CN108637249A - A kind of neodymium iron boron magnetic body sintering process - Google Patents
A kind of neodymium iron boron magnetic body sintering process Download PDFInfo
- Publication number
- CN108637249A CN108637249A CN201810572612.6A CN201810572612A CN108637249A CN 108637249 A CN108637249 A CN 108637249A CN 201810572612 A CN201810572612 A CN 201810572612A CN 108637249 A CN108637249 A CN 108637249A
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- Prior art keywords
- neodymium iron
- iron boron
- magnetic body
- boron magnetic
- temperature
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
- B22F3/1003—Use of special medium during sintering, e.g. sintering aid
- B22F3/1007—Atmosphere
- B22F3/101—Changing atmosphere
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Power Engineering (AREA)
- Mechanical Engineering (AREA)
- Hard Magnetic Materials (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
Abstract
The invention discloses a kind of neodymium iron boron magnetic body sintering process, and molding neodymium iron boron magnetic body is placed in sintering furnace, 750 850 DEG C were warming up to through 150 180 minutes after vacuumizing, keeps the temperature 20 40 minutes；1,000 1050 DEG C were warming up to using 60 70 minutes, keeps the temperature 10 30 minutes；1,050 1100 DEG C were warming up to using 0 10 minutes, keeps the temperature 300 350 minutes；It is finally filled with inert gas cooling, obtains Sintered NdFeB magnet.The present invention is using staged heating pre-burning so that becomes smaller with the temperature gradient at center outside magnet, improves magnet performance and qualification rate after sintering；By the way of air quenching and natural cooling, the tempering of neodymium iron boron green compact is realized by in-furnace temperature, reaches energy-efficient purpose；Inert gas convection current is utilized in heating, insulating process simultaneously so that gas, the volatile materials of sintering process releasing are taken out of when vacuumizing by inert gas, and protection green compact is not oxidized.
Description
Technical field
The invention belongs to magnet preparing technical field more particularly to a kind of neodymium iron boron magnetic body sintering process.
Background technology
Neodymium iron boron magnetic body is because having high magnetic energy product, coercivity and high-energy density, in modern industry and electronic technology
It is widely used in equal fields.The process for making of neodymium iron boron magnetic body is：Alloy melting → hydrogen is crushed coarse powder → air-flow processed and grinds
Fine powder → sizing → isostatic pressed → sintering → is surface-treated → magnetizes use.Wherein sintering is a committed step, sintering process
Quality directly decide the performance and qualification rate of neodymium iron boron magnetic body.
Since neodymium iron boron powder is adsorbed with the substances such as a large amount of nitrogen, oxygen, carbon, different temperatures of these substances in sintering process
Section releases, and the material demand released is extracted or diluted in time, otherwise will consume the rich neodymium phase in neodymium iron boron magnetic body
Cause material oxidation.In addition, since sintering process curve is complicated, when needing to keep higher vacuum degree in sintering process, and being sintered
Between it is long, energy consumption is big, causes cost higher.A large amount of energy consumptions can be saved by shortening sintering time, to be effectively reduced manufacture
Cost has good economy and social effect.
Invention content
In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides one kind capable of significantly reducing sintering time, and has
Effect avoids the neodymium iron boron magnetic body sintering process that neodymium iron boron magnetic body aoxidizes.
The technical solution adopted by the present invention is：A kind of neodymium iron boron magnetic body sintering process, includes the following steps：
（1）Molding neodymium iron boron magnetic body is placed in sintering furnace, through 150-180 minutes heating-up times from room temperature liter after vacuumizing
Temperature keeps the temperature 20-40 minutes to 750-850 DEG C of the first temperature；
（2）By step（1）Treated, and neodymium iron boron magnetic body was warming up to second temperature 1000- by 60-70 minutes heating-up times
1050 DEG C, keep the temperature 10-30 minutes；
（3）By step（2）Treated, and neodymium iron boron magnetic body was warming up to third temperature 1050- by 0-10 minutes heating-up times
1100 DEG C, keep the temperature 300-350 minutes；
（4）By step（3）Treated, and neodymium iron boron magnetic body is placed in cooling in inert gas environment, obtains Sintered NdFeB magnet.
Further, the step（4）In be placed in inert gas it is cooling, it is specially cold using inert gas air quenching is filled with
But to 600-650 DEG C, 400-450 DEG C is then naturally cooled to, is come out of the stove after air quenching is cooled to room temperature again.
Further, the step（1）In inert gas can be filled with into sintering furnace while vacuumize, make inertia in stove
Gas pressure is stablized in 100-200Pa, waits after the completion of keeping the temperature, and stopping is filled with inert gas, is evacuated to the vacuum degree of setting.
Further, the step（1）, step（2）Heating, in insulating process, can be according to cycle time toward sintering furnace
Periodically is passed through inert gas；The cycle time includes duration of ventilation and interval time；The duration of ventilation is 10-20s；
The interval time is 1-20 times of duration of ventilation.
Further, the step（1）It vacuumizes vacuum degree in rear sintering furnace and is less than or equal to 2Pa.
