CN117702205A - Nickel-cobalt-tungsten alloy electrodeposition solution for electroplating sintered neodymium-iron-boron permanent magnet and application thereof - Google Patents
Nickel-cobalt-tungsten alloy electrodeposition solution for electroplating sintered neodymium-iron-boron permanent magnet and application thereof Download PDFInfo
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- 229910001080 W alloy Inorganic materials 0.000 title claims abstract description 110
- 229910001172 neodymium magnet Inorganic materials 0.000 title claims abstract description 110
- YCOASTWZYJGKEK-UHFFFAOYSA-N [Co].[Ni].[W] Chemical compound [Co].[Ni].[W] YCOASTWZYJGKEK-UHFFFAOYSA-N 0.000 title claims abstract description 102
- 238000009713 electroplating Methods 0.000 title claims abstract description 70
- QJVKUMXDEUEQLH-UHFFFAOYSA-N [B].[Fe].[Nd] Chemical compound [B].[Fe].[Nd] QJVKUMXDEUEQLH-UHFFFAOYSA-N 0.000 title claims abstract description 59
- 238000004070 electrodeposition Methods 0.000 title claims abstract description 20
- 239000011248 coating agent Substances 0.000 claims abstract description 29
- 238000000576 coating method Methods 0.000 claims abstract description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 22
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims abstract description 18
- 239000008139 complexing agent Substances 0.000 claims abstract description 15
- 239000003381 stabilizer Substances 0.000 claims abstract description 14
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 13
- DBMJMQXJHONAFJ-UHFFFAOYSA-M Sodium laurylsulphate Chemical compound [Na+].CCCCCCCCCCCCOS([O-])(=O)=O DBMJMQXJHONAFJ-UHFFFAOYSA-M 0.000 claims abstract description 11
- 239000000080 wetting agent Substances 0.000 claims abstract description 11
- QWMFKVNJIYNWII-UHFFFAOYSA-N 5-bromo-2-(2,5-dimethylpyrrol-1-yl)pyridine Chemical compound CC1=CC=C(C)N1C1=CC=C(Br)C=N1 QWMFKVNJIYNWII-UHFFFAOYSA-N 0.000 claims abstract description 10
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims abstract description 10
- 235000011114 ammonium hydroxide Nutrition 0.000 claims abstract description 10
- MEYVLGVRTYSQHI-UHFFFAOYSA-L cobalt(2+) sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Co+2].[O-]S([O-])(=O)=O MEYVLGVRTYSQHI-UHFFFAOYSA-L 0.000 claims abstract description 9
- 229910000029 sodium carbonate Inorganic materials 0.000 claims abstract description 9
- KERTUBUCQCSNJU-UHFFFAOYSA-L nickel(2+);disulfamate Chemical compound [Ni+2].NS([O-])(=O)=O.NS([O-])(=O)=O KERTUBUCQCSNJU-UHFFFAOYSA-L 0.000 claims abstract description 7
- 239000002904 solvent Substances 0.000 claims abstract description 3
- 238000000227 grinding Methods 0.000 claims description 42
- 238000000034 method Methods 0.000 claims description 41
- 150000003839 salts Chemical class 0.000 claims description 31
- 239000002253 acid Substances 0.000 claims description 30
- 238000005406 washing Methods 0.000 claims description 29
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid group Chemical group C(CC(O)(C(=O)O)CC(=O)O)(=O)O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 15
- MIMUSZHMZBJBPO-UHFFFAOYSA-N 6-methoxy-8-nitroquinoline Chemical compound N1=CC=CC2=CC(OC)=CC([N+]([O-])=O)=C21 MIMUSZHMZBJBPO-UHFFFAOYSA-N 0.000 claims description 11
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 11
- 229910017604 nitric acid Inorganic materials 0.000 claims description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 10
- 230000004913 activation Effects 0.000 claims description 10
- 238000005238 degreasing Methods 0.000 claims description 10
- 229910002804 graphite Inorganic materials 0.000 claims description 10
- 239000010439 graphite Substances 0.000 claims description 10
- 230000003213 activating effect Effects 0.000 claims description 9
- FTLYMKDSHNWQKD-UHFFFAOYSA-N (2,4,5-trichlorophenyl)boronic acid Chemical group OB(O)C1=CC(Cl)=C(Cl)C=C1Cl FTLYMKDSHNWQKD-UHFFFAOYSA-N 0.000 claims description 8
- 229940085605 saccharin sodium Drugs 0.000 claims description 8
- 239000004902 Softening Agent Substances 0.000 claims description 7
- DLDJFQGPPSQZKI-UHFFFAOYSA-N but-2-yne-1,4-diol Chemical group OCC#CCO DLDJFQGPPSQZKI-UHFFFAOYSA-N 0.000 claims description 7
- RGHNJXZEOKUKBD-SQOUGZDYSA-N D-gluconic acid Chemical compound OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C(O)=O RGHNJXZEOKUKBD-SQOUGZDYSA-N 0.000 claims description 6
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 claims description 4
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 claims description 4
- 239000004327 boric acid Substances 0.000 claims description 4
- 239000011975 tartaric acid Substances 0.000 claims description 4
- 235000002906 tartaric acid Nutrition 0.000 claims description 4
- RGHNJXZEOKUKBD-UHFFFAOYSA-N D-gluconic acid Natural products OCC(O)C(O)C(O)C(O)C(O)=O RGHNJXZEOKUKBD-UHFFFAOYSA-N 0.000 claims description 3
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 claims description 3
- VMHLLURERBWHNL-UHFFFAOYSA-M Sodium acetate Chemical compound [Na+].CC([O-])=O VMHLLURERBWHNL-UHFFFAOYSA-M 0.000 claims description 3
- 125000005619 boric acid group Chemical group 0.000 claims description 3
- 239000000174 gluconic acid Substances 0.000 claims description 3
- 235000012208 gluconic acid Nutrition 0.000 claims description 3
- 239000001632 sodium acetate Substances 0.000 claims description 3
- 235000017281 sodium acetate Nutrition 0.000 claims description 3
- FIPWRIJSWJWJAI-UHFFFAOYSA-N Butyl carbitol 6-propylpiperonyl ether Chemical class C1=C(CCC)C(COCCOCCOCCCC)=CC2=C1OCO2 FIPWRIJSWJWJAI-UHFFFAOYSA-N 0.000 claims 1
- 239000011247 coating layer Substances 0.000 claims 1
- 230000007797 corrosion Effects 0.000 abstract description 22
- 238000005260 corrosion Methods 0.000 abstract description 22
- 239000011159 matrix material Substances 0.000 abstract description 7
- 230000003647 oxidation Effects 0.000 abstract description 5
- 238000007254 oxidation reaction Methods 0.000 abstract description 5
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- 230000008025 crystallization Effects 0.000 abstract description 4
- 230000002035 prolonged effect Effects 0.000 abstract description 4
- 239000002932 luster Substances 0.000 abstract 1
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- 238000012360 testing method Methods 0.000 description 51
- 239000000243 solution Substances 0.000 description 43
- 238000004506 ultrasonic cleaning Methods 0.000 description 41
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 36
- 230000035939 shock Effects 0.000 description 26
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 25
- 238000002474 experimental method Methods 0.000 description 24
- 230000008569 process Effects 0.000 description 23
- 230000032683 aging Effects 0.000 description 21
- 239000007788 liquid Substances 0.000 description 21
- 239000000463 material Substances 0.000 description 19
- 230000007935 neutral effect Effects 0.000 description 19
- 230000005587 bubbling Effects 0.000 description 18
- 229910052759 nickel Inorganic materials 0.000 description 18
- 239000007921 spray Substances 0.000 description 18
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 12
- 238000005554 pickling Methods 0.000 description 11
- 239000000843 powder Substances 0.000 description 10
- 229910052779 Neodymium Inorganic materials 0.000 description 9
- 238000004140 cleaning Methods 0.000 description 9
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 9
- MOWMLACGTDMJRV-UHFFFAOYSA-N nickel tungsten Chemical compound [Ni].[W] MOWMLACGTDMJRV-UHFFFAOYSA-N 0.000 description 9
- 229910052593 corundum Inorganic materials 0.000 description 8
