CN115537796A - Surface protection method of sintered neodymium-iron-boron magnet and product thereof - Google Patents
Surface protection method of sintered neodymium-iron-boron magnet and product thereof Download PDFInfo
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- 229910001172 neodymium magnet Inorganic materials 0.000 title claims abstract description 97
- 230000004224 protection Effects 0.000 title claims abstract description 29
- 238000000034 method Methods 0.000 title claims abstract description 26
- 239000011241 protective layer Substances 0.000 claims abstract description 133
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 68
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 67
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims abstract description 64
- 230000001681 protective effect Effects 0.000 claims abstract description 58
- 239000000843 powder Substances 0.000 claims abstract description 54
- 229910052751 metal Inorganic materials 0.000 claims abstract description 51
- 239000002184 metal Substances 0.000 claims abstract description 51
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- 229910052725 zinc Inorganic materials 0.000 claims description 24
- 239000011701 zinc Substances 0.000 claims description 24
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
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- BPSIOYPQMFLKFR-UHFFFAOYSA-N trimethoxy-[3-(oxiran-2-ylmethoxy)propyl]silane Chemical group CO[Si](OC)(OC)CCCOCC1CO1 BPSIOYPQMFLKFR-UHFFFAOYSA-N 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- 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
- 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
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- 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
- 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
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
- C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
- C23F13/06—Constructional parts, or assemblies of cathodic-protection apparatus
- C23F13/08—Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto
- C23F13/12—Electrodes characterised by the material
- C23F13/14—Material for sacrificial anodes
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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
- H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
- H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
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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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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- 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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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Metallurgy (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Organic Chemistry (AREA)
- Power Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
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- Environmental & Geological Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Hard Magnetic Materials (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
Abstract
The invention relates to a surface protection method of a sintered neodymium iron boron magnet and a product thereof. The method comprises the following steps: providing a sintered neodymium-iron-boron magnet; forming a zinc-aluminum-titanium protective solution on the surface of the sintered neodymium-iron-boron magnet to obtain a prefabricated body, wherein the zinc-aluminum-titanium protective solution mainly comprises metal powder, molybdate and a silane coupling agent, the metal powder comprises titanium powder, flaky zinc powder and flaky aluminum powder, the average thickness of the flaky zinc powder and the flaky aluminum powder is less than or equal to 2.5 mu m, the thickness size deviation is less than or equal to 25%, the average diameter of the flaky zinc powder and the flaky aluminum powder is greater than or equal to 15 mu m, the diameter size deviation is less than or equal to 30%, the particle size of the titanium powder is 1.5-5 mu m, and the mass fraction of the titanium powder in the metal powder is 0.8-15%; and drying the prefabricated body, sintering at 250-370 ℃, and forming a protective layer on the surface of the sintered neodymium iron boron magnet. The method can improve the protective performance of the protective layer on the basis of keeping the high magnetism of the sintered neodymium-iron-boron magnet.
Description
Technical Field
The invention relates to the field of surface protection of magnetic materials, in particular to a surface protection method of a sintered neodymium iron boron magnet and a product thereof.
Background
The sintered Nd-Fe-B permanent magnetic material is widely applied due to the high magnetic performance, but the sintered Nd-Fe-B permanent magnetic material has poor corrosion resistance under various environments. The surface protection treatment is a main method for improving the corrosion resistance of the neodymium iron boron magnet. At present, the surface protection treatment technology for sintering the neodymium iron boron permanent magnet material comprises composite electroplating, composite chemical plating, hot dipping, electrophoretic coating, magnetron sputtering and the like. Although the corrosion resistance of the sintered Nd-Fe-B permanent magnet material can be improved to different degrees through surface protection treatment, the performance of the sintered Nd-Fe-B permanent magnet material is damaged in the surface protection treatment process, and the problem of environmental pollution which cannot be solved by air, water and the like is also solved. Therefore, the development of environment-friendly protective coating technology with high corrosion resistance is increasingly required in the field of sintered neodymium iron boron permanent magnet materials.
The Dacromet coating has excellent corrosion resistance and can be widely applied to the fields of ocean engineering, shipbuilding, electric power chemical industry and the like. However, the conventional Dacromet coating contains heavy metal chromium ions (Cr) 6+ ) But is restricted in use. Therefore, a chromium-free zinc-aluminum (Zn-Al) coating technology meeting new environmental protection requirements is produced at the same time, and becomes a new technology in the field of steel surface protection. However, because the sintered nd-fe-b permanent magnet material has the characteristics of low corrosion resistance and the like, the problem that the magnet is corroded still occurs in the process of coating the Zn-Al coating on the surface of the sintered nd-fe-b permanent magnet material magnet, so that the magnetic property of the magnet is influenced, and in addition, the Zn-Al coating has the problems of weak bonding force with the magnet, poor protective performance and the like.
Disclosure of Invention
In view of the above, it is necessary to provide a surface protection method for a sintered nd-fe-b magnet and a product thereof; the surface protection method enables the surface of the sintered neodymium-iron-boron magnet to form the protective layer, can remarkably improve the protective performance of the protective layer on the basis of keeping the high magnetic performance of the sintered neodymium-iron-boron magnet, and enhances the binding force between the protective layer and the magnet.
A surface protection method for a sintered NdFeB magnet comprises the following steps:
providing a sintered neodymium-iron-boron magnet;
forming zinc-aluminum-titanium protective liquid on the surface of the sintered neodymium-iron-boron magnet to obtain a prefabricated body; the zinc-aluminum-titanium protective solution mainly comprises metal powder, molybdate and a silane coupling agent, wherein the metal powder comprises titanium powder, flaky zinc powder and flaky aluminum powder, the average thickness of flaky zinc powder and the average thickness of flaky aluminum powder are less than or equal to 2.5 mu m, the deviation of thickness and size is less than or equal to 25%, the average diameter of flaky zinc powder and the average diameter of flaky aluminum powder are greater than or equal to 15 mu m, the deviation of diameter and size is less than or equal to 30%, the particle size of the titanium powder is 1.5-5 mu m, and the mass fraction of the titanium powder in the metal powder is 0.8-15%; and
drying the zinc-aluminum-titanium protective liquid in the preform, sintering at the temperature of 250-370 ℃, and forming a protective layer on the surface of the sintered neodymium-iron-boron magnet, wherein the protective layer comprises a zinc simple substance, an aluminum simple substance, a titanium simple substance, a zinc-containing metal oxide and a titanium-containing metal oxide.
