CN116065145A - Preparation and passivation treatment method of neodymium iron boron magnetic steel passivation solution - Google Patents
Preparation and passivation treatment method of neodymium iron boron magnetic steel passivation solution Download PDFInfo
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- CN116065145A CN116065145A CN202211681558.1A CN202211681558A CN116065145A CN 116065145 A CN116065145 A CN 116065145A CN 202211681558 A CN202211681558 A CN 202211681558A CN 116065145 A CN116065145 A CN 116065145A
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- passivation
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- iron boron
- neodymium iron
- passivation solution
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- 238000002161 passivation Methods 0.000 title claims abstract description 242
- 229910001172 neodymium magnet Inorganic materials 0.000 title claims abstract description 75
- 238000000034 method Methods 0.000 title claims abstract description 58
- QJVKUMXDEUEQLH-UHFFFAOYSA-N [B].[Fe].[Nd] Chemical compound [B].[Fe].[Nd] QJVKUMXDEUEQLH-UHFFFAOYSA-N 0.000 title claims abstract description 50
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 39
- 239000010959 steel Substances 0.000 title claims abstract description 39
- 238000002360 preparation method Methods 0.000 title claims abstract description 36
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 62
- 239000008367 deionised water Substances 0.000 claims abstract description 42
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 42
- 238000010438 heat treatment Methods 0.000 claims abstract description 40
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 26
- 238000005406 washing Methods 0.000 claims abstract description 26
- 239000000463 material Substances 0.000 claims abstract description 22
- 238000001035 drying Methods 0.000 claims abstract description 19
- 238000002791 soaking Methods 0.000 claims abstract description 19
- 238000001816 cooling Methods 0.000 claims abstract description 17
- 238000007599 discharging Methods 0.000 claims abstract description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 38
- 239000001301 oxygen Substances 0.000 claims description 38
- 229910052760 oxygen Inorganic materials 0.000 claims description 38
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 24
- 238000005554 pickling Methods 0.000 claims description 21
- 239000001509 sodium citrate Substances 0.000 claims description 20
- NLJMYIDDQXHKNR-UHFFFAOYSA-K sodium citrate Chemical compound O.O.[Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NLJMYIDDQXHKNR-UHFFFAOYSA-K 0.000 claims description 20
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 18
- 239000008399 tap water Substances 0.000 claims description 15
- 235000020679 tap water Nutrition 0.000 claims description 15
- 230000001502 supplementing effect Effects 0.000 claims description 14
- 238000006243 chemical reaction Methods 0.000 claims description 13
- 238000007789 sealing Methods 0.000 claims description 13
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 12
- 229910017604 nitric acid Inorganic materials 0.000 claims description 12
- PAZHGORSDKKUPI-UHFFFAOYSA-N lithium metasilicate Chemical compound [Li+].[Li+].[O-][Si]([O-])=O PAZHGORSDKKUPI-UHFFFAOYSA-N 0.000 claims description 10
- 229910052912 lithium silicate Inorganic materials 0.000 claims description 10
- 239000011684 sodium molybdate Substances 0.000 claims description 10
- 235000015393 sodium molybdate Nutrition 0.000 claims description 10
- TVXXNOYZHKPKGW-UHFFFAOYSA-N sodium molybdate (anhydrous) Chemical compound [Na+].[Na+].[O-][Mo]([O-])(=O)=O TVXXNOYZHKPKGW-UHFFFAOYSA-N 0.000 claims description 10
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 claims description 8
- 239000007788 liquid Substances 0.000 claims description 8
- 229960001922 sodium perborate Drugs 0.000 claims description 8
- YKLJGMBLPUQQOI-UHFFFAOYSA-M sodium;oxidooxy(oxo)borane Chemical compound [Na+].[O-]OB=O YKLJGMBLPUQQOI-UHFFFAOYSA-M 0.000 claims description 8
- 238000003756 stirring Methods 0.000 claims description 8
- VTIIJXUACCWYHX-UHFFFAOYSA-L disodium;carboxylatooxy carbonate Chemical compound [Na+].[Na+].[O-]C(=O)OOC([O-])=O VTIIJXUACCWYHX-UHFFFAOYSA-L 0.000 claims description 6
- BFXIKLCIZHOAAZ-UHFFFAOYSA-N methyltrimethoxysilane Chemical compound CO[Si](C)(OC)OC BFXIKLCIZHOAAZ-UHFFFAOYSA-N 0.000 claims description 6
- 229940045872 sodium percarbonate Drugs 0.000 claims description 6
- LFQCEHFDDXELDD-UHFFFAOYSA-N tetramethyl orthosilicate Chemical compound CO[Si](OC)(OC)OC LFQCEHFDDXELDD-UHFFFAOYSA-N 0.000 claims description 6
- ZNOCGWVLWPVKAO-UHFFFAOYSA-N trimethoxy(phenyl)silane Chemical compound CO[Si](OC)(OC)C1=CC=CC=C1 ZNOCGWVLWPVKAO-UHFFFAOYSA-N 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 5
- 238000005238 degreasing Methods 0.000 claims description 5
- 238000005237 degreasing agent Methods 0.000 claims description 5
- 239000013527 degreasing agent Substances 0.000 claims description 5
- 239000012530 fluid Substances 0.000 claims description 5
- 239000011521 glass Substances 0.000 claims description 5
- 238000009210 therapy by ultrasound Methods 0.000 claims description 5
- MJEMIOXXNCZZFK-UHFFFAOYSA-N ethylone Chemical compound CCNC(C)C(=O)C1=CC=C2OCOC2=C1 MJEMIOXXNCZZFK-UHFFFAOYSA-N 0.000 claims description 2
- 230000007797 corrosion Effects 0.000 abstract description 8
- 238000005260 corrosion Methods 0.000 abstract description 8
- 150000003839 salts Chemical class 0.000 abstract description 6
- 229910052761 rare earth metal Inorganic materials 0.000 abstract description 3
- 150000002910 rare earth metals Chemical class 0.000 abstract description 3
- 230000000694 effects Effects 0.000 description 9
- 238000011068 loading method Methods 0.000 description 7
- 239000007789 gas Substances 0.000 description 6
- 239000002994 raw material Substances 0.000 description 6
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 239000007921 spray Substances 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000006056 electrooxidation reaction Methods 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000005240 physical vapour deposition Methods 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
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- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/60—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using alkaline aqueous solutions with pH greater than 8
- C23C22/62—Treatment of iron or alloys based thereon
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- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
- C23C22/48—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
- C23C22/50—Treatment of iron or alloys based thereon
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- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/68—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous solutions with pH between 6 and 8
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- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/73—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process
- C23C22/74—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process for obtaining burned-in conversion coatings
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- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
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- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/10—Oxidising
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- 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
- H01F1/0572—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 with a protective layer
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
- 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
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- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2222/00—Aspects relating to chemical surface treatment of metallic material by reaction of the surface with a reactive medium
- C23C2222/20—Use of solutions containing silanes
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Abstract
The invention relates to the technical field of rare earth material surface engineering, in particular to a preparation method and a passivation treatment method of neodymium iron boron magnetic steel passivation solution. The preparation of the neodymium iron boron magnetic steel passivation solution comprises the preparation of the passivation solution A and the preparation of the passivation solution B; the passivation treatment method comprises a pretreatment process of the step S1 neodymium iron boron and a passivation treatment process of the step S2 neodymium iron boron; the passivation treatment process of the step S2 neodymium iron boron comprises the following steps of: step S21: immersing the pretreated NdFeB magnetic steel black sheet in the passivation solution A for 2-6min; step S22: rinsing with deionized water for 30-45s; step S23: soaking in the passivation solution B for 1-5min; step S24: washing with absolute ethanol for 30-45s; step S25: drying in an oven or a drying tunnel at 100-120 ℃ for 2-5min; step S26: transferring the dried magnetic sheet to a high-temperature passivation furnace for heat treatment, preserving heat at 300-450 ℃ for 20-30min, rapidly cooling to 150-200 ℃ within 5min, cooling to room temperature, discharging, and finishing the passivation treatment. The passivation film prepared by the invention has the advantages of improved salt fog performance and greatly improved corrosion resistance.
