CN115602400B - Antioxidant neodymium-iron-boron magnet and preparation method thereof - Google Patents
Antioxidant neodymium-iron-boron magnet and preparation method thereof Download PDFInfo
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- CN115602400B CN115602400B CN202211182513.XA CN202211182513A CN115602400B CN 115602400 B CN115602400 B CN 115602400B CN 202211182513 A CN202211182513 A CN 202211182513A CN 115602400 B CN115602400 B CN 115602400B
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- iron
- neodymium
- boron magnet
- boron
- magnet
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- 229910001172 neodymium magnet Inorganic materials 0.000 title claims abstract description 139
- 239000003963 antioxidant agent Substances 0.000 title claims abstract description 22
- 230000003078 antioxidant effect Effects 0.000 title claims abstract description 22
- 238000002360 preparation method Methods 0.000 title abstract description 21
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims abstract description 50
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 43
- 230000003647 oxidation Effects 0.000 claims abstract description 39
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 39
- 229910052742 iron Inorganic materials 0.000 claims abstract description 35
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 claims abstract description 22
- 238000000034 method Methods 0.000 claims abstract description 19
- 238000005245 sintering Methods 0.000 claims abstract description 19
- 238000001556 precipitation Methods 0.000 claims abstract description 17
- 239000011248 coating agent Substances 0.000 claims abstract description 13
- 238000000576 coating method Methods 0.000 claims abstract description 13
- 239000001257 hydrogen Substances 0.000 claims abstract description 13
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 13
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052684 Cerium Inorganic materials 0.000 claims abstract description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052688 Gadolinium Inorganic materials 0.000 claims abstract description 8
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 8
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 claims abstract description 8
- UIWYJDYFSGRHKR-UHFFFAOYSA-N gadolinium atom Chemical compound [Gd] UIWYJDYFSGRHKR-UHFFFAOYSA-N 0.000 claims abstract description 8
- 238000002074 melt spinning Methods 0.000 claims abstract description 8
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 claims abstract description 8
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 7
- 229910052796 boron Inorganic materials 0.000 claims abstract description 7
- 229910052779 Neodymium Inorganic materials 0.000 claims abstract description 6
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 6
- 229910052802 copper Inorganic materials 0.000 claims abstract description 6
- 239000010949 copper Substances 0.000 claims abstract description 6
- 238000000227 grinding Methods 0.000 claims abstract description 6
- 239000012535 impurity Substances 0.000 claims abstract description 6
- 238000000748 compression moulding Methods 0.000 claims abstract description 4
- YDEXUEFDPVHGHE-GGMCWBHBSA-L disodium;(2r)-3-(2-hydroxy-3-methoxyphenyl)-2-[2-methoxy-4-(3-sulfonatopropyl)phenoxy]propane-1-sulfonate Chemical compound [Na+].[Na+].COC1=CC=CC(C[C@H](CS([O-])(=O)=O)OC=2C(=CC(CCCS([O-])(=O)=O)=CC=2)OC)=C1O YDEXUEFDPVHGHE-GGMCWBHBSA-L 0.000 claims description 36
- -1 iron ion Chemical class 0.000 claims description 29
- 229920001046 Nanocellulose Polymers 0.000 claims description 21
- 239000002244 precipitate Substances 0.000 claims description 19
- 239000012266 salt solution Substances 0.000 claims description 18
- 229910021578 Iron(III) chloride Inorganic materials 0.000 claims description 16
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 claims description 16
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 11
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical group [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 10
- 235000011114 ammonium hydroxide Nutrition 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 10
- 238000001816 cooling Methods 0.000 claims description 7
- 239000006247 magnetic powder Substances 0.000 claims description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 6
- 238000003723 Smelting Methods 0.000 claims description 6
- 229960002089 ferrous chloride Drugs 0.000 claims description 6
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 claims description 6
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
- 238000002791 soaking Methods 0.000 claims description 5
- 239000011790 ferrous sulphate Substances 0.000 claims description 4
- 235000003891 ferrous sulphate Nutrition 0.000 claims description 4
- 229910000359 iron(II) sulfate Inorganic materials 0.000 claims description 4
- 229910052786 argon Inorganic materials 0.000 claims description 3
- 238000000462 isostatic pressing Methods 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 3
- 238000002844 melting Methods 0.000 claims description 3
- 230000008018 melting Effects 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims description 2
- 239000012716 precipitator Substances 0.000 claims description 2
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims 1
- QJVKUMXDEUEQLH-UHFFFAOYSA-N [B].[Fe].[Nd] Chemical compound [B].[Fe].[Nd] QJVKUMXDEUEQLH-UHFFFAOYSA-N 0.000 abstract description 19
- 239000010410 layer Substances 0.000 description 28
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 27
- 230000000052 comparative effect Effects 0.000 description 18
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 15
- 238000012360 testing method Methods 0.000 description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- 238000001514 detection method Methods 0.000 description 9
- 230000005389 magnetism Effects 0.000 description 9
- 230000003064 anti-oxidating effect Effects 0.000 description 8
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 description 8
- 238000011056 performance test Methods 0.000 description 8
- 239000000843 powder Substances 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
- 229960004887 ferric hydroxide Drugs 0.000 description 7
- IEECXTSVVFWGSE-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Fe+3] IEECXTSVVFWGSE-UHFFFAOYSA-M 0.000 description 7