In one embodiment, the mass fraction of the titanium powder in the metal powder is 0.8% -10%.
In one embodiment, the weight ratio of the flaky zinc powder to the flaky aluminum powder in the metal powder is 3.
In one embodiment, the mass fraction of the metal powder in the zinc-aluminum-titanium protective solution is 25% -35%, the mass fraction of the molybdate in the zinc-aluminum-titanium protective solution is 2% -3%, and the mass fraction of the silane coupling agent in the zinc-aluminum-titanium protective solution is 38% -45%.
In one embodiment, the average flake diameters of the zinc flake powder and the aluminum flake powder are each independently selected from 15 μm to 100 μm.
In one embodiment, the molybdate is selected from ammonium molybdate.
According to the invention, the titanium powder is added into the metal powder raw material, so that the interlayer distance between the flaky zinc powder and the flaky aluminum powder under a specific size is increased, and further, the dispersibility of the metal powder is effectively improved through the synergistic effect of the titanium powder, the flaky zinc powder and the flaky aluminum powder, so that the metal powder is uniformly distributed on the surface of the sintered neodymium-iron-boron magnet. Furthermore, the zinc-aluminum-titanium protective solution is sintered at a specific temperature, so that the metal powder is partially oxidized under the oxidation action of molybdate, the crosslinking of the metal powder and a silane coupling agent is facilitated, the surface of the sintered neodymium-iron-boron magnet is provided with an alternatively stacked lamellar network structure, corrosive media are effectively prevented from entering the sintered neodymium-iron-boron magnet, and the protective performance of the protective layer is improved. Meanwhile, titanium particles are distributed among the parallel stacked sheets, a communicated net rack micro-area can be formed, the corrosion current can be dispersed, and the protection performance of the protection layer is further improved.
In addition, chemical bonding is formed between the protective layer and the sintered NdFeB magnet through a silane coupling agent in the sintering process, so that the problem that the sintered NdFeB magnet is corroded is solved, the sintered NdFeB magnet can keep higher magnetic performance, and the bonding force between the protective layer and the sintered NdFeB magnet can be enhanced.
The sintered NdFeB magnet coated with the protective layer is prepared by the surface protection method of the sintered NdFeB magnet.
In one embodiment, the protective layer is an alternating stacked sheet network structure, wherein the sheets are parallel to the surface of the sintered nd-fe-b magnet.
In one embodiment, the lamellar network structure further comprises titanium particles, and the titanium particles are distributed among the lamellae.
In one embodiment, the thickness of the protective layer is 10 μm to 1000 μm.
According to the sintered neodymium-iron-boron magnet coated with the protective layer, the protective layer can play a role in protecting the cathode of the sacrificial anode of the sintered neodymium-iron-boron magnet, so that the corrosion resistance of the sintered neodymium-iron-boron magnet coated with the protective layer can be obviously improved on the basis of keeping the high magnetic performance of the sintered neodymium-iron-boron magnet, under the same condition, the corrosion resistance of the sintered neodymium-iron-boron magnet coated with the protective layer is improved by two orders of magnitude compared with that of the sintered neodymium-iron-boron magnet, and the time for resisting neutral salt fog can be up to 1440h or more.
Drawings
FIG. 1 is a scanning electron microscope image of flake zinc powders, flake aluminum powders and titanium powder raw materials used in example 1, example 2, comparative example 2 and comparative example 3 of the present invention;
fig. 2 is a scanning electron microscope image of the surface of the sintered nd-fe-b magnet coated with the protective layer prepared in example 1, example 2, comparative example 5 and comparative example 6 of the present invention under different magnifications;
fig. 3 is a scanning electron microscope image of the surface of the sintered ndfeb magnet coated with the protective layer prepared in embodiment 1 of the present invention and a distribution diagram of elements of zinc, aluminum and titanium in the surface;
fig. 4 is a scanning electron microscope image of a cross section of the sintered nd-fe-b magnet coated with a protective layer prepared in example 1 of the present invention and an elemental analysis thereof;
FIG. 5 is an X-ray diffraction pattern of the surface of the sintered NdFeB magnet coated with the protective layer prepared in example 1 of the invention;
fig. 6 is an infrared spectrum of the surface of the sintered nd-fe-b magnet coated with the protective layer prepared in example 1 of the present invention;
FIG. 7 is a graph showing thermogravimetry and differential thermal history during temperature increase of 0 to 500 ℃ for a preform prepared in example 1 of the present invention and a preform prepared in comparative example 1;
fig. 8 is a scanning electron microscope image of the surface of the sintered ndfeb magnet coated with the protective layer prepared in example 1 of the present invention after different test durations in a neutral salt spray test;
fig. 9 is a polarization curve diagram of the sintered ndfeb magnet coated with the protective layer prepared in example 1 of the present invention, the sintered ndfeb magnet coated with the protective layer prepared in comparative example 1, and the sintered ndfeb magnet in a 3.5% sodium chloride solution;
fig. 10 is a polarization curve diagram of the sintered ndfeb magnet coated with the protective layer prepared in example 1 of the present invention in a 3.5% sodium chloride solution after different test periods in a neutral salt spray test;
fig. 11 is a Nyquist diagram and a bode diagram of the sintered nd-fe-b magnet coated with the protective layer prepared in example 1 of the present invention after being soaked in a 3.5% sodium chloride solution for different lengths of time, and a Nyquist diagram and a bode diagram of the sintered nd-fe-b magnet in a 3.5% sodium chloride solution after being tested for different lengths of time in a neutral salt spray test;
fig. 12 is a graph of demagnetization curves and magnetic performance data analysis of the preform prepared in example 1, the protective layer-coated sintered ndfeb magnet prepared in example 1, and the protective layer-coated sintered ndfeb magnet prepared in comparative example 1.
Detailed Description
In order to facilitate an understanding of the present invention, the present invention will be described in more detail below. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as being limited to the embodiments or examples set forth herein. Rather, these embodiments or examples are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments or examples only and is not intended to be limiting of the invention.