Description
Technical Field
The invention relates to the technical field of rare earth material surface engineering, in particular to a preparation method and a passivation treatment method of neodymium iron boron magnetic steel passivation solution.
Background
Since the last century 80 s of M.Sagawa, croat and M.C.Koon reported neodymium-iron-boron permanent magnet materials at the same time, neodymium-iron-boron magnets have received a great deal of attention in the scientific and technical fields due to their excellent physical properties. Compared with the traditional ferrite magnet, the neodymium-iron-boron magnet has excellent performances of high magnetic energy product, high remanence, high coercivity, high conductivity and the like, and is widely applied to the fields of generators, motors, communication equipment and the like. The neodymium-iron-boron permanent magnet material is a multiphase alloy, the potential difference between phases is large, the neodymium-iron-boron permanent magnet material is loose and porous due to a powder metallurgy or sintering process, high-temperature oxidation, wet-heat hydrogen absorption and electrochemical corrosion are easy to occur, and the service performance and the service life of the neodymium-iron-boron permanent magnet material are seriously affected.
The methods for improving the corrosion resistance of the neodymium iron boron permanent magnet material mainly comprise two methods: firstly, adding alloy elements into a base material, and improving the corrosion resistance of a grain boundary by changing the composition and the structure of a rare earth-rich phase; secondly, the corrosion resistance of the permanent magnet material is improved by preparing a surface protection layer to block the permanent magnet material and a corrosive medium. The former can fundamentally improve the corrosion resistance, but the improvement is limited, and the magnetic property of the alloy element can be adversely affected by the alloy element, and the process is complex and the cost is high. The latter is only a surface protection process, but can greatly improve the corrosion resistance of the magnet on the premise of ensuring that the magnetic performance is not affected. The surface protection technology mainly comprises passivation, phosphating, electroplating, chemical plating, physical vapor deposition, spraying and the like. The passivation is a surface protection process applied to the technical field earlier, and along with the expansion of the application range of the neodymium iron boron permanent magnet material, the practical requirements cannot be met, so that the prior art needs to be optimized and upgraded.
Disclosure of Invention
In order to overcome the defects, the first technical purpose of the invention is to a preparation method of neodymium iron boron magnetic steel passivation solution.
The second technical aim of the invention is to provide the neodymium-iron-boron magnetic steel passivation solution obtained by the preparation method of the neodymium-iron-boron magnetic steel passivation solution.
The third technical aim of the invention is to provide a passivation treatment method using the neodymium iron boron magnetic steel passivation solution.
The first technical purpose of the invention is realized by the following technical scheme:
the preparation method of the neodymium iron boron magnetic steel passivation solution comprises the steps of preparing the passivation solution A and preparing the passivation solution B:
the preparation method of the passivation solution A comprises the following steps:
step A1: adding sodium hydroxide or potassium hydroxide, lithium silicate, sodium citrate and deionized water in a certain proportion into a glass reaction kettle with water bath heating, controlling the pH value to be 10-12, and controlling the water bath temperature to be 45-60 ℃;
step A2: slowly dripping TEOS or TMOS into the solution in the first step for 10-15h, and continuing to react for 2h after the material is completely added;
step A3: slowly dripping absolute ethyl alcohol and one or more of methyltrimethoxysilane, phenyltrimethoxysilane, KH550 and KH560 into the solution in the step 2, and continuously reacting for 2 hours after the dripping is finished, so that the preparation of the passivation solution A is completed;
the preparation of the passivation solution B comprises the following steps:
step B1: under the room temperature condition, sodium percarbonate or sodium perborate, sodium molybdate, sodium citrate and deionized water are sequentially added into a reaction kettle and uniformly stirred;
step B2: adding one or two of KH550 and KH792 into the solution, stirring and reacting for 6-10h, discharging, and preparing passivation solution B.
According to the invention, the neodymium iron boron magnetic steel is subjected to passivation liquid treatment through the preparation of the specific passivation liquid A and the preparation of the passivation liquid B, so that a uniform passivation protection layer is formed on the surface of the magnetic steel, and the operation is convenient and the protection effect is obvious.
As a further improvement of the invention, in the preparation step of the passivation solution A, the mass ratio of sodium hydroxide or potassium hydroxide is 0.5-1.5%, lithium silicate is 1-3%, sodium citrate is 0.5-1.5%, TEOS or TMOS is 6-10%, absolute ethyl alcohol is 0.5-1.5%, one or more of methyltrimethoxysilane, phenyltrimethoxysilane, KH550 and KH560 is 0.1-0.5%, and the balance is deionized water.
As a further improvement of the invention, in the preparation step of the passivation solution B, the content of sodium percarbonate or sodium perborate is 0.5-1.2%, the content of sodium molybdate is 0.6-1.5%, the content of sodium citrate is 0.2-0.8%, one or two of KH550 and KH792 is 0.2-0.5% by mass ratio, and the balance is deionized water.