- 239000010431 corundum Substances 0.000 description 8
- 238000012216 screening Methods 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- 230000035882 stress Effects 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000000758 substrate Substances 0.000 description 5
- 229910052796 boron Inorganic materials 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000001962 electrophoresis Methods 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- RRIWRJBSCGCBID-UHFFFAOYSA-L nickel sulfate hexahydrate Chemical compound O.O.O.O.O.O.[Ni+2].[O-]S([O-])(=O)=O RRIWRJBSCGCBID-UHFFFAOYSA-L 0.000 description 2
- 229940116202 nickel sulfate hexahydrate Drugs 0.000 description 2
- TXRHHNYLWVQULI-UHFFFAOYSA-L nickel(2+);disulfamate;tetrahydrate Chemical compound O.O.O.O.[Ni+2].NS([O-])(=O)=O.NS([O-])(=O)=O TXRHHNYLWVQULI-UHFFFAOYSA-L 0.000 description 2
- DURPTKYDGMDSBL-UHFFFAOYSA-N 1-butoxybutane Chemical class CCCCOCCCC DURPTKYDGMDSBL-UHFFFAOYSA-N 0.000 description 1
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000013473 artificial intelligence Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
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- 238000005265 energy consumption Methods 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- LAIZPRYFQUWUBN-UHFFFAOYSA-L nickel chloride hexahydrate Chemical compound O.O.O.O.O.O.[Cl-].[Cl-].[Ni+2] LAIZPRYFQUWUBN-UHFFFAOYSA-L 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- -1 phenylsulfonyl imide Chemical class 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
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- 238000010298 pulverizing process Methods 0.000 description 1
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- 239000010865 sewage Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
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- Electroplating Methods And Accessories (AREA)
- Electroplating And Plating Baths Therefor (AREA)
Abstract
The invention discloses a nickel-cobalt-tungsten alloy electrodeposition solution for electroplating a sintered neodymium-iron-boron permanent magnet and application thereof, wherein the electrodeposition solution comprises the following components: 80-100 g/L of tetrahydrated nickel sulfamate, 80-100 g/L of sodium tungstate dihydrate, 10-30 g/L of cobalt sulfate heptahydrate, 220-240 g/L of complexing agent, 20-30 g/L of stabilizer, 35-45 g/L of sodium carbonate, 1-3ml/L of ammonia water with mass concentration of 25-28%, 0.1-0.3 g/L of sodium dodecyl sulfate as wetting agent, 10-15g/L of softener, 0.5-2g/L of main gloss agent and water as solvent. After the electroplating solution is electroplated on the surface of the magnet, a smooth nickel-cobalt-tungsten alloy coating which is good in stability, continuous and uniform in coating, compact in crystallization, bright and uniform in color and luster and free of residual stress can be formed, the service life of the neodymium-iron-boron permanent magnet is greatly prolonged, the neodymium-iron-boron permanent magnet matrix and the nickel-cobalt-tungsten alloy coating have extremely high binding force, the internal stress of the nickel-cobalt-tungsten alloy coating is low, the corrosion resistance is extremely high, the nickel-cobalt-tungsten alloy coating can resist high-temperature oxidation, and the hardness is extremely high, so that the nickel-cobalt-tungsten alloy coating has extremely high wear resistance.
Description
Technical Field
The invention relates to a nickel-cobalt-tungsten alloy electrodeposition solution for electroplating sintered neodymium-iron-boron permanent magnets and application thereof.
Background
The neodymium iron boron material has excellent magnetic performance, is widely applied to the fields of electronics, electrical appliances, motors, medical appliances, acoustics, wind power equipment, new energy automobiles and the like, and is one of the magnetic materials with the strongest magnetic performance discovered so far. However, due toThe limitation of the preparation and processing technology of the NdFeB permanent magnet leads to poor corrosion resistance and easy pulverization of the magnet. Neodymium iron boron has three phases: main phase (Nd) 2 Fe 14 B) A neodymium-rich phase, a boron-rich phase, wherein the neodymium-rich phase and the boron-rich phase are generally distributed at the grain boundary, the neodymium-rich phase is extremely easily corroded by oxidation, and the main phase of the magnet (Nd 2 Fe 14 B) The volume fraction of the metal neodymium is far greater than that of the neodymium-rich phase and the boron-rich phase, and the potentials of the phases are different, so that innumerable tiny primary cells are formed to generate galvanic corrosion, inter-crystal corrosion is further accelerated, in addition, the chemical property of the metal neodymium is relatively active, the metal neodymium is easily oxidized by oxygen in the air, and even if the metal neodymium encounters water, the metal neodymium reacts to release hydrogen, so that the service life of the neodymium-iron-boron permanent magnet can be prolonged by surface protection.
The surface protection of the existing sintered NdFeB material comprises electrogalvanizing, nickel electroplating, chemical nickel, electrophoresis and the like, wherein neutral salt fog resistance of the galvanized material and the nickel plating is relatively poor, high-temperature high-pressure accelerated aging test resistance of the electrophoresis is relatively poor, and compared with the former treatment modes, the chemical nickel plating has higher mechanical property and corrosion resistance, but plating solution is more complex to maintain, has higher high-temperature energy consumption, is unstable and is easy to decompose, sewage treatment is relatively difficult, and the production cost is higher, so that the popularization and the application of the material in a large area are limited.
The electroplated nickel-cobalt-tungsten alloy is one of the potential chromium-substituting electroplating technologies, has the advantages of high hardness, high wear resistance, high-temperature oxidation resistance and good corrosion resistance, is commonly used for devices such as internal combustion engine cylinders, piston rings, hot forging dies, contactors, clock movements and the like, but the traditional nickel-tungsten alloy electroplating technology has the same defects or imperfections, namely the content of nickel and tungsten in an alloy coating is not easy to control, so that the nickel-cobalt-tungsten alloy coating is of a crystalline state and an amorphous state alloy formed after plating, wherein the mechanical property and the chemical property of the latter are better than those of the former, and the mature stable, easy to operate and maintain management and simple and controllable electroplated nickel-cobalt-tungsten alloy electroplating technology (adding cobalt elements on the basis of the traditional electroplated nickel-tungsten alloy) is required to ensure that the amorphous nickel-cobalt-tungsten alloy coating with low internal stress, high binding force and corrosion resistance is obtained after plating. The neodymium iron boron permanent magnet material has few reports of directly electroplating nickel cobalt tungsten alloy on a magnet substrate so far, and obviously the whole industry is not paid attention to the electroplating technology or has no mature process technology support so as to be used for magnet electroplating and realize mass industrialized production.