The invention provides a surface protection method of a sintered neodymium-iron-boron magnet, which comprises the following steps:
s1, providing a sintered neodymium-iron-boron magnet;
s2, forming zinc-aluminum-titanium protective liquid on the surface of the sintered neodymium-iron-boron magnet to obtain a prefabricated body; the zinc-aluminum-titanium protective solution mainly comprises metal powder, molybdate and a silane coupling agent, wherein the metal powder comprises titanium powder, flaky zinc powder and flaky aluminum powder, the average thickness of flaky zinc powder and the average thickness of flaky aluminum powder are less than or equal to 2.5 mu m, the deviation of thickness and size is less than or equal to 25%, the average diameter of flaky zinc powder and the average diameter of flaky aluminum powder are greater than or equal to 15 mu m, the deviation of diameter and size is less than or equal to 30%, the particle size of the titanium powder is 1.5-5 mu m, and the mass fraction of the titanium powder in the metal powder is 0.8-15%; and
s3, drying the zinc-aluminum-titanium protective liquid in the preform, sintering at the temperature of 250-370 ℃, and forming a protective layer on the surface of the sintered neodymium-iron-boron magnet, wherein the protective layer comprises a zinc simple substance, an aluminum simple substance, a titanium simple substance, a zinc-containing metal oxide and a titanium-containing metal oxide.
In order to enhance the bonding force between the surface of the sintered ndfeb magnet and the zinc-aluminum-titanium protective liquid, in step S1, the sintered ndfeb magnet is preferably cleaned and dried to remove an oxide layer and other impurities on the surface of the sintered ndfeb magnet.
In the step S2, the titanium powder is added into the metal powder raw material, so that the interlayer distance between the flaky zinc powder and the flaky aluminum powder under a specific size is increased, and further, the dispersity of the metal powder is effectively improved through the synergistic effect of the titanium powder, the flaky zinc powder and the flaky aluminum powder, so that the metal powder is uniformly distributed on the surface of the sintered neodymium-iron-boron magnet, and a protective layer with high binding force and excellent protective performance is favorably obtained.
The applicant finds that the content of titanium powder has an important influence on the performance of the zinc-aluminum-titanium protective liquid through long-term and intensive research. The titanium powder can increase the distance between the flaky zinc powder and the flaky aluminum powder, is favorable for improving the wettability of molybdate and a silane coupling agent, can also improve the hardness of the protective layer, and prevents the protective layer from generating penetrating cracks, thereby improving the protective performance of the protective layer. However, when the addition amount of the titanium powder reaches a certain proportion, the protective layer treated at a certain temperature generates large macrocracks, so that the protective effect of the protective layer is greatly reduced. Therefore, in order to enable the protective layer to have high protective effect and high hardness, the mass fraction of the titanium powder in the metal powder is 0.8% -15%, and further, the mass fraction of the titanium powder in the metal powder is preferably 0.8% -10%, and more preferably 5% -10%.
Meanwhile, based on the chemical activity of the aluminum element, when the flaky aluminum powder in the zinc-aluminum-titanium protective liquid reaches a certain content, the protective effect of the protective layer is reduced along with the increase of the specific gravity of the flaky aluminum powder in the zinc-aluminum-titanium protective liquid. Therefore, in order to ensure that the protective layer has strong adhesion and can realize long-acting protective effect, in the zinc-aluminum-titanium protective solution, the weight ratio of the flaky zinc powder to the flaky aluminum powder is 3.
In order to further improve the uniformity of the flaky zinc powder and the flaky aluminum powder on the surface of the sintered neodymium-iron-boron magnet, the average sheet diameters of the flaky zinc powder and the flaky aluminum powder are preferably respectively and independently selected from 15 μm to 100 μm.
In one embodiment, the mass fraction of the metal powder in the zinc-aluminum-titanium protective solution is 25% to 35%, the mass fraction of the molybdate in the zinc-aluminum-titanium protective solution is 2% to 3%, and the mass fraction of the silane coupling agent in the zinc-aluminum-titanium protective solution is 38% to 45%.
In one embodiment, the zinc-aluminum-titanium protective solution further comprises an emulsifier, a dispersant, a defoaming agent and an organic solvent.
Further, the mass fraction of the emulsifier in the zinc-aluminum-titanium protective solution is 9% -12%, the mass fraction of the dispersant in the zinc-aluminum-titanium protective solution is 7% -10%, the mass fraction of the defoaming agent in the zinc-aluminum-titanium protective solution is 1% -2%, and the mass fraction of the organic solvent in the zinc-aluminum-titanium protective solution is 4% -7%.
Specifically, the emulsifier is selected from at least one of alkylphenol ethoxylate-10 (OP-10), polysorbate-20 and fatty alcohol polyoxyethylene ether (AE 0-9), the dispersant is selected from at least one of polyethylene glycol-400 (PEG-400) and polyethylene glycol-200 (PEG-200), the silane coupling agent in the silane coupling agent hydrolysate is selected from gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane (KH-560), the defoaming agent is selected from polyether modified silicone oil, and the organic solvent is selected from at least one of methanol and isooctanol.
In one embodiment, the organic solvent may be selected from a mixed solvent of methanol and isooctanol, specifically, methanol is present in a weight fraction of 3% to 5% in the zinc-aluminum-titanium protective solution, and isooctanol is present in a weight fraction of 1% to 2% in the zinc-aluminum-titanium protective solution.
In order to promote the crosslinking of the metal powder and the silane coupling agent, the silane coupling agent and deionized water are mixed according to the weight ratio of 1.5-1.
In an embodiment, the method for forming the zinc-aluminum-titanium protective solution on the surface of the sintered ndfeb magnet may be spraying, dipping, spin coating, brushing, or the like, which is not limited in this application.
In the step S3, the zinc-aluminum-titanium protective liquid in the preform is dried firstly, so that the structural shaping of the protective layer is facilitated, and the protective layer is prevented from generating macroscopic cracks due to direct high-temperature sintering of the zinc-aluminum-titanium protective liquid.
Furthermore, the zinc-aluminum-titanium protective solution is sintered at 250-370 ℃, so that the metal powder is partially oxidized under the oxidation action of molybdate, the crosslinking of the metal powder and a silane coupling agent is facilitated, an alternately stacked lamellar network structure is formed on the surface of the sintered neodymium-iron-boron magnet, corrosive media are effectively prevented from entering, and the protective performance of the protective layer is improved. Meanwhile, titanium particles are distributed among the parallelly stacked sheet layers, a conductive net rack micro-area can be formed, the corrosion current can be dispersed, and the protection performance of the protection layer is further improved.