- 230000007797 corrosion Effects 0.000 description 6
- 238000005260 corrosion Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 239000002253 acid Substances 0.000 description 5
- 239000003513 alkali Substances 0.000 description 5
- 235000014413 iron hydroxide Nutrition 0.000 description 5
- 239000013049 sediment Substances 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 238000011049 filling Methods 0.000 description 4
- SURQXAFEQWPFPV-UHFFFAOYSA-L iron(2+) sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Fe+2].[O-]S([O-])(=O)=O SURQXAFEQWPFPV-UHFFFAOYSA-L 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 230000002829 reductive effect Effects 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 3
- 229920002678 cellulose Polymers 0.000 description 3
- 239000001913 cellulose Substances 0.000 description 3
- 238000005253 cladding Methods 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 230000006835 compression Effects 0.000 description 3
- 239000008367 deionised water Substances 0.000 description 3
- 229910021641 deionized water Inorganic materials 0.000 description 3
- 125000001165 hydrophobic group Chemical group 0.000 description 3
- 229910021506 iron(II) hydroxide Inorganic materials 0.000 description 3
- 239000003921 oil Substances 0.000 description 3
- 238000007747 plating Methods 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000011241 protective layer Substances 0.000 description 3
- 239000012047 saturated solution Substances 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 238000004381 surface treatment Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229910001448 ferrous ion Inorganic materials 0.000 description 2
- 230000002209 hydrophobic effect Effects 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 239000012466 permeate Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 210000002345 respiratory system Anatomy 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000004108 freeze drying Methods 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 239000000543 intermediate Substances 0.000 description 1
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 239000002985 plastic film Substances 0.000 description 1
- 229920006255 plastic film Polymers 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Classifications
-
- 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
- H01F41/026—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets protecting methods against environmental influences, e.g. oxygen, by surface treatment
-
- 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
- H01F41/0266—Moulding; Pressing
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- Hard Magnetic Materials (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
Abstract
The application relates to the technical field of neodymium-iron-boron magnets, in particular to an antioxidant neodymium-iron-boron magnet and a preparation method thereof, wherein the antioxidant neodymium-iron-boron magnet comprises the following components in percentage by weight: 15-20wt% of neodymium, 0.1-0.5wt% of copper, 3-8wt% of boron, 10-15wt% of cerium, 0.1-0.5wt% of aluminum, 0.1-1wt% of gadolinium, 0.01-0.2wt% of ferric oxide, and the balance of iron and other unavoidable impurities, wherein the ferric oxide is coated on the outer surface of the neodymium-iron-boron magnet through a precipitation method; the preparation method of the antioxidant neodymium-iron-boron magnet comprises the following steps: melt-spinning, hydrogen breaking and grinding, compression molding, sintering processing and coating of an outer layer. The application has the advantage of improving the oxidation resistance of the NdFeB magnet while not affecting the magnetic performance of the NdFeB magnet as much as possible.
Description
Technical Field
The application relates to the technical field of neodymium-iron-boron magnets, in particular to an antioxidant neodymium-iron-boron magnet and a preparation method thereof.
Background
According to different production processes, the neodymium-iron-boron permanent magnet material can be divided into two types of sintered neodymium-iron-boron and bonded neodymium-iron-boron. Because sintered neodymium iron boron has higher magnetic energy product, coercive force and working temperature, the method can be suitable for a plurality of different technical fields, and the sintered neodymium iron boron is mainly produced on the market at present.
However, sintered neodymium iron boron has lower compactness, and high internal porosity of the magnet, so that the sintered neodymium iron boron is more easily oxidized and corroded, and in order to reduce corrosion damage and prolong the service life of the magnet, the magnet needs to be subjected to certain protection treatment, and the surface of the magnet is electroplated with gold, nickel, zinc and the like by a common protection method at present.
In view of the above related art, the inventors believe that, due to limitations of the electroplating industry, the plating layer on the surface of the magnet tends to be uneven in thickness and even has a plurality of pores, so that the purpose of protecting the magnet while not affecting the magnetic performance of the neodymium-iron-boron magnet as much as possible cannot be well achieved by the plating layer.
Disclosure of Invention
The application provides an antioxidant neodymium-iron-boron magnet and a preparation method thereof in order to improve the oxidation resistance of the neodymium-iron-boron magnet while not affecting the magnetic performance of the neodymium-iron-boron magnet as much as possible.
The application provides an antioxidant neodymium-iron-boron magnet and a preparation method thereof, which adopts the following technical scheme:
in a first aspect, the application provides an antioxidant neodymium iron boron magnet, which adopts the following technical scheme:
an antioxidant neodymium-iron-boron magnet comprises the following components in percentage by weight: 15-20wt% of neodymium, 0.1-0.5wt% of copper, 3-8wt% of boron, 10-15wt% of cerium, 0.1-0.5wt% of aluminum, 0.1-1wt% of gadolinium, 0.01-0.2wt% of ferric oxide, and the balance of iron and other unavoidable impurities, wherein the ferric oxide is coated on the outer surface of the neodymium-iron-boron magnet through a precipitation method.
