CN117275922A - Preparation method for improving coercivity of bulk neodymium or cerium-based permanent magnet by using trace rare earth - Google Patents
Preparation method for improving coercivity of bulk neodymium or cerium-based permanent magnet by using trace rare earth Download PDFInfo
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- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 127
- 150000002910 rare earth metals Chemical class 0.000 title claims abstract description 123
- 238000002360 preparation method Methods 0.000 title claims abstract description 39
- 229910052779 Neodymium Inorganic materials 0.000 title claims abstract description 31
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 title claims abstract description 27
- 229910052684 Cerium Inorganic materials 0.000 title claims abstract description 17
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 title claims abstract description 17
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 334
- 239000001257 hydrogen Substances 0.000 claims abstract description 334
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 310
- 238000000227 grinding Methods 0.000 claims abstract description 42
- 238000000465 moulding Methods 0.000 claims abstract description 40
- 238000005245 sintering Methods 0.000 claims abstract description 31
- 238000005516 engineering process Methods 0.000 claims abstract description 26
- 238000002074 melt spinning Methods 0.000 claims abstract description 21
- 239000000126 substance Substances 0.000 claims abstract description 20
- 238000010521 absorption reaction Methods 0.000 claims description 137
- 238000006356 dehydrogenation reaction Methods 0.000 claims description 68
- 238000000034 method Methods 0.000 claims description 62
- 238000005336 cracking Methods 0.000 claims description 43
- 238000001816 cooling Methods 0.000 claims description 28
- 238000000605 extraction Methods 0.000 claims description 24
- 238000007599 discharging Methods 0.000 claims description 20
- 229920006395 saturated elastomer Polymers 0.000 claims description 20
- 238000010438 heat treatment Methods 0.000 claims description 14
- 238000009413 insulation Methods 0.000 claims description 8
- 229910052692 Dysprosium Inorganic materials 0.000 claims description 6
- 150000002431 hydrogen Chemical class 0.000 claims description 3
- 229910052721 tungsten Inorganic materials 0.000 claims description 3
- 229910052727 yttrium Inorganic materials 0.000 claims description 3
- 230000005389 magnetism Effects 0.000 abstract description 8
- 238000004519 manufacturing process Methods 0.000 abstract description 7
- 239000000463 material Substances 0.000 abstract description 4
- 230000000694 effects Effects 0.000 abstract description 3
- 230000000052 comparative effect Effects 0.000 description 34
- 230000008569 process Effects 0.000 description 32
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 21
- 238000005259 measurement Methods 0.000 description 16
- 239000000203 mixture Substances 0.000 description 14
- 238000004321 preservation Methods 0.000 description 12
- 238000005324 grain boundary diffusion Methods 0.000 description 11
- 125000004122 cyclic group Chemical group 0.000 description 5
- 238000002156 mixing Methods 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 4
- OHVLMTFVQDZYHP-UHFFFAOYSA-N 1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-2-[4-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]piperazin-1-yl]ethanone Chemical compound N1N=NC=2CN(CCC=21)C(CN1CCN(CC1)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)=O OHVLMTFVQDZYHP-UHFFFAOYSA-N 0.000 description 3
- HMUNWXXNJPVALC-UHFFFAOYSA-N 1-[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperazin-1-yl]-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethanone Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)N1CCN(CC1)C(CN1CC2=C(CC1)NN=N2)=O HMUNWXXNJPVALC-UHFFFAOYSA-N 0.000 description 3
- LDXJRKWFNNFDSA-UHFFFAOYSA-N 2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-1-[4-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]piperazin-1-yl]ethanone Chemical compound C1CN(CC2=NNN=C21)CC(=O)N3CCN(CC3)C4=CN=C(N=C4)NCC5=CC(=CC=C5)OC(F)(F)F LDXJRKWFNNFDSA-UHFFFAOYSA-N 0.000 description 3
- WZFUQSJFWNHZHM-UHFFFAOYSA-N 2-[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperazin-1-yl]-1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethanone Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)N1CCN(CC1)CC(=O)N1CC2=C(CC1)NN=N2 WZFUQSJFWNHZHM-UHFFFAOYSA-N 0.000 description 3
- JQMFQLVAJGZSQS-UHFFFAOYSA-N 2-[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperazin-1-yl]-N-(2-oxo-3H-1,3-benzoxazol-6-yl)acetamide Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)N1CCN(CC1)CC(=O)NC1=CC2=C(NC(O2)=O)C=C1 JQMFQLVAJGZSQS-UHFFFAOYSA-N 0.000 description 3
- CONKBQPVFMXDOV-QHCPKHFHSA-N 6-[(5S)-5-[[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperazin-1-yl]methyl]-2-oxo-1,3-oxazolidin-3-yl]-3H-1,3-benzoxazol-2-one Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)N1CCN(CC1)C[C@H]1CN(C(O1)=O)C1=CC2=C(NC(O2)=O)C=C1 CONKBQPVFMXDOV-QHCPKHFHSA-N 0.000 description 3
- 230000032683 aging Effects 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 238000010902 jet-milling Methods 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- VZSRBBMJRBPUNF-UHFFFAOYSA-N 2-(2,3-dihydro-1H-inden-2-ylamino)-N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]pyrimidine-5-carboxamide Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C(=O)NCCC(N1CC2=C(CC1)NN=N2)=O VZSRBBMJRBPUNF-UHFFFAOYSA-N 0.000 description 2
- YLZOPXRUQYQQID-UHFFFAOYSA-N 3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-1-[4-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]piperazin-1-yl]propan-1-one Chemical compound N1N=NC=2CN(CCC=21)CCC(=O)N1CCN(CC1)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F YLZOPXRUQYQQID-UHFFFAOYSA-N 0.000 description 2
- QJVKUMXDEUEQLH-UHFFFAOYSA-N [B].[Fe].[Nd] Chemical compound [B].[Fe].[Nd] QJVKUMXDEUEQLH-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 238000001652 electrophoretic deposition Methods 0.000 description 2
- 238000009713 electroplating Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 229910001172 neodymium magnet Inorganic materials 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 229910052702 rhenium Inorganic materials 0.000 description 2
- 238000007650 screen-printing Methods 0.000 description 2
- 238000002490 spark plasma sintering Methods 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 229910052771 Terbium Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000012010 growth Effects 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000005289 physical deposition Methods 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000007916 tablet composition Substances 0.000 description 1
- GZCRRIHWUXGPOV-UHFFFAOYSA-N terbium atom Chemical compound [Tb] GZCRRIHWUXGPOV-UHFFFAOYSA-N 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Classifications
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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
-
- 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
-
- 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
- H01F41/0293—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 diffusion of rare earth elements, e.g. Tb, Dy or Ho, into permanent magnets
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Hard Magnetic Materials (AREA)
Abstract
The invention discloses a preparation method for improving the coercivity of a bulk neodymium or cerium-based permanent magnet by using trace rare earth, belongs to the field of permanent magnet materials, and solves the technical problems of improving the coercivity of the bulk permanent magnet, reducing production cost and realizing industrialized mass production. The preparation method for improving the coercivity of the bulk neodymium or cerium-based permanent magnet by using trace rare earth comprises the following steps: s1, preparing a rapid hardening sheet by adopting a rapid hardening melt-spinning technology; s2, processing the rare earth simple substance into a rare earth metal sheet with the thickness of 2-7 mm; s3, adding the rapid hardening sheet and the rare earth metal sheet into a hydrogen breaking furnace together for hydrogen breaking; s4, carrying out air flow grinding after hydrogen breaking; s5, carrying out air flow grinding and molding; and S6, sintering after molding to obtain the large permanent magnet. The preparation method of the invention achieves the technical effects of greatly improving the coercive force and hardly reducing the residual magnetism of the magnet under the condition of adding less than 1 percent of rare earth.