As a further improvement of the invention, the pH value of the passivation solution A is controlled between 5 and 9.
As a further improvement of the invention, the pH value of the passivation solution B is controlled between 9 and 11.
The second technical purpose of the invention is realized by the following technical proposal:
the neodymium iron boron magnetic steel passivation solution is prepared by a preparation method of the neodymium iron boron magnetic steel passivation solution, and comprises passivation solution A and passivation solution B, wherein the pH value of the passivation solution A is 5-9, and the pH value of the passivation solution B is 9-11.
The third technical purpose of the invention is realized by the following technical proposal:
a passivation treatment method using the neodymium iron boron magnetic steel passivation solution comprises a pretreatment process of step S1 neodymium iron boron and a passivation treatment process of step S2 neodymium iron boron;
the pretreatment process of the step S1 neodymium iron boron comprises the following steps:
s11: soaking a NdFeB magnetic steel black sheet in 3-6% degreasing agent solution for 5-10min, and then carrying out ultrasonic treatment for 2-3min;
s12: ultrasonic washing with tap water for 30-60s;
s13: rinsing with tap water for 30-60s;
s14: soaking and pickling in 2% -4% nitric acid solution for 10-25s;
s15: ultrasonic washing with tap water for 30-60s;
s16: washing with deionized water for 10-25s;
s17: washing with absolute ethanol for 10-25s;
s18: oven or drying in a drying tunnel at 120-140 deg.C for 2-5min;
the passivation treatment process of the step S2 neodymium iron boron comprises the following steps of:
step S21: immersing the pretreated NdFeB magnetic steel black sheet in the passivation solution A for 2-6min;
step S22: rinsing with deionized water for 30-45s;
step S23: soaking in the passivation solution B for 1-5min;
step S24: washing with absolute ethanol for 30-45s;
step S25: drying in an oven or a drying tunnel at 100-120 ℃ for 2-5min;
step S26: transferring the dried magnetic sheet to a high-temperature passivation furnace for heat treatment, preserving heat at 300-450 ℃ for 20-30min, rapidly cooling to 150-200 ℃ within 5min, cooling to room temperature, discharging, and finishing the passivation treatment.
The invention sequentially carries out pretreatment, passivation solution A and passivation solution B, so that a uniform passivation protection layer is formed on the surface of the magnetic steel, and the operation is convenient and the protection effect is obvious.
As a still further improvement of the present invention, step S11: the temperature of the degreasing fluid is controlled to be 45-55 ℃;
as a still further improvement of the present invention, step S14: soaking and pickling in 2% -4% nitric acid solution for 10-25s, wherein 3% nitric acid solution is preferable, and the pickling time is controlled to be 10-15 s just after pickling, and the pickling time is controlled to be 15-25s along with the process that the concentration of the acid solution is reduced from 3% to 2%.
As a still further improvement of the present invention, step S16: the conductivity of deionized water is more than or equal to 10MΩ.
As a still further improvement of the present invention, step S21: the pretreated neodymium iron boron black sheet is soaked in the passivation solution A for 2 to 6min, preferably 3 to 5min.
As a still further improvement of the present invention, step S22: the conductivity of deionized water is more than or equal to 10MΩ.
As a still further improvement of the present invention, step S24: the water content in the absolute ethyl alcohol is gradually increased due to the introduction of the first treatment liquid, so that the water content is controlled within 5 percent.
As a still further improvement of the present invention, step S26: transferring the dried magnetic sheet to high temperature passivation furnace for heat treatment, maintaining at 300-450deg.C for 25-40min, preferably at 350-400deg.C for 30-40min, and rapidly cooling to 150-250deg.C, preferably 180-200deg.C within 5min.
Preferably, the high-temperature passivation furnace comprises a passivation furnace, and a working cavity is arranged in the passivation furnace; still include high-efficient oxygen control assembly, high-efficient oxygen control assembly includes ultrasonic heater, the vacuum pump, the circulating pump, the intake pipe, the outlet duct, make-up air pipe and temperature sensor, ultrasonic heater installs in the bottom of passivation stove, the top left side at passivation stove is installed to the vacuum pump, the input and the top left side intercommunication of working chamber of vacuum pump, the top right side at passivation stove is installed to the circulating pump, the input and the output intercommunication of circulating pump of intake pipe, the output and the left end middle part intercommunication of working chamber of intake pipe, the input and the right-hand member middle part intercommunication of working chamber of outlet duct, the output and the input intercommunication of circulating pump of make-up air pipe, temperature sensor installs on the top of working chamber, temperature sensor is connected with the ultrasonic heater electricity.
When the existing high-temperature passivation furnace is used, a plurality of groups of magnetic sheets are uniformly placed in the high-temperature passivation furnace, then high-temperature catalysis is carried out through the furnace body, certain oxygen is introduced into the furnace body to accelerate the oxidation passivation speed of the surfaces of the magnetic sheets, and the magnetic sheets are taken out after passivation is finished, so that the heat treatment of the magnetic sheets is finished. The prior high-temperature passivation furnace is found in use, because the concentration of oxygen in the furnace is different, the passivation efficiency of a plurality of groups of magnetic sheets is often inconsistent, so that the passivation time is further required to be prolonged, and the oxygen amount in the furnace cannot be controlled when oxygen is conveyed into the furnace, so that the waste of oxygen is caused or the passivation speed of the magnetic sheets is low, and the like, so that the passivation effect is poor.
When the high-temperature passivation furnace carries out heat treatment on the magnetic sheets, a plurality of groups of magnetic sheets are added into the high-temperature passivation furnace at the same time, then a vacuum pump is started to vacuumize a working cavity, after the vacuum degree in the working cavity reaches a certain degree, air in the working cavity is relatively small, then a gas supplementing pipe and a circulating pump are started, oxygen can be led into an air inlet pipe, the working cavity and an air outlet pipe at the moment, circulation is started through the circulating pump, the oxygen concentration in the working cavity is relatively uniform, an ultrasonic heater is started to uniformly heat the working cavity, the magnetic sheets can be oxidized at the uniform oxygen concentration and the uniform high temperature, so that the passivation heat treatment effect is achieved, and in the process of continuously consuming oxygen, the oxygen concentration in the working cavity is ensured by the gas supplementing pipe due to the fact that the oxygen amount in the working cavity is reduced and the vacuum degree is improved; through the device, can carry out the even control of oxygen concentration in the high temperature passivation stove by high accuracy, improve the uniformity and the speed of magnetic sheet passivation to the practicality has been strengthened. The high-temperature passivation furnace provided by the invention has the advantages that the high-temperature baking is uniformly controlled, the passivation film is further densified and ceramic, and oxygen in the air and the base material are subjected to oxidation reaction, so that oxides are formed on the surface of the base material, a passivation layer of passivation solution and a passivation layer of the oxidized base material are formed, and the protection effect of the double-layer passivation layer is achieved.
