WO2023070735A1 - 稀土磁粉的表面处理方法、注塑稀土磁材料及其制备方法 - Google Patents

稀土磁粉的表面处理方法、注塑稀土磁材料及其制备方法 Download PDF

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WO2023070735A1
WO2023070735A1 PCT/CN2021/129091 CN2021129091W WO2023070735A1 WO 2023070735 A1 WO2023070735 A1 WO 2023070735A1 CN 2021129091 W CN2021129091 W CN 2021129091W WO 2023070735 A1 WO2023070735 A1 WO 2023070735A1
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magnetic powder
rare earth
earth magnetic
phosphating
weak acid
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PCT/CN2021/129091
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English (en)
French (fr)
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胡江平
金志洪
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横店集团东磁股份有限公司
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Priority to EP21827559.2A priority Critical patent/EP4199016A4/en
Publication of WO2023070735A1 publication Critical patent/WO2023070735A1/zh

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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
    • H01F1/0551—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0552—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 in the form of particles, e.g. rapid quenched powders or ribbon flakes with a protective layer
    • 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
    • H01F1/0555—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together
    • H01F1/0558—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together bonded together
    • 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
    • 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
    • H01F1/0578—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 bonded together
    • 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
    • H01F1/059—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and Va elements, e.g. Sm2Fe17N2
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H01F41/0266—Moulding; Pressing