Description
Technical Field
The invention belongs to the technical field of permanent magnet materials, and particularly relates to a preparation method for improving coercivity of a bulk neodymium or cerium-based permanent magnet by using trace rare earth.
Background
In recent years, the level of application of magnetic materials has increased significantly. Currently, neodymium-iron-boron magnets are widely applied to the fields of aviation, aerospace, electronics, automobiles, sensors, petrochemical industry, magnetic transmission and the like. With the increase of application range, the requirements on the performance of the magnet are higher and higher remanence and coercive force are required.
At present, a method for improving the coercive force of neodymium iron boron is mainly a grain boundary diffusion process, which comprises the following steps: 1) Heavy rare earth (dysprosium, terbium and the like) is added in the process of magnet alloy smelting or air-flow grinding, and the method is not limited in volume for preparing the magnet, but the added heavy rare earth can reduce the residual magnetism of the magnet on one hand and limit the improvement of the coercive force of the magnet on the other hand. 2-15 wt.% of heavy rare earth is generally required to be added, and the cost of the product is greatly increased along with the consumption of resources and the reduction of the reserve of the heavy rare earth resources, and the heavy rare earth such as Dy, tb and the like is expensive; 2) The sintered magnet, the bonded magnet, the hot-pressed thermal deformation magnet and the like are subjected to grain boundary diffusion treatment such as Dy, tb and the like by utilizing heavy rare earth, such as a vapor deposition method, a coating method, an electrophoretic deposition method, an electroplating method, a screen printing method and the like, and the coercive force of the magnet can be greatly improved under the condition that the residual magnetism of the magnet is hardly reduced, but the method is only suitable for the magnet with the thickness of millimeter level, and the magnetic performance requirement is hardly met by utilizing the method for the magnet with large mass, so that the method is limited in scale application and is not beneficial to industrial production, and the heavy rare earth with the weight of 2-5 wt.% is required to be added, and the problem of product cost improvement is also caused.
The Chinese patent No. 111063536A discloses a grain boundary diffusion method suitable for a bulk rare earth permanent magnet material, which is characterized in that the method carries out grain boundary diffusion treatment on a magnet by a spark plasma sintering technology, improves the comprehensive performance of the magnet and enables the grain boundary diffusion technology to be suitable for the bulk magnet without being influenced by the thickness of the magnet. However, the existing spark plasma sintering technology cannot prepare neodymium/cerium-based permanent magnets in batches, the preparation cost is high, the material utilization rate is low, and the proportion of heavy rare earth to be added is not disclosed. Therefore, how to greatly improve the coercive force of the bulk permanent magnet and realize mass preparation industrial production under the condition of hardly reducing residual magnetism by adding trace rare earth becomes a technical problem to be solved.
Disclosure of Invention
In view of the above analysis, the present invention aims to provide a preparation method for improving the coercivity of a bulk neodymium or cerium-based permanent magnet by using trace rare earth, so as to solve the technical problems of how to reduce the production cost and/or realize industrialized mass production while greatly improving the coercivity of the bulk permanent magnet under the condition of hardly reducing the remanence of the magnet.
The aim of the invention is mainly realized by the following technical scheme:
the invention provides a preparation method for improving coercive force of a bulk neodymium or cerium-based permanent magnet by utilizing trace rare earth, which comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology;
s2, processing the rare earth simple substance into a rare earth metal sheet with the thickness of 2-7 mm;
s3, adding the rapid hardening sheet in the step S1 and the rare earth metal sheet in the step S2 into a hydrogen breaking furnace together for hydrogen breaking;
s4, carrying out air flow grinding after hydrogen breaking;
s5, carrying out air flow grinding and molding;
and S6, sintering after molding to obtain the large permanent magnet.
Further, in step S1, the mass percentages of the components of the rapid hardening tablet are: re: 0-15%; pr (Pr) a Nd b :28 to 32.5 percent, wherein a: 0-25%, b: 75-100%, a+b=100%; b:0.85 to 1.1 percent; co:0 to 0.4 percent; cu:0 to 0.3 percent; nb:0 to 1 percent; zr:0 to 0.3 percent; al:0 to 2 percent; ga:0 to 1 percent; m:0 to 1 percent; the balance being Fe; re is one or more of Dy, tb, ho, gd, la, ce and Y, cerium based if Re contains Ce, neodymium based if Re does not contain Ce, and M is one or more of Si, cr, mo, ti and W.
Further, in step S2, the rare earth element includes Nd, pr, tb, dy, ho, gd, er.
Further, step S3 includes the following sub-steps:
s3.1, adding the rapid hardening sheet and the rare earth metal sheet into a hydrogen breaking furnace according to the proportion of the rare earth metal sheet accounting for 0.2-1% of the total weight;
step S3.2, detecting leakage of the hydrogen cracking furnace;
step S3.3, heating the hydrogen cracking furnace to 120-200 ℃, and preserving heat for 0.5-2 h;
s3.4, carrying out hydrogen absorption-hydrogen extraction circulation for 2-5 times;
s3.5, absorbing hydrogen, and raising the furnace temperature after the hydrogen absorption is saturated;
s3.6, when the furnace temperature is raised to 550-600 ℃, starting thermal insulation dehydrogenation;
and S3.7, after dehydrogenation, cooling the hydrogen breaking furnace to below 40 ℃ and discharging.
Further, in the step 3.4, the hydrogen absorption pressure is 0.15-0.3 MPa, and the single hydrogen absorption time is 0.2-1 h.
Further, in the step 3.5, the hydrogen absorption pressure is 0.15-0.3 MPa, the hydrogen absorption time is different according to different charging amounts, and when the charging amount is less than or equal to 300kg, the hydrogen absorption time is more than or equal to 2 hours; the furnace charge is more than 300kg and less than or equal to 600kg, and the hydrogen absorption time is more than or equal to 3h; the furnace charge is more than 600kg and less than or equal to 1250kg, and the hydrogen absorption time is more than or equal to 4h.
Further, in step 3.5, the hydrogen absorption saturation is such that the hydrogen pressure falls within a range of 0.001MPa within 10 minutes.