By adopting the technical scheme, the oxidation resistance of the neodymium-iron-boron magnet is effectively improved by coating the outer surface of the neodymium-iron-boron magnet with a layer of iron oxide, the iron oxide has good light resistance and heat resistance, has very stable property at a certain temperature, can not react with oxygen and water in the air, has excellent alkali resistance and has certain resistance to common weak acid and dilute acid, and in addition, when the iron oxide is used as a protective layer, water, oil, organic solvent and the like can not permeate the iron oxide, and other impurity elements are not introduced into the neodymium-iron-boron magnet; when the content of the ferric oxide coated on the outer surface of the neodymium-iron-boron magnet is low, the oxidation resistance and the corrosion resistance of the neodymium-iron-boron magnet are low, but when the content of the ferric oxide is excessive, the thickness of the ferric oxide layer is too thick, and the magnetic performance of the neodymium-iron-boron magnet is influenced.
Preferably, the iron oxide is coated on the surface of the neodymium-iron-boron magnet in the following form: and (3) completely soaking the neodymium-iron-boron magnet in an iron ion salt solution, dropwise adding an alkaline precipitant, reacting the iron ion salt with the alkaline precipitant to generate precipitate, coating the surface of the neodymium-iron-boron magnet with iron ions in a precipitation form, then taking out the neodymium-iron-boron magnet, and sintering to obtain the neodymium-iron-boron magnet coated with ferric oxide.
Through adopting above-mentioned technical scheme, adopt the precipitation method to carry out surface treatment to the neodymium iron boron magnet, because the neodymium iron boron magnet is immersed in the salt solution completely, when the reaction produced the sediment, all produced in each direction of magnet and have the sediment to the sediment can be more even cladding at the magnet surface, simultaneously, only need the concentration of control iron ion salt solution and the speed of dropwise add alkaline precipitant, can control the homogeneity and the thickness of the sedimentary bed on magnet surface, thereby make the iron oxide layer of final cladding play better antioxidation when not influencing the magnetism of neodymium iron boron magnet as far as possible.
Preferably, sodium lignin sulfonate is added to the iron ion salt solution.
By adopting the technical scheme, the sodium lignin sulfonate is a water-soluble natural high polymer, is ecological and environment-friendly, has two groups of hydrophilic and hydrophobic, and can be agglomerated after the iron ion salt and the alkaline precipitant react to generate the precipitate.
Preferably, the sodium lignin sulfonate is added in an amount of 0.01 to 0.03 times by weight of the iron ion salt solution.
Through adopting above-mentioned technical scheme, the sodium lignin sulfonate of adding is too little, can not play the effect of dispersion neodymium iron boron magnet surface sediment well, but when sodium lignin sulfonate addition is too much, sediment mutual exclusion phenomenon aggravates, probably leads to the perspective that the deposit layer cladding on neodymium iron boron magnet surface appears tiny hole.
Preferably, spherical nanocellulose is added into the iron ion salt solution.
By adopting the technical scheme, the nanocellulose is adsorbed on the surface of the neodymium-iron-boron magnet, and the spherical nanocellulose is very stable before 320 ℃, so that the spherical nanocellulose is still adsorbed on the surface of the neodymium-iron-boron magnet after heating to generate ferric oxide, and the spherical nanocellulose has good high temperature resistance, so that the high temperature stability of an antioxidant neodymium-iron-boron magnet finished product is effectively improved; the sodium lignin sulfonate partially dissolved in water enters the inside of the neodymium-iron-boron magnet through the pores, and in the process of heating to generate ferric oxide, as the moisture is gradually reduced, the sodium lignin sulfonate is separated out, the nanocellulose and the sodium lignin sulfonate are matched to form a self-adaptive structure, so that the porosity of the inside of the neodymium-iron-boron magnet is reduced, the local stress of an interface is weakened, the brittle fracture and fatigue fracture of the structure of the neodymium-iron-boron magnet in the working process are relieved, and the working life of the neodymium-iron-boron magnet is prolonged.
Preferably, the iron ion salt is one of ferrous sulfate, ferrous chloride and ferric chloride. Preferably, the iron ion salt is ferric chloride, and the alkaline precipitant is ammonia water.
By adopting the technical scheme, the ferrous ion has strong reducibility, is easy to oxidize in the air and is troublesome to store, and the ferric sulfate has certain toxicity, so that the ferric chloride is adopted as the iron ion salt; the alkaline precipitant can adopt sodium hydroxide or ammonia water, wherein the sodium hydroxide is strong in alkali and has strong corrosiveness, and if the sodium hydroxide volatilizes due to improper storage, eyes and respiratory tracts of workers are easily damaged, so that the ammonia water is adopted as the alkaline precipitant to effectively improve the safety of production; ferric chloride and ammonia water react at normal temperature to generate ferric hydroxide precipitate, ferric hydroxide is coated on the surface of the neodymium-iron-boron magnet, and the neodymium-iron-boron magnet is taken out and sintered to obtain the ferric oxide protective layer.