In addition, chemical bonding is formed between the protective layer and the sintered NdFeB magnet through a silane coupling agent in the sintering process, so that the problem that the sintered NdFeB magnet is corroded is solved, the sintered NdFeB magnet can keep higher magnetic performance, and the bonding force between the protective layer and the sintered NdFeB magnet can be enhanced.
In one embodiment, the aluminum-containing metal oxide further comprises molybdenum, and the molybdenum is derived from ammonium molybdate.
In particular, the zinc-containing metal oxide is selected from ZnO, znMoO 4 At least one of titanium-containing metal oxides selected from TiO 2 。
In one embodiment, the protective layer further comprises a metal oxide containing aluminum.
To further analyze the formation principle of the protective layer during sintering, the present invention provides the following chemical reaction formula (1):
wherein, in the first stage, the silane coupling agent is hydrolyzed to generate Si-OH; in the second stage, si-OH can be reacted with the hydroxyl (M) on the surface of titanium powder, zinc flake powder, aluminum flake powder 1 -OH，M 1 Zinc powder, aluminum powder, titanium powder) to form Si-O-M 1 And can also be combined with hydroxyl (M) on the surface of the sintered NdFeB magnet 2 -OH，M 2 Representing sintered neodymium-iron-boron magnet) to form Si-O-M 2 (ii) a In the third stage, si-O-M can be formed by dehydrating condensation between Si-OH and Si-OH 1 With Si-O-M 2 Forming an oligomeric siloxane Si-O-Si structure between the two. Therefore, a compact protective layer coated on the surface of the sintered neodymium-iron-boron magnet can be formed through sintering treatment.
Based on this, because abundant chemical bonding is produced in the sintering between the surface of inoxidizing coating and sintered neodymium iron boron magnetism body, further strengthened the cohesion between inoxidizing coating and the sintered neodymium iron boron magnetism body.
Specifically, the drying temperature is 80-100 ℃, and the drying time is 5-15 min; the sintering temperature is preferably 240-450 ℃, and the sintering time is 10-60 min, preferably 25-40 min.
The invention also provides a sintered neodymium iron boron magnet coated with the protective layer.
According to the sintered neodymium-iron-boron magnet coated with the protective layer, the protective layer can play a role in protecting the cathode of the sacrificial anode of the sintered neodymium-iron-boron magnet, so that the corrosion resistance of the sintered neodymium-iron-boron magnet coated with the protective layer can be obviously improved on the basis of keeping the high magnetic performance of the sintered neodymium-iron-boron magnet, under the same condition, the corrosion resistance of the sintered neodymium-iron-boron magnet coated with the protective layer is improved by two orders of magnitude compared with that of the sintered neodymium-iron-boron magnet, and the time for resisting neutral salt fog can be up to 1440h or more.
In one embodiment, the protective layer is a network of alternately stacked sheets, wherein the sheets are parallel to the surface of the sintered ndfeb magnet.
Further, the lamellar network structure also comprises titanium particles, and the titanium particles are distributed among the lamellae.
Specifically, the components of the titanium particles comprise titanium and titanium-containing metal oxide, wherein the titanium-containing metal oxide is selected from titanium dioxide.
In one embodiment, in the sintered neodymium iron boron magnet coated with the protective layer, the thickness of the protective layer is 10 μm to 1000 μm, which is beneficial to preventing micropores and microcracks on the surface of the protective layer from penetrating into the coating, thereby further improving the protective performance.
Hereinafter, the surface protection method of the sintered nd-fe-b magnet and the product thereof will be further described by the following specific examples.
Example 1
And cleaning and drying the sintered neodymium-iron-boron magnet.
Using flaky zinc powder (diameter 19 μm and thickness 2 μm), flaky aluminum powder (diameter 19 μm and thickness 2.5 μm) and titanium powder (particle size 3.3 μm) as metal powder, wherein the mass fraction of the titanium powder in the metal powder is 10%, and the weight ratio of the flaky zinc powder to the flaky aluminum powder is 5. Uniformly mixing 33.5% of metal powder, 9.5% of OP-10, 8.9% of PEG-400, 4.67% of methanol, 2.8% of ammonium molybdate, 1.7% of isooctanol, 1.7% of polyether modified silicone oil and 42% of silane coupling agent hydrolysate to obtain the zinc-aluminum-titanium protective liquid, wherein the silane coupling agent hydrolysate is prepared by mixing KH-560 and deionized water in a weight ratio of 1. And spraying the zinc-aluminum-titanium protective liquid on the surface of the sintered neodymium-iron-boron magnet to obtain a prefabricated body.
And drying the prefabricated body at 100 ℃ for 10min, and then sintering at 320 ℃ for 30min to obtain the sintered NdFeB magnet coated with the protective layer.
The microscopic morphology of the raw materials of the flaky zinc powder, the flaky aluminum powder and the titanium powder was analyzed by a Scanning Electron Microscope (SEM), and the results are shown in fig. 1. As can be seen from (a) the flaky zinc powder and (d) the flaky aluminum powder in fig. 1, the flaky zinc powder and the flaky aluminum powder with the diameter size tend to be distributed more in parallel in a natural state without external force, while the particles of (c) the titanium powder are irregular.
The microscopic morphology of the surface of the sintered ndfeb magnet coated with the protective layer obtained by the SEM was analyzed under different magnifications, and as shown in fig. 2 (b) and 3 (a), it was found that some micropores and microcracks were randomly distributed in the protective layer. And the elemental analysis is performed on (a) in fig. 3, and as a result, as shown in fig. 3 (b) to (d), it can be seen that the zinc element, the aluminum element, and the titanium element are uniformly distributed in the protective layer without significant agglomeration, and the titanium element is dispersed between the zinc element and the aluminum element.
Further, the cross-sectional morphology and elements of the sintered nd-fe-b magnet coated with the protective layer are analyzed, and the result is shown in fig. 4. As can be seen from fig. 4 (a), the flaky zinc powder and the flaky aluminum powder are stacked in parallel on the surface of the sintered ndfeb magnet, and hard titanium particles are wrapped between the sheets, and the thickness of the protective layer is about 27 μm. As can be seen from fig. 4 (b), part of the zinc element, a small amount of the aluminum element, and part of the titanium element in the protective layer are diffused into the sintered ndfeb magnet.