Further, in the step 3.6, the dehydrogenation time is different according to different charging amounts, the charging amount is less than or equal to 300kg, and the dehydrogenation time is 4-6 hours; 300kg < charging amount less than or equal to 600kg, and dehydrogenation time is 6-8 h;600kg < charging amount less than or equal to 800kg, and dehydrogenation time is 8-10 h;800kg < charging amount less than or equal to 1000kg, and dehydrogenation time is 10-12 h; the furnace charge is less than 1000kg and less than or equal to 1250kg, and the dehydrogenation time is 12-14 h.
Further, in the step 3.7, the cooling time of the hydrogen breaking furnace is different according to the different charging amounts, the charging amount is less than or equal to 800kg, and the cooling time is more than or equal to 4 hours; the furnace charge is more than 800kg and less than or equal to 1250kg, and the cooling time is more than or equal to 6h.
Further, in step S6, the thickness of the bulk permanent magnet is 10mm or more.
Compared with the prior art, the invention has the beneficial effects that at least:
(1) The invention reduces the particle size of powder to below 10 mu m by adding rare earth simple substance metal sheet while breaking hydrogen in rapid hardening sheet, and heating and heat preserving and repeated hydrogen absorption/extraction cycle processes before hydrogen absorption, thus providing favorable conditions for the first relatively strong grain boundary diffusion reaction.
(2) The invention achieves the technical effects of improving the coercive force and hardly reducing the residual magnetism under the condition of adding less than 1 percent of rare earth, and improves the residual magnetism by more than 0.1 and kGs and the coercive force by more than 5kOe compared with the permanent magnet prepared by the conventional process without rare earth treatment.
(3) On the premise of adding the same proportion of rare earth, the rare earth addition mode of hydrogen breaking of the rapid hardening tablet and the rare earth metal tablet is better than the addition of ingredients for preparing the rapid hardening tablet or the addition effect of an air flow mill after hydrogen breaking, the remanence is relatively improved by 0.1-0.4 kGs, the coercive force is relatively improved by 1-3 kOe, the usage amount of the rare earth is relatively reduced, and the production cost is reduced.
(4) The preparation method can improve the coercive force of the bulk permanent magnet with the thickness of more than 10mm, and solves the technical problems that the existing grain boundary diffusion treatment method, such as a physical deposition method, a coating method and the like, is only suitable for sintered magnets with the thickness of a few millimeters, and cannot improve the coercive force of the bulk permanent magnet.
(5) The existing method for improving the coercivity of the magnet is to additionally arrange equipment and a process for improving the coercivity of the magnet outside the conventional process flow for preparing the permanent magnet, and the additionally arranged equipment and process are small-sized, experimental and high-energy-consumption equipment and process which are not beneficial to industrialization, and the preparation method for improving the coercivity of the magnet only uses the conventional and mature equipment and process for preparing the permanent magnet, so that the method is beneficial to low-cost industrialized mass production.
Drawings
FIG. 1 is a flow chart of the preparation process of the invention;
FIG. 2 is a flow chart of the hydrogen destruction process of the present invention;
FIG. 3 is a graph of the sintering process of the present invention.
Detailed Description
The following describes in further detail the preparation of a method for increasing the coercivity of a bulk neodymium or cerium based permanent magnet using trace amounts of rare earths in conjunction with specific examples, which are for illustrative purposes only, and the present invention is not limited to these examples. The content of the components in the invention is mass percent.
The invention provides a preparation method for improving coercive force of a bulk neodymium or cerium-based permanent magnet by utilizing trace rare earth, which comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology;
s2, processing the rare earth simple substance into a rare earth metal sheet with the thickness of 2-7 mm;
s3, adding the rapid hardening sheet in the step S1 and the rare earth metal sheet in the step S2 into a hydrogen breaking furnace together for hydrogen breaking;
s4, carrying out air flow grinding after hydrogen breaking;
s5, carrying out air flow grinding and molding;
and S6, sintering after molding to obtain the large permanent magnet.
FIG. 1 is a flow chart of the preparation process of the invention.
Specifically, in step S1, the rapid hardening and melt-spinning technology is a conventional technology in the technical field of permanent magnets, and the rapid hardening tablet comprises the following components in percentage by mass: re: 0-15%; pr (Pr) a Nd b :28 to 32.5 percent, wherein a: 0-25%, b: 75-100%, a+b=100%; b:0.85 to 1.1 percent; co:0 to 0.4 percent; cu:0 to 0.3 percent; nb:0 to 1 percent; zr:0 to 0.3 percent; al:0 to 2 percent; ga:0 to 1 percent; m:0 to 1 percent; the balance being Fe; re is one or more of Dy, tb, ho, gd, la, ce and Y, cerium based if Re contains Ce, neodymium based if Re does not contain Ce, and M is one or more of Si, cr, mo, ti and W.
Specifically, in step S2, the rare earth element includes Nd, pr, tb, dy, ho, gd, er and the like.
Specifically, in step S3, the hydrogen breaking process includes the following sub-steps:
s3.1, adding the rapid hardening sheet and the rare earth metal sheet into a hydrogen breaking furnace according to the proportion of the rare earth metal sheet accounting for 0.2-1% of the total weight;
step S3.2, detecting leakage of the hydrogen cracking furnace;
step S3.3, heating the hydrogen cracking furnace to 120-200 ℃, and preserving heat for 0.5-2 h;
s3.4, carrying out hydrogen absorption-hydrogen extraction circulation for 2-5 times;
s3.5, absorbing hydrogen, and raising the furnace temperature after the hydrogen absorption is saturated;
s3.6, when the furnace temperature is raised to 550-600 ℃, starting thermal insulation dehydrogenation;
and S3.7, after dehydrogenation, cooling the hydrogen breaking furnace to below 40 ℃ and discharging.
FIG. 2 is a flow chart of the hydrogen destruction process of the present invention.
In step 3.1, the total weight of the rapid hardening sheet and the rare earth metal sheet added to the hydrogen breaking furnace is referred to as the charging amount.
Specifically, in step S3.4, the hydrogen absorption pressure is 0.15 to 0.3MPa, the single hydrogen absorption time is 0.2 to 1h, the hydrogen absorption-hydrogen extraction cycle is the first time of the cycle after the first time of hydrogen absorption, and then the second time of hydrogen absorption and then the second time of hydrogen extraction, and this is the second time of the cycle, such as 2 to 5 times of repeated operation cycles.
Specifically, in the step S3.5, the hydrogen absorption pressure is 0.15-0.3 MPa, the hydrogen absorption time is different according to different charging amounts, and when the charging amount is less than or equal to 300kg, the hydrogen absorption time is more than or equal to 2 hours; the furnace charge is more than 300kg and less than or equal to 600kg, and the hydrogen absorption time is more than or equal to 3h;600kg < charging amount less than or equal to 1250kg, hydrogen absorption time more than or equal to 4h, and under the condition of meeting the hydrogen absorption time, when the hydrogen pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature starts to rise.
Specifically, in the step S3.6, the dehydrogenation time is different according to the different charging amounts, the charging amount is less than or equal to 300kg, and the dehydrogenation time is 4-6 hours; 300kg < charging amount less than or equal to 600kg, and dehydrogenation time is 6-8 h;600kg < charging amount less than or equal to 800kg, and dehydrogenation time is 8-10 h;800kg < charging amount less than or equal to 1000kg, and dehydrogenation time is 10-12 h; the furnace charge is less than 1000kg and less than or equal to 1250kg, and the dehydrogenation time is 12-14 h.
