CN102039407B - Method for decreasing harmful gases in process of sintering sintered neodymium iron boron (NdFeB) magnet - Google Patents
Method for decreasing harmful gases in process of sintering sintered neodymium iron boron (NdFeB) magnet Download PDFInfo
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- 238000005245 sintering Methods 0.000 title claims abstract description 79
- 238000000034 method Methods 0.000 title claims abstract description 42
- 229910001172 neodymium magnet Inorganic materials 0.000 title claims abstract description 20
- 239000007789 gas Substances 0.000 title claims abstract description 8
- QJVKUMXDEUEQLH-UHFFFAOYSA-N [B].[Fe].[Nd] Chemical compound [B].[Fe].[Nd] QJVKUMXDEUEQLH-UHFFFAOYSA-N 0.000 title abstract description 6
- 230000003247 decreasing effect Effects 0.000 title abstract 2
- 239000001257 hydrogen Substances 0.000 claims abstract description 68
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 68
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 26
- 238000006356 dehydrogenation reaction Methods 0.000 claims abstract description 16
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 13
- 239000000956 alloy Substances 0.000 claims abstract description 13
- 239000001996 bearing alloy Substances 0.000 claims description 36
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 36
- 238000010792 warming Methods 0.000 claims description 20
- 229910000521 B alloy Inorganic materials 0.000 claims description 11
- 238000013022 venting Methods 0.000 claims description 8
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 7
- 230000004913 activation Effects 0.000 claims description 7
- 229910052750 molybdenum Inorganic materials 0.000 claims description 7
- 239000011733 molybdenum Substances 0.000 claims description 7
- 229910052777 Praseodymium Inorganic materials 0.000 claims description 5
- 229910052742 iron Inorganic materials 0.000 claims description 5
- 230000000505 pernicious effect Effects 0.000 claims description 5
- 229910052779 Neodymium Inorganic materials 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 229910052748 manganese Inorganic materials 0.000 claims description 4
- 229910002335 LaNi5 Inorganic materials 0.000 claims description 3
- 229910052684 Cerium Inorganic materials 0.000 claims description 2
- 229910052692 Dysprosium Inorganic materials 0.000 claims description 2
- 229910052688 Gadolinium Inorganic materials 0.000 claims description 2
- 229910052689 Holmium Inorganic materials 0.000 claims description 2
- 229910018561 MmNi5 Inorganic materials 0.000 claims description 2
- 229910052771 Terbium Inorganic materials 0.000 claims description 2
- 229910052791 calcium Inorganic materials 0.000 claims description 2
- 229910052804 chromium Inorganic materials 0.000 claims description 2
- 229910052733 gallium Inorganic materials 0.000 claims description 2
- 229910052738 indium Inorganic materials 0.000 claims description 2
- 238000009413 insulation Methods 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 229910052758 niobium Inorganic materials 0.000 claims description 2
- 239000000470 constituent Substances 0.000 claims 1
- 238000010298 pulverizing process Methods 0.000 claims 1
- 150000002431 hydrogen Chemical class 0.000 abstract description 8
- 230000005587 bubbling Effects 0.000 abstract description 2
- 230000003647 oxidation Effects 0.000 abstract description 2
- 238000007254 oxidation reaction Methods 0.000 abstract description 2
- 230000003213 activating effect Effects 0.000 abstract 1
- 229910052751 metal Inorganic materials 0.000 abstract 1
- 239000002184 metal Substances 0.000 abstract 1
- 238000004321 preservation Methods 0.000 abstract 1
- 230000029058 respiratory gaseous exchange Effects 0.000 abstract 1
- 230000000630 rising effect Effects 0.000 abstract 1
- 238000004381 surface treatment Methods 0.000 abstract 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 20
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 20
- 239000000843 powder Substances 0.000 description 12
- 229910021529 ammonia Inorganic materials 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 10
- 239000000047 product Substances 0.000 description 10
- 239000000203 mixture Substances 0.000 description 8
- 238000007747 plating Methods 0.000 description 8
- 239000011265 semifinished product Substances 0.000 description 8
- 238000002474 experimental method Methods 0.000 description 7
- 230000032683 aging Effects 0.000 description 6
- 239000000428 dust Substances 0.000 description 6
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 6
- 238000003801 milling Methods 0.000 description 6
- 238000005554 pickling Methods 0.000 description 6
- 238000012545 processing Methods 0.000 description 6
- 238000013467 fragmentation Methods 0.000 description 5
- 238000006062 fragmentation reaction Methods 0.000 description 5
- 230000006698 induction Effects 0.000 description 5