Disclosure of Invention
Aiming at the technical problems in the prior art, the purpose of the application is to provide a nickel-cobalt-tungsten alloy electrodeposition solution for electroplating sintered NdFeB permanent magnets and application thereof. The invention provides a preparation method of a functional and protective nickel-cobalt-tungsten alloy coating for a sintered neodymium-iron-boron permanent magnet and a preparation method of an electrodeposition solution, wherein after the electrodeposition solution is electroplated on the surface of the magnet, a smooth nickel-cobalt-tungsten alloy coating with good stability, continuous and uniform coating, compact crystallization, bright and uniform color and no residual stress can be formed, and the service life of the neodymium-iron-boron permanent magnet is greatly prolonged.
The technical scheme adopted by the application is as follows:
the nickel-cobalt-tungsten alloy electrodeposition solution for electroplating sintered NdFeB permanent magnets comprises the following components: 80-100 g/L of tetrahydrated nickel sulfamate, 80-100 g/L of sodium tungstate dihydrate, 10-30 g/L of cobalt sulfate heptahydrate, 220-240 g/L of complexing agent, 20-30 g/L of stabilizer, 35-45 g/L of sodium carbonate, 1-3ml/L of ammonia water with mass concentration of 25-28%, 0.1-0.3 g/L of sodium dodecyl sulfate as wetting agent, 10-15g/L of softener, 0.5-2g/L of main gloss agent and water as solvent.
Further, the complexing agent is citric acid, tartaric acid, ethylenediamine tetraacetic acid and gluconic acid, and the molar ratio is 1:0.5 to 2:1 to 4: 1-4, preferably in a molar ratio of 1:1:2:2; the stabilizer is boric acid and sodium acetate according to the mole ratio of 1-5: 1, preferably in a molar ratio of 3:1.
Further, the softening agent is saccharin sodium or bisbenzenesulfonimide, and the main gloss agent is 1, 4-butynediol or butyl ether salt.
In the preferred scheme, all chemical raw materials are AR analytical pure or electroplating grade, and the water used is pure water with conductivity of less than 10 us/cm.
The invention provides an electroplating process method for directly electroplating nickel cobalt tungsten alloy on a sintered NdFeB permanent magnet.
In the preferred embodiment, all electroplating methods are barrel plating.
The invention provides a process for directly electroplating nickel-cobalt-tungsten alloy on a sintered NdFeB permanent magnet, which comprises the following specific steps:
(1) Grinding chamfer
The brown fused alumina abrasive is added into the vibration grinder to grind and chamfer the black piece of the sintered NdFeB permanent magnet, the effect is to pour the R angle out of the edge of the magnet so as to avoid corner collapse caused by collision in the subsequent electroplating process, in addition, the roughness of the surface of the magnet can be changed to play a role in polishing, the oxide skin of the surface of the magnet can be loosened, and the smooth proceeding of the pickling process is facilitated.
(2) Ultrasonic degreasing
Preparing oil removing liquid with the concentration of 30-70g/L by using S-210 commercial oil removing powder, adding the prepared oil removing liquid into an ultrasonic cleaning tank, carrying out ultrasonic internal oil removing on the ground and polished neodymium-iron-boron permanent magnet for 5-10min at the temperature of 50-60 ℃, and stripping various greasy dirt attached to the surface of the magnet by utilizing cavitation of ultrasonic waves to provide a clean surface for the pickling process, wherein the S-210 commercial oil removing powder is purchased from Suzhou and Union chemical materials Co.
(3) Acid washing rust removal
The sintered NdFeB permanent magnet is pickled by using an industrial nitric acid aqueous solution with the mass concentration of 2.5-3.5%, the black oxide skin on the outer layer is removed, ultrasonic vibration cleaning is assisted in the pickling process, and boron ash on the surface of the pickled magnet can be removed, so that the magnet substrate is exposed.
(4) Acid salt activation
The surface of the magnet after acid washing is activated by using 10-30 g/L of ammonium bifluoride aqueous solution, so as to provide a clean and uniform electrodeposited surface for subsequent electroplating.
(5) Electroplated nickel cobalt tungsten alloy
And (3) taking the activated magnet as a cathode, taking graphite as an anode, and placing the magnet into the nickel-cobalt-tungsten alloy electrodepositing solution provided by the application for electroplating, and washing after the electroplating is finished.
Further, in the electrodeposition process, the temperature of the nickel-cobalt-tungsten alloy electrodeposition solution is 70-80 ℃, the pH value is 6.5-7.5, and the cathode current density is 1-4A/dm 2 The thickness of the nickel-cobalt-tungsten alloy coating is 8-10um.
The invention provides a process method for directly electroplating nickel-cobalt-tungsten alloy on a sintered NdFeB permanent magnet, which is characterized by comprising the following steps of: (1) The addition of the complexing agent and the stabilizer in the process ensures that the whole plating liquid system is extremely stable, the complexing agent fully complexes metal ions, and the stabilizer reconciles various components in the plating liquid, thereby solving the problems that the components of the plating liquid are easy to be out of proportion in the traditional nickel-tungsten alloy plating process, so that the nickel-tungsten content in the alloy plating layer is difficult to control, thereby influencing the mechanical property and the chemical property of the final nickel-tungsten alloy plating layer, and further influencing the bonding force between the plating layer and a magnet matrix and the high-temperature oxidation resistance. (2) The technological method is simple and easy to operate, convenient to maintain and manage, and solves the defects that the traditional nickel-tungsten alloy electroplating technology is easy to generate pits, rough in coating and uneven in thickness distribution after electroplating. (3) The nickel-cobalt-tungsten alloy coating obtained by the process method has extremely high binding force with the neodymium-iron-boron permanent magnet matrix, and the nickel-cobalt-tungsten alloy coating has low internal stress, extremely high corrosion resistance and extremely excellent dispersion capability and coverage capability of the electrodeposition solution. (4) The process does not contain fluorine and phosphorus elements, belongs to a novel environment-friendly and nontoxic process, has little corrosiveness to equipment and surrounding environment, and can easily treat the generated wastewater. (5) After electroplating on the surface of the magnet, a smooth nickel-cobalt-tungsten alloy amorphous plating layer with good stability, continuous and uniform plating layer, compact crystallization, bright and uniform color and no residual stress can be formed, and the service life of the neodymium-iron-boron permanent magnet is greatly prolonged due to the higher corrosion resistance.
The invention can obtain a nickel-cobalt-tungsten alloy coating which is well combined with the neodymium-iron-boron permanent magnet matrix, has low internal stress and high corrosion resistance, so that the sintered neodymium-iron-boron permanent magnet prepared by the process has wider application range, and is especially used in the fields of mobile phones, emerging electronic products, new energy automobiles, artificial intelligence and the like.
The beneficial effects obtained by the invention are as follows:
1) The neodymium-iron-boron permanent magnet matrix and the nickel-cobalt-tungsten alloy plating layer have extremely high binding force, the internal stress of the nickel-cobalt-tungsten alloy plating layer is lower, the corrosion resistance is extremely high, the high-temperature oxidation resistance can be realized, the hardness is extremely high, the wear resistance is extremely high, the dispersion capacity and the coverage capacity of the electrodeposition solution are extremely good, and the like.