In a second aspect, the application provides a preparation method of an antioxidant neodymium iron boron magnet, which adopts the following technical scheme: the preparation method of the antioxidant neodymium-iron-boron magnet comprises the following steps:
s1, melting and melt-spinning: according to the set weight ratio, adding neodymium, copper, boron, cerium, aluminum and gadolinium into a vacuum smelting furnace, smelting at high temperature under the protection of argon, pouring the molten liquid onto the surface of a rotating water-cooled metal roller, and carrying out melt spinning to obtain melt spinning sheets;
s2, hydrogen crushing and grinding: putting the melt-spun piece into a hydrogen breaking furnace for hydrogen breaking, and then putting the melt-spun piece into an air flow mill for grinding to obtain magnetic powder;
s3, press forming: placing the magnetic powder in a die, performing compression molding and isostatic pressing treatment to obtain a sintered green body;
s4, sintering: putting the sintered green compact into a vacuum sintering furnace, sintering under the protection of nitrogen, preserving heat for 2-5h after sintering, naturally cooling to 450-550 ℃, discharging, and air cooling to room temperature to obtain a neodymium-iron-boron magnet;
s5, coating the outer layer: and soaking the neodymium-iron-boron magnet in a salt solution, dropwise adding a precipitator, taking out and heating after the outer layer of the neodymium-iron-boron magnet is coated with a layer of precipitate, and thus obtaining the antioxidant neodymium-iron-boron magnet.
Through adopting above-mentioned technical scheme, inside porosity of sintered neodymium iron boron magnetism body is higher, and oxygen easily gets into inside the neodymium iron boron magnetism body, leads to the oxidation corrosion of neodymium iron boron magnetism body, through annealing in order to realize the refinement of crystalline grain to improve the compactness of neodymium iron boron magnetism body, reduce the inside porosity of neodymium iron boron magnetism body, inhibit the oxidation corrosion of magnet.
Preferably, in S5, a plurality of dropping apparatuses for dropping the precipitant are provided, and the dropping apparatuses are disposed around the neodymium-iron-boron magnet at intervals.
By adopting the technical scheme, if the precipitant is dripped into one place, partial generated precipitants can be accumulated on the surface of the neodymium-iron-boron magnet, and the application ensures the uniformity of the precipitant layer while effectively improving the efficiency of coating the precipitant layer outside the magnet by arranging a plurality of dripping instruments to generate precipitants around the magnet.
Preferably, in S5, the speed of dropping the precipitant is 80-120mL/min.
By adopting the technical scheme, the speed of dripping the precipitant is too slow, so that the preparation time is too long, and the industrial production efficiency is affected; excessive precipitation is generated rapidly in a short time when the precipitating agent is dripped too fast, the precipitation is not dispersed, and uneven thickness of a precipitation layer on the surface of the neodymium-iron-boron magnet is easily caused, so that the magnetic performance of the magnet is affected.
In summary, the application has the following beneficial effects:
1. according to the application, the oxidation resistance of the neodymium-iron-boron magnet is effectively improved by coating the outer surface of the neodymium-iron-boron magnet with a layer of ferric oxide, the ferric oxide has good light resistance and heat resistance, has very stable property at a certain temperature, can not react with oxygen and water in air, has excellent alkali resistance and has certain resistance to common weak acid and dilute acid, in addition, when the neodymium-iron-boron magnet is used as a protective layer, water, oil, organic solvents and the like can not permeate the ferric oxide, and the ferric oxide itself does not introduce other impurity elements into the neodymium-iron-boron magnet.
2. According to the application, the surface treatment is carried out on the neodymium-iron-boron magnet by adopting a precipitation method, and as the neodymium-iron-boron magnet is completely immersed in the salt solution, precipitates are generated in all directions of the magnet when the precipitates are generated by reaction, so that the precipitates can be uniformly coated on the surface of the magnet, and meanwhile, the uniformity and thickness of a precipitation layer on the surface of the magnet can be controlled by only controlling the concentration of the iron ion salt solution and the speed of dropwise adding the alkaline precipitant, so that the finally coated iron oxide layer plays a good role in antioxidation while the magnetism of the neodymium-iron-boron magnet is not influenced as much as possible.
3. The sodium lignin sulfonate is a water-soluble natural high polymer, is ecological and environment-friendly, has two groups of hydrophilic and hydrophobic, and can be used for effectively inhibiting the aggregation of the precipitates coated on the surface of the neodymium-iron-boron magnet by adding the sodium lignin sulfonate, wherein the hydrophobic group of the sodium lignin sulfonate is directionally adsorbed on the surface of the precipitate and the hydrophilic group is directed to the aqueous solution after the initial generated precipitate is powder after the iron ion salt and the alkaline precipitant react to generate the precipitate.
Detailed Description
The present application will be described in further detail with reference to examples.
Preparation examples of starting materials and intermediates
Neodymium powder, copper powder, cerium powder, aluminum powder and gadolinium powder: the rare earth content is more than or equal to 99.9%, the granularity can be adjusted according to the requirement, and the embodiment specifically takes 1-3 μm as an example.
Low carbon ferroboron powder: the boron content is 20-25%, the carbon content is less than or equal to 0.05-0.1%, the granularity can be adjusted according to the requirement, and the embodiment is specifically illustrated by taking 4-6 mu m as an example.
Iron powder: the iron content is greater than or equal to 99.9%, the granularity of which can be adjusted according to the need, and the embodiment is specifically illustrated by taking 4-6 mu m as an example.
Ferric chloride: the content of ferric chloride is more than or equal to 96 percent.