- 230000008018 melting Effects 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 239000010935 stainless steel Substances 0.000 description 5
- 229910001220 stainless steel Inorganic materials 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000003786 synthesis reaction Methods 0.000 description 4
- 239000003054 catalyst Substances 0.000 description 3
- 208000037656 Respiratory Sounds Diseases 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- YZCKVEUIGOORGS-IGMARMGPSA-N Protium Chemical compound [1H] YZCKVEUIGOORGS-IGMARMGPSA-N 0.000 description 1
- 241000720974 Protium Species 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000006253 efflorescence Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- PUDIUYLPXJFUGB-UHFFFAOYSA-N praseodymium atom Chemical compound [Pr] PUDIUYLPXJFUGB-UHFFFAOYSA-N 0.000 description 1
- 238000012797 qualification Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 206010037844 rash Diseases 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention provides a method for decreasing harmful gases in the process of sintering a sintered neodymium iron boron (NdFeB) magnet, which comprises the following steps: crushing a hydrogen storage alloy into a plurality of small hydrogen storage alloy blocks, and putting the small hydrogen storage alloy blocks into a dehydrogenation unit after activating the small hydrogen storage metal blocks by using high-purity hydrogen, wherein the dehydrogenation unit is an airtight stainless box and provided with a mechanical driving device for controlling opening and closing; fixing the box on the furnace body inner wall of a sintering furnace, and connecting the mechanical driving device with the box so as to control the opening and closing of the box; at the heat preservation and breathing stage of rising the temperature of sintering a blank to 800-1000 DEG C, opening the box by the mechanical driving device so as to cause the small hydrogen storage alloy blocks to be exposed in the sintering atmosphere when a vacuum pump vacuumizes to 10Pa or below 10Pa; and closing the box after the vacuum degree reaches 10-2Pa. The method provided by the invention can be used to obviously improve oxidation resistance of the manufactured magnet in an external environment, and after the magnet blank is subject to plate surface treatment, bubbling and cracks are greatly reduced.
Description
Technical field
The present invention relates to a kind of sintering method of neodymium iron boron magnetic body of environmental protection, particularly relate to a kind of method that reduces the pernicious gas in Sintered NdFeB magnet sintering process.
Background technology
In existing Sintered NdFeB magnet production technology, by the quick-fried technique of hydrogen, improve in a large number the magnetic property of blank magnet, therefore at sintering, being warmed up to high temperature (800 ℃～1000 ℃) can releasing hydrogen gas (H during the stage
2).The oil vapour that the volatile substances such as lubricant that add when magnet green compact powder mixes powder in addition and Diffusion Pump Oil Backstreaming cause can volatilize methane (CH in the sintering temperature rise period
4) gas, if can not extract in time methane out, the adsorbed water steam (H that methane can give off with magnet green compact
2o) reaction, reaction equation is: CH
4+ 2H
2o → CO
2+ 4H
2, also can releasing hydrogen gas H
2.In the sintering furnace system of sealing, when vacuum is poor, in stove, has a lot of air, and in air, contain 78% nitrogen.At hot stage, hydrogen and nitrogen generation ammonia synthesis reaction, reaction equation is: 3H
2+ N
2=2NH
3.When sintering finishes blow-on, can smell dense ammonia odor, further prove ammonia synthesis reaction has occurred in sintering furnace.The reaction condition of this reaction is high-temperature pressure, and the catalyst of reaction can be iron catalyst.The catalyst of the ammonia synthesis reaction occurring in the sintering process of neodymium iron boron magnetic body is neodymium iron boron magnetic body green compact and oxide thereof.On the one hand, the ammonia of generation can enter in red-hot magnet green compact, forms ammino neodymium iron boron with magnet green compact, and reaction equation is: NH
3+ NdFeB → NdFeBNH
3(powder), before reaction, magnet green compact are the regular solids after moulding, have formed pressed powder after reaction; On the other hand, for this ammonia synthesis reaction, pulverous magnet green compact are easier to play catalytic action, can accelerate the generation of ammonia, and ammonia can react with magnet green compact the more pressed powder of generation, thereby form vicious circle.Like this, after reaction, the shape of magnet green compact is damaged, and certainly also just no longer has magnetic property.If remain protium in magnet blank, can cause magnet blank inside to occur crackle, and occur bubbling at the overlay coating of finished product magnet, affect the qualification rate of product.