Specifically, in the step S3.7, the cooling time of the hydrogen breaking furnace is different according to the different charging amounts, the charging amount is less than or equal to 800kg, and the cooling time is more than or equal to 4 hours; the furnace charge is more than 800kg and less than or equal to 1250kg, and the cooling time is more than or equal to 6h.
The first grain boundary diffusion is completed during the hydrogen breaking process. Hydrogen absorptionHeating and preserving heat before the process, so that the rare earth simple substance and the rapid hardening sheet are easier to absorb hydrogen at a certain temperature and pressure and then expand in volume, the rare earth and the rapid hardening sheet are broken into particles with the size of about 125 mu m, and the particle size of the powder can be further reduced to below 10 mu m after repeated hydrogen absorption/hydrogen extraction circulation treatment; during dehydrogenation, reH is added x 、Nd 2 Fe 14 BH y Reduction to Re, nd 2 Fe 14 B，Re、Nd 2 Fe 14 B is a solid phase transformation process and nucleation and growth process, thus completing the first relatively strong grain boundary diffusion reaction.
Specifically, in step S6, the molded magnet to be sintered is placed in a sintering furnace, and the vacuum is applied for 1-2 hours to make the vacuum degree of the sintering furnace be 1X 10 -1 Heating is started when Pa is lower, heating is started at 5 ℃/min, and the temperature is raised to 300-400 ℃ and is kept for 1.5 hours, so that organic matters in the permanent magnet are better released; continuously heating at 5 ℃/min, and preserving heat for 2 hours at 600-700 ℃ to release hydrogen in the magnet; continuously heating to 800-1000 ℃ and preserving heat for 1h, so that on one hand, the hydrogen in the magnet is further released, and on the other hand, the temperature in the furnace can be homogenized, and the phenomenon of local high temperature is avoided; continuously heating to a high temperature stage 1020-1090 ℃ and preserving heat for 5 hours to finish a sintering state; when the temperature is reduced to 880-930 ℃, preserving heat for 2 hours to finish primary aging treatment; when the temperature is reduced to below 70 ℃, the temperature is raised to the secondary aging treatment temperature of 460-530 ℃ at 5 ℃/min, and the secondary aging treatment is completed after heat preservation for 5 hours; discharging when the furnace temperature is reduced to below 70 ℃. In the sintering process, rare earth is added at about 600 ℃ to form a rare earth-rich phase around the main phase of the magnet, so that a uniform rare earth epitaxial layer is formed, and the second crystal boundary diffusion is completed. FIG. 3 is a graph of the sintering process of the present invention.
The molded body in step S5 is sintered in step S6 to cause shrinkage, and is an anisotropic magnet having a different shrinkage ratio in different directions, generally having a shrinkage ratio of 1.18 to 1.38, so that a larger molded body is produced by calculation according to the shrinkage ratio in different directions depending on the size of the permanent magnet to be produced, and such molded body can satisfy the final permanent magnet size requirement after sintering shrinkage. The thickness of the large permanent magnet is more than 10mm, and the permanent magnet can not improve the coercive force to the permanent magnet meeting the magnetic requirement through a grain boundary diffusion treatment method after sintering, wherein the grain boundary diffusion treatment method after sintering comprises a vapor deposition method, a coating method, an electrophoretic deposition method, an electroplating method, a screen printing method, a discharge plasma sintering technology and the like.
Finally, magnetic performance indexes of the sintered permanent magnet are detected, including remanence Br (kGs), intrinsic coercivity Hcj (kOe) and the like.
Comparative example
The permanent magnet is prepared by adopting a conventional rapid hardening sheet-hydrogen breaking-air flow grinding-forming-sintering process, no rare earth is added for treatment in the preparation process, no temperature is raised before hydrogen absorption in the hydrogen breaking process, and no cycle of hydrogen absorption and hydrogen extraction is realized. Specifically, the preparation method of the large neodymium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:29%; b:0.9%; co:0.3%; cu:0.2%; zr:0.05%; ga:0.1%; the balance being Fe;
step S2, adding 280kg of the rapid hardening sheet in the step S1 into a hydrogen breaking furnace for hydrogen breaking;
step S2.1, detecting leakage of the hydrogen cracking furnace;
s2.2, the hydrogen absorption pressure is 0.15MPa, after the hydrogen absorption is carried out for 2 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature is started;
s2.3, when the furnace temperature is raised to 580 ℃, the heat preservation and dehydrogenation are started, and the dehydrogenation time is 5 hours;
and S2.4, after dehydrogenation, cooling the hydrogen cracking furnace for 4 hours, and discharging at 35 ℃.
S3, carrying out air flow grinding after hydrogen breaking;
s4, carrying out air flow grinding and molding;
and S5, sintering after molding to obtain the cuboid large-block permanent magnet with the size of 30 multiplied by 25 multiplied by 15 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Example 1
The rapid hardening tablet composition, weight and comparative example in example 1 were exactly the same. Specifically, the preparation method of the large neodymium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:29%; b:0.9%; co:0.3%; cu:0.2%; zr:0.05%; ga:0.1%; the balance being Fe;
s2, processing a rare earth simple substance Tb into a rare earth metal sheet with the thickness of 3 mm;
s3, adding the rapid hardening sheet in the step S1 and the rare earth metal sheet in the step S2 into a hydrogen breaking furnace together for hydrogen breaking;
s3.1, adding the rapid hardening sheet and the rare earth metal sheet into a hydrogen breaking furnace according to the proportion of the rare earth metal sheet accounting for 0.3 percent of the total weight, wherein the total weight is 280kg;
step S3.2, detecting leakage of the hydrogen cracking furnace;
s3.3, heating the hydrogen cracking furnace to 150 ℃, and preserving heat for 1h;
s3.4, carrying out hydrogen absorption-hydrogen extraction circulation for 3 times, wherein the hydrogen absorption pressure is 0.15MPa, and the single hydrogen absorption time is 1h;
s3.5, the hydrogen absorption pressure is 0.15MPa, after the hydrogen absorption is carried out for 2 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature is started;
s3.6, when the furnace temperature is raised to 580 ℃, the heat preservation and dehydrogenation are started, and the dehydrogenation time is 5 hours;
and S3.7, after dehydrogenation, cooling the hydrogen cracking furnace for 4 hours, and discharging at 35 ℃.
S4, carrying out air flow grinding after hydrogen breaking;
s5, carrying out air flow grinding and molding;
and S6, sintering after molding to obtain the cuboid large-block permanent magnet with the size of 30mm multiplied by 25mm multiplied by 15 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Comparative examples 1 to 1
The basic components and weight of the rapid hardening tablets in comparative example 1-1 are exactly the same as those in example 1, except that 0.3% of Tb is added in the preparation of the rapid hardening tablets in comparative example 1-1, and then the temperature is not raised before hydrogen absorption in the hydrogen breaking process, and no cycle of hydrogen absorption-hydrogen extraction is performed.