2) The test is proved by a large number of parallel comparison tests: when the nickel-cobalt-tungsten alloy plating layer with compact and uniform crystallization is tested by using a GB/T5270-2005 cold-hot circulation experimental method to test the binding force between the sintered neodymium-iron-boron permanent magnet matrix and the nickel-cobalt-tungsten alloy, the test result shows that the nickel-cobalt-tungsten alloy plating layer can bear more than 20 times of cyclic thermal shock tests (220 ℃ for 1 h), and the surface of the plating layer has no phenomena of bubbling, peeling, falling and the like, thereby proving that the binding force between the plating layer and the magnet matrix is good; the nickel-cobalt-tungsten alloy coating prepared by the method is used for PCT (high-temperature high-pressure accelerated aging test) (the experimental conditions are 120 ℃,2atm and 100% RH), and the coating still has no any changes such as bubbling, fracture, stripping, rust and the like after 1500 hours, so that the comprehensive performance of the coating is very good; the nickel-cobalt-tungsten alloy plating layer prepared by the method is tested according to GB/T10125-2021 neutral salt spray test standard (35 ℃,5% NaCl, PH=7), and the result shows that the nickel-cobalt-tungsten alloy plating layer still has no corrosion phenomenon after 480 hours, thus the plating layer has extremely high corrosion resistance.
Detailed Description
The invention is illustrated and described below in connection with the following detailed examples, but the invention is not limited to these examples.
Except the special description, the complexing agent is a mixture prepared from citric acid, tartaric acid, ethylenediamine tetraacetic acid and gluconic acid according to a molar ratio of 1:1:2:2; the stabilizer is boric acid and sodium acetate with the molar ratio of 3:1, and the mass concentration of ammonia water is 25-28%.
Example 1
The method for electroplating nickel-cobalt-tungsten alloy on the sintered NdFeB permanent magnet comprises the following steps:
(1) Grinding and chamfering: and (3) putting 4kg of sintered NdFeB permanent magnet black sheets with the specification of (8 x 5 x 2) mm into a vibration grinding machine, adding 30kg of inclined triangular brown corundum grinding material with the specification of (8 x 8), respectively vibrating and grinding the grinding machine for 3 hours at the vibration frequencies of 30HZ, 40HZ and 50HZ, and selecting the sintered NdFeB permanent magnets by sorting and screening after finishing, and cleaning by ultrasonic waves.
(2) Ultrasonic degreasing: the commercial deoiling powder of S-210 prepares deoiling liquid with the concentration of 50g/L by water, the prepared deoiling liquid is added into an ultrasonic cleaning tank, the ground and polished neodymium-iron-boron permanent magnet is subjected to ultrasonic cleaning and deoiling at the temperature of 50 ℃ for 10min, and the ultrasonic cleaning is carried out and then the neodymium-iron-boron permanent magnet is washed cleanly.
(3) Acid washing and rust removal: and (3) acid washing and descaling the magnet subjected to ultrasonic cleaning by dilute nitric acid with the mass concentration of 2.5%, and removing boron powder on the surface of the magnet in the middle process by ultrasonic cleaning.
(4) Acid salt activation: preparing 20 g/L ammonium bifluoride solution, activating the magnet after pickling for 1min, and then washing with water.
(5) Electroplating nickel-cobalt-tungsten alloy: the activated magnet is put into a nickel cobalt tungsten alloy plating solution for electroplating, and the plating solution comprises the following components: 80 g/L of tetrahydrated nickel sulfamate, 80 g/L of sodium tungstate dihydrate, 10g/L of cobalt sulfate heptahydrate, 220 g/L of complexing agent, 20 g/L of stabilizer, 35 g/L of sodium carbonate, 1ml/L of ammonia water with the mass concentration of 25-28%, 0.1 g/L of sodium dodecyl sulfate as wetting agent, 10g/L of saccharin sodium as softening agent, 0.5g/L of 1, 4-butynediol as main light agent, 70 ℃ of nickel cobalt tungsten alloy plating solution, 6.5 pH value adjustment, electroplating treatment by taking neodymium iron boron permanent magnet as a cathode and taking an anode as graphite, wherein the current density of the cathode is 1A/dm 2 The electroplating time is 180min, and the thickness of the nickel-cobalt-tungsten alloy coating is 8um.
(6) GB/T5270-2005 cold-hot cycle thermal shock experiment 1-1:
(7) And taking 100 sintered NdFeB permanent magnets plated with nickel-cobalt-tungsten alloy for cold-hot cycle thermal shock experiments, wherein experimental results show that the nickel-cobalt-tungsten alloy plating layer has no phenomena of bubbling, peeling, falling and the like after 20 times of thermal shock, so that the bonding force between the plating layer and the magnet base material is good, and the experimental results are shown in Table 1.
(8) PCT (high temperature high pressure accelerated aging test) 1-2:
(9) The sintered NdFeB permanent magnet 100 sheets of the nickel-cobalt-tungsten alloy plated in the embodiment 1 are subjected to a high-temperature high-pressure accelerated aging test, and the plating layer still does not have any changes such as bubbling, fracture, stripping, rust and the like after 1500 hours, so that the comprehensive performance of the plating layer is very good, and the experimental results are shown in Table 2.
(10) NSS (neutral salt spray test) 1-3:
(11) 100 sintered NdFeB permanent magnets plated with the nickel-cobalt-tungsten alloy in the example 1 are taken for a neutral salt spray test, no rust phenomenon is found in the plating layer after 480 hours, the corrosion resistance of the plating layer is good, and the experimental results are shown in Table 3.
Example 2
The method for electroplating nickel-cobalt-tungsten alloy on the sintered NdFeB permanent magnet comprises the following steps:
(1) Grinding and chamfering: and (3) putting 4kg of sintered NdFeB permanent magnet black sheets with the specification of (8 x 5 x 2) mm into a vibration grinding machine, adding 30kg of inclined triangular brown corundum grinding material with the specification of (8 x 8), respectively vibrating and grinding the grinding machine for 3 hours at the vibration frequencies of 30HZ, 40HZ and 50HZ, and selecting the sintered NdFeB permanent magnets by sorting and screening after finishing, and cleaning by ultrasonic waves.
(2) Ultrasonic degreasing: the commercial deoiling powder of S-210 prepares deoiling liquid with the concentration of 50g/L by water, the prepared deoiling liquid is added into an ultrasonic cleaning tank, the ground and polished neodymium-iron-boron permanent magnet is subjected to ultrasonic cleaning and deoiling at the temperature of 50 ℃ for 10min, and the ultrasonic cleaning is carried out and then the neodymium-iron-boron permanent magnet is washed cleanly.
(3) Acid washing and rust removal: and (3) acid washing and descaling the magnet subjected to ultrasonic cleaning by using dilute nitric acid with the mass concentration of 2.5%, and removing boron powder on the surface of the magnet in the middle process by assisting ultrasonic cleaning.
(4) Acid salt activation: preparing 20 g/L ammonium bifluoride solution, activating the magnet after pickling for 1min, and then washing with water.