Therefore be badly in need of a kind of method that reduces the hydrogen in Sintered NdFeB magnet sintering process of invention, and then reduce the generation of ammonia, avoid magnet green compact powdered.
Summary of the invention
The object of the present invention is to provide a kind of method that reduces the pernicious gas in Sintered NdFeB magnet sintering process, the hydrogen being discharged to be absorbed in hot stage magnet green compact, thereby the quality of raising Sintered NdFeB magnet.
According to an aspect of the present invention, provide a kind of method that reduces the pernicious gas in Sintered NdFeB magnet sintering process, described method comprises the steps:
(1) hydrogen bearing alloy is broken into fritter hydrogen bearing alloy, after high-purity hydrogen activation, puts into a dehydrogenation unit, described dehydrogenation unit is airtight stainless box, and opens and closes to control with a mechanical driving device;
(2) described box is fixed on the inboard wall of furnace body of sintering furnace, and described mechanical driving device is connected with described box, to control the switch of box;
(3) at blank sintering, be warming up to 800 ℃～1000 ℃ insulation venting during the stage, until vavuum pump, be evacuated to 10Pa or 10Pa when following, by described mechanical driving device, open described box, hydrogen bearing alloy is exposed in sintering atmosphere;
(4) treat that vacuum reaches 10
-2after Pa, close described box.
Wherein, it is sintered rare-earth permanent magnetic material that described magnet consists of R-T-B,
Wherein, R is at least two kinds of elements that are selected from Nd, Pr, Dy, Tb, Gd, Ho, and R content is 28～35wt.%;
T is Fe and be selected from least one element in Co, Ni, Cu, Al, Ga, Cr, Mn, Nb and In, and content is 63.8～71.1wt.%;
B content is 0.9～1.2wt.%.
Best, utilization of the present invention be the function that hydrogen bearing alloy can absorb hydrogen.
Best, described hydrogen bearing alloy is LaNi5 or mishmetal class MmNi5 material, and wherein Mm is La and the mishmetal that is selected from least one element in Ce, Pr, Nd.
Best, described hydrogen bearing alloy also comprises at least one element in Co, Ca, Cu, Mn, Fe and Al.Like this, can reduce the price of hydrogen bearing alloy, also can improve the ability of alloy storage hydrogen release hydrogen simultaneously.
Best, the size of described fritter hydrogen bearing alloy is 10 * 10 * 10mm
3.
Best, the volume of described hydrogen bearing alloy accounts for below 2/3 of volume of described box.
Best, the top of described box to the distance of sintering furnace molybdenum band surpasses 10cm.
Best, the purity of described high-purity hydrogen is more than 99.99%.
In order to reach the object that absorbs hydrogen, hydrogen bearing alloy need to be exposed in sintering atmosphere, need hydrogen bearing alloy to be placed on the body of heater inside of sintering furnace.As preferred embodiment, can absorb hydrogen with the best lanthanon hydrogen storage alloy of application performance.
By use method provided by the present invention in the process of Sintered NdFeB magnet, the time shorten that can make the venting stage in sintering process is original 60%, and the vacuum in sintering furnace improved a lot more originally, vacuum is by original 1Pa～7 * 10
-1pa brings up to 1 * 10
-1pa.After sintering finishes, magnet blank becomes regular solid shape, does not generate pulverous magnet blank, and does not smell ammonia odor during blow-on.The outward appearance of the magnet blank after sintering is silvery white in color, and adopts HAST experiment to detect and learns the magnet that the present invention makes, and places 48 hours rear surfaces and does not occur powder phenomenon-tion, and the oxidation resistance in external environment is significantly increased.Magnet blank, after plate surface is processed, occurs that the ratio of foaming, seminess greatly reduces.
The specific embodiment
In order more clearly to explain the present invention, will illustrate in greater detail preferred embodiment below.