Specifically, the preparation method of the large neodymium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:29%; b:0.9%; co:0.3%; cu:0.2%; zr:0.05%; ga:0.1%; tb:0.3%; the balance being Fe;
step S2, adding 280kg of the rapid hardening sheet in the step S1 into a hydrogen breaking furnace for hydrogen breaking;
step S2.1, detecting leakage of the hydrogen cracking furnace;
s2.2, the hydrogen absorption pressure is 0.15MPa, after the hydrogen absorption is carried out for 2 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature is started;
s2.3, when the furnace temperature is raised to 580 ℃, the heat preservation and dehydrogenation are started, and the dehydrogenation time is 5 hours;
and S2.4, after dehydrogenation, cooling the hydrogen cracking furnace for 4 hours, and discharging at 35 ℃.
S3, carrying out air flow grinding after hydrogen breaking;
s4, carrying out air flow grinding and molding;
and S5, sintering after molding to obtain the cuboid large-block permanent magnet with the size of 30mm multiplied by 25mm multiplied by 15 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Comparative examples 1 to 2
The rapid hardening sheet composition, the rare earth metal sheet thickness of the rare earth simple substance Tb, and the mixture ratio and total weight of the rapid hardening sheet composition and the rare earth metal sheet in comparative examples 1-2 are identical to those in example 1, except that the rapid hardening sheet and the rare earth metal sheet in comparative examples 1-2 are hydrogen-broken independently, no temperature rise occurs before hydrogen absorption in the hydrogen breaking process, no cyclic hydrogen absorption-hydrogen extraction are performed, and then the two are mixed in proportion before air flow grinding.
Specifically, the preparation method of the large neodymium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:29%; b:0.9%; co:0.3%; cu:0.2%; zr:0.05%; ga:0.1%; the balance being Fe;
s2, processing a rare earth simple substance Tb into a rare earth metal sheet with the thickness of 3 mm;
step S3, respectively adding the rapid hardening sheet in the step S1 and the rare earth metal sheet in the step S2 into a hydrogen breaking furnace to break hydrogen twice;
step S3.1, detecting leakage of the hydrogen cracking furnace;
s3.2, the hydrogen absorption pressure is 0.15MPa, after the hydrogen absorption is carried out for 2 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature is started;
s3.3, when the furnace temperature is raised to 580 ℃, the heat preservation and dehydrogenation are started, and the dehydrogenation time is 5 hours;
and S3.4, after dehydrogenation, cooling the hydrogen cracking furnace for 4 hours, and discharging at 35 ℃.
S4, rapidly hardening the hydrogen-broken rare earth TbH and the hydrogen-broken rare earth TbH x According to 99.7: mixing 280kg of the mixture with 0.3 to carry out air current grinding;
s5, carrying out air flow grinding and molding;
and S6, sintering after molding to obtain the cuboid large-block permanent magnet with the size of 30mm multiplied by 25mm multiplied by 15 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Example 2
The preparation method of the large neodymium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:29.5%; b:0.93%; co:0.5%; cu:0.2%; zr:0.1%; ga:0.2%; the balance being Fe;
s2, processing a rare earth simple substance Tb into a rare earth metal sheet with the thickness of 3 mm;
s3, adding the rapid hardening sheet in the step S1 and the rare earth metal sheet in the step S2 into a hydrogen breaking furnace together for hydrogen breaking;
s3.1, adding the rapid hardening sheet and the rare earth metal sheet into a hydrogen breaking furnace according to the proportion of the rare earth metal sheet accounting for 0.9 percent of the total weight, wherein the total weight is 600kg;
step S3.2, detecting leakage of the hydrogen cracking furnace;
step S3.3, heating the hydrogen cracking furnace to 200 ℃, and preserving heat for 1.5 hours;
s3.4, carrying out hydrogen absorption-hydrogen extraction circulation for 2 times, wherein the hydrogen absorption pressure is 0.3MPa, and the single hydrogen absorption time is 0.2h;
s3.5, the hydrogen absorption pressure is 0.3MPa, after the hydrogen absorption is carried out for 3 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature is started;
s3.6, when the furnace temperature is raised to 590 ℃, the heat preservation and dehydrogenation are started, and the dehydrogenation time is 8 hours;
and S3.7, after dehydrogenation, cooling the hydrogen cracking furnace for 5 hours, and discharging at the temperature of 30 ℃.
S4, carrying out air flow grinding after hydrogen breaking;
s5, carrying out air flow grinding and molding;
and S6, sintering after molding to obtain the cuboid large-block permanent magnet with the size of 35mm multiplied by 27mm multiplied by 23 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Comparative example 2-1
The basic components and weight of the rapid hardening tablets in comparative example 2-1 are exactly the same as those in example 2, except that 0.9% of Tb is added in the preparation of the rapid hardening tablets in comparative example 2-1, and then the temperature is not raised before hydrogen absorption in the hydrogen breaking process, and no cycle of hydrogen absorption-hydrogen extraction is performed.
Specifically, the preparation method of the large neodymium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:29.5%; b:0.93%; co:0.5%; cu:0.2%; zr:0.1%; ga:0.2%; tb:0.9%; the balance being Fe;
step S2, adding 600kg of the rapid hardening tablets in the step S1 into a hydrogen breaking furnace for hydrogen breaking;
step S2.1, detecting leakage of the hydrogen cracking furnace;
s2.2, the hydrogen absorption pressure is 0.3MPa, after hydrogen absorption for 3 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature starts to rise;
s2.3, when the furnace temperature is raised to 590 ℃, the heat preservation and dehydrogenation are started, and the dehydrogenation time is 8 hours;
and S2.4, after dehydrogenation, cooling the hydrogen cracking furnace for 5 hours, and discharging at the temperature of 30 ℃.
S3, carrying out air flow grinding after hydrogen breaking;
s4, carrying out air flow grinding and molding;
and S5, sintering after molding to obtain the cuboid large-block permanent magnet with the size of 35mm multiplied by 27mm multiplied by 23 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Comparative examples 2 to 2
The rapid hardening sheet component, the rare earth metal sheet thickness of the rare earth simple substance Tb, and the mixture ratio and total weight of the rapid hardening sheet component and the rare earth metal sheet in the comparative example 2-2 are identical to those in the example 2, except that the rapid hardening sheet and the rare earth metal sheet in the comparative example 2-2 are subjected to hydrogen breaking respectively and independently, no temperature rise occurs before hydrogen absorption in the hydrogen breaking process, no cyclic hydrogen absorption-hydrogen extraction are performed, and then the rapid hardening sheet and the rare earth metal sheet are mixed in proportion before air flow grinding.