Definitions

  • the invention relates to the field of rare earth permanent magnets, in particular to a surface treatment method of rare earth magnetic powder, an injection molding rare earth magnetic material and a preparation method thereof.
  • Injection magnets are produced by melting, blending, extruding and granulating organic polymer resin and magnetic powder.
  • Commonly used polymer resins include polyamide PA6, PA66, PA12, PA11, PA612 series and polyphenylene sulfide PPS, polyether ether ketone PEEK, etc. with better temperature resistance; magnetic powder has ferrite (FeO ) and rare earth magnetic powder with high performance: neodymium iron boron (Nd-Fe-B), iron nitrogen (Sm-Fe-N), samarium cobalt (Sm-Co), etc.
  • rare earth magnetic powder is different from ferrite powder.
  • Rare earth magnetic powder itself belongs to alloy powder.
  • the magnetic powder is extremely easy to be oxidized, resulting in a significant decrease in performance.
  • rare earth powder with fine powder particle size such as heterosexual SmFeN powder, etc.
  • the manufacturer in order to improve the magnetic properties of the heterosexual SmFeN powder, the manufacturer often adjusts the powder particle size, resulting in the existence of a lot of ultrafine powder, and the particle size of these ultrafine powders is often only 1-2 ⁇ m. These powders It is easily oxidized, and it may even spontaneously ignite when exposed to high temperature air.
  • the rare earth magnetic powder in order to prepare high-performance injection molding rare earth magnetic raw materials, it is usually necessary to surface treat the rare earth magnetic powder first to provide a protective layer on the surface of the magnetic powder, so that the magnetic powder can reduce its oxidation during processing and protect its magnetic properties.
  • many companies use coupling treatment to treat the surface of magnetic powder.
  • the coupling treatment can improve the combination with the binder PA and PPS, and the binder is dissolved and wrapped in the twin-screw extruder.
  • the magnetic powder can protect the magnetic powder inside the binder from oxidation, but before the binder completely covers the magnetic powder, the magnetic powder may still be oxidized to a large extent.
  • the patent CN201510454107.8 also mentions the method of treating the rare earth SmFeN magnetic powder by soaking the magnetic powder in the coupling agent and phosphoric acid composite solution.
  • Phosphoric acid solution can form a certain phosphating film on the surface of the powder, thereby improving the high temperature resistance of the magnetic powder and protecting the magnetic powder from oxidation during the granulation process.
  • Phosphoric acid forms a phosphate crystal nucleus on the active point of the magnetic powder surface, and then Continue to grow to form a stable phosphating film.
  • the quality and integrity of the phosphating film have a great correlation with the number of active points on the surface of the magnetic powder.
  • the active points on the surface of the magnetic powder are very weak, and it is difficult to form a stable high-quality phosphating film. , resulting in the subsequent high-temperature granulation process, so that the treated rare earth magnetic powder still has the risk of being oxidized to a large extent.
  • the main purpose of the present invention is to provide a surface treatment method of rare earth magnetic powder, injection molding rare earth magnetic material and its preparation method, to solve the problem in the prior art that the rare earth magnetic powder has weak anti-oxidation ability, resulting in poor magnetic properties of the rare earth magnetic material after injection molding .
  • a method for surface treatment of rare earth magnetic powder includes the following steps: step S1, adding rare earth magnetic powder to a weak acid solution to perform weak acid treatment on the surface of the rare earth magnetic powder to form Weakly acidified magnetic powder; wherein the weak acid in the weak acid solution, the weak acid is an inorganic weak acid with an acidity coefficient pKa value greater than 4.5 and/or an organic weak acid with an acidity coefficient greater than 1.0; step S2, using a phosphating solution to carry out phosphating treatment on the weakly acidified magnetic powder to form Phosphating magnetic powder: step S3, mixing the phosphating magnetic powder with a coupling agent to perform coupling treatment on the phosphating magnetic powder, and then drying to obtain surface-treated rare earth magnetic powder.
  • the weak acid is one or more of oxalic acid, acetic acid and carbonic acid; preferably, the pH value of the weak acid solution is 5-7; preferably, ethanol is used to adjust the pH value of the weak acid solution; preferably, the weak acid solution and rare earth magnetic powder The volume ratio is 1.5 to 3:1.
  • step S1 after the rare earth magnetic powder is added to the weak acid solution, the first ultrasonic vibration is performed to perform weak acidification treatment; preferably, the power of the first ultrasonic vibration is 1500-2500W, and the duration is 2-5min.
  • the phosphating solution is a zinc-based phosphating solution or a manganese-based phosphating solution; preferably, after the weak acidification treatment is completed, the phosphating solution is directly added to the system containing the weakly acidified magnetic powder until the pH value of the system reaches 4 ⁇ 5, and then carry out the second ultrasonic vibration to carry out phosphating treatment; preferably, the power of the second ultrasonic vibration is 1000-1500W, and the duration is 10-15min.
  • the coupling agent is a silane coupling agent, preferably one or more of KH550, KH560, and KH792; preferably, after the phosphating treatment is completed, the coupling agent is directly added to the system containing phosphating magnetic powder , and then carry out the third ultrasonic vibration to carry out the coupling treatment; preferably, the amount of the coupling agent added is 0.5-1% of the weight of the rare earth magnetic powder; preferably, the power of the third ultrasonic vibration is 1200-2000W, and the duration is 10-15 minutes; preferably, vacuum drying is used in the drying process, and the drying temperature is 70-90°C.
  • the rare earth magnetic powder is one or more of homosexual NdFeB magnetic powder, heterosexual NdFeB magnetic powder, homosexual NdFeN magnetic powder, heterosexual NdFeN magnetic powder, samarium cobalt magnetic powder.
  • a method for preparing an injection-molded rare earth magnetic material which includes the following steps: using the above-mentioned surface treatment method to carry out surface treatment on the rare earth magnetic powder; mixing the surface treated rare earth magnetic powder with a binder , and then extruded and granulated to obtain an injection-molded rare earth magnetic material.
  • the binder is one or more of nylon, polyphenylene sulfide, and polyether ether ketone; preferably, the amount of the binder is 8-15% of the weight of the rare earth magnetic powder.
  • the extrusion granulation process adopts a twin-screw extruder, and the extrusion granulation temperature is 200-310°C.
  • an injection-molded rare earth magnetic material is also provided, which is prepared by the above-mentioned preparation method.
  • the invention provides a surface treatment method of rare earth magnetic powder, which comprises sequentially performing weak acid treatment, phosphating treatment and coupling treatment on the rare earth magnetic powder.
  • Weak acid treatment is the basis of phosphating treatment and coupling treatment, which can increase the number of active points on the surface of rare earth magnetic powder, and at the same time dissolve the insoluble ferrous and iron compound impurities on the surface of rare earth magnetic powder to convert them into weak acid ferrous .
  • Phosphating and coupling treatment after weak acid treatment can form a more complete and high-quality phosphating film and coupling protective layer on the surface of rare earth magnetic powder, so that the treated rare earth magnetic powder has better Oxidation resistance, the rare earth magnetic powder can be protected from oxidation before and during subsequent injection molding with the binder, and the obtained injection molding rare earth magnetic material has better magnetic properties.