(5) Electroplating nickel-cobalt-tungsten alloy: will activateThe good magnet is put into a nickel cobalt tungsten alloy plating solution for electroplating, and the plating solution comprises the following components: 90 g/L of nickel sulfamate tetrahydrate, 90 g/L of sodium tungstate dihydrate, 20 g/L of cobalt sulfate heptahydrate, 230 g/L of complexing agent, 25 g/L of stabilizer, 40 g/L of sodium carbonate, 2ml/L of ammonia water with the mass concentration of 25-28%, 0.2 g/L of sodium dodecyl sulfate as wetting agent, 12.5g/L of softener (bisbenzenesulfonimide), 1g/L of main light agent 1, 4-butynediol, 75 ℃ of nickel cobalt tungsten alloy plating solution, 7 pH value, plating treatment by taking neodymium iron boron permanent magnet as a cathode and taking an anode as graphite, wherein the current density of the cathode is 1.5A/dm 2 The electroplating time is 140min, and the thickness of the nickel-cobalt-tungsten alloy coating is 9um.
(6) GB/T5270-2005 cold-hot cycle thermal shock experiment 2-1:
(7) The 100 sintered neodymium-iron-boron permanent magnets plated with the nickel-cobalt-tungsten alloy in the embodiment 2 are subjected to cold-hot cycle thermal shock experiments, and experimental results show that the nickel-cobalt-tungsten alloy plating layer has no phenomena of bubbling, peeling, falling and the like after 20 times of thermal shock, so that the bonding force between the plating layer and the magnet base material is good, and the experimental results are shown in table 1.
(8) PCT (high temperature high pressure accelerated aging test) 2-2:
(9) The 100 sintered NdFeB permanent magnet sheets plated with the nickel-cobalt-tungsten alloy in the embodiment 2 are subjected to a high-temperature high-pressure accelerated aging test, and the plating layer still does not have any changes such as bubbling, fracture, stripping, rust and the like after 1500 hours, so that the comprehensive performance of the plating layer is very good, and the experimental results are shown in Table 2.
(10) NSS (neutral salt spray test) 2-3:
(11) 100 sintered NdFeB permanent magnets plated with the nickel-cobalt-tungsten alloy in the example 2 are taken for neutral salt spray test, no rust phenomenon is found in the plating layer after 480 hours, the corrosion resistance of the plating layer is good, and the experimental results are shown in Table 3.
Example 3
The method for electroplating nickel-cobalt-tungsten alloy on the sintered NdFeB permanent magnet comprises the following steps:
(1) Grinding and chamfering: and (3) putting 4kg of sintered NdFeB permanent magnet black sheets with the specification of (8 x 5 x 2) mm into a vibration grinding machine, adding 30kg of inclined triangular brown corundum grinding material with the specification of (8 x 8), respectively vibrating and grinding the grinding machine for 3 hours at the vibration frequencies of 30HZ, 40HZ and 50HZ, and selecting the sintered NdFeB permanent magnets by sorting and screening after finishing, and cleaning by ultrasonic waves.
(2) Ultrasonic degreasing: the commercial deoiling powder of S-210 prepares deoiling liquid with the concentration of 50g/L by using water, the prepared deoiling liquid is added into an ultrasonic cleaning tank, the ground and polished neodymium-iron-boron permanent magnet is subjected to ultrasonic cleaning and deoiling at the temperature of 50 ℃, the temperature is 50 ℃, the time is 10min, and the ultrasonic cleaning is carried out and then the neodymium-iron-boron permanent magnet is cleaned.
(3) Acid washing and rust removal: and (3) acid washing and descaling the magnet subjected to ultrasonic cleaning by using dilute nitric acid with the mass concentration of 2.5%, and removing boron powder on the surface of the magnet in the middle process by assisting ultrasonic cleaning.
(4) Acid salt activation: preparing 20 g/L ammonium bifluoride solution, activating the magnet after pickling for 1min, and then washing with water.
(5) Electroplating nickel-cobalt-tungsten alloy: the activated magnet is put into a nickel cobalt tungsten alloy plating solution for electroplating, and the plating solution comprises the following components: 100 g/L of nickel sulfamate tetrahydrate, 100 g/L of sodium tungstate dihydrate, 30 g/L of cobalt sulfate heptahydrate, 240 g/L of complexing agent, 30 g/L of stabilizer, 45 g/L of sodium carbonate, 3ml/L of ammonia water with the mass concentration of 25-28%, 0.3 g/L of sodium dodecyl sulfate as wetting agent, 15g/L of softener (bis (phenylsulfonyl imide)), 2g/L of main light agent (Ding Miweng salt), 2g/L of nickel cobalt tungsten alloy plating solution with the temperature of 80 ℃ and the pH value of 7.5, electroplating treatment by taking neodymium-iron-boron permanent magnet as a cathode and taking an anode as graphite, wherein the current density of the cathode is 2A/dm 2 The electroplating time is 120min, and the thickness of the nickel-cobalt-tungsten alloy coating is 10um.
(6) GB/T5270-2005 cold-hot cycle thermal shock experiment 3-1:
(7) The 100 sintered neodymium-iron-boron permanent magnets plated with the nickel-cobalt-tungsten alloy in the embodiment 3 are subjected to cold-hot cycle thermal shock experiments, and experimental results show that the nickel-cobalt-tungsten alloy plating layer has no phenomena of bubbling, peeling, falling and the like after 20 times of thermal shock, so that the bonding force between the plating layer and the magnet base material is good, and the experimental results are shown in table 1.
(8) PCT (high temperature high pressure accelerated aging test) 3-2:
(9) The 100 sintered NdFeB permanent magnet sheets plated with the nickel-cobalt-tungsten alloy in the embodiment 3 are subjected to a high-temperature high-pressure accelerated aging test, and the plating layer still does not have any changes such as bubbling, fracture, stripping, rust and the like after 1500 hours, so that the comprehensive performance of the plating layer is very good, and the experimental results are shown in Table 2.
(10) NSS (neutral salt spray test) 3-3:
(11) 100 sintered NdFeB permanent magnets plated with nickel-cobalt-tungsten alloy in example 3 were taken for neutral salt spray test, no rust phenomenon was found in the plating layer after 480 hours, and the corrosion resistance of the plating layer was very good, and the experimental results are shown in Table 3.
Example 4 (comparative example)
The method for electroplating nickel-cobalt-tungsten alloy on the sintered NdFeB permanent magnet comprises the following steps:
(1) Grinding and chamfering: and (3) putting 4kg of sintered NdFeB permanent magnet black sheets with the specification of (8 x 5 x 2) mm into a vibration grinding machine, adding 30kg of inclined triangular brown corundum grinding material with the specification of (8 x 8), respectively vibrating and grinding the grinding machine for 3 hours at the vibration frequencies of 30HZ, 40HZ and 50HZ, and selecting the sintered NdFeB permanent magnets by sorting and screening after finishing, and cleaning by ultrasonic waves.
(2) Ultrasonic degreasing: the commercial deoiling powder of S-210 prepares deoiling liquid with the concentration of 50g/L by using water, the prepared deoiling liquid is added into an ultrasonic cleaning tank, the ground and polished neodymium-iron-boron permanent magnet is subjected to ultrasonic cleaning and deoiling at the temperature of 50 ℃, the temperature is 50 ℃, the time is 10min, and the ultrasonic cleaning is carried out and then the neodymium-iron-boron permanent magnet is cleaned.