Specifically, the preparation method of the large neodymium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:29.5%; b:0.93%; co:0.5%; cu:0.2%; zr:0.1%; ga:0.2%; the balance being Fe;
s2, processing a rare earth simple substance Tb into a rare earth metal sheet with the thickness of 3 mm;
step S3, respectively adding the rapid hardening sheet in the step S1 and the rare earth metal sheet in the step S2 into a hydrogen breaking furnace to break hydrogen twice;
step S3.1, detecting leakage of the hydrogen cracking furnace;
s3.2, the hydrogen absorption pressure is 0.3MPa, after the hydrogen absorption is carried out for 3 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature is started;
s3.3, when the furnace temperature is raised to 590 ℃, the heat preservation and dehydrogenation are started, and the dehydrogenation time is 8 hours;
and S3.4, after dehydrogenation, cooling the hydrogen cracking furnace for 5 hours, and discharging at the temperature of 30 ℃.
S4, rapidly hardening the hydrogen-broken rare earth TbH and the hydrogen-broken rare earth TbH x According to 99.1: mixing 600kg with 0.9 for jet milling;
s5, carrying out air flow grinding and molding;
and S6, sintering after molding to obtain the cuboid large-block permanent magnet with the size of 35mm multiplied by 27mm multiplied by 23 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Example 3
The preparation method of the large neodymium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:29.5%; b:0.93%; co:0.3%; cu:0.2%; zr:0.1%; ga:0.2%; the balance being Fe;
s2, processing rare earth simple substance Dy into a rare earth metal sheet with the thickness of 7 mm;
s3, adding the rapid hardening sheet in the step S1 and the rare earth metal sheet in the step S2 into a hydrogen breaking furnace together for hydrogen breaking;
s3.1, adding the rapid hardening sheet and the rare earth metal sheet into a hydrogen breaking furnace according to the proportion of the rare earth metal sheet accounting for 0.3 percent of the total weight, wherein the total weight is 300kg;
step S3.2, detecting leakage of the hydrogen cracking furnace;
s3.3, heating the hydrogen cracking furnace to 120 ℃, and preserving heat for 2 hours;
s3.4, carrying out 4 times of hydrogen absorption-hydrogen extraction circulation, wherein the hydrogen absorption pressure is 0.2MPa, and the single hydrogen absorption time is 0.5h;
s3.5, the hydrogen absorption pressure is 0.2MPa, after the hydrogen absorption is carried out for 2 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature is started;
s3.6, when the furnace temperature is raised to 550 ℃, starting thermal insulation dehydrogenation for 6 hours;
and S3.7, after dehydrogenation, cooling the hydrogen cracking furnace for 5 hours, and discharging at the temperature of 30 ℃.
S4, carrying out air flow grinding after hydrogen breaking;
s5, carrying out air flow grinding and molding;
and S6, sintering after molding to obtain the cuboid large-block permanent magnet with the dimensions of 30mm multiplied by 27mm multiplied by 25 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Comparative example 3-1
The basic components and weights of the rapid hardening tablets in comparative example 3-1 are exactly the same as those in example 3, except that 0.3% of Dy is added in the preparation of the rapid hardening tablets in comparative example 3-1, and then, no temperature is raised before hydrogen absorption during hydrogen breaking, and no cycle of hydrogen absorption-hydrogen extraction is performed.
Specifically, the preparation method of the large neodymium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:29.5%; b:0.93%; co:0.3%; cu:0.2%; zr:0.1%; ga:0.2%; dy:0.3%; the balance being Fe;
step S2, adding 300kg of the rapid hardening sheet in the step S1 into a hydrogen breaking furnace for hydrogen breaking;
step S2.1, detecting leakage of the hydrogen cracking furnace;
s2.2, the hydrogen absorption pressure is 0.2MPa, after the hydrogen absorption is carried out for 2 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature is started;
s2.3, when the furnace temperature is raised to 550 ℃, starting thermal insulation dehydrogenation for 6 hours;
and S2.4, after dehydrogenation, cooling the hydrogen cracking furnace for 5 hours, and discharging at the temperature of 30 ℃.
S3, carrying out air flow grinding after hydrogen breaking;
s4, carrying out air flow grinding and molding;
and S5, sintering after molding to obtain the cuboid large-block permanent magnet with the dimensions of 30mm multiplied by 27mm multiplied by 25 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Comparative example 3-2
The rapid hardening sheet composition, the rare earth metal sheet thickness of rare earth simple substance Dy, and the mixture ratio and total weight of the rapid hardening sheet composition and rare earth metal sheet in comparative example 3-2 are identical to those of example 3, except that the rapid hardening sheet and the rare earth metal sheet of comparative example 3-2 are hydrogen-broken independently, and neither temperature is raised before hydrogen absorption nor cycle hydrogen absorption-hydrogen extraction in the hydrogen breaking process, and then the two are mixed in proportion before air flow grinding.
Specifically, the preparation method of the large neodymium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:29.5%; b:0.93%; co:0.3%; cu:0.2%; zr:0.1%; ga:0.2%; the balance being Fe;
s2, processing rare earth simple substance Dy into a rare earth metal sheet with the thickness of 7 mm;
step S3, respectively adding the rapid hardening sheet in the step S1 and the rare earth metal sheet in the step S2 into a hydrogen breaking furnace to break hydrogen twice;
step S3.1, detecting leakage of the hydrogen cracking furnace;
s3.2, the hydrogen absorption pressure is 0.2MPa, after the hydrogen absorption is carried out for 2 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature is started;
s3.3, when the furnace temperature is raised to 550 ℃, the heat preservation and dehydrogenation are started, and the dehydrogenation time is 6 hours;
and S3.4, after dehydrogenation, cooling the hydrogen cracking furnace for 5 hours, and discharging at the temperature of 30 ℃.
S4, rapidly hardening tablets after hydrogen breakage and rare earth DyH after hydrogen breakage x According to 99.7:0.3 mixing 300kg and carrying out jet milling;
s5, carrying out air flow grinding and molding;
and S6, sintering after molding to obtain the cuboid large-block permanent magnet with the dimensions of 30mm multiplied by 27mm multiplied by 25 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Example 4
The preparation method of the large neodymium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:29%; b:0.95%; co:0.3%; cu:0.2%; zr:0.1%; ga:0.2%; the balance being Fe;
s2, processing the rare earth simple substance Nd into a rare earth metal sheet with the thickness of 2 mm;
s3, adding the rapid hardening sheet in the step S1 and the rare earth metal sheet in the step S2 into a hydrogen breaking furnace together for hydrogen breaking;
s3.1, adding the rapid hardening sheet and the rare earth metal sheet into a hydrogen breaking furnace according to the proportion of the rare earth metal sheet accounting for 0.5 percent of the total weight, wherein the total weight is 600kg;
step S3.2, detecting leakage of the hydrogen cracking furnace;
step S3.3, heating the hydrogen cracking furnace to 160 ℃, and preserving heat for 0.5h;
s3.4, carrying out 5 times of hydrogen absorption-hydrogen extraction circulation, wherein the hydrogen absorption pressure is 0.25MPa, and the single hydrogen absorption time is 0.8h;
s3.5, the hydrogen absorption pressure is 0.25MPa, after the hydrogen absorption is carried out for 3 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature is started;
s3.6, when the furnace temperature is increased to 570 ℃, starting thermal insulation dehydrogenation for 7h;
and S3.7, after dehydrogenation, cooling the hydrogen cracking furnace for 6 hours, and discharging at 25 ℃.