Further, the step（4）Middle inert gas is argon gas.
Further, the step（4）In can be used nitrogen substitute inert gas cooled down.
Further, the molding neodymium iron boron magnetic body is cylinder.
The beneficial effects of the invention are as follows：Staged heating carries out pre-burning to neodymium iron boron magnetic body so that outside neodymium iron boron magnetic body
Become smaller with the temperature gradient at center, when reaching sintering temperature so that the central part of neodymium iron boron green compact is rapidly achieved sintering temperature
Degree improves the density and magnet performance of sintered NdFeB green compact；In such a way that both air quenching and natural cooling are combined, pass through
It is sintered in-furnace temperature and realizes the tempering of neodymium iron boron green compact, energy-saving effect is apparent, and the magnet performance prepared is without significant difference；Together
When heat up and insulating process in utilize inert gas convection current so that gas that sintering process is released, volatile materials take out it is true
It is taken out of by inert gas when empty, protection neodymium iron boron green compact is not oxidized.
Specific implementation mode
For a further understanding of the present invention, the preferred embodiment of the invention is described with reference to embodiment, still
It should be appreciated that these descriptions are intended merely to the feature and advantage further illustrated the present invention, rather than to invention claim
Limitation.
Embodiment 1
The present invention provides a kind of neodymium iron boron magnetic body sintering process, include the following steps：
（1）Molding neodymium iron boron magnetic body is placed in sintering furnace, after vacuumizing through 160 minutes heating-up times from room temperature to
First 800 DEG C of temperature keeps the temperature 30 minutes；It vacuumizes vacuum degree in rear sintering furnace and is less than or equal to 2Pa；In heating, thermostatic process
Neodymium iron boron magnetic body green compact generated steam, the organic matter etc. contained in sintering procedure has been discharged；
（2）By step（1）Treated, and neodymium iron boron magnetic body was warming up to 1050 DEG C of second temperature by 65 minutes heating-up times, protected
Rich neodymium mutually a large amount of appearance at a temperature of temperature 20 minutes, 1050 DEG C in neodymium iron boron magnetic body, the recombination of main phase particle, large-sized hole disappear
It loses, magnet densification accelerates；Pre-burning is carried out to neodymium iron boron magnetic body before reaching sintering temperature so that outside neodymium iron boron magnetic body in
The temperature gradient of the heart becomes smaller, and when reaching sintering temperature, is easy so that neodymium iron boron magnetic body central part reaches sintering temperature so that
Sintered neodymium iron boron green compact is more preferable in density, magnet consistency；
（3）By step（2）Treated, and neodymium iron boron magnetic body was warming up to 1075 DEG C of third temperature by 10 minutes heating-up times, i.e.,
330 minutes are kept the temperature after reaching sintering temperature, keeps the temperature the long period, ensures that main phase particle is slowly grown up, realizes the complete cause of magnet
Densification effectively avoids the abnormal growth of magnet crystal grain, and sintering temperature is excessively high in sintering process can lead to magnet burning, go out
Existing abnormal grain growth, too low this of sintering temperature can lead to magnet underburnt, and magnet density is too low, the declines such as remanent magnetism；
（4）By step（3）Treated, and that neodymium iron boron magnetic body is placed in is cooling in inert gas environment, and argon may be selected in the inert gas
That is, under protection of argon gas gas is quickly cooled down to obtain Sintered NdFeB magnet by circulating cooling wind turbine；Alternatively, can also adopt
It is substituted inert gas with nitrogen, hydrogen and is cooled down.
Preferably, the step（1）In molding neodymium iron boron magnetic body be cylinder, wherein containing 0.02-0.06wt%'s
Antioxidant.
Embodiment 2
Step（4）In be placed in inert gas environment cooling, be specially cooled to 600-650 DEG C using air quenching, it is then naturally cold
But it to 400-450 DEG C, comes out of the stove after air quenching is cooled to room temperature again；Other steps are the same as embodiment 1.
Embodiment 3
Step（1）In inert gas can be filled with into sintering furnace while vacuumize, so that inert gas pressure is stablized and exist
100-200Pa waits after the completion of keeping the temperature that stopping is filled with inert gas, is evacuated to the vacuum degree of setting；The inert gas is optional
With argon gas, because of argon gas convection current, the more easily quilt when vacuumizing such as gas, volatile materials, organic matter that sintering process is released
Argon gas is taken out of, has good sintering atmosphere, protection green compact not oxidized；Other steps are the same as embodiment 1.
Embodiment 4
The step（1）, step（2）Heating, in insulating process, can be passed through toward sintering furnace periodically according to cycle time lazy
Property gas；The cycle time includes duration of ventilation and interval time；The duration of ventilation is 10-20s；The interval time is
1-20 times of duration of ventilation；Argon gas can be selected in the inert gas, because of argon gas convection current, the gas of sintering process releasing, volatilization
Property substance, organic matter etc. be easier to be taken out of by argon gas when vacuumizing, there is good sintering atmosphere, protect green compact not by oxygen
Change；Other steps are the same as embodiment 1.