(3) Acid washing and rust removal: and (3) acid washing and descaling the magnet subjected to ultrasonic cleaning by using dilute nitric acid with the mass concentration of 2.5%, and removing boron powder on the surface of the magnet in the middle process by assisting ultrasonic cleaning.
(4) Acid salt activation: preparing 20 g/L ammonium bifluoride solution, activating the magnet after pickling for 1min, and then washing with water.
(5) Electroplating the watt nickel: placing the activated magnet into a watt nickel plating solution for electroplating, wherein the plating solution comprises the following components: 200 g/L nickel sulfate hexahydrate, 40 g/L nickel chloride hexahydrate, 40 g/L boric acid, 0.1 g/L sodium dodecyl sulfate as wetting agent, 10g/L softener (saccharin sodium), 1g/L main gloss agent (Ding Miweng salt),the plating solution is electroplated with NdFeB permanent magnet as cathode and graphite as anode at 50 deg.c and pH 4.0 and with cathode current density of 1A/dm 2 The electroplating time is 120min, and the thickness of the nickel coating is 8um.
(6) GB/T5270-2005 cold and hot cycle thermal shock experiment 4-1:
(7) The 100 sintered neodymium-iron-boron permanent magnet plated with nickel in example 4 was subjected to a thermal shock test in a thermal cycle, and the test results showed that 22 nickel plating layers had the phenomena of bubbling, peeling, falling off and the like after 5 times of thermal shock, which indicated that the bonding force between the plating layers and the magnet substrate was poor, and the test results are shown in table 1.
(8) PCT (high temperature high pressure accelerated aging test) 4-2:
(9) 100 sintered neodymium-iron-boron permanent magnets plated with nickel in example 4 were subjected to a high-temperature high-pressure accelerated aging test, and 98 plates were found to have changes such as bubbling, fracture, stripping and rust after 100 hours, which indicated that the comprehensive performance of the plates was not good enough, and the test results are shown in table 2.
(10) NSS (neutral salt spray test) 4-3:
(11) 100 sintered NdFeB permanent magnets plated with nickel in example 4 were taken for neutral salt spray test, and after 48 hours, the plating layer was found to have rust phenomenon, which indicates that the corrosion resistance of the plating layer is poor, and the experimental results are shown in Table 3.
Example 5 (comparative example)
The method for electroplating nickel-cobalt-tungsten alloy on the sintered NdFeB permanent magnet comprises the following steps:
(1) Grinding and chamfering: and (3) putting 4kg of sintered NdFeB permanent magnet black sheets with the specification of (8 x 5 x 2) mm into a vibration grinding machine, adding 30kg of inclined triangular brown corundum grinding material with the specification of (8 x 8), respectively vibrating and grinding the grinding machine for 3 hours at the vibration frequencies of 30HZ, 40HZ and 50HZ, and selecting the sintered NdFeB permanent magnets by sorting and screening after finishing, and cleaning by ultrasonic waves.
(2) Ultrasonic degreasing: the commercial deoiling powder of S-210 prepares deoiling liquid with the concentration of 50g/L by using water, the prepared deoiling liquid is added into an ultrasonic cleaning tank, the ground and polished neodymium-iron-boron permanent magnet is subjected to ultrasonic cleaning and deoiling at the temperature of 50 ℃, the temperature is 50 ℃, the time is 10min, and the ultrasonic cleaning is carried out and then the neodymium-iron-boron permanent magnet is cleaned.
(3) Acid washing and rust removal: and (3) acid washing and descaling the magnet subjected to ultrasonic cleaning by using dilute nitric acid with the mass concentration of 2.5%, and removing boron powder on the surface of the magnet in the middle process by assisting ultrasonic cleaning.
(4) Acid salt activation: preparing 20 g/L ammonium bifluoride solution, activating the magnet after pickling for 1min, and then washing with water.
(5) Electroplating traditional nickel-tungsten alloy: placing the activated magnet into a traditional nickel-tungsten plating solution for electroplating, wherein the plating solution comprises the following components: 60 g/L nickel sulfate hexahydrate, 20 g/L sodium tungstate dihydrate, 100 g/L citric acid, 0.1 g/L sodium dodecyl sulfate as wetting agent, 10g/L saccharin sodium as softening agent, 1g/L main gloss agent (1.4 butynediol), 60 ℃ of plating solution, 6.5 of pH, electroplating by taking a neodymium-iron-boron permanent magnet as a cathode and taking an anode as graphite, wherein the current density of the cathode is 1A/dm 2 The electroplating time is 200min, and the thickness of the nickel coating is 8um.
(6) GB/T5270-2005 cold and hot cycle thermal shock experiment 5-1:
(7) The 100 sintered neodymium-iron-boron permanent magnet plated with nickel in example 5 was subjected to a thermal shock test by a thermal cycle, and the test results showed that 10 nickel plating layers had the phenomena of bubbling, peeling, falling off and the like after 5 times of thermal shock, which indicated that the bonding force between the plating layers and the magnet substrate was poor, and the test results are shown in table 1.
(8) PCT (high temperature high pressure accelerated aging test) 5-2:
(9) 100 sintered neodymium-iron-boron permanent magnets plated with nickel in example 5 were subjected to a high-temperature high-pressure accelerated aging test, and after 100 hours, 14 plating layers were found to have the changes of bubbling, fracture, stripping, rust and the like, which indicates that the comprehensive performance of the plating layers is not good enough, and the experimental results are shown in Table 2.
(10) NSS (neutral salt spray test) 5-3:
(11) 100 sintered NdFeB permanent magnets plated with nickel in example 5 were taken for neutral salt spray test, and after 96 hours, the plating layer was found to have 5 rusting phenomena, which indicates that the corrosion resistance of the plating layer is not good enough, and the experimental results are shown in Table 3.
Example 6 (comparative example)
The method for electroplating nickel-cobalt-tungsten alloy on the sintered NdFeB permanent magnet comprises the following steps:
(1) Grinding and chamfering: and (3) putting 4kg of sintered NdFeB permanent magnet black sheets with the specification of (8 x 5 x 2) mm into a vibration grinding machine, adding 30kg of inclined triangular brown corundum grinding material with the specification of (8 x 8), respectively vibrating and grinding the grinding machine for 3 hours at the vibration frequencies of 30HZ, 40HZ and 50HZ, and selecting the sintered NdFeB permanent magnets by sorting and screening after finishing, and cleaning by ultrasonic waves.
(2) Ultrasonic degreasing: the commercial deoiling powder of S-210 prepares deoiling liquid with the concentration of 50g/L by using water, the prepared deoiling liquid is added into an ultrasonic cleaning tank, the ground and polished neodymium-iron-boron permanent magnet is subjected to ultrasonic cleaning and deoiling at the temperature of 50 ℃, the temperature is 50 ℃, the time is 10min, and the ultrasonic cleaning is carried out and then the neodymium-iron-boron permanent magnet is cleaned.
(3) Acid washing and rust removal: and (3) acid washing and descaling the magnet subjected to ultrasonic cleaning by using dilute nitric acid with the mass ratio of 2.5%, and removing boron powder on the surface of the magnet in the middle process by assisting ultrasonic cleaning.