S4, carrying out air flow grinding after hydrogen breaking;
s5, carrying out air flow grinding and molding;
and S6, sintering after molding to obtain the cuboid large-block permanent magnet with the dimensions of 63mm multiplied by 54mm multiplied by 38 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Comparative example 4-1
The basic components and weight of the rapid hardening tablets in comparative example 4-1 were exactly the same as in example 4, except that 0.5% of Nd was added to the rapid hardening tablets in comparative example 4-1, and then, no temperature was raised before hydrogen absorption during hydrogen breaking, and no cycle of hydrogen absorption-hydrogen extraction was performed.
Specifically, the preparation method of the large neodymium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:29%; b:0.95%; co:0.3%; cu:0.2%; zr:0.1%; ga:0.2%; nd:0.5%; the balance being Fe;
step S2, adding 600kg of the rapid hardening tablets in the step S1 into a hydrogen breaking furnace for hydrogen breaking;
step S2.1, detecting leakage of the hydrogen cracking furnace;
s2.2, the hydrogen absorption pressure is 0.25MPa, after hydrogen absorption for 3 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature starts to rise;
s2.3, when the furnace temperature is increased to 570 ℃, starting thermal insulation dehydrogenation for 7h;
and S2.4, after dehydrogenation, cooling the hydrogen cracking furnace for 6 hours, and discharging at 25 ℃.
S3, carrying out air flow grinding after hydrogen breaking;
s4, carrying out air flow grinding and molding;
and S5, sintering after molding to obtain the cuboid large-block permanent magnet with the dimensions of 63mm multiplied by 54mm multiplied by 38 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Comparative example 4-2
The rapid hardening sheet composition, the rare earth metal sheet thickness of the rare earth simple substance Nd, and the mixture ratio and total weight of the rapid hardening sheet composition and the rare earth metal sheet of the comparative example 4-2 are identical to those of the example 4, except that the rapid hardening sheet and the rare earth metal sheet of the comparative example 4-2 are subjected to hydrogen breaking respectively and independently, no temperature rise occurs before hydrogen absorption in the hydrogen breaking process, no cyclic hydrogen absorption-hydrogen extraction are performed, and then the rapid hardening sheet and the rare earth metal sheet are mixed in proportion before air flow grinding.
Specifically, the preparation method of the large neodymium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:29%; b:0.95%; co:0.3%; cu:0.2%; zr:0.1%; ga:0.2%; the balance being Fe;
s2, processing the rare earth simple substance Nd into a rare earth metal sheet with the thickness of 2 mm;
step S3, respectively adding the rapid hardening sheet in the step S1 and the rare earth metal sheet in the step S2 into a hydrogen breaking furnace to break hydrogen twice;
step S3.1, detecting leakage of the hydrogen cracking furnace;
s3.2, the hydrogen absorption pressure is 0.25MPa, after hydrogen absorption for 3 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature starts to rise;
s3.3, when the furnace temperature is increased to 570 ℃, starting thermal insulation dehydrogenation for 7h;
and S3.4, after dehydrogenation, cooling the hydrogen cracking furnace for 6 hours, and discharging at 25 ℃.
S4, rapidly hardening tablets after hydrogen breakage and rare earth NdH after hydrogen breakage x According to 99.5: mixing 600kg with 0.5, and air milling;
s5, carrying out air flow grinding and molding;
and S6, sintering after molding to obtain the cuboid large-block permanent magnet with the dimensions of 63mm multiplied by 54mm multiplied by 38 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Example 5
The preparation method of the bulk cerium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:28.5%; b:0.95%; co:0.3%; cu:0.2%; zr:0.1%; ga:0.2%; ce:0.5%; the balance being Fe;
s2, processing the rare earth simple substance Pr into a rare earth metal sheet with the thickness of 5 mm;
s3, adding the rapid hardening sheet in the step S1 and the rare earth metal sheet in the step S2 into a hydrogen breaking furnace together for hydrogen breaking;
s3.1, adding the rapid hardening sheet and the rare earth metal sheet into a hydrogen breaking furnace according to the proportion of the rare earth metal sheet accounting for 1% of the total weight, wherein the total weight is 400kg;
step S3.2, detecting leakage of the hydrogen cracking furnace;
s3.3, heating the hydrogen cracking furnace to 180 ℃, and preserving heat for 0.8h;
s3.4, carrying out 5 times of hydrogen absorption-hydrogen extraction circulation, wherein the hydrogen absorption pressure is 0.25MPa, and the single hydrogen absorption time is 0.8h;
s3.5, the hydrogen absorption pressure is 0.25MPa, after the hydrogen absorption is carried out for 3 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature is started;
s3.6, when the furnace temperature is raised to 600 ℃, the heat preservation and dehydrogenation are started, and the dehydrogenation time is 7 hours;
and S3.7, after dehydrogenation, cooling the hydrogen cracking furnace for 6 hours, and discharging at the temperature of 30 ℃.
S4, carrying out air flow grinding after hydrogen breaking;
s5, carrying out air flow grinding and molding;
and S6, sintering after molding to obtain the cuboid large-block permanent magnet with the size of 70mm multiplied by 60mm multiplied by 54 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Comparative example 5-1
The basic components and weight of the rapid hardening tablets in comparative example 5-1 are exactly the same as those in example 5, except that 1.0% Pr is added in the preparation of the rapid hardening tablets in comparative example 5-1, and then the temperature is not raised before hydrogen absorption in the hydrogen breaking process, and no cycle of hydrogen absorption-hydrogen extraction is performed.
Specifically, the preparation method of the bulk cerium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:28.5%; b:0.95%; co:0.3%; cu:0.2%; zr:0.1%; ga:0.2%; ce:0.5%; pr:1.0%; the balance being Fe;
step S2, adding 400kg of the rapid hardening tablets in the step S1 into a hydrogen breaking furnace for hydrogen breaking;
step S2.1, detecting leakage of the hydrogen cracking furnace;
s2.2, the hydrogen absorption pressure is 0.25MPa, after hydrogen absorption for 3 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature starts to rise;
s2.3, when the furnace temperature is raised to 600 ℃, the heat preservation and dehydrogenation are started, and the dehydrogenation time is 7 hours;
and S2.4, after dehydrogenation, cooling the hydrogen cracking furnace for 6 hours, and discharging at the temperature of 30 ℃.
S3, carrying out air flow grinding after hydrogen breaking;
s4, carrying out air flow grinding and molding;
and S5, sintering after molding to obtain the cuboid large-block permanent magnet with the size of 70mm multiplied by 60mm multiplied by 54 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Comparative example 5-2
The rapid hardening sheet composition, the rare earth metal sheet thickness of the rare earth element Pr, and the mixture ratio and total weight of the rapid hardening sheet composition and the rare earth metal sheet of the comparative example 5-2 are identical to those of the example 5, except that the rapid hardening sheet and the rare earth metal sheet of the comparative example 5-2 are subjected to hydrogen breaking respectively and independently, no temperature rise occurs before hydrogen absorption in the hydrogen breaking process, no cyclic hydrogen absorption-hydrogen extraction are performed, and then the rapid hardening sheet and the rare earth metal sheet are mixed in proportion before air flow grinding.