The components of the surface of the prepared sintered nd-fe-b magnet coated with the protective layer were analyzed by an X-ray diffractometer (XRD), and the results are shown in fig. 5, which shows that the protective layer mainly includes Zn, al, ti, and TiO 2 ZnO and ZnMoO 4 。
The prepared sintered neodymium iron boron magnet surface coated with the protective layer is subjected to spectral analysis by an infrared spectrometer (FT-IR), and the result is shown in FIG. 6, which shows that the thickness is 3357cm -1 、1641cm -1 、858cm -1 And 906cm -1 The band observed here belongs to the-OH vibrational mode. At 2994cm -1 、2884cm -1 And 1257cm -1 The band observed here belongs to the-CH vibrational mode. At 2158cm -1 And 1203cm -1 The bands observed belong to the-Si-H and C-O-C vibrational modes. At 1053cm -1 And 1091cm -1 The bands observed here belong to the Si-O-Si vibrational mode, the appearance of bands of the Si-O-Si vibrational mode implying that there is slight condensation of the silane hydrolysis products.
Thermogravimetric analysis of the preform at 0-500 ℃ temperature rise was performed, and the results are shown in fig. 7 (b), showing a significant mass loss in the thermogravimetric curve with increasing temperature. Wherein the mass loss in the range of 30 ℃ to 97 ℃ is related to the evaporation of volatile methanol in the solvent, in particular, the endothermic peak at 92.3 ℃ corresponds to the evaporation of methanol in the solvent. The mass loss between 109 ℃ and 155 ℃ is due to water evaporation in the solvent and condensation of hydroxyl groups attached to Si and C atoms, specifically, an endothermic peak at 109.7 ℃ in graph (a) and an endothermic peak at 154.7 ℃ in graph (b) correspond to volatilization of water molecules and condensation of hydroxyl groups in the overcoat layer of example 1 and the overcoat layer of comparative example 1, respectively, and, as can be seen from these two endothermic peaks, the sintering temperature of the overcoat layer of example 1 is higher than that of comparative example 1. The endothermic peak appearing around 420 ℃ indicates the decomposition of the organofunctional group of the silane coupling agent, which corresponds to the final mass loss of the curve. This also further demonstrates the formation principle of the protective layer during sintering as shown in chemical reaction formula (1).
Example 2
And cleaning and drying the sintered neodymium-iron-boron magnet.
Using flaky zinc powder (diameter is 19 μm, thickness is 2 μm), flaky aluminum powder (diameter is 15 μm, thickness is 2.5 μm) and titanium powder (particle size is 3.3 μm) as metal powder, wherein in the metal powder, the mass fraction of the titanium powder is 5%, and the weight ratio of the flaky zinc powder to the flaky aluminum powder is 5. Uniformly mixing 33.5% of metal powder, 9% of OP-10, 8.9% of PEG-400, 4.67% of methanol, 2.8% of ammonium molybdate, 1.7% of isooctanol, 1.7% of polyether modified silicone oil and 42% of silane coupling agent hydrolysate to obtain the zinc-aluminum-titanium protective liquid, wherein the silane coupling agent hydrolysate is prepared by mixing KH-560 and deionized water in a weight ratio of 1. And spraying the zinc-aluminum-titanium protective liquid on the surface of the sintered neodymium-iron-boron magnet to obtain a prefabricated body.
Drying the preform at 100 deg.C for 10min, and thenAnd sintering at 320 ℃ for 30min to obtain the sintered NdFeB magnet coated with the protective layer. Wherein the protective layer mainly comprises Zn, al, ti and TiO 2 ZnO and ZnMoO 4 。
The microstructure of the flaky aluminum powder is shown in fig. 1 (e), and the microstructure of the surface of the prepared sintered neodymium iron boron magnet coated with the protective layer is shown in fig. 2 (a).
Example 3
And cleaning and drying the sintered neodymium-iron-boron magnet.
Using flaky zinc powder (diameter 25 μm, thickness 2.5 μm), flaky aluminum powder (diameter 18 μm, thickness 2 μm) and titanium powder (particle size 2 μm) as metal powder, wherein in the metal powder, the mass fraction of the titanium powder is 10%, and the weight ratio of the flaky zinc powder to the flaky aluminum powder is 3. Uniformly mixing 25% of metal powder, 9% of OP-10, 7% of PEG-400, 3% of methanol, 2% of ammonium molybdate, 1% of isooctanol, 1% of polyether modified silicone oil and 38% of silane coupling agent hydrolysate to obtain the zinc-aluminum-titanium protective liquid, wherein the silane coupling agent hydrolysate is prepared by mixing KH-560 and deionized water in a weight ratio of 1. And spraying the zinc-aluminum-titanium protective liquid on the surface of the sintered neodymium-iron-boron magnet to obtain a prefabricated body.
And drying the prefabricated body at 100 ℃ for 10min, and then sintering at 300 ℃ for 45min to obtain the sintered NdFeB magnet coated with the protective layer. Wherein the protective layer mainly comprises Zn, al, ti and TiO 2 ZnO and ZnMoO 4 。
Example 4
And cleaning and drying the sintered neodymium-iron-boron magnet.
Using flaky zinc powder (diameter is 18 μm, thickness is 1.5 μm), flaky aluminum powder (diameter is 25 μm, thickness is 1.5 μm) and titanium powder (particle size is 5 μm) as metal powder, wherein, in the metal powder, the mass fraction of the titanium powder is 10%, and the weight ratio of the flaky zinc powder to the flaky aluminum powder is 7. Uniformly mixing 35% of metal powder, 12% of OP-10, 10% of PEG-400, 5% of methanol, 3% of ammonium molybdate, 2% of isooctanol, 2% of polyether modified silicone oil and 45% of silane coupling agent hydrolysate to obtain the zinc-aluminum-titanium protective liquid, wherein the silane coupling agent hydrolysate is prepared by mixing KH-560 and deionized water in a weight ratio of 1. And spraying the zinc-aluminum-titanium protective liquid on the surface of the sintered neodymium-iron-boron magnet to obtain a prefabricated body.
And drying the prefabricated body at 100 ℃ for 10min, and then sintering at 280 ℃ for 60min to obtain the sintered NdFeB magnet coated with the protective layer. Wherein the protective layer mainly comprises Zn, al, ti and TiO 2 ZnO and ZnMoO 4 。
Comparative example 1
The metal powder adopts flaky zinc powder and flaky aluminum powder in a weight ratio of 5.