Ferrous chloride: the content of ferrous chloride is more than or equal to 90 percent, the content of insoluble matters is less than or equal to 0.5 percent, and the content of free acid is less than or equal to 1 percent.
Ferrous sulfate heptahydrate: the content of ferrous sulfate is more than or equal to 85 percent, the content of titanium dioxide is less than or equal to 1 percent, and the content of insoluble matters is less than or equal to 0.5 percent.
Industrial grade ammonia water: the ammonia content is 25-25%.
Sodium hydroxide: the content of sodium hydroxide is more than or equal to 99 percent.
Deionized water: high-grade pure GR with water content more than or equal to 99.99%.
Sodium lignin sulfonate: the sodium lignin sulfonate content is more than or equal to 99 percent.
Citric acid solution: and (3) dissolving the purchased citric acid (the citric acid content is more than or equal to 99%) in deionized water to prepare the citric acid solution with the pH value of 2.3.
Spherical nanocellulose: placing the purchased cellulose (the cellulose content is more than or equal to 99%) in 50% sodium hydroxide solution, stirring for 30min at 30 ℃ at 300rpm, then dripping citric acid solution into the cellulose treated by alkali until the pH value is=3, heating to 120 ℃ under the condition of maintaining the pH value=3, reacting for 30min, and freeze-drying to obtain the spherical nano cellulose.
Examples
Example 1
An antioxidant neodymium-iron-boron magnet comprises the following components in percentage by weight: 17wt% of neodymium, 0.2wt% of copper, 5wt% of boron, 12wt% of cerium, 0.3wt% of aluminum, 0.4wt% of gadolinium, 0.01wt% of ferric oxide, and the balance of iron and other unavoidable impurities.
The preparation method of the antioxidant neodymium-iron-boron magnet comprises the following steps:
s1, melting and melt-spinning: according to the set weight percentage and the content of various powder materials, calculating the weight required by the raw materials, putting neodymium powder, copper powder, low-carbon ferroboron powder, cerium powder, aluminum powder, gadolinium powder and iron powder into a vacuum smelting furnace according to the calculated result, vacuumizing to the vacuum degree of less than or equal to 1.5Pa, starting heating, continuously vacuumizing to the vacuum degree of less than or equal to 1Pa, filling argon, heating to 1100 ℃, after iron is completely melted, smelting for 8-10min, pouring the molten liquid onto the surface of a rotating water-cooled metal roller, and carrying out belt throwing to obtain a belt throwing sheet;
s2, hydrogen crushing and grinding: putting the melt-spun piece into a hydrogen breaking furnace, vacuumizing to be less than or equal to 1Pa, filling hydrogen, breaking hydrogen for 4 hours to obtain a hydrogen broken material, vacuumizing an air flow mill, filling nitrogen into the air flow mill until the vacuum degree is 0.25MPa, and putting the hydrogen broken material into the air flow mill to grind for 3 hours to obtain magnetic powder;
s3, press forming: filling magnetic powder into a die with a specific shape, performing compression molding on the magnetic powder by using a pulse magnetic field of 6T to obtain a compression block, tightly wrapping the compression block by using a plastic film, and performing isostatic pressing treatment on the compression block under the oil pressure of 300Mpa to obtain a sintered green compact;
s4, sintering: putting the sintered green compact into a vacuum sintering furnace, heating to 1050 ℃ under the protection of nitrogen gas for sintering, preserving heat for 2-5h after sintering, naturally cooling the neodymium-iron-boron magnet to 500 ℃ in the sintering furnace, taking out the neodymium-iron-boron magnet at 500 ℃, and air-cooling the neodymium-iron-boron magnet to room temperature to obtain the neodymium-iron-boron magnet;
s5, coating the outer layer: dissolving ferric chloride in deionized water, preparing a ferric chloride saturated solution, soaking a neodymium iron boron magnet in the ferric chloride saturated solution, adding sodium lignin sulfonate and spherical nanocellulose into the ferric chloride saturated solution, wherein the added weight of the sodium lignin sulfonate is 0.02 times of that of an iron ion salt solution, the added weight of the spherical nanocellulose is 0.1 time of that of the sodium lignin sulfonate, 8 dropping instruments for dropping precipitants are arranged around the ferric chloride, the 8 dropping instruments are respectively used for dropping ammonia water at 100mL/min, taking out the neodymium iron boron magnet after the outer layer of the neodymium iron boron magnet is coated with a layer of ferric hydroxide for precipitation, heating under the protection of nitrogen, keeping the temperature at 130 ℃ for 3 hours, and naturally cooling to obtain the antioxidant neodymium iron boron magnet with the outer surface coated with ferric oxide.
Examples 2 to 5
Examples 2 to 5 the iron oxide content was adjusted based on the preparation method of example 1, and specific formulation ratios are shown in table 1.
Table 1 examples 2-5 schematic Table of the component proportions
Comparative example
Comparative example 1
Comparative example 1 the preparation method of example 1 was followed without coating with an iron oxide layer.
Comparative example 2
Comparative example 2 the preparation method of example 1 was not covered with an iron oxide layer, but a nickel layer was electroplated on the outer surface of the neodymium-iron-boron magnet.