Preferably, the high-temperature passivation furnace further comprises a one-way valve, an air preheater, a feeding plate, four groups of wheels and a sealing ring, wherein the one-way valve is arranged at the input end of the air supplementing pipe, and the air preheater is arranged on the air inlet pipe;
the front end of the passivation furnace is provided with a furnace door, four groups of wheels are uniformly arranged at the bottom end of the feeding plate, and the feeding plate is in sliding connection with the working cavity;
the rear end of the furnace door is provided with a sealing groove, and the sealing ring is installed in the sealing groove in a matching way.
The high-temperature passivation furnace can accurately control the temperature through the special structure, ensure the uniformity of temperature distribution in the furnace, and improve the controllability of oxygen content in the furnace.
Preferably, the high-temperature passivation furnace further comprises a handle, wherein the top end of the handle is hinged with the front end of the feeding plate.
Preferably, the high-temperature passivation furnace further comprises a vacuum gauge, wherein the vacuum gauge is arranged on the left side of the front end of the furnace door.
Preferably, the high-temperature passivation furnace further comprises an alarm, wherein the alarm is arranged on the right side of the front end of the furnace door and is electrically connected with the vacuum gauge.
In summary, the invention has the following beneficial effects:
1. the salt fog performance of the passivation film prepared by the invention is improved from original 2-4 hours to 8-12 hours, and the corrosion resistance is greatly improved;
2. when the high-temperature passivation furnace carries out heat treatment on the magnetic sheets, a plurality of groups of magnetic sheets are added into the high-temperature passivation furnace at the same time, then a vacuum pump is started to vacuumize a working cavity, after the vacuum degree in the working cavity reaches a certain degree, air in the working cavity is relatively small, then a gas supplementing pipe and a circulating pump are started, oxygen can be led into an air inlet pipe, the working cavity and an air outlet pipe at the moment, circulation is started through the circulating pump, the oxygen concentration in the working cavity is relatively uniform, an ultrasonic heater is started to uniformly heat the working cavity, the magnetic sheets can be oxidized at the uniform oxygen concentration and the uniform high temperature, so that the passivation heat treatment effect is achieved, and in the process of continuously consuming oxygen, the oxygen concentration in the working cavity is ensured by the gas supplementing pipe due to the fact that the oxygen amount in the working cavity is reduced and the vacuum degree is improved; through the device, can carry out the even control of oxygen concentration in the high temperature passivation stove by high accuracy, improve the uniformity and the speed of magnetic sheet passivation to the practicality has been strengthened. The high-temperature passivation furnace disclosed by the invention has the advantages that the high-temperature baking is uniformly controlled, the passivation film is further densified and ceramic, and oxygen in the air and the base material are subjected to oxidation reaction, so that oxides are formed on the surface of the base material, a passivation layer of passivation solution and a passivation layer of the oxidized base material are formed, and the protection effect of the double-layer passivation layer is achieved;
3. the passivation solution disclosed by the invention does not generate harmful substances to human bodies and environment, and is safe and environment-friendly.
Drawings
FIG. 1 is a schematic structural view of a high-temperature passivation furnace for heat treatment of magnetic sheets according to the present invention;
FIG. 2 is a schematic left-hand view of a high-temperature passivation furnace for heat treatment of magnetic sheets according to the present invention;
FIG. 3 is a schematic view showing the rear view of a furnace door of the high-temperature passivation furnace for heat treatment of magnetic sheets according to the present invention;
FIG. 4 is a schematic diagram showing the structure of a front view of a high-temperature passivation furnace for heat treatment of magnetic sheets according to the present invention;
the reference numerals in the drawings: 1. a passivation furnace; 2. a working chamber; 3. an ultrasonic heater; 4. a vacuum pump; 5. a circulation pump; 6. an air inlet pipe; 7. an air outlet pipe; 8. an air supplementing pipe; 9. a temperature sensor; 10. a one-way valve; 11. an air preheater; 12. a loading plate; 13. a wheel; 14. a furnace door; 15. a handle; 16. a seal ring; 17. a vacuum gauge; 18. an alarm.
Detailed Description
Example 1
A surface passivation treatment method for NdFeB magnetic steel comprises the following steps:
1. preparation of passivation solution
1.1 preparation of passivation solution A
The passivation solution A is prepared from the following raw materials in percentage by mass: sodium hydroxide content 0.5%, lithium silicate content 1%, sodium citrate content 0.5%, TEOS 6%, absolute ethyl alcohol content 0.5%, methyltrimethoxysilane content 0.5%, and deionized water balance.
Step A1: the sodium hydroxide, lithium silicate, sodium citrate and deionized water with the above proportion are added into a glass reaction kettle with water bath heating at one time, the pH value is controlled to be 10, and the water bath temperature is controlled to be 45 ℃.
Step A2: TEOS is slowly dripped into the solution in the first step, the dripping time is controlled to be 10 hours, and the reaction is continued for 2 hours after the charging is finished.
Step A3: and slowly dripping absolute ethyl alcohol and methyltrimethoxysilane into the solution in the step 2, and continuously reacting for 2 hours after the dripping is finished, so that the composition of the passivation solution A is finished.
1.2 preparation of passivation solution B,
the passivation solution B is prepared from the following raw materials in percentage by mass: sodium percarbonate 0.5%, sodium molybdate 0.6%, sodium citrate 0.2%, KH 550.5%, and deionized water in balance.
Step B1: and under the room temperature condition, sequentially adding sodium percarbonate, sodium molybdate, sodium citrate and deionized water into the reaction kettle and uniformly stirring.
Step B2: KH550 is added into the solution, stirring reaction is carried out for 6 hours, discharging is carried out, and the preparation of the passivation B solution is completed.
The pH value of the passivation solution A is controlled to be 5; the pH value of the passivation solution B is controlled at 9.