Comparative example 2
Comparative example 2 differs from example 1 in that a flaky zinc powder having a diameter of 10 μm and a thickness of 2 μm was used instead of a flaky zinc powder having a diameter of 19 μm and a thickness of 2 μm. The microscopic morphology of the flaky zinc powder raw material is shown in FIG. 1 (f).
Comparative example 3
Comparative example 3 is different from example 1 in that a flake aluminum having a diameter of 10 μm and a thickness of 2.5 μm is used instead of a flake aluminum having a diameter of 19 μm and a thickness of 2.5. Mu.m. Wherein the microscopic morphology of the aluminum flake raw material is shown in fig. 1 (b).
Comparative example 4
Comparative example 4 differs from example 1 in that the zinc flake powder and aluminum flake powder in the weight ratio of 1.
Comparative example 5
Comparative example 5 is different from example 1 in that titanium powder having a mass fraction of 20% is used instead of titanium powder having a mass fraction of 10%. The microstructure of the surface of the sintered ndfeb magnet coated with the protective layer is shown in fig. 2 (c).
Comparative example 6
Comparative example 6 is different from example 1 in that titanium powder having a mass fraction of 40% is used instead of titanium powder having a mass fraction of 10%. The microstructure of the surface of the sintered nd-fe-b magnet coated with the protective layer is shown in fig. 2 (d).
The sintered neodymium-iron-boron magnet coated with the protective layer prepared in the embodiment 1 is subjected to neutral salt spray tests for different periods of time, and the surface topography of the magnet after different test periods of time is shown in fig. 8. Therefore, the surface of the protective layer begins to crack due to the increase of corrosion internal stress of the protective layer after 10 days of test; the cracks on the surface of the protective layer are gradually covered or "repaired" by corrosion products after 20 days of testing; after the test for 40 days, the cracks on the surface of the protective layer basically disappear, and the surface of the protective layer becomes more compact; after 60 days of testing, the surface cracks of the protective layer increase, and the protective function of the protective layer begins to lose effectiveness.
Further, the surface of the sintered nd-fe-b magnet coated with the protective layer after the neutral salt spray test for different periods of time is subjected to elemental analysis, and the results are shown in table 1.
TABLE 1
In combination with table 1, it can be further demonstrated that after a test duration of 60 days, the Fe content increases, indicating that failure begins to occur after the protective layer.
The sintered ndfeb magnet coated with the protective layer prepared in example 1, the sintered ndfeb magnet coated with the protective layer prepared in comparative example 1, and the sintered ndfeb magnet were subjected to a polarization curve test, and the results are shown in fig. 9 and table 2.
TABLE 2
As can be seen from fig. 9 and table 2, compared with the sintered ndfeb magnet, the self-corrosion potentials of the sintered ndfeb magnet coated with the protective layer in example 1 and the sintered ndfeb magnet coated with the protective layer in comparative example 1 are significantly shifted negatively, which indicates that both protective layers can play a role in protecting the cathode of the sacrificial anode. The self-corrosion potential of the sintered ndfeb magnet coated with the protective layer in example 1 was shifted by 0.02V negatively compared to the sintered ndfeb magnet, and shifted by 0.21 positively compared to the sintered ndfeb magnet coated with the protective layer in comparative example 1. According to the thermodynamic concept of corrosion potential, only the corrosion tendency can be explained, and from the self-corrosion potential result, the corrosion resistance of the sintered neodymium-iron-boron magnet coated with the protective layer in the embodiment 1 is improved to a certain extent compared with the sintered neodymium-iron-boron magnet coated with the protective layer in the comparative example 1. The self-corrosion current density is a dynamic concept, the corrosion rates of different samples can be described, the self-corrosion current density of the sintered neodymium iron boron magnet coated with the protective layer in the embodiment 1 is reduced by one order of magnitude and two orders of magnitude respectively compared with the self-corrosion current density of the sintered neodymium iron boron magnet coated with the protective layer in the comparative example 1, and according to the Faraday law, the corrosion rate is in direct proportion to the corrosion current for the same magnet. Therefore, the corrosion resistance of the sintered ndfeb magnet coated with the protective layer in example 1 is improved by one order of magnitude compared with the sintered ndfeb magnet coated with the protective layer in comparative example 1, and is improved by two orders of magnitude compared with the sintered ndfeb magnet. Compared with the sintered neodymium iron boron magnet and the sintered neodymium iron boron magnet coated with the protective layer in the comparative example 1, the sintered neodymium iron boron magnet coated with the protective layer in the example 1 has higher polarization resistance and more excellent corrosion resistance.
The sintered ndfeb magnet coated with the protective layer prepared in example 1 was subjected to a polarization curve test in a 3.5% sodium chloride solution after different test periods in a neutral salt spray test, and the results are shown in fig. 10 and table 3.
TABLE 3
As can be seen from fig. 10 and table 3, the self-etching potentials of the sintered ndfeb magnet coated with the protective layer before 30 days of etching are similar, the etching current density increases first and then decreases, and the polarization resistance (Rp) decreases first and then increases. This is due to the fact that the electrochemically inert layer of oxide or silane on the surface of the coating is destroyed by the electrolyte during the initial period of corrosion. The metal in the protective layer is activated by corrosive ions, and the corrosion current density phase is gradually increased along with the gradual increase of the activated area of the metal zinc and the metal aluminum. This indicates that the protective layer, which is the anode of the ndfeb magnet, is more susceptible to corrosion, and the protective mechanism for the protective layer is cathodic protection of the ndfeb magnet by sacrificing zinc and aluminum. As the corrosion time reaches 20 days, rp is gradually increased, and the corrosion current density is increased by one order of magnitude compared with that of 10 days of corrosion, which shows that corrosion products generated by metal zinc, aluminum and oxides thereof in the protective layer are precipitated in micropores and microcracks of the protective layer, so that the penetration of electrolyte is hindered, and the active area of the metal sheet is reduced. When the corrosion time reaches 30 days, the surface of the protective layer becomes denser, the corrosion current density is reduced by one order of magnitude relative to 20 days of corrosion, and the corrosion rate is reduced. When the corrosion time is prolonged to 40 days, the self-corrosion potential is gradually moved forward, the corrosion current density is gradually reduced, the polarization resistance is increased, the corrosion tendency of the protective layer is weakened, and the corrosion rate is slowed down. After the protective time of the protective layer reaches 60 days, the corrosion current density is larger by one order of magnitude compared with the magnet, and the polarization resistance is reduced, which shows that the corrosion medium directly contacts with the neodymium iron boron magnet through cracks or holes after the corrosion of the protective layer, and the protective function of the protective layer begins to lose efficacy.