(4) Acid salt activation: preparing 20 g/L ammonium bifluoride solution, activating the magnet after pickling for 1min, and then washing with water.
(5) Electroplating nickel-cobalt-tungsten alloy: the activated magnet is put into a nickel cobalt tungsten alloy plating solution for electroplating, and the plating solution comprises the following components: 80 g/L of tetrahydrated nickel sulfamate, 80 g/L of sodium tungstate dihydrate, 10g/L of cobalt sulfate heptahydrate, 220 g/L of complexing agent, 0g/L of stabilizer, 35 g/L of sodium carbonate, 1ml/L of ammonia water with the mass concentration of 25-28%, 0.1 g/L of sodium dodecyl sulfate as wetting agent, 10g/L of saccharin sodium as softening agent, 0.5g/L of 1, 4-butynediol as main light agent, 70 ℃ of nickel cobalt tungsten alloy plating solution, 6.5 of pH value, electroplating treatment by taking a neodymium iron boron permanent magnet as a cathode and taking an anode as graphite, wherein the current density of the cathode is 1A/dm 2 The electroplating time is 180min, and the thickness of the nickel-cobalt-tungsten alloy coating is 8um.
(6) GB/T5270-2005 cold and hot cycle thermal shock experiment 6-1:
(7) The 100 sintered neodymium-iron-boron permanent magnet plated with the nickel-cobalt-tungsten alloy in the embodiment 6 is subjected to a cold-hot cycle thermal shock experiment, and experimental results show that after 20 times of thermal shock, the nickel-cobalt-tungsten alloy plating layer has 26 phenomena of bubbling, skinning, falling and the like, which indicate that the bonding force between the plating layer and the magnet substrate is poor, and experimental results are shown in table 1.
(8) PCT (high temperature high pressure accelerated aging test) 6-2:
(9) 100 sintered NdFeB permanent magnets plated with nickel-cobalt-tungsten alloy in example 6 were subjected to high-temperature high-pressure accelerated aging test, and after 100 hours, the plating layer was found to have changes such as bubbling, fracture, stripping and rust, which indicated that the comprehensive performance of the plating layer was poor, and the experimental results are shown in Table 2.
(10) NSS (neutral salt spray test) 6-3:
(11) 100 sintered NdFeB permanent magnets plated with nickel-cobalt-tungsten alloy in example 6 were taken for neutral salt spray test, and after 96 hours, the plating layer was found to have rust phenomenon, which indicates that the corrosion resistance of the plating layer is poor, and the experimental results are shown in Table 3.
Example 7 (comparative example)
The method for electroplating nickel-cobalt-tungsten alloy on the sintered NdFeB permanent magnet comprises the following steps:
(1) Grinding and chamfering: and (3) putting 4kg of sintered NdFeB permanent magnet black sheets with the specification of (8 x 5 x 2) mm into a vibration grinding machine, adding 30kg of inclined triangular brown corundum grinding material with the specification of (8 x 8), respectively vibrating and grinding the grinding machine for 3 hours at the vibration frequencies of 30HZ, 40HZ and 50HZ, and selecting the sintered NdFeB permanent magnets by sorting and screening after finishing, and cleaning by ultrasonic waves.
(2) Ultrasonic degreasing: the commercial deoiling powder of S-210 prepares deoiling liquid with the concentration of 50g/L by using water, the prepared deoiling liquid is added into an ultrasonic cleaning tank, the ground and polished neodymium-iron-boron permanent magnet is subjected to ultrasonic cleaning and deoiling at the temperature of 50 ℃, the temperature is 50 ℃, the time is 10min, and the ultrasonic cleaning is carried out and then the neodymium-iron-boron permanent magnet is cleaned.
(3) Acid washing and rust removal: and (3) acid washing and descaling the magnet subjected to ultrasonic cleaning by using dilute nitric acid with the mass ratio of 2.5%, and removing boron powder on the surface of the magnet in the middle process by assisting ultrasonic cleaning.
(4) Acid salt activation: preparing 20 g/L ammonium bifluoride solution, activating the magnet after pickling for 1min, and then washing with water.
(5) Electroplating nickel-cobalt-tungsten alloy: placing the activated magnet into nickel cobaltElectroplating is carried out in a tungsten alloy plating solution, and the plating solution comprises the following components: 80 g/L of tetrahydrated nickel sulfamate, 80 g/L of sodium tungstate dihydrate, 10g/L of cobalt sulfate heptahydrate, 220 g/L of complexing agent (the complexing agent is formed by mixing citric acid and tartaric acid according to the mol ratio of 1:1), 25 g/L of stabilizer, 35 g/L of sodium carbonate, 1ml/L of ammonia water with the mass concentration of 25-28%, 0.1 g/L of sodium dodecyl sulfate as wetting agent, 10g/L of saccharin sodium as softening agent, 0.5g/L of 1, 4-butynediol as main light agent, 70 ℃ of nickel cobalt tungsten alloy plating solution, 6.5 of pH, and electroplating treatment by taking neodymium-iron-boron permanent magnet as a cathode and taking an anode as graphite, wherein the current density of the cathode is 1A/dm 2 The electroplating time is 180min, and the thickness of the nickel-cobalt-tungsten alloy coating is 8um.
(6) GB/T5270-2005 thermal shock experiment 7-1:
(7) 100 sintered NdFeB permanent magnets plated with nickel-cobalt-tungsten alloy in the embodiment 7 are subjected to cold-hot cycle thermal shock experiments, and experimental results show that 16 nickel-cobalt-tungsten alloy plating layers have the phenomena of bubbling, skinning, falling and the like after 20 times of thermal shock, which indicate that the bonding force between the plating layers and the magnet base material is poor, and the experimental results are shown in Table 1.
(8) PCT (high temperature high pressure accelerated aging test) 7-2:
(9) 100 sintered NdFeB permanent magnets plated with nickel-cobalt-tungsten alloy in example 7 were subjected to high-temperature high-pressure accelerated aging test, and after 100 hours, the plating layer was found to have changes such as bubbling, fracture, stripping and rust, which indicated that the comprehensive performance of the plating layer was poor, and the experimental results are shown in Table 2.
(10) NSS (neutral salt spray test) 7-3:
(11) 100 sintered NdFeB permanent magnets plated with nickel-cobalt-tungsten alloy in example 7 were taken for neutral salt spray test, and after 96 hours, the plating layer was found to have rust phenomenon, which indicates that the corrosion resistance of the plating layer is poor, and the experimental results are shown in Table 3.
Example 8 (comparative example)
The method for electroplating nickel-cobalt-tungsten alloy on the sintered NdFeB permanent magnet comprises the following steps:
(1) Grinding and chamfering: and (3) putting 4kg of sintered NdFeB permanent magnet black sheets with the specification of (8 x 5 x 2) mm into a vibration grinding machine, adding 30kg of inclined triangular brown corundum grinding material with the specification of (8 x 8), respectively vibrating and grinding the grinding machine for 3 hours at the vibration frequencies of 30HZ, 40HZ and 50HZ, and selecting the sintered NdFeB permanent magnets by sorting and screening after finishing, and cleaning by ultrasonic waves.