Embodiment 1
The alloy that is 9.7Pr-19Nd-4Dy-0.5Al-0.1Cu-1.2Co-1.0B-surplus Fe by composition carries out vacuum induction melting and obtains Nd Fe B alloys, after thick, middle fragmentation, carry out the quick-fried processing of hydrogen, with airflow milling abrasive dust, obtain 3.7～4.0 μ m Nd Fe B alloys powder.Green compact compacting is of a size of D20 * 28.In sintering furnace, place dehydrogenation unit, the body of heater that is placed on sintering furnace is inner.Wherein, described dehydrogenation unit is an airtight stainless steel box, is wherein placed with and is broken into 10 * 10 * 10mm
3fritter by the LaNi5 hydrogen bearing alloy after 99.99% high-purity hydrogen activation, and this device is controlled the opening and closing of box with a mechanical driving device, wherein hydrogen bearing alloy accounts for 1/3 of box volume, and described cartridge top to sintering furnace molybdenum band distance is 15cm.Green compact are put into sintering furnace sintering timeliness, and sintering process is: be warming up to 300 ℃ and be incubated 1h; Then be warming up to 900 ℃ and be incubated 1.5h; Be warming up to again 1060 ℃ and be incubated 5h, carry out subsequently Ageing Treatment.900 ℃ of venting stages, when vavuum pump is evacuated to 10Pa, by described mechanical driving device, open described box, hydrogen bearing alloy is exposed in sintering atmosphere, after reaching 10-2Pa, vacuum closes described box.Sintering is complete, magnet blank product is processed into the semi-finished product (black-film) of D20 * 2, then carries out pickling plating.
Embodiment 2
The alloy that is 10.3Pr-20Nd-4Dy-0.5Tb-0.2Gd-0.5Al-0.1Cu-1.2Co-1.2B-surplus Fe by composition carries out vacuum induction melting and obtains Nd Fe B alloys, after thick, middle fragmentation, carry out the quick-fried processing of hydrogen, with airflow milling abrasive dust, obtain 3.7～4.0 μ m Nd Fe B alloys powder.Green compact compacting is of a size of D20 * 28.In sintering furnace, place dehydrogenation unit, the body of heater that is placed on sintering furnace is inner.Wherein, described dehydrogenation unit is an airtight stainless steel box, is wherein placed with and is broken into 10 * 10 * 10mm
3fritter by the LaCeNi5 hydrogen bearing alloy after 99.99% high-purity hydrogen activation, and this device is controlled the opening and closing of box with a mechanical driving device, wherein hydrogen bearing alloy accounts for 1/3 of box volume, and described cartridge top to sintering furnace molybdenum band distance is 15cm.Green compact are put into sintering furnace sintering timeliness, and sintering process is: be warming up to 300 ℃ and be incubated 1h; Then be warming up to 900 ℃ (800 ℃) and be incubated 1.5h; Be warming up to again 1060 ℃ and be incubated 5h, carry out subsequently Ageing Treatment.800 ℃ of venting stages, when vavuum pump is evacuated to 8Pa, by described mechanical driving device, open described box, hydrogen bearing alloy is exposed in sintering atmosphere, treat that vacuum reaches 10
-2after Pa, close described box.Sintering is complete, magnet blank product is processed into the semi-finished product (black-film) of D20 * 2, then carries out pickling plating.
Embodiment 3
The alloy that is 25.6Nd-2.4Dy-0.1Ga-0.9B-surplus Fe by composition carries out strip PROCESS FOR TREATMENT and becomes strip, after carry out the quick-fried processing of hydrogen, with airflow milling abrasive dust, obtain 3.7～4.0 μ m Nd Fe B alloys powder.Green compact compacting is of a size of D20 * 28.In sintering furnace, place dehydrogenation unit, the body of heater that is placed on sintering furnace is inner.Wherein, described dehydrogenation unit is an airtight stainless steel box, is wherein placed with and is broken into 10 * 10 * 10mm
3fritter by the LaCePrNi5 hydrogen bearing alloy after 99.99% high-purity hydrogen activation, and this device is controlled the opening and closing of box with a mechanical driving device, wherein hydrogen bearing alloy accounts for 1/3 of box volume, and described cartridge top to sintering furnace molybdenum band distance is 15cm.Green compact are put into sintering furnace sintering timeliness, and sintering process is: be warming up to 300 ℃ and be incubated 1h; Then be warming up to 1000 ℃ and be incubated 1.5h; Be warming up to again 1050 ℃ and be incubated 5h, carry out subsequently Ageing Treatment.1000 ℃ of venting stages, when vavuum pump is evacuated to 8Pa, by described mechanical driving device, open described box, hydrogen bearing alloy is exposed in sintering atmosphere, treat that vacuum reaches 10
-2after Pa, close described box.Sintering is complete, magnet blank product is processed into the semi-finished product (black-film) of D20 * 2, then carries out pickling plating.
