercitive method, which is characterized in that by sintered NdFeB
Magnet is immersed in Ga solution, using the characteristic of Ga, Ga enriched layers is formed in magnet surface region, to improve the anti-corrosion of magnet
Property and coercivity, include the following steps：
1) pretreated Sintered NdFeB magnet will be passed through and solid-state Ga takes and is placed in crucible in right amount；
2) crucible obtained by step 1) is placed in vacuum heat treatment furnace and is heat-treated.
3) crucible after step 2) being heat-treated takes out, and is heated to 30 DEG C in air, magnet is taken from the Ga of melting
Go out.
Further, Sintered NdFeB magnet is immersed in liquid Ga melts in step 2) and is come into full contact with, Ga may be implemented
It is fully spread on magnet surface layer.
Further, the temperature that the heat treatment described in step 2) uses is 400-600 DEG C, time 0.5-1h, vacuum degree
More than 10-2Pa。
The beneficial effects of the invention are as follows：
1) magnet is placed in solid-state Ga in same container using the present invention and is heat-treated, a large amount of liquid Ga is not only
Enter magnet along rich-Nd phase, more Ga are fully spread on magnet surface layer, form Ga enriched layers, can be by magnet and extraneous ring
Border completely cuts off, and plays the role of coating for protection against corrosion, can not only improve the corrosion resistance of magnet, while improving the coercivity of magnet.The work
Skill can also control Ga by adjusting the temperature and time of heat treatment and enter content and distribution in magnet；
2) of the invention since heat treatment process is in Ga liquid solutions, it is attached that diffusion temperature can be reduced to rich-Nd phase fusing point
Closely, therefore only level-one is needed to be heat-treated, and heat treatment time can be shortened to less than 1h.Therefore
Present invention process is simpler, and cost is less expensive.
Description of the drawings
The electron probe figure for the magnet A1 that Fig. 1 embodiments 1 obtain.
Specific implementation mode
Principles and features of the present invention are described below in conjunction with example, the given examples are served only to explain the present invention, and
It is non-to be used to limit the scope of the present invention.
Embodiment 1：
1) it is the Sintered NdFeB magnet of 10mm*10mm*4mm to take appearance and size, is denoted as A0, is carried out at the polishing of surface to it
Reason；
2) pretreated magnet will be passed through and solid-state Ga takes and is placed in crucible in right amount；
3) crucible is placed in vacuum heat treatment furnace, the heat treatment of 0.5h is carried out at 500 DEG C, vacuum degree is more than 10-2Pa；
4) crucible is taken out after being heat-treated, 30 DEG C is heated in air, then takes magnet from the Ga of melting
Go out, is denoted as A1；
5) the original magnet A0 and magnet A1 by oozing Ga processing is taken respectively, the polishing treatment in six faces is carried out to it, so
It is placed in autoclave simultaneously afterwards, carries out high temperature and pressure (temperature is 121 DEG C, 2 atmospheric pressure) corrosion of 55h, taken after corrosion
Go out magnet, calculates weightless.
1 A1 of table is compared with A0 corrosion resistances
| Project | Initial weight/g | Weight/g after corrosion | It is weightless |
| A0 | 2.9410 | 2.9316 | 0.320% |
| A1 | 2.7936 | 2.7865 | 0.204% |
2 A1 of table and A0 comparison of magnetic property
| Project | Br/(kGs) | Hcj/(kOe) | (BH)max/(MGOe) | Hk/Hcj |
| A0 | 13.48 | 13.37 | 44.69 | 0.98 |
| A1 | 12.98 | 15.82 | 42.17 | 0.98 |
By the corrosion resistance and comparison of magnetic property of A1 and A0, in conjunction with Fig. 1, it can be deduced that, Sintered NdFeB magnet is soaked
Bubble, due to the diffusion property of Ga, can form Ga layers in magnet surface region, on the one hand improve the resistance to of magnet in liquid Ga
Corrosion, the weightlessness after corrosion are reduced to 0.204% by 0.320%；On the other hand the coercivity for improving magnet, from 13.37kOe
15.82kOe is risen to, and remanent magnetism slightly reduces.
Embodiment 2：
1) it is the Sintered NdFeB magnet of 10mm*10mm*4mm to take appearance and size, is denoted as B0, is carried out at the polishing of surface to it
Reason；
2) pretreated magnet will be passed through and solid-state Ga takes and is placed in crucible in right amount；
3) crucible is placed in vacuum heat treatment furnace, the heat treatment of 0.5h is carried out at 600 DEG C, vacuum degree is more than 10-2Pa；
4) crucible is taken out after being heat-treated, 30 DEG C is heated in air, then takes magnet from the Ga of melting
Go out, is denoted as B1；
5) the original magnet B0 and magnet B1 by oozing Ga processing is taken respectively, the polishing treatment in six faces is carried out to it, so
It is placed in autoclave simultaneously afterwards, carries out high temperature and pressure (temperature is 121 DEG C, 2 atmospheric pressure) corrosion of 55h, taken after corrosion
Go out magnet, calculates weightless.