Staged heating of the present invention carries out pre-burning to neodymium iron boron magnetic body so that outside neodymium iron boron magnetic body and the temperature at center is terraced
Degree becomes smaller, when reaching sintering temperature so that the central part of neodymium iron boron green compact is rapidly achieved sintering temperature, improves sintering neodymium iron
The density and magnet performance of boron green compact；It is real by being sintered in-furnace temperature in such a way that both air quenching and natural cooling are combined
Existing neodymium iron boron green compact tempering, energy-saving effect is apparent, and the magnet performance prepared is without significant difference；It is heating up and is keeping the temperature simultaneously
In the process utilize inert gas convection current so that sintering process release gas, volatile materials when vacuumizing by inert gas
It takes out of, protection neodymium iron boron green compact is not oxidized.
The above is only the better embodiment of the present invention, therefore all constructions according to described in present patent application range,
The equivalent change or modification that feature and principle are done, is included within the scope of present patent application.
Claims (8)
1. a kind of neodymium iron boron magnetic body sintering process, which is characterized in that include the following steps：
Molding neodymium iron boron magnetic body is placed in sintering furnace, through 150-180 minutes heating-up times from room temperature after vacuumizing
To 750-850 DEG C of the first temperature, 20-40 minutes are kept the temperature；
By step（1）Treated, and neodymium iron boron magnetic body was warming up to second temperature 1000-1050 by 60-70 minutes heating-up times
DEG C, keep the temperature 10-30 minutes；
By step（2）Treated, and neodymium iron boron magnetic body was warming up to third temperature 1050-1100 by 0-10 minutes heating-up times
DEG C, keep the temperature 300-350 minutes；
By step（3）Treated, and neodymium iron boron magnetic body is placed in cooling in inert gas environment, obtains Sintered NdFeB magnet.
2. neodymium iron boron magnetic body sintering process according to claim 1, it is characterised in that：The step（4）In be placed in inertia
It is cooled down in gas, being filled with inert gas air quenching for use is cooled to 600-650 DEG C, then naturally cools to 400-450 DEG C, again
Air quenching is come out of the stove after being cooled to room temperature.
3. neodymium iron boron magnetic body sintering process according to claim 1, it is characterised in that：The step（1）In vacuumize
It can be filled with inert gas into sintering furnace simultaneously, so that inert gas pressure in stove is stablized in 100-200Pa, wait after the completion of keeping the temperature,
Stopping is filled with inert gas, is evacuated to the vacuum degree of setting.
4. neodymium iron boron magnetic body sintering process according to claim 1, it is characterised in that：The step（1）, step（2）'s
In heating, insulating process, inert gas can be passed through toward sintering furnace periodically according to cycle time；The cycle time includes logical
Gas time and interval time；The duration of ventilation is 10-20s；The interval time is 1-20 times of duration of ventilation.
5. neodymium iron boron magnetic body sintering process according to claim 1, it is characterised in that：The step（1）It is burnt after vacuumizing
Vacuum degree is less than or equal to 2Pa in freezing of a furnace.
6. neodymium iron boron magnetic body sintering process according to claim 1, it is characterised in that：The step（4）Middle inert gas
For argon gas.
7. neodymium iron boron magnetic body sintering process according to claim 1, it is characterised in that：The step（4）In nitrogen can be used
Gas substitutes inert gas and is cooled down.
8. neodymium iron boron magnetic body sintering process according to claim 1, it is characterised in that：The molding neodymium iron boron magnetic body is
Cylinder.
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Cited By (4)
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| CN109590463A (en) * | 2018-12-18 | 2019-04-09 | 浙江中杭新材料科技有限公司 | A kind of preparation method of high-coercive force neodymium iron boron magnetic body |
| CN109637767A (en) * | 2018-12-18 | 2019-04-16 | 浙江中杭新材料科技有限公司 | A kind of sintering method of neodymium iron boron magnetic body |
| CN109686557A (en) * | 2018-12-18 | 2019-04-26 | 宁波中杭磁材有限公司 | A kind of preparation method of corrosion-resistant Ne-Fe-B magnet |
| CN112038084A (en) * | 2020-09-08 | 2020-12-04 | 安徽万磁电子有限公司 | Sintering process for magnet production |
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| CN109590463A (en) * | 2018-12-18 | 2019-04-09 | 浙江中杭新材料科技有限公司 | A kind of preparation method of high-coercive force neodymium iron boron magnetic body |
| CN109637767A (en) * | 2018-12-18 | 2019-04-16 | 浙江中杭新材料科技有限公司 | A kind of sintering method of neodymium iron boron magnetic body |
| CN109686557A (en) * | 2018-12-18 | 2019-04-26 | 宁波中杭磁材有限公司 | A kind of preparation method of corrosion-resistant Ne-Fe-B magnet |
| CN109637767B (en) * | 2018-12-18 | 2020-08-21 | 浙江中杭新材料科技有限公司 | Sintering method of neodymium iron boron magnet |
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| CN112038084A (en) * | 2020-09-08 | 2020-12-04 | 安徽万磁电子有限公司 | Sintering process for magnet production |
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Application publication date: 20181012 |