2. Passivation process
2.1 pretreatment Process of NdFeB
Step S11: soaking the NdFeB black sheet in 3% degreasing agent solution for 5min, and then carrying out ultrasonic treatment for 2min.
Step S12: ultrasonic washing with tap water for 30s.
Step S13: and rinsing with tap water for 30s.
Step S14: pickling in 2% nitric acid solution for 10s.
Step S15: ultrasonic washing with tap water for 30s.
Step S16: washing with deionized water for 10s.
Step S17: washing with absolute ethanol for 10s.
Step S18: oven or drying tunnel at 120deg.C for 2min.
2.2 passivation treatment process of NdFeB
Step S21: and immersing the pretreated NdFeB black sheet in the passivation solution A for 2min.
Step S22: deionized water rinse for 30s.
Step S23: soaking in passivation solution B for 1min.
Step S24: washing with absolute ethanol for 30s.
Step S25: drying in an oven or a drying tunnel at 100 ℃ for 2min.
Step S26: transferring the dried magnetic sheet to a high-temperature passivation furnace for heat treatment, preserving heat at 300 ℃ for 20min, rapidly cooling to 150 ℃ within 5min, cooling to room temperature, discharging, and finishing the passivation treatment.
Example 2
A surface passivation treatment method for NdFeB magnetic steel comprises the following steps:
1. preparation of passivation solution
1.1 preparation of passivation solution A
Preparing a passivation solution A raw material: 1.5% of potassium hydroxide, 3% of lithium silicate, 1.5% of sodium citrate, 10% of TMOS, 0.5% of absolute ethyl alcohol, 0.1% of phenyl trimethoxy silane and the balance of deionized water.
Step A1: the potassium hydroxide, lithium silicate, sodium citrate and deionized water in the above proportion are added into a glass reaction kettle with water bath heating at one time, the pH value is controlled to be 12, and the water bath temperature is controlled to be 60 ℃.
Step A2: and slowly dripping TMOS into the solution in the first step for 15h, and continuing to react for 2h after the addition is finished.
Step A3: and slowly dripping absolute ethyl alcohol and phenyl trimethoxy silane into the solution in the step 2, and continuously reacting for 2 hours after the dripping is finished, so that the composition of the passivation solution A is finished.
1.2 preparation of passivation solution B,
preparing a passivation solution B raw material: sodium perborate 1.2%, sodium molybdate 1.5%, sodium citrate 0.8%, KH 792.2%, and deionized water in balance.
Step B1: and under the room temperature condition, sequentially adding sodium perborate, sodium molybdate, sodium citrate and deionized water into a reaction kettle, and uniformly stirring.
Step B2: adding one or two of KH792 into the solution, stirring and reacting for 10h, discharging, and preparing the passivation solution B.
The pH value of the passivation solution A is controlled to be 9; the pH value of the passivation solution B is controlled at 11.
2. Passivation process
2.1 pretreatment Process of NdFeB
Step S11: soaking the NdFeB black sheet in 3-6% degreasing agent solution for 10min, and then performing ultrasonic treatment for 3min.
Step S12: ultrasonic washing with tap water for 60s.
Step S13: and rinsing with tap water for 60s.
Step S14: pickling in 4% nitric acid solution for 25s.
Step S15: ultrasonic washing with tap water for 60s.
Step S16: washing with deionized water for 25s.
Step S17: washing with absolute ethanol for 25s.
Step S18: oven or drying tunnel at 140 deg.C for 5min.
2.2 passivation treatment process of NdFeB
Step S21: and immersing the pretreated NdFeB black sheet in the passivation solution A for 6min.
Step S22: deionized water rinse for 45s.
Step S23: soaking in passivation solution B for 5min.
Step S24: washing with absolute ethanol for 45s.
Step S25: drying in an oven or a drying tunnel at 120 ℃ for 5min.
Step S26: transferring the dried magnetic sheet to a high-temperature passivation furnace for heat treatment, preserving heat at 450 ℃ for 30min, rapidly cooling to 200 ℃ within 5min, cooling to room temperature, discharging, and finishing the passivation treatment.
Example 3
A surface passivation treatment method for NdFeB magnetic steel comprises the following steps:
1. preparation of passivation solution
1.1 preparation of passivation solution A
Preparing a passivation solution A raw material: 1% of sodium hydroxide, 1-3% of lithium silicate, 1% of sodium citrate, 8% of TEOS, 1% of absolute ethyl alcohol, 0.3% of KH560 and the balance of deionized water.
Step A1: the sodium hydroxide, lithium silicate, sodium citrate and deionized water with the above proportion are added into a glass reaction kettle with water bath heating at one time, the pH value is controlled to 11, and the water bath temperature is controlled to 50 ℃.
Step A2: TEOS is slowly dripped into the solution in the first step, the dripping time is controlled to be 13 hours, and the reaction is continued for 2 hours after the charging is finished.
Step A3: and (3) slowly dripping absolute ethyl alcohol and KH560 into the solution in the step (2), and continuing to react for 2 hours after the dripping is finished, so that the composition of the passivation solution A is finished.
1.2 preparation of passivation solution B,
preparing a passivation solution B raw material: sodium perborate content 0.9%, sodium molybdate content 1%, sodium citrate content 0.5%, according to mass ratio 1:1 to form KH550 and KH792 which are 0.4 percent and the balance of deionized water.
Step B1: and under the room temperature condition, sequentially adding sodium perborate, sodium molybdate, sodium citrate and deionized water into a reaction kettle, and uniformly stirring.
Step B2: adding KH550 and KH792 into the solution, stirring and reacting for 8 hours, discharging, and preparing the passivation solution B.
The pH value of the passivation solution A is controlled to be 7; the pH value of the passivation solution B is controlled at 10.
2. Passivation process
2.1 pretreatment Process of NdFeB
Step S11: soaking the NdFeB black sheet in 4% degreasing agent solution for 6min, and then carrying out ultrasonic treatment for 2.5min.
Step S12: ultrasonic washing with tap water for 40s.
Step S13: and rinsing with tap water for 50s.
Step S14: pickling in 3% nitric acid solution for 15s.
Step S15: ultrasonic washing is carried out on tap water for 50s.
Step S16: washing with deionized water for 15s.
Step S17: washing with absolute ethanol for 15s.
Step S18: oven or drying tunnel at 130deg.C for 3min.
2.2 passivation treatment process of NdFeB
Step S21: and immersing the pretreated NdFeB black sheet in the passivation solution A for 4min.
Step S22: rinsing with deionized water for 35s.