3 B1 of table is compared with B0 corrosion resistances
| Project | Initial weight/g | Weight/g after corrosion | It is weightless |
| B0 | 2.9524 | 2.9423 | 0.341% |
| B1 | 2.7939 | 2.7870 | 0.207% |
4 B1 of table and B0 comparison of magnetic property
| Project | Br/(kGs) | Hcj/(kOe) | (BH)max/(MGOe) | Hk/Hcj |
| B0 | 13.50 | 13.37 | 44.72 | 0.98 |
| B1 | 12.95 | 15.97 | 42.39 | 0.98 |
Embodiment 3：
1) it is the Sintered NdFeB magnet of 10mm*10mm*4mm to take appearance and size, is denoted as C0, is carried out at the polishing of surface to it
Reason；
2) pretreated magnet will be passed through and solid-state Ga takes and is placed in crucible in right amount；
3) crucible is placed in vacuum heat treatment furnace, the heat treatment of 1h is carried out at 400 DEG C, vacuum degree is more than 10-2Pa；
4) crucible is taken out after being heat-treated, 30 DEG C is heated in air, then takes magnet from the Ga of melting
Go out, is denoted as C1；
5) the original magnet C0 and magnet C1 by oozing Ga processing is taken respectively, the polishing treatment in six faces is carried out to it, so
It is placed in autoclave simultaneously afterwards, carries out high temperature and pressure (temperature is 121 DEG C, 2 atmospheric pressure) corrosion of 55h, taken after corrosion
Go out magnet, calculates weightless.
5 C1 of table is compared with C0 corrosion resistances
| Project | Initial weight/g | Weight/g after corrosion | It is weightless |
| C0 | 2.9539 | 2.9440 | 0.335% |
| C1 | 2.9632 | 2.9550 | 0.237% |
6 C1 of table and C0 comparison of magnetic property
。
Claims (4)
1. a kind of raising sintered Nd-Fe-B permanent magnet corrosion resistance and coercitive method, which is characterized in that by sintered NdFeB magnetic
Body is immersed in Ga solution, using the characteristic of Ga, Ga enriched layers is formed in magnet surface region, to improve the corrosion resistance of magnet
And coercivity, include the following steps：
1) pretreated Sintered NdFeB magnet will be passed through and solid-state Ga takes and is placed in crucible in right amount；
2) crucible obtained by step 1) is placed in vacuum heat treatment furnace and is heat-treated；
3) crucible after step 2) being heat-treated takes out, and is heated to 30 DEG C in air, magnet is taken out from the Ga of melting.
2. a kind of raising sintered Nd-Fe-B permanent magnet corrosion resistance described in accordance with the claim 1 and coercitive method, feature
It is, Sintered NdFeB magnet is immersed in liquid Ga melts in step 2) and is come into full contact with, realizes that Ga is abundant on magnet surface layer
Diffusion.
3. a kind of raising sintered Nd-Fe-B permanent magnet corrosion resistance described in accordance with the claim 1 and coercitive method, feature
It is, for the temperature that the heat treatment described in step 2) uses for 400-600 DEG C, time 0.5-1h, vacuum degree is more than 10-2Pa。
4. the sintered Nd-Fe-B permanent magnet being prepared according to claim 1-3 any one of them methods.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810435836.2A CN108682550A (en) | 2018-05-08 | 2018-05-08 | A kind of raising Sintered NdFeB magnet corrosion resistance and coercitive method |
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| CN201810435836.2A CN108682550A (en) | 2018-05-08 | 2018-05-08 | A kind of raising Sintered NdFeB magnet corrosion resistance and coercitive method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112010721A (en) * | 2020-08-06 | 2020-12-01 | 西安近代化学研究所 | Boron-containing fuel-rich propellant and preparation method thereof |
| CN112712955A (en) * | 2020-12-23 | 2021-04-27 | 安徽大地熊新材料股份有限公司 | Sintered neodymium-iron-boron magnet and preparation method thereof |
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| JP2005209932A (en) * | 2004-01-23 | 2005-08-04 | Tdk Corp | Rare-earth magnet and manufacturing method thereof, and manufacturing apparatus |
| CN105845301A (en) * | 2015-08-13 | 2016-08-10 | 北京中科三环高技术股份有限公司 | Rare earth permanent magnet and preparation method of rare earth permanent magnet |
| CN106783124A (en) * | 2016-12-05 | 2017-05-31 | 华南理工大学 | A kind of grain boundary decision Al Cu alloys improve the corrosion proof method of neodymium iron boron magnetic body |
| CN106887323A (en) * | 2017-03-07 | 2017-06-23 | 北京科技大学 | A kind of method that grain boundary decision prepares high-coercive force neodymium iron boron magnetic body |
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2018
- 2018-05-08 CN CN201810435836.2A patent/CN108682550A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005209932A (en) * | 2004-01-23 | 2005-08-04 | Tdk Corp | Rare-earth magnet and manufacturing method thereof, and manufacturing apparatus |
| CN105845301A (en) * | 2015-08-13 | 2016-08-10 | 北京中科三环高技术股份有限公司 | Rare earth permanent magnet and preparation method of rare earth permanent magnet |
| CN106783124A (en) * | 2016-12-05 | 2017-05-31 | 华南理工大学 | A kind of grain boundary decision Al Cu alloys improve the corrosion proof method of neodymium iron boron magnetic body |
| CN106887323A (en) * | 2017-03-07 | 2017-06-23 | 北京科技大学 | A kind of method that grain boundary decision prepares high-coercive force neodymium iron boron magnetic body |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112010721A (en) * | 2020-08-06 | 2020-12-01 | 西安近代化学研究所 | Boron-containing fuel-rich propellant and preparation method thereof |
| CN112712955A (en) * | 2020-12-23 | 2021-04-27 | 安徽大地熊新材料股份有限公司 | Sintered neodymium-iron-boron magnet and preparation method thereof |
| CN112712955B (en) * | 2020-12-23 | 2023-02-17 | 安徽大地熊新材料股份有限公司 | Sintered neodymium-iron-boron magnet and preparation method thereof |
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