Embodiment 4
The alloy that is 30.5Pr-2Dy-0.1Al-0.1Ga-1.0B-surplus Fe by composition carries out vacuum induction melting and obtains praseodymium ferroboron, carries out the quick-fried processing of hydrogen after thick, middle fragmentation, with airflow milling abrasive dust, obtains 3.7～4.2 μ m Nd Fe B alloys powder.Green compact compacting is of a size of D20 * 28.In sintering furnace, place dehydrogenation unit, the body of heater that is placed on sintering furnace is inner.Wherein, described dehydrogenation unit is an airtight stainless steel box, is wherein placed with and is broken into 10 * 10 * 10mm
3fritter by the Mm0.3-Ni3.55-Ca1.5 hydrogen bearing alloy after 99.99% high-purity hydrogen activation, wherein Mm is LaCePrNd mixture, and this device is controlled the opening and closing of box with a mechanical driving device, wherein hydrogen bearing alloy accounts for 1/3 of box volume, and described cartridge top to sintering furnace molybdenum band distance is 15cm.Green compact are put into sintering furnace sintering timeliness, and sintering process is: be warming up to 300 ℃ and be incubated 1h; Then be warming up to 1000 ℃ and be incubated 1.5h; Be warming up to again 1060 ℃ and be incubated 5h, carry out subsequently Ageing Treatment.1000 ℃ of venting stages, when vavuum pump is evacuated to 8Pa, by described mechanical driving device, open described box, hydrogen bearing alloy is exposed in sintering atmosphere, treat that vacuum reaches 10
-2after Pa, close described box.Sintering is complete, magnet blank product is processed into the semi-finished product (black-film) of D20 * 2, then carries out pickling plating.
Embodiment 5
The alloy that is 10Pr-20.5Nd-2Dy-0.5Ho-0.1Al-0.1Ga-1.0B-surplus Fe by composition carries out vacuum induction melting and obtains Nd Fe B alloys, after thick, middle fragmentation, carry out the quick-fried processing of hydrogen, with airflow milling abrasive dust, obtain 3.7～4.2 μ m Nd Fe B alloys powder.Green compact compacting is of a size of D20 * 28.In sintering furnace, place dehydrogenation unit, the body of heater that is placed on sintering furnace is inner.Wherein, described dehydrogenation unit is an airtight stainless steel box, is wherein placed with and is broken into 10 * 10 * 10mm
3fritter by the Mm0.3-Ni3.55-Co0.75-Mn0.47-Al0.3 hydrogen bearing alloy after 99.99% high-purity hydrogen activation, wherein Mm is LaCePrNd mixture, and this device is controlled the opening and closing of box with a mechanical driving device, wherein hydrogen bearing alloy accounts for 1/3 of box volume, and described cartridge top to sintering furnace molybdenum band distance is 15cm.Green compact are put into sintering furnace sintering timeliness, and sintering process is: be warming up to 300 ℃ and be incubated 1h; Then be warming up to 1000 ℃ and be incubated 1.5h; Be warming up to again 1060 ℃ and be incubated 5h, carry out subsequently Ageing Treatment.1000 ℃ of venting stages, when vavuum pump is evacuated to 8Pa, by described mechanical driving device, open described box, hydrogen bearing alloy is exposed in sintering atmosphere, treat that vacuum reaches 10
-2after Pa, close described box.Sintering is complete, magnet blank product is processed into the semi-finished product (black-film) of D20 * 2, then carries out pickling plating.
Comparative example 1
The alloy that is 9.7Pr-19Nd-4Dy-0.5Al-0.1Cu-1.2Co-1.0B-surplus Fe by composition carries out vacuum induction melting and obtains Nd Fe B alloys, after thick, middle fragmentation, carry out the quick-fried processing of hydrogen, with airflow milling abrasive dust, obtain 3.7～4.0 μ m Nd Fe B alloys powder.Green compact compacting is of a size of D20 * 28.Green compact are put into sintering furnace sintering timeliness, and sintering process is: be warming up to 300 ℃ and be incubated 1h; Then be warming up to 900 ℃ and be incubated 1.5h; Be warming up to again 1060 ℃ and be incubated 5h, carry out subsequently Ageing Treatment.Sintering is complete, magnet blank product is processed into the semi-finished product (black-film) of D20 * 2, then carries out pickling plating.
To using hydrogen bearing alloy embodiment 1～5 and not using the magnet that hydrogen bearing alloy comparative example 1 sintering obtains to carry out respectively the check of following three aspects, whether effective to improving Sintered NdFeB magnet quality to contrast method provided by the present invention.