Specifically, the preparation method of the bulk cerium-based permanent magnet comprises the following steps:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology, wherein the rapid hardening tablet comprises the following components in percentage by mass: nd:28.5%; b:0.95%; co:0.3%; cu:0.2%; zr:0.1%; ga:0.2%; ce:0.5%; the balance being Fe;
s2, processing the rare earth simple substance Pr into a rare earth metal sheet with the thickness of 5 mm;
step S3, respectively adding the rapid hardening sheet in the step S1 and the rare earth metal sheet in the step S2 into a hydrogen breaking furnace to break hydrogen twice;
step S3.1, detecting leakage of the hydrogen cracking furnace;
s3.2, the hydrogen absorption pressure is 0.25MPa, after hydrogen absorption for 3 hours, when the hydrogen absorption pressure falls within 0.001MPa within 10 minutes, the hydrogen absorption is saturated, the hydrogen absorption is stopped, and the furnace temperature starts to rise;
s3.3, when the furnace temperature is raised to 600 ℃, the heat preservation and dehydrogenation are started, and the dehydrogenation time is 7 hours;
and S3.4, after dehydrogenation, cooling the hydrogen cracking furnace for 6 hours, and discharging at the temperature of 30 ℃.
S4, rapidly hardening tablets after hydrogen breakage and rare earth PrH after hydrogen breakage x According to 99:1 mixing 400kg and carrying out jet milling;
s5, carrying out air flow grinding and molding;
and S6, sintering after molding to obtain the cuboid large-block permanent magnet with the size of 70mm multiplied by 60mm multiplied by 54 mm.
The sintered magnet was randomly drawn out to form a cylinder with a diameter of 10mm and a height of 10mm, and the magnetic properties were measured, and the measurement results are shown in Table 1.
Table 1: comparative tables of magnetic Properties of examples and comparative examples
As can be seen from Table 1, the permanent magnet prepared by the embodiment of the invention has the advantages that the residual magnetism is improved by more than 0.1 and kGs and the coercive force is improved by more than 5kOe compared with the permanent magnet prepared by the conventional process without adding heavy rare earth treatment. For rare earth with the same proportion, the addition modes are different, such as adding in an air flow mill during preparation of a rapid hardening tablet or adding after hydrogen breaking, and the hydrogen breaking process is different, such as no temperature rise and no cyclic hydrogen absorption-hydrogen extraction before hydrogen absorption in the hydrogen breaking process, and the permanent magnet prepared by the process is 0.1-0.4 kGs lower than the residual magnetism of the permanent magnet prepared by the embodiment of the invention and 1-3 kOe lower than the coercive force.
The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention.
Claims (10)
1. The preparation method for improving the coercivity of the bulk neodymium or cerium-based permanent magnet by using trace rare earth is characterized by comprising the following steps of:
s1, preparing a rapid hardening tablet by adopting a rapid hardening melt-spinning technology;
s2, processing the rare earth simple substance into a rare earth metal sheet with the thickness of 2-7 mm;
s3, adding the rapid hardening sheet in the step S1 and the rare earth metal sheet in the step S2 into a hydrogen breaking furnace together for hydrogen breaking;
s4, carrying out air flow grinding after hydrogen breaking;
s5, carrying out air flow grinding and molding;
and S6, sintering after molding to obtain the large permanent magnet.
2. The method according to claim 1, wherein in the step S1, the mass percentage of the components of the rapid hardening sheet is: re: 0-15%; pr (Pr) a Nd b :28 to 32.5 percent, wherein a: 0-25%, b: 75-100%, a+b=100%; b:0.85 to 1.1 percent; co:0 to 0.4 percent;
cu:0 to 0.3 percent; nb:0 to 1 percent; zr:0 to 0.3 percent; al:0 to 2 percent; ga:0 to 1 percent; m:0 to 1 percent; the balance being Fe; re is one or more of Dy, tb, ho, gd, la, ce and Y, cerium based if Re contains Ce, neodymium based if Re does not contain Ce, and M is one or more of Si, cr, mo, ti and W.
3. The method according to claim 1, wherein in the step S2, the rare earth element includes Nd, pr, tb, dy, ho, gd, er.
4. The method according to claim 1, wherein said step S3 comprises the sub-steps of:
s3.1, adding the rapid hardening sheet and the rare earth metal sheet into a hydrogen breaking furnace according to the proportion of the rare earth metal sheet accounting for 0.2-1% of the total weight;
step S3.2, detecting leakage of the hydrogen cracking furnace;
step S3.3, heating the hydrogen cracking furnace to 120-200 ℃, and preserving heat for 0.5-2 h;
s3.4, carrying out hydrogen absorption-hydrogen extraction circulation for 2-5 times;
s3.5, absorbing hydrogen, and raising the furnace temperature after the hydrogen absorption is saturated;
s3.6, when the furnace temperature is raised to 550-600 ℃, starting thermal insulation dehydrogenation;
and S3.7, after dehydrogenation, cooling the hydrogen breaking furnace to below 40 ℃ and discharging.
5. The method according to claim 4, wherein in the step 3.4, the hydrogen absorption pressure is 0.15 to 0.3MPa, and the single hydrogen absorption time is 0.2 to 1h.
6. The method according to claim 4, wherein in the step 3.5, the hydrogen absorption pressure is 0.15-0.3 MPa, the hydrogen absorption time is different according to the charging amount, and when the charging amount is less than or equal to 300kg, the hydrogen absorption time is more than or equal to 2 hours; the furnace charge is more than 300kg and less than or equal to 600kg, and the hydrogen absorption time is more than or equal to 3h; the furnace charge is more than 600kg and less than or equal to 1250kg, and the hydrogen absorption time is more than or equal to 4h.
7. The method according to claim 4, wherein in the step 3.5, the hydrogen absorption saturation is a decrease in hydrogen pressure within 10 minutes within 0.001 MPa.
8. The method according to claim 4, wherein in the step 3.6, the dehydrogenation time is different according to the charging amount, the charging amount is less than or equal to 300kg, and the dehydrogenation time is 4-6 hours; 300kg < charging amount less than or equal to 600kg, and dehydrogenation time is 6-8 h;600kg < charging amount less than or equal to 800kg, and dehydrogenation time is 8-10 h;800kg < charging amount less than or equal to 1000kg, and dehydrogenation time is 10-12 h; the furnace charge is less than 1000kg and less than or equal to 1250kg, and the dehydrogenation time is 12-14 h.
9. The method according to claim 4, wherein in the step 3.7, the cooling time of the hydrogen breaking furnace is different according to the charging amount, the charging amount is less than or equal to 800kg, and the cooling time is more than or equal to 4h; the furnace charge is more than 800kg and less than or equal to 1250kg, and the cooling time is more than or equal to 6h.
10. The method according to claim 1, wherein in the step S6, the thickness of the bulk permanent magnet is 10mm or more.
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