Performance test
1. Magnetic properties
The neodymium-iron-boron magnet materials provided in examples 1 to 6 and comparative examples 1 and 2 of the present application were subjected to magnetic property detection according to the GB/T3217 permanent magnet (hard magnet) material magnetic test method.
2. Oxidation resistance
Neodymium iron boron magnets provided in examples 1 to 6 and comparative examples 1 and 2 of the present application were subjected to Neutral Salt Spray (NSS) test according to GB/T10125-1997, and the time of first occurrence of rust spots on the surface of the magnets was measured, and the test results are shown in Table 2.
TABLE 2 Performance test data Table for examples 1-5 and comparative examples 1-2
Referring to table 2, it can be seen from comparative examples 1, 1 and 2 that the oxidation resistance of the neodymium-iron-boron magnet can be greatly improved by coating an oxidation resistant layer on the outer surface of the neodymium-iron-boron magnet, and the magnetic performance is hardly affected, wherein the oxidation resistance of example 1 is superior to that of example 2, probably because the plating process is inevitably uneven or has a plurality of holes, and the neodymium-iron-boron magnet is subjected to surface treatment by a precipitation method.
As can be seen from comparative examples 1 to 5, when the content of iron oxide coated on the outer surface of the neodymium-iron-boron magnet is small, the oxidation resistance and corrosion resistance of the neodymium-iron-boron magnet are weak, but when the content of iron oxide is too large, the thickness of the iron oxide layer is too thick, and the magnetic performance of the neodymium-iron-boron magnet is affected.
To further study the influence of each component and preparation parameters on the performance of the cylindrical magnet, the application further carries out the verification of the following examples.
Examples 6 to 10
Examples 6-10 the weight of sodium lignin sulfonate added to the ferric chloride solution was adjusted based on the preparation method of example 4. Sodium lignin sulfonate was not added in example 6; the added weight of sodium lignin sulfonate in example 7 is 0.005 times of that of the iron ion salt solution; the added weight of sodium lignin sulfonate in example 8 is 0.01 times of that of the iron ion salt solution; the added weight of sodium lignin sulfonate in example 9 is 0.03 times of that of the iron ion salt solution; the weight of sodium lignin sulfonate added in example 10 was 0.04 times that of the iron ion salt solution.
The anti-oxidation neodymium iron boron magnets prepared in examples 6 to 10 were subjected to the above magnetic property detection and oxidation resistance detection, and the test results are shown in Table 3.
Table 3 table of performance test data for example 4 and examples 6-10
Referring to table 3, sodium lignin sulfonate has both hydrophilic and hydrophobic groups, and when ferric hydroxide precipitates, the hydrophobic groups of sodium lignin sulfonate are directionally adsorbed on the surface of the precipitate, and the hydrophilic groups are directed to the aqueous solution, so that adjacent precipitates are dispersed due to mutual repulsion of the same charges on the surface.
In comparative example 4 and examples 6 and 7, the neodymium iron boron magnet of example 4 is superior to examples 6 and 7 in terms of magnetic properties and oxidation resistance, because the generated iron hydroxide precipitate is not well dispersed when sodium lignin sulfonate is not added or the addition amount of sodium lignin sulfonate is too small, and thus part of the iron hydroxide precipitate adsorbed on the outer surface of the magnet is agglomerated, so that the iron hydroxide layer is too thick in some places and too thin in some places.
In comparative examples 4 and examples 8 to 10, it is known that the oxidation resistance of the neodymium-iron-boron magnet is continuously improved with the increase of the added weight of sodium lignin sulfonate, but when the sodium lignin sulfonate is excessively added, the oxidation resistance of the neodymium-iron-boron magnet is rather reduced, and the excessive sodium lignin sulfonate may cause the inhibition between adjacent precipitates to be too strong, so that holes appear in the iron hydroxide layer coated on the outside of the magnet, holes also exist in the finally sintered iron oxide layer, and oxygen contacts the neodymium-iron-boron magnet from the holes and enters the holes in the magnet due to the high internal porosity of the sintered neodymium-iron-boron, so that the magnet is easily oxidized and corroded.
Example 11
Example 11 the preparation of S4 was modified on the basis of the component ingredients of example 9. In example 11, the sintered green compact was put into a vacuum sintering furnace, heated to 1050 ℃ under nitrogen protection to perform sintering, and naturally cooled to room temperature after the sintering was completed, thereby obtaining a neodymium iron boron magnet.
The anti-oxidation neodymium iron boron magnet prepared in example 11 was subjected to the above magnetic property detection and oxidation resistance detection, and the test results are shown in table 4.
Table 4 performance test data table for example 9 and example 11
Referring to table 4, it is apparent from comparative examples 9 and 11 that the oxidation resistance of example 9 is superior to that of example 11, probably because the annealing process is adopted in example 9, so that the internal structure of the neodymium-iron-boron magnet is close to the equilibrium state, and the grains are refined, thereby improving the compactness of the neodymium-iron-boron magnet, reducing the porosity of the interior of the magnet, and thus inhibiting the oxidation corrosion of the magnet.