Step S23: soaking in passivation solution B for 3min.
Step S24: washing with absolute ethanol for 35s.
Step S25: drying in an oven or a drying tunnel at 120 ℃ for 3min.
Step S26: transferring the dried magnetic sheet to a high-temperature passivation furnace for heat treatment, preserving the heat at 350 ℃ for 25min, then rapidly cooling to 180 ℃ within 5min, then cooling to room temperature, discharging, and finishing the passivation treatment.
As shown in fig. 1 to 4, the high-temperature passivation furnace for heat treatment of magnetic sheets of the present invention comprises a passivation furnace 1, wherein a working cavity 2 is arranged inside the passivation furnace 1;
the high-efficiency oxygen control assembly comprises an ultrasonic heater 3, a vacuum pump 4, a circulating pump 5, an air inlet pipe 6, an air outlet pipe 7, an air supplementing pipe 8 and a temperature sensor 9, wherein the ultrasonic heater 3 is arranged at the bottom end of the passivation furnace 1, the vacuum pump 4 is arranged at the left side of the top end of the passivation furnace 1, the input end of the vacuum pump 4 is communicated with the left side of the top end of the working cavity 2, the circulating pump 5 is arranged at the right side of the top end of the passivation furnace 1, the input end of the air inlet pipe 6 is communicated with the output end of the circulating pump 5, the output end of the air inlet pipe 6 is communicated with the middle part of the left end of the working cavity 2, the input end of the air outlet pipe 7 is communicated with the input end of the circulating pump 5, the output end of the air supplementing pipe 8 is communicated with the input end of the circulating pump 5, the temperature sensor 9 is arranged at the top end of the working cavity 2, and the temperature sensor 9 is electrically connected with the ultrasonic heater 3; when the heat treatment of the magnetic sheets is carried out, a plurality of groups of magnetic sheets are simultaneously added into a high-temperature passivation furnace, then a vacuum pump is started to vacuumize a working cavity, after the vacuum degree in the working cavity reaches a certain degree, air in the working cavity is relatively small, then a gas supplementing pipe and a circulating pump are started, at the moment, oxygen can be led into an air inlet pipe, the working cavity and an air outlet pipe, circulation is started through the circulating pump, at the moment, the oxygen concentration in the working cavity is relatively uniform, then an ultrasonic heater is started to uniformly heat the working cavity, at the moment, the magnetic sheets can be oxidized at uniform oxygen concentration and uniform high temperature, so that the passivation heat treatment effect is achieved, and in the process of continuously consuming oxygen, the oxygen is continuously consumed, the air is supplemented through the gas supplementing pipe due to the fact that the vacuum degree is improved; through the device, can carry out the even control of oxygen concentration in the high temperature passivation stove by high accuracy, improve the uniformity and the speed of magnetic sheet passivation to the practicality has been strengthened.
The invention relates to a high-temperature passivation furnace for magnetic sheet heat treatment, which also comprises a one-way valve 10, wherein the one-way valve 10 is arranged at the input end of an air supplementing pipe 8; the check valve can automatically supplement air through the check valve in the process of continuously consuming oxygen in the working cavity, so that the practicability is enhanced.
The invention relates to a high-temperature passivation furnace for magnetic sheet heat treatment, which also comprises an air preheater 11, wherein the air preheater 11 is arranged on an air inlet pipe 6; the air preheater can circularly heat oxygen, so that the constant heat in the working cavity is ensured, the heating efficiency is improved, and the practicability is enhanced.
The invention relates to a high-temperature passivation furnace for magnetic sheet heat treatment, which also comprises a feeding plate 12 and four groups of wheels 13, wherein the front end of the passivation furnace 1 is provided with a furnace door 14, the four groups of wheels 13 are uniformly arranged at the bottom end of the feeding plate 12, and the feeding plate 12 is in sliding connection with a working cavity 2; when carrying out the material loading of magnetic sheet, can place the magnetic sheet on the loading board earlier, then promote the loading board and enter into the working chamber, wait after the heat treatment completion, take out the loading board and take out the working chamber and carry out the unloading of magnetic sheet, make the material loading and unloading of magnetic sheet more convenient to the practicality has been strengthened.
The invention relates to a high-temperature passivation furnace for magnetic sheet heat treatment, which further comprises a handle 15, wherein the top end of the handle 15 is hinged with the front end of a feeding plate 12; the handle can be more convenient to push-and-pull the loading plate, so that the practicability is enhanced.
The invention relates to a high-temperature passivation furnace for magnetic sheet heat treatment, which further comprises a sealing ring 16, wherein the rear end of a furnace door 14 is provided with a sealing groove, and the sealing ring 16 is arranged in the sealing groove in a matching way; the sealing ring can further improve the vacuumizing efficiency of the vacuum pump, so that the practicability is enhanced.
The invention relates to a high-temperature passivation furnace for magnetic sheet heat treatment, which also comprises a vacuum gauge 17, wherein the vacuum gauge 17 is arranged at the left side of the front end of a furnace door 14; the vacuum gauge can observe the vacuum degree in the working cavity more intuitively, so that the practicability is enhanced.
The invention relates to a high-temperature passivation furnace for magnetic sheet heat treatment, which further comprises an alarm 18, wherein the alarm 18 is arranged on the right side of the front end of a furnace door 14, and the alarm 18 is electrically connected with a vacuum gauge 17; when the material is taken in preparation for opening the furnace door, a certain vacuum degree possibly exists in the working cavity to cause the difficulty in opening the furnace door, when the vacuum gauge detects that the vacuum degree in the working cavity is lower than a set value, the vacuum gauge can control the alarm to alarm, the staff is reminded to release pressure and then open the door, and therefore practicability is improved.
When the high-temperature passivation furnace for the magnetic sheet heat treatment is in operation, the magnetic sheet can be firstly placed on the feeding plate, then the feeding plate is pushed to enter the working cavity, the furnace door is closed, then the vacuum pump is started to vacuumize the working cavity, after the vacuum degree in the working cavity reaches a certain degree, the air in the working cavity is relatively small, then the air supplementing pipe and the circulating pump are started, at the moment, oxygen can be introduced into the air inlet pipe, the working cavity and the air outlet pipe, circulation is started through the circulating pump, at the moment, the oxygen concentration in the working cavity is relatively uniform, then the ultrasonic heater is started to uniformly heat the working cavity, at the moment, the magnetic sheet can be oxidized at the uniform oxygen concentration and the uniform high temperature, so that the passivation heat treatment effect is achieved.