The sintered nd-fe-b magnet coated with the protective layer prepared in example 1 was immersed in a 3.5% sodium chloride solution for different lengths of time, and the samples subjected to different test lengths in the neutral salt spray test were subjected to performance tests, and the results are shown in fig. 11.
The sintered ndfeb magnet coated with the protective layer prepared in example 1, the sintered ndfeb magnet coated with the protective layer prepared in comparative example 1, and the preform prepared in example 1 were subjected to magnetic property testing, and the results are shown in fig. 12. As can be seen from fig. 12 (a), demagnetization curves of the preform of example 1, the sintered ndfeb magnet coated with the protective layer of example 1, and the sintered ndfeb magnet coated with the protective layer of comparative example 1 almost coincide, indicating that the protective layer has almost no significant effect on the intrinsic magnetic properties of the sintered ndfeb magnet. As can be seen from fig. 12 (b), the coercivity (Hcj), remanence (Br) and maximum energy product ((BH) max) of the sintered ndfeb magnet coated with the protective layer of example 1 are hardly changed, and the Squareness (Squareness) of the magnet is slightly lowered, compared to the preform of example 1, which indicates that the magnetic performance of the preform is not substantially changed but the resistance to the external magnetic field is slightly lowered by the sintering process.
The examples 1 to 4 and comparative examples 4 to 6 were subjected to comprehensive property tests, and the results are shown in Table 4.
TABLE 4
As can be seen from examples 1-4 in Table 4, when the specific gravity of the flaky zinc powder and the flaky aluminum powder in the coating is 7; when the specific gravity of the flaky zinc powder and the flaky aluminum powder is 5; when the specific gravity of the flaky zinc powder and the flaky aluminum powder is 3; when the specific gravity of the flaky zinc powder and the flaky aluminum powder is between 7 and 1, the sintered neodymium-iron-boron magnet coated with the protective layer has better corrosion resistance. According to comparative example 4, however, when the specific gravity of the flaky zinc powder and the flaky aluminum powder is 1, the corrosion resistance is lowered, probably because the aluminum powder is more active and the corrosion rate in the corrosive solution is too fast to perform a long-term protection effect. Therefore, the comprehensive performance of the sintered neodymium iron boron magnet coated with the protective layer is the best when the ratio of zinc, aluminum and titanium is 5.
As can be seen from examples 1 to 4 and comparative examples 4 to 6 in table 4, as the content of titanium increases, the corrosion resistance and hardness of the protective layer increase and then decrease, the protective layer performance is better with a titanium powder content of 10% in the metal powder, and larger macrocracks occur with a titanium powder content exceeding 15%, thereby decreasing the protective layer performance.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is specific and detailed, but not to be understood as limiting the scope of the invention. It should be noted that various changes and modifications can be made by those skilled in the art without departing from the spirit of the invention, and these changes and modifications are all within the scope of the invention. Therefore, the protection scope of the present patent should be subject to the appended claims.
Claims (10)
1. The surface protection method of the sintered neodymium-iron-boron magnet is characterized by comprising the following steps of:
providing a sintered neodymium iron boron magnet;
forming zinc-aluminum-titanium protective liquid on the surface of the sintered neodymium-iron-boron magnet to obtain a prefabricated body; the zinc-aluminum-titanium protective solution mainly comprises metal powder, molybdate and a silane coupling agent, wherein the metal powder comprises titanium powder, flaky zinc powder and flaky aluminum powder, the average thickness of flaky zinc powder and the average thickness of flaky aluminum powder are less than or equal to 2.5 mu m, the deviation of thickness and size is less than or equal to 25%, the average diameter of flaky zinc powder and the average diameter of flaky aluminum powder are greater than or equal to 15 mu m, the deviation of diameter and size is less than or equal to 30%, the particle size of the titanium powder is 1.5-5 mu m, and the mass fraction of the titanium powder in the metal powder is 0.8-15%; and
and drying the zinc-aluminum-titanium protective liquid in the preform, sintering at the temperature of 250-370 ℃, and forming a protective layer on the surface of the sintered neodymium-iron-boron magnet, wherein the protective layer comprises a simple zinc substance, a simple aluminum substance, a simple titanium substance, a metal oxide containing zinc and a metal oxide containing titanium.
2. The surface protection method for the sintered neodymium-iron-boron magnet according to claim 1, wherein the mass fraction of the titanium powder in the metal powder is 0.8% -10%.
3. The surface protection method for the sintered neodymium-iron-boron magnet is characterized in that, in the metal powder, the weight ratio of the flaky zinc powder to the flaky aluminum powder is 3.
4. The surface protection method for the sintered neodymium-iron-boron magnet according to claim 1, wherein the mass fraction of the metal powder in the zinc-aluminum-titanium protective solution is 25% -35%, the mass fraction of the molybdate in the zinc-aluminum-titanium protective solution is 2% -3%, and the mass fraction of the silane coupling agent in the zinc-aluminum-titanium protective solution is 38% -45%.
5. The surface protection method for the sintered NdFeB magnet as claimed in claim 1, wherein the average sheet diameter of the zinc flakes and the average sheet diameter of the aluminum flakes are respectively and independently selected from 15 μm-100 μm.
6. The method for protecting the surface of a sintered neodymium-iron-boron magnet according to claim 1, wherein the molybdate is selected from ammonium molybdate.
7. A sintered ndfeb magnet coated with a protective layer, wherein the sintered ndfeb magnet coated with the protective layer is prepared by the surface protection method of the sintered ndfeb magnet according to any one of claims 1 to 6.
8. The bonded NdFeB magnet of claim 7, wherein the protective layer is a network of stacked sheets, wherein the sheets are parallel to the surface of the bonded NdFeB magnet.
9. The coated sintered ndfeb magnet of claim 8, further comprising titanium particles in the network of sheets, the titanium particles being distributed between the sheets.