Examples 12 and 13
In the embodiment 12, the number of drip apparatuses around the neodymium-iron-boron magnet in the step S5 is adjusted on the basis of the component components in the embodiment 9, and in the embodiment 12, 8 drip apparatuses are arranged above the center of the neodymium-iron-boron magnet, wherein the drip speed is 100mL/min; in example 13, the number of the dropping devices was 16, and the dropping devices were distributed around the NdFeB magnet at intervals, and the dropping speed was 50mL/min.
The anti-oxidation neodymium iron boron magnets prepared in examples 12 and 13 were subjected to the above magnetic property detection and oxidation resistance detection, and the test results are shown in table 5.
Table 5 table of performance test data for example 9 and examples 12, 13
Referring to table 5, it is clear from comparative examples 9 and examples 12 and 13 that if the precipitant is added dropwise only at one place, part of the generated precipitant is deposited on the surface of the neodymium-iron-boron magnet, so that the thickness of the iron hydroxide layer is uneven, which affects both magnetic performance and oxidation resistance; the quantity of ferric hydroxide generated in a certain time is certain, at the moment, eight dropping instruments can fully meet the requirement, and then the dropping instruments are added, so that the residual magnetism and the oxidation resistance of the finally prepared oxidation-resistant neodymium-iron-boron magnet are hardly influenced, but the quantity of the dropping instruments which need maintenance is increased, so that the production cost is improved.
Examples 14 to 17
Examples 14 to 17 the dripping speed of the dripping apparatus in S5 was adjusted based on the composition of example 9, and in example 14, the dripping speed was 50mL/min; in example 15, the dropping speed was 80mL/min; in example 16, the dropping speed was 100mL/min, and in example 17, the dropping speed was 120mL/min.
The anti-oxidation NdFeB magnets prepared in examples 14 to 17 were subjected to the above magnetic property test and oxidation resistance test, and the time after each time of coating of the NdFeB magnet was recorded, and the test results are shown in Table 6.
Table 6 table of performance test data for example 9 and examples 14-17
| Remanence, KGs | Maximum magnetic energy product, MGOe | Oxidation resistance/h | Coating time/h | |
| Example 9 | 1.45 | 51.7 | 54.6 | 3.7 |
| Example 14 | 1.44 | 51.6 | 54.3 | 5 |
| Example 15 | 1.44 | 51.6 | 54.5 | 3.3 |
| Example 16 | 1.44 | 51.6 | 54.2 | 3 |
| Example 17 | 1.44 | 51.6 | 51.9 | 2.7 |
Referring to table 6, it is apparent from comparative examples 9 and 14 to 17 that, when the dropping speed is too slow, the influence on the remanence and oxidation resistance of the neodymium iron boron magnet is not great, but the speed of generating ferric hydroxide is slow, so that the preparation time of the oxidation resistant magnet is long, the industrial production efficiency is affected, and when the dropping speed is too fast, excessive precipitation is rapidly generated in a short time, the precipitation is not too fast dispersed, the thickness of the precipitation layer on the surface of the neodymium iron boron magnet is easily uneven, and the magnetic property and oxidation resistance of the magnet are affected.
Examples 18 to 20
Examples 18 to 20 the kinds of iron ion salts and alkaline precipitants were adjusted based on the preparation method of example 9. In example 18, ferrous hydroxide was produced by reacting ferrous sulfate with aqueous ammonia, and rapidly oxidized in air to ferric hydroxide; in example 19, ferrous hydroxide was produced by reacting ferrous chloride with sodium hydroxide; in example 20, ferrous hydroxide was produced by reacting ferrous chloride with aqueous ammonia.
The anti-oxidation NdFeB magnets prepared in examples 18 to 20 were subjected to the above magnetic property test and oxidation resistance test, and the test results are shown in Table 7.
Table 7 table of performance test data for example 9 and examples 18-20
Referring to Table 7, in comparative examples 9 and 18 to 20, different iron ion salts are matched with different alkaline precipitants, the magnetism and the oxidation resistance of the finally obtained NdFeB magnet are not greatly different, but the reduction of ferrous ions is strong, the iron ions are easy to oxidize in air, and the storage cost is high; sodium hydroxide is strong alkali and has strong corrosiveness, if the sodium hydroxide is volatilized due to improper storage, eyes and respiratory tracts of workers are easily damaged, so that the iron ion salt is set to be ferric chloride, the alkaline precipitant is set to be ammonia water, and the production safety is effectively improved while the cost is controlled.
Examples 21 to 23
Examples 21-23 the content of spherical nanocellulose in the ferric chloride solution was adjusted on the basis of the preparation method of example 9. No spherical nanocellulose was added in example 21, the content of spherical nanocellulose in example 22 was 0.05 times that of sodium lignin sulfonate, and the content of spherical nanocellulose in example 23 was 0.2 times that of sodium lignin sulfonate.
The anti-oxidation neodymium iron boron magnets prepared in examples 21 to 23 were subjected to the above magnetic property detection and oxidation resistance detection, and the test results are shown in Table 8.