Example 4
The difference from example 3 is that step S11: the temperature of the degreasing fluid is controlled to be 45 ℃;
step S14: soaking in 3wt% nitric acid solution, and controlling the pickling time to be 15s with the process of decreasing the acid concentration from 3% to 2% during pickling for 10 seconds.
Step S16: the conductivity of deionized water is more than or equal to 10MΩ.
Example 5
The difference from example 3 is that step S11: the temperature of the degreasing fluid is controlled to 55 ℃;
step S14: soaking in 3wt% nitric acid solution, and controlling the pickling time to be 15 seconds just after pickling, wherein the pickling time is controlled to be 25 seconds along with the process that the concentration of the acid solution is reduced from 3% to 2%.
Step S16: the conductivity of deionized water is more than or equal to 10MΩ.
Example 6
The difference from example 3 is that step S11: the temperature of the degreasing fluid is controlled to be 50 ℃;
step S14: soaking in 3wt% nitric acid solution, and controlling the pickling time to be 12 seconds just after pickling, wherein the pickling time is controlled to be 18 seconds along with the process that the concentration of the acid solution is reduced from 3% to 2%.
Step S16: the conductivity of deionized water is more than or equal to 10MΩ.
Example 7
The difference from example 3 is step S21: and immersing the pretreated NdFeB black sheet in the passivation solution A for 4min.
Step S22: the conductivity of deionized water was 15mΩ.
Step S24: the water content in the absolute ethanol is gradually increased due to the introduction of the first treatment liquid, so that the water content is controlled to be 5%.
Step S26: transferring the dried magnetic sheet to a high-temperature passivation furnace for heat treatment, preserving the heat at 350 ℃ for 30min, and then rapidly cooling to 190 ℃ within 5min.
Example 8
The difference from example 3 is step S21: and immersing the pretreated NdFeB black sheet in the passivation solution A for 3min.
Step S22: the conductivity of deionized water was 10mΩ.
Step S24: the water content in the absolute ethanol is gradually increased due to the introduction of the first treatment liquid, so that the water content is controlled to be 3%.
Step S26: transferring the dried magnetic sheet to a high-temperature passivation furnace for heat treatment, preserving the heat at 300 ℃ for 25min, and then rapidly cooling to 150 ℃ within 5min.
Example 9
The difference from example 3 is step S21: and immersing the pretreated neodymium iron boron black sheet in the passivation solution A for 5min.
Step S22: the conductivity of deionized water was 13mΩ.
Step S24: the water content in the absolute ethanol is gradually increased due to the introduction of the first treatment liquid, so that the water content is controlled to be 4%.
Step S26: transferring the dried magnetic sheet to a high-temperature passivation furnace for heat treatment, preserving the heat at 450 ℃ for 40min, and then rapidly cooling to 200 ℃ within 5min.
Comparative example 1
The difference is that no passivation solution A was prepared and no pretreated NdFeB black flakes were immersed in passivation solution A as in example 1.
Comparative example 2
The difference is that no passivation solution B was prepared, and the neodymium iron boron black sheet after being soaked in the passivation solution a and rinsed with deionized water was soaked in the passivation solution B.
Detection experiment: according to national standard, salt spray resistance test is carried out on the obtained NdFeB magnetic steel product (film thickness is about 0.2 micrometer), and the experimental result is as follows:
experimental data show that the salt spray resistance of the neodymium iron boron magnetic steel treated by the specific passivation solution and the passivation method in examples 1-9 is greatly improved compared with the salt spray resistance of the original passivation technology and comparative examples 1 and 2, and the corrosion resistance is greatly improved. And as the film thickness increases, the salt spray resistance time of the neodymium iron boron magnetic steel is higher.
The present embodiment is only for explanation of the present invention and is not to be construed as limiting the present invention, and modifications to the present embodiment, which may not creatively contribute to the present invention 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 invention.
Claims (10)
1. The preparation method of the neodymium iron boron magnetic steel passivation solution is characterized by comprising the steps of preparing the passivation solution A and preparing the passivation solution B:
the preparation method of the passivation solution A comprises the following steps:
step A1: adding sodium hydroxide or potassium hydroxide, lithium silicate, sodium citrate and deionized water in a certain proportion into a glass reaction kettle with water bath heating, controlling the pH value to be 10-12, and controlling the water bath temperature to be 45-60 ℃;
step A2: slowly dripping TEOS or TMOS into the solution in the first step for 10-15h, and continuing to react for 2h after the material is completely added;
step A3: slowly dripping absolute ethyl alcohol and one or more of methyltrimethoxysilane, phenyltrimethoxysilane, KH550 and KH560 into the solution in the step 2, and continuously reacting for 2 hours after the dripping is finished, so that the preparation of the passivation solution A is completed;
the preparation of the passivation solution B comprises the following steps:
step B1: under the room temperature condition, sodium percarbonate or sodium perborate, sodium molybdate, sodium citrate and deionized water are sequentially added into a reaction kettle and uniformly stirred;
step B2: adding one or two of KH550 and KH792 into the solution, stirring and reacting for 6-10h, discharging, and preparing passivation solution B.
2. The method for preparing the neodymium iron boron magnetic steel passivation solution according to claim 1, which is characterized in that: in the preparation step of the passivation solution A, the mass ratio of sodium hydroxide or potassium hydroxide is 0.5-1.5%, lithium silicate content is 1-3%, sodium citrate content is 0.5-1.5%, TEOS or TMOS content is 6-10%, absolute ethyl alcohol content is 0.5-1.5%, one or more of methyltrimethoxysilane, phenyltrimethoxysilane, KH550 and KH560 content is 0.1-0.5%, and the balance is deionized water.
3. The method for preparing the neodymium iron boron magnetic steel passivation solution according to claim 2, which is characterized in that: in the preparation step of the passivation solution B, the mass ratio of the sodium percarbonate or sodium perborate is 0.5-1.2%, the sodium molybdate is 0.6-1.5%, the sodium citrate is 0.2-0.8%, one or two of KH550 and KH792 is 0.2-0.5%, and the balance is deionized water.
4. The neodymium iron boron magnetic steel passivation solution is characterized in that: the neodymium iron boron magnetic steel passivation solution is obtained by the preparation method of the neodymium iron boron magnetic steel passivation solution according to any one of claims 1 to 3, and comprises passivation solution A and passivation solution B, wherein the pH value of the passivation solution A is 5 to 9, and the pH value of the passivation solution B is 9 to 11.