10. The sintered nd-fe-b magnet with a cladding protective layer according to any one of claims 7 to 9, wherein the thickness of the protective layer is 10 μm to 1000 μm.
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Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1453069A1 (en) * | 2001-11-09 | 2004-09-01 | Neomax Co., Ltd. | Rare-earth permanent magnet having corrosion-resistant coating, process for producing the same, and treating liquid for forming corrosion-resistant coating |
| CN102031522A (en) * | 2010-12-15 | 2011-04-27 | 白雪铠 | Neodymium-iron-boron magnet of aluminum or aluminum alloy composite coating and preparation method thereof |
| WO2011081170A1 (en) * | 2009-12-28 | 2011-07-07 | 日立金属株式会社 | Corrosion-resistant magnet and method for producing the same |
| CN102732871A (en) * | 2011-04-15 | 2012-10-17 | 中国科学院金属研究所 | Neodymium iron boron magnet material phosphating treatment and organic coating double layers protection method |
| CN103611667A (en) * | 2013-11-28 | 2014-03-05 | 中国科学院金属研究所 | Water-based inorganic-and-organic composite coating double-layer protection method for surface of Nd-Fe-B magnet material |
| CN104018133A (en) * | 2014-06-04 | 2014-09-03 | 北京汇磁粉体材料有限公司 | Multilayer composite protective coating on surface of sintered NdFeB magnet by multi-arc ion plating and process thereof |
| CN104984889A (en) * | 2015-06-18 | 2015-10-21 | 安徽大地熊新材料股份有限公司 | Zinc-aluminum coating enhanced with particles in micro-nano sizes and production method of zinc-aluminum coating |
| CN106128744A (en) * | 2016-08-16 | 2016-11-16 | 安徽大地熊新材料股份有限公司 | A kind of organic coating of Sintered NdFeB magnet surface temporary protection and preparation method thereof |
| CN107739534A (en) * | 2017-10-30 | 2018-02-27 | 杭州思垓防腐材料有限公司 | A kind of alcohol radical inorganic composite coating and preparation method thereof |
| CN108746642A (en) * | 2018-06-15 | 2018-11-06 | 杭州海声科技有限公司 | A kind of preparation method of the rare earth-transition metal nitride Magnaglo through surfacecti proteon processing |
| CN110189908A (en) * | 2019-06-25 | 2019-08-30 | 江苏赛清科技有限公司 | The method of Nd-Fe-B magnetic material aqueous, environmental protective shallow layer composite protective |
| CN111041440A (en) * | 2019-12-20 | 2020-04-21 | 浙江中杭新材料科技有限公司 | Surface protection method of neodymium iron boron permanent magnet |
| CN112940554A (en) * | 2021-03-12 | 2021-06-11 | 西北工业大学 | Zn-Al coating with sintered neodymium-iron-boron as base body and preparation method thereof |
| US20220076866A1 (en) * | 2020-09-07 | 2022-03-10 | Yantai Dongxing Magnetic Materials Inc. | Preparation device and method of ceramic coating on a sintered type NdFeB permanent magnet |
-
2022
- 2022-09-02 CN CN202211074891.6A patent/CN115537796A/en active Pending
Patent Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1453069A1 (en) * | 2001-11-09 | 2004-09-01 | Neomax Co., Ltd. | Rare-earth permanent magnet having corrosion-resistant coating, process for producing the same, and treating liquid for forming corrosion-resistant coating |
| WO2011081170A1 (en) * | 2009-12-28 | 2011-07-07 | 日立金属株式会社 | Corrosion-resistant magnet and method for producing the same |
| CN102031522A (en) * | 2010-12-15 | 2011-04-27 | 白雪铠 | Neodymium-iron-boron magnet of aluminum or aluminum alloy composite coating and preparation method thereof |
| CN102732871A (en) * | 2011-04-15 | 2012-10-17 | 中国科学院金属研究所 | Neodymium iron boron magnet material phosphating treatment and organic coating double layers protection method |
| CN103611667A (en) * | 2013-11-28 | 2014-03-05 | 中国科学院金属研究所 | Water-based inorganic-and-organic composite coating double-layer protection method for surface of Nd-Fe-B magnet material |
| CN104018133A (en) * | 2014-06-04 | 2014-09-03 | 北京汇磁粉体材料有限公司 | Multilayer composite protective coating on surface of sintered NdFeB magnet by multi-arc ion plating and process thereof |
| CN104984889A (en) * | 2015-06-18 | 2015-10-21 | 安徽大地熊新材料股份有限公司 | Zinc-aluminum coating enhanced with particles in micro-nano sizes and production method of zinc-aluminum coating |
| CN106128744A (en) * | 2016-08-16 | 2016-11-16 | 安徽大地熊新材料股份有限公司 | A kind of organic coating of Sintered NdFeB magnet surface temporary protection and preparation method thereof |
| CN107739534A (en) * | 2017-10-30 | 2018-02-27 | 杭州思垓防腐材料有限公司 | A kind of alcohol radical inorganic composite coating and preparation method thereof |
| CN108746642A (en) * | 2018-06-15 | 2018-11-06 | 杭州海声科技有限公司 | A kind of preparation method of the rare earth-transition metal nitride Magnaglo through surfacecti proteon processing |
| CN110189908A (en) * | 2019-06-25 | 2019-08-30 | 江苏赛清科技有限公司 | The method of Nd-Fe-B magnetic material aqueous, environmental protective shallow layer composite protective |
| CN111041440A (en) * | 2019-12-20 | 2020-04-21 | 浙江中杭新材料科技有限公司 | Surface protection method of neodymium iron boron permanent magnet |
| US20220076866A1 (en) * | 2020-09-07 | 2022-03-10 | Yantai Dongxing Magnetic Materials Inc. | Preparation device and method of ceramic coating on a sintered type NdFeB permanent magnet |
| CN112940554A (en) * | 2021-03-12 | 2021-06-11 | 西北工业大学 | Zn-Al coating with sintered neodymium-iron-boron as base body and preparation method thereof |
Non-Patent Citations (1)
| Title |
|---|
| YOUWEN YANG等: "The Preparation and Properties of ZnAl Coating for Ring-Shaped Bonded NdFeB Magnet with High Corrosion Resistance", 《JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE》, vol. 31, 27 September 2021 (2021-09-27), pages 1003 - 1008, XP037680511, DOI: 10.1007/s11665-021-06259-1 * |
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