(2) Ultrasonic degreasing: the commercial deoiling powder of S-210 prepares deoiling liquid with the concentration of 50g/L by using water, the prepared deoiling liquid is added into an ultrasonic cleaning tank, the ground and polished neodymium-iron-boron permanent magnet is subjected to ultrasonic cleaning and deoiling at the temperature of 50 ℃, the temperature is 50 ℃, the time is 10min, and the ultrasonic cleaning is carried out and then the neodymium-iron-boron permanent magnet is cleaned.
(3) Acid washing and rust removal: and (3) acid washing and descaling the magnet subjected to ultrasonic cleaning by using dilute nitric acid with the mass ratio of 2.5%, and removing boron powder on the surface of the magnet in the middle process by assisting ultrasonic cleaning.
(4) Acid salt activation: preparing 20 g/L ammonium bifluoride solution, activating the magnet after pickling for 1min, and then washing with water.
(5) Electroplating nickel-cobalt-tungsten alloy: the activated magnet is put into a nickel cobalt tungsten alloy plating solution for electroplating, and the plating solution comprises the following components: 80 g/L of tetrahydrated nickel sulfamate, 80 g/L of sodium tungstate dihydrate, 10g/L of cobalt sulfate heptahydrate, 100 g/L of complexing agent, 10g/L of stabilizer, 35 g/L of sodium carbonate, 1ml/L of ammonia water with the mass concentration of 25-28%, 0.1 g/L of sodium dodecyl sulfate as wetting agent, 10g/L of saccharin sodium as softening agent, 0.5g/L of 1, 4-butynediol as main light agent, 70 ℃ of nickel cobalt tungsten alloy plating solution, 6.5 of pH value, electroplating treatment by taking a neodymium iron boron permanent magnet as a cathode and taking an anode as graphite, wherein the current density of the cathode is 1A/dm 2 The electroplating time is 240min, and the thickness of the nickel-cobalt-tungsten alloy coating is 8um.
(6) GB/T5270-2005 cold and hot cycle thermal shock experiment 8-1:
(7) 100 sintered NdFeB permanent magnets plated with nickel-cobalt-tungsten alloy in example 8 were subjected to cold-hot cycle thermal shock experiments, and experimental results show that after 20 times of thermal shock, 29 nickel-cobalt-tungsten alloy plating layers have the phenomena of bubbling, skinning, falling and the like, which indicate that the bonding force between the plating layers and the magnet base material is poor, and experimental results are shown in Table 1.
(8) PCT (high temperature high pressure accelerated aging test) 8-2:
(9) 100 sintered NdFeB permanent magnets plated with nickel-cobalt-tungsten alloy in example 8 were subjected to high-temperature high-pressure accelerated aging test, and after 100 hours, the plating layer was found to have changes such as bubbling, fracture, stripping and rust, which indicated that the comprehensive performance of the plating layer was poor, and the experimental results are shown in Table 2.
(10) NSS (neutral salt spray test) 8-3:
(11) 100 sintered NdFeB permanent magnets plated with nickel-cobalt-tungsten alloy in example 8 were taken for neutral salt spray test, and after 96 hours, the plating layer was found to have rust phenomenon, which indicates that the corrosion resistance of the plating layer is poor, and the experimental results are shown in Table 3.
Table 1: GB/T5270-2005 cold-hot circulation thermal shock experiment record
Table 2: PCT (high temperature high pressure accelerated aging test) record
| Examples | PCT high temperature and high pressure accelerated aging test (hours) |
| Experiment 1-2 of example 1 | Greater than 1500 |
| Experiment 2-2 of example 2 | Greater than 1500 |
| Experiment 3-2 of example 3 | Greater than 1500 |
| Experiment 4-2 of example 4 | ≤100 |
| Experiment 5-2 of example 5 | ≤100 |
| Experiment 6-2 of example 6 | ≤100 |
| Experiment 7-2 of example 7 | ≤100 |
| Experiment 8-2 of example 8 | ≤100 |
Table 3: NSS (neutral salt spray test) record
Compared with the traditional nickel-tungsten alloy plating, the nickel-cobalt-tungsten alloy plating layer prepared by the invention has extremely high improvement and surpass the comprehensive performance and corrosion resistance both in the bonding force between the plating layer and the base material and in the high-temperature high-pressure accelerated aging test.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.
Claims (8)
1. The nickel-cobalt-tungsten alloy electrodeposition solution for electroplating sintered neodymium-iron-boron permanent magnet is characterized by comprising the following components: 80-100 g/L of tetrahydrated nickel sulfamate, 80-100 g/L of sodium tungstate dihydrate, 10-30 g/L of cobalt sulfate heptahydrate, 220-240 g/L of complexing agent, 20-30 g/L of stabilizer, 35-45 g/L of sodium carbonate, 1-3ml/L of ammonia water with mass concentration of 25-28%, 0.1-0.3 g/L of sodium dodecyl sulfate as wetting agent, 10-15g/L of softener, 0.5-2g/L of main gloss agent and water as solvent.
2. The nickel-cobalt-tungsten alloy electrodeposition solution for electroplating sintered neodymium-iron-boron permanent magnet according to claim 1, wherein the complexing agent is citric acid, tartaric acid, ethylenediamine tetraacetic acid, and gluconic acid in a molar ratio of 1: 0.5-2: 1-4: 1-4, preferably a molar ratio of 1:1:2:2; the stabilizer is boric acid and sodium acetate according to the molar ratio of 1-5: 1, preferably in a molar ratio of 3:1.
3. A nickel cobalt tungsten alloy electrodeposition solution for electroplating sintered neodymium iron boron permanent magnet according to claim 1, wherein the softening agent is saccharin sodium or bis-benzenesulfonimide and the primary gloss agent is 1, 4-butynediol or butoxide salt.
4. Use of a nickel cobalt tungsten alloy electrodeposition solution for electroplating sintered neodymium iron boron permanent magnets according to claim 1, characterized by the following steps:
1) Sequentially carrying out grinding chamfering and ultrasonic degreasing on the surface of the NdFeB permanent magnet;
2) Acid washing is carried out on the neodymium-iron-boron permanent magnet by adopting a dilute nitric acid solution to remove oxide skin;
3) Acid salt activation: activating the neodymium iron boron permanent magnet subjected to acid washing and descaling by using ammonium bifluoride solution;
4) Electroplating the activated neodymium-iron-boron permanent magnet by adopting the nickel-cobalt-tungsten alloy electrodeposition solution according to claim 1, and forming a nickel-cobalt-tungsten alloy coating on the surface of the neodymium-iron-boron permanent magnet.
5. The method according to claim 4, wherein the nickel-cobalt-tungsten alloy electrodepositing solution has a temperature of 70-80 ℃ and a pH of 6.5-7.5 and a cathodic current density of 1-4A/dm during the electrodeposition 2 The neodymium-iron-boron permanent magnet is used as a cathode, and the anode is graphite.
6. The use of a nickel cobalt tungsten alloy electrodeposition solution for electroplating sintered neodymium iron boron permanent magnet according to claim 4, wherein the nickel cobalt tungsten alloy coating layer has a thickness of 8-10um.
7. The method according to claim 4, wherein in step 2), the mass concentration of the dilute nitric acid solution is 2.5-3.5%.
8. The method according to claim 4, wherein in step 3), the concentration of the ammonium bifluoride solution is 10-30 g/L and the treatment time is 1-3min.
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