5. A passivation treatment method using the neodymium iron boron magnetic steel passivation solution according to claim 4 is characterized in that: comprises a pretreatment process of step S1 neodymium iron boron and a passivation treatment process of step S2 neodymium iron boron;
the pretreatment process of the step S1 neodymium iron boron comprises the following steps:
s11: soaking a NdFeB magnetic steel black sheet in 3-6% degreasing agent solution for 5-10min, and then carrying out ultrasonic treatment for 2-3min;
s12: ultrasonic washing with tap water for 30-60s;
s13: rinsing with tap water for 30-60s;
s14: soaking and pickling in 2% -4% nitric acid solution for 10-25s;
s15: ultrasonic washing with tap water for 30-60s;
s16: washing with deionized water for 10-25s;
s17: washing with absolute ethanol for 10-25s;
s18: oven or drying in a drying tunnel at 120-140 deg.C for 2-5min;
the passivation treatment process of the step S2 neodymium iron boron comprises the following steps of:
step S21: immersing the pretreated NdFeB magnetic steel black sheet in the passivation solution A for 2-6min;
step S22: rinsing with deionized water for 30-45s;
step S23: soaking in the passivation solution B for 1-5min;
step S24: washing with absolute ethanol for 30-45s;
step S25: drying in an oven or a drying tunnel at 100-120 ℃ for 2-5min;
step S26: transferring the dried magnetic sheet to a high-temperature passivation furnace for heat treatment, preserving heat at 300-450 ℃ for 20-30min, rapidly cooling to 150-200 ℃ within 5min, cooling to room temperature, discharging, and finishing the passivation treatment.
6. The passivation method using the neodymium iron boron magnetic steel passivation solution according to claim 5, wherein the passivation method comprises the following steps: step S11: the temperature of the degreasing fluid is controlled to be 45-55 ℃;
step S14: soaking and pickling for 10-25s in 2% -4% nitric acid solution, wherein 3% nitric acid solution is preferable, and the pickling time is controlled to be 10-15 seconds when pickling is performed, and the pickling time is controlled to be 15-25s along with the process that the concentration of the acid solution is reduced from 3% to 2%;
step S16: the conductivity of deionized water is more than or equal to 10MΩ.
7. The passivation method using the neodymium iron boron magnetic steel passivation solution according to claim 6, wherein the passivation method is characterized in that: step S21: soaking the pretreated neodymium iron boron black sheet in the passivation solution A for 2-6min, preferably 3-5min;
step S22: the conductivity of deionized water is more than or equal to 10MΩ;
step S24: the water content in the absolute ethyl alcohol is gradually increased due to the introduction of the first treatment liquid, so that the water content is controlled within 5 percent.
8. The passivation method using the neodymium iron boron magnetic steel passivation solution according to claim 7, wherein the passivation method comprises the following steps: step S26: transferring the dried magnetic sheet to high temperature passivation furnace for heat treatment, maintaining at 300-450deg.C for 25-40min, preferably at 350-400deg.C for 30-40min, and rapidly cooling to 150-250deg.C, preferably 180-200deg.C within 5min.
9. The passivation method using the neodymium iron boron magnetic steel passivation solution according to claim 5, wherein the passivation method comprises the following steps: the high-temperature passivation furnace for the magnetic sheet heat treatment comprises a passivation furnace (1) and a high-efficiency oxygen control assembly, wherein a working cavity (2) is arranged in the passivation furnace (1);
the high-efficiency oxygen control assembly comprises an ultrasonic heater (3), a vacuum pump (4), a circulating pump (5), an air inlet pipe (6), an air outlet pipe (7), an air supplementing pipe (8) and a temperature sensor (9), wherein the ultrasonic heater (3) is arranged at the bottom end of the passivation furnace (1), the vacuum pump (4) is arranged at the left side of the top end of the passivation furnace (1), the input end of the vacuum pump (4) is communicated with the left side of the top end of the working cavity (2), the circulating pump (5) is arranged at the right side of the top end of the passivation furnace (1), the input end of the air inlet pipe (6) is communicated with the output end of the circulating pump (5), the output end of the air outlet pipe (7) is communicated with the middle of the right end of the working cavity (2), the output end of the air outlet pipe (7) is communicated with the input end of the circulating pump (5), the temperature sensor (9) is arranged at the top end of the working cavity (2), and the temperature sensor (9) is electrically connected with the ultrasonic heater (3).
10. The passivation method using the neodymium iron boron magnetic steel passivation solution according to claim 9, characterized in that: the high-temperature passivation furnace further comprises a one-way valve (10), an air preheater (11), a feeding plate (12), four groups of wheels (13) and a sealing ring (16), wherein the one-way valve (10) is arranged at the input end of the air supplementing pipe (8), and the air preheater (11) is arranged on the air inlet pipe (6);
the front end of the passivation furnace (1) is provided with a furnace door (14), four groups of wheels (13) are uniformly arranged at the bottom end of the feeding plate (12), and the feeding plate (12) is in sliding connection with the working cavity (2);
the rear end of the furnace door (14) is provided with a sealing groove, and a sealing ring (16) is arranged in the sealing groove in a matching way.
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| US6224986B1 (en) * | 1998-07-22 | 2001-05-01 | Shin-Etsu Chemical Co., Ltd. | Rare earth permanent magnet of high corrosion resistance |
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| CN114164423A (en) * | 2021-11-30 | 2022-03-11 | 广东达志化学科技有限公司 | Chromium-free passivation solution and preparation method and application thereof |
| CN216243557U (en) * | 2021-10-19 | 2022-04-08 | 杭州永磁集团振泽磁业有限公司 | Dedicated nitrogen gas circulation case structure of neodymium iron boron magnetism body |
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| US6224986B1 (en) * | 1998-07-22 | 2001-05-01 | Shin-Etsu Chemical Co., Ltd. | Rare earth permanent magnet of high corrosion resistance |
| US20150225856A1 (en) * | 2014-02-13 | 2015-08-13 | Ewald Doerken Ag | Method for the manufacture of a substrate provided with a chromium vi-free and cobalt-free passivation |
| CN107109658A (en) * | 2014-12-30 | 2017-08-29 | 埃瓦尔德德肯有限公司 | Passivation composition comprising silane-modified silicate compound |
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| CN114164423A (en) * | 2021-11-30 | 2022-03-11 | 广东达志化学科技有限公司 | Chromium-free passivation solution and preparation method and application thereof |
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