Table 8 performance test data table for example 9 and example 21
Referring to table 8, in comparative examples 9 and examples 21 to 22, as the addition amount of the spherical nanocellulose increases, the oxidation resistance of the finally prepared oxidation-resistant neodymium-iron-boron magnet is continuously improved. This is probably because the spherical nanocellulose added in the solution spontaneously adsorbs on the surface of the neodymium-iron-boron magnet, and the spherical nanocellulose itself has good high temperature resistance, meanwhile, because in the process of generating precipitation, part of sodium lignin sulfonate dissolved in water enters the inside of the neodymium-iron-boron magnet through pores, in the process of heating to generate ferric oxide, because the moisture gradually decreases, sodium lignin sulfonate is separated out, the nanocellulose and sodium lignin sulfonate are matched to form a self-adaptive structure, the porosity of the inside of the neodymium-iron-boron magnet is reduced, and the oxidation resistance of the finally prepared oxidation-resistant neodymium-iron-boron magnet is further improved.
In comparative example 9 and example 23, when the addition amount of the spherical nanocellulose exceeds a certain amount, the oxidation resistance of the magnet is not greatly changed. This is probably because when the addition amount of the spherical nanocellulose is too large, part of the nano zinc oxide is not adsorbed on the surface of the neodymium-iron-boron magnet, but is suspended in the solution.
The present embodiment is only for explanation of the present application and is not to be construed as limiting the present application, and modifications to the present embodiment, which may not creatively contribute to the present application as required by those skilled in the art after reading the present specification, are all protected by patent laws within the scope of claims of the present application.
Claims (7)
1. An antioxidant neodymium-iron-boron magnet is characterized by comprising the following components in percentage by weight: 15-20wt% of neodymium, 0.1-0.5wt% of copper, 3-8wt% of boron, 10-15wt% of cerium, 0.1-0.5wt% of aluminum, 0.1-1wt% of gadolinium, 0.01-0.2wt% of ferric oxide and the balance of iron and other unavoidable impurities, wherein the ferric oxide is coated on the outer surface of the neodymium-iron-boron magnet through a precipitation method, and the ferric oxide is coated on the surface of the neodymium-iron-boron magnet through the following modes: and (3) completely soaking the neodymium-iron-boron magnet in an iron ion salt solution, dropwise adding an alkaline precipitant, reacting the iron ion salt with the alkaline precipitant to generate precipitate, coating the surface of the neodymium-iron-boron magnet with iron ions in a precipitation form, then taking out the neodymium-iron-boron magnet, and sintering to obtain the neodymium-iron-boron magnet coated with ferric oxide, wherein sodium lignin sulfonate and spherical nanocellulose are added into the iron ion salt solution.
2. An oxidation resistant neodymium iron boron magnet according to claim 1, wherein: the added weight of the sodium lignin sulfonate is 0.01-0.03 times of that of the iron ion salt solution.
3. An oxidation resistant neodymium iron boron magnet according to claim 1, wherein: the iron ion salt is one of ferrous sulfate, ferrous chloride and ferric chloride.
4. An oxidation resistant neodymium iron boron magnet according to claim 1, wherein: the iron ion salt is ferric chloride, and the alkaline precipitant is ammonia water.
5. A method for preparing an antioxidant neodymium-iron-boron magnet according to any one of claims 1 to 4, comprising the steps of:
s1, melting and melt-spinning: according to the set weight ratio, adding neodymium, copper, boron, cerium, aluminum and gadolinium into a vacuum smelting furnace, smelting at high temperature under the protection of argon, pouring the molten liquid onto the surface of a rotating water-cooled metal roller, and carrying out melt spinning to obtain melt spinning sheets;
s2, hydrogen crushing and grinding: putting the melt-spun piece into a hydrogen breaking furnace for hydrogen breaking, and then putting the melt-spun piece into an air flow mill for grinding to obtain magnetic powder;
s3, press forming: placing the magnetic powder in a die, performing compression molding and isostatic pressing treatment to obtain a sintered green body;
s4, sintering: putting the sintered green compact into a vacuum sintering furnace, sintering under the protection of nitrogen, preserving heat for 2-5h after sintering, naturally cooling to 450-550 ℃, discharging, and air cooling to room temperature to obtain a neodymium-iron-boron magnet;
s5, coating the outer layer: and soaking the neodymium-iron-boron magnet in a salt solution, dropwise adding a precipitator, taking out and heating after the outer layer of the neodymium-iron-boron magnet is coated with a layer of precipitate, and thus obtaining the antioxidant neodymium-iron-boron magnet.
6. The method for preparing the antioxidant neodymium-iron-boron magnet according to claim 5, wherein the method comprises the following steps: in S5, a plurality of dropping instruments for dropping precipitants are arranged, and the dropping instruments are arranged around the NdFeB magnet at intervals.
7. The method for preparing the antioxidant neodymium-iron-boron magnet according to claim 5, wherein the method comprises the following steps: in S5, the speed of dripping the precipitant is 80-120mL/min.
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| JP2005210094A (en) * | 2003-12-25 | 2005-08-04 | Tdk Corp | Rare earth magnet |
| JP2007005619A (en) * | 2005-06-24 | 2007-01-11 | Aisin Seiki Co Ltd | Corrosion resistant magnet and method of manufacturing same |
| CN101809690A (en) * | 2007-09-27 | 2010-08-18 | 日立金属株式会社 | Process for production of surface-modified rare earth sintered magnets and surface-modified rare earth sintered magnets |
| CN106517354A (en) * | 2016-12-13 | 2017-03-22 | 中国科学院青岛生物能源与过程研究所 | Nanometer alpha-phase iron oxide and preparation method thereof |
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