(1) respectively sintering is come out of the stove after and the magnet blank placed after 48h carry out appearance test.Interventions Requested are: after the color of the magnet blank after sintering is come out of the stove and placement 48h, whether magnet blank surface occurs efflorescence.
(2) adopt HAST experiment to carry out corrosion-resistant experiment to semi-finished product (black-film), the experiment condition of HAST experiment is: temperature: 130 ℃; Humidity: 95%; Pressure (atm): 2.6; Time: 96h.Choose at random 100 semi-finished product (black-film) and carry out corrosion-resistant experiment, experiment finishes the average weightless result of rear measurement.
(3) choose at random 10000 plating and complete product, statistics surface occurs that the plating of bubble, crackle completes the ratio of product.
The result of the check of above three aspects is as shown in table 1.
Table 1
The present invention is illustrated by embodiment above, and still, the present invention is not limited to particular example as described herein and embodiment.Any those of skill in the art are easy to be further improved without departing from the spirit and scope of the present invention and perfect, therefore the present invention is only subject to the restriction of content and the scope of the claims in the present invention, and its intention contains all alternative and equivalents that are included in the spirit and scope of the invention being limited by this claim.
Claims (9)
1. a method that reduces the pernicious gas in Sintered NdFeB magnet sintering process, is characterized in that, described method comprises the steps:
(1) hydrogen bearing alloy is broken into fritter hydrogen bearing alloy, after high-purity hydrogen activation, puts into a dehydrogenation unit, described dehydrogenation unit is airtight stainless box, and opens and closes to control with a mechanical driving device;
(2) described box is fixed on the inboard wall of furnace body of sintering furnace, and described mechanical driving device is connected with described box, to control the switch of box;
(3) at Nd Fe B alloys green sintering, be warming up to 800 ℃～1000 ℃ insulation venting during the stage, until vavuum pump, be evacuated to 10Pa when following, by described mechanical driving device, open described box, hydrogen bearing alloy is exposed in sintering atmosphere;
(4) treat that vacuum reaches 10
-2after pa, close described box.
2. method according to claim 1, is characterized in that, it is Sintered NdFeB magnet that described magnet consists of R-T-B, wherein:
R is Nd and be selected from least one element in Pr, Dy, Tb, Gd, Ho, and R content is 28～35wt.%;
T is Fe and be selected from least one element in Co, Ni, Cu, Al, Ga, Cr, Mn, Nb and In, and content is 63.8～71.1wt.%;
B content is 0.9～1.2wt.%; Each constituent content sum is 100wt.%.
3. method according to claim 1 and 2, magnet pulverizing process is used the quick-fried technique of hydrogen.
4. method according to claim 1 and 2, is characterized in that, described hydrogen bearing alloy is LaNi5 hydrogen bearing alloy or mishmetal class MmNi5 alloy, and wherein Mm is La and the mishmetal that is selected from least one element in Ce, Nd, Pr.
5. method according to claim 4, is characterized in that, described hydrogen bearing alloy also comprises at least one element in Co, Ca, Cu, Mn, Fe and Al.
6. method according to claim 1, is characterized in that, the size of described fritter hydrogen bearing alloy is 10 * 10 * 10mm
3.
7. method according to claim 4, is characterized in that, the volume of described hydrogen bearing alloy accounts for below 2/3 of volume of described box.
8. method according to claim 7, is characterized in that, the top of described box to the distance of sintering furnace molybdenum band surpasses 10cm.
9. method according to claim 1, is characterized in that, the purity of described high-purity hydrogen is more than 99.99%.
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|---|---|---|---|
| CN200910235433.4A CN102039407B (en) | 2009-10-14 | 2009-10-14 | Method for decreasing harmful gases in process of sintering sintered neodymium iron boron (NdFeB) magnet |
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|---|---|---|---|
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| CN102039407B true CN102039407B (en) | 2014-09-17 |
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| CN103572083B (en) * | 2012-07-18 | 2016-12-21 | 三环瓦克华（北京）磁性器件有限公司 | A kind of sintering method of neodymium iron boron magnetic body |
| CN104289710B (en) * | 2014-09-30 | 2016-08-31 | 许用华 | A kind of graphite sintering box with aerofluxus and sealing function |
| CN115383122B (en) * | 2022-08-25 | 2023-07-14 | 太原科技大学 | Hydrogen crushing preparation method of 2:17 sintered samarium cobalt permanent magnet |
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| CN1321990A (en) * | 2000-05-02 | 2001-11-14 | 住友特殊金属株式会社 | Method for mfg. rare earth sintered magnet |
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