  • the rare earth magnetic powder in the prior art has weak oxidation resistance, which leads to poor magnetic properties of the injection molded rare earth magnetic material.
  • the invention provides the surface treatment method of rare earth magnetic powder, which comprises the following steps:
  • Step S1 adding the rare earth magnetic powder to the weak acid solution to perform weak acid treatment on the surface of the rare earth magnetic powder to form a weak acidified magnetic powder; wherein the weak acid in the weak acid solution is an inorganic weak acid with a pKa value greater than 4.5 and/or an acidity coefficient greater than 1.0 organic weak acid;
  • Step S2 phosphating the weakly acidified magnetic powder with a phosphating solution to form phosphating magnetic powder
  • Step S3 mixing the phosphating magnetic powder with a coupling agent to perform coupling treatment on the phosphating magnetic powder, and then drying to obtain surface-treated rare earth magnetic powder.
  • the invention provides a surface treatment method of rare earth magnetic powder, which comprises sequentially performing weak acid treatment, phosphating treatment and coupling treatment on the rare earth magnetic powder.
  • Weak acid treatment is the basis of phosphating treatment and coupling treatment, which can increase the number of active points on the surface of rare earth magnetic powder, and at the same time dissolve the insoluble ferrous and iron compound impurities on the surface of rare earth magnetic powder to convert them into weak acid ferrous .
  • the increase in the number of active points can increase the number of sites on the surface of the rare earth magnetic powder that participate in the phosphating reaction and coupling reaction, so that the degree of phosphating during the phosphating process can be improved, and the coupling process can be more sufficient.
  • the weak acid ferrous formed by the dissolution of impurities such as ferrous and iron compounds can act as a phosphating nucleus to a certain extent during the phosphating process because it is close to or remains on the surface of the rare earth magnetic powder, and is also conducive to the growth and formation of the phosphating film.
  • impurities such as ferrous and iron compounds
  • the above two reasons are helpful to improve the integrity and quality of the phosphating film, and the coupling protective layer is correspondingly more complete.
  • phosphating and coupling treatment after weak acid treatment can form a more complete and high-quality phosphating film and coupling protective layer on the surface of rare earth magnetic powder, so that the treated rare earth magnetic powder has more Good oxidation resistance can protect the rare earth magnetic powder from being oxidized before and during subsequent injection molding with the binder, and the obtained injection molding rare earth magnetic material has better magnetic properties.
  • the present invention performs phosphating treatment and coupling treatment sequentially after weak acidification treatment, so that the growth of phosphating film can be more complete, corresponding
  • the coupling protection layer is also more complete, which is further conducive to the improvement of the oxidation resistance of the rare earth magnetic powder.
  • this operation is more conducive to improving the compatibility and binding force of the rare earth magnetic powder with the polymer material in the later mixing and granulation process.
  • using the surface treatment method provided by the present invention to treat the rare earth magnetic powder can significantly improve its oxidation resistance, and correspondingly can prepare high performance and high stability injection molded rare earth magnetic materials.
  • the above-mentioned weak acid adopts an inorganic weak acid with an acidity coefficient pKa value greater than 4.5 and/or an organic weak acid with an acidity coefficient greater than 1.0, which can increase the number of active points on the surface of the magnetic powder as much as possible without damaging the rare earth magnetic powder body.
  • the weak acid is one or more of oxalic acid, acetic acid and carbonic acid.
  • the pH value of the weak acid solution is 5-7. Controlling the pH value of the weak acid solution within the above range is conducive to controlling the stability of the weak acid treatment, and at the same time promotes a more sufficient weak acid treatment, which further improves the growth quality and integrity of the subsequent phosphating film and coupling protective layer. promotion.
  • ethanol can be used as a pH regulator to adjust the pH value of the weak acid solution to 5-7.
  • Specific solvents in the weak acid solution include, but are not limited to, one or more of isopropanol, ethanol, and deionized water.
  • the amount of the above-mentioned weak acid solution can be added as long as it can fully cover the rare earth magnetic powder.
  • the volume ratio of the weak acid solution to the rare earth magnetic powder is 1.5-3:1.
  • the weak acid treatment can also dissolve the ferrous and iron compound impurities on the surface of the rare earth magnetic powder, turning them into weak acid ferrous.
  • These weak ferrous acids have played the role of phosphating nuclei to a certain extent in the process of phosphating treatment.
  • the first ultrasonic vibration is carried out to carry out the weak acidification treatment.
  • the weak acid ferrous can be more evenly distributed on the surface of the weak acid magnetic powder, so that the growth of the phosphating film is more uniform and complete, and it also helps to improve the efficiency of phosphating treatment.
  • the slight friction between the magnetic powders during the ultrasonic vibration process can also improve the morphology of the magnetic powders on a microscopic level, making them closer to spherical, thereby improving the fluidity of subsequent products, improving the orientation of injection molded products, and further improving injection molded rare earth.
  • Magnetic properties of magnetic materials Preferably, the power of the first ultrasonic vibration is 1500-2500W, and the duration is 2-5 minutes. With this power and duration, the above functions can be more fully exerted. The preferred power is 2000W.
  • the phosphating solution is a zinc-based phosphating solution or a manganese-based phosphating solution (available from Elms). Using the above phosphating solution can more fully phosphate the weakly acidified magnetic powder, and the formed phosphating film has higher quality and is more complete and stable. More preferably, a zinc-based phosphating solution is used as the phosphating solution (eg Elsim BW-231 zinc-manganese-based phosphating solution for special materials).
  • the phosphating solution is directly added to the system containing the weak acidification magnetic powder until the pH value of the system reaches 4-5, Then carry out the second ultrasonic vibration to carry out phosphating treatment.
  • the power of the second ultrasonic vibration is 1000-1500W, and the duration is 10-15min, more preferably the power is 1500W.
  • the coupling agent is a silane coupling agent.
  • the use of silane coupling agent can form a better coupling protective film on the surface of the phosphating magnetic powder, and it can further improve the fusion between the magnetic powder and the binder during the subsequent injection granulation process with the binder, The material distribution is more uniform, and the magnetic properties of the final material are better.
  • the coupling agent is one or more of KH550, KH560, and KH792.
  • the coupling agent is added in an amount of 0.5-1% by weight of the rare earth magnetic powder.
  • Controlling the amount of the coupling agent within the above range can make it fully distributed on the surface of the phosphating magnetic powder, which is more conducive to improving the oxidation resistance of the magnetic powder and the fusion with the binder during the injection molding process, so that the final granulation can be obtained
  • the material has better magnetic properties and stability.
  • the power of the third ultrasonic vibration is 1200-2000W, and the duration is 10-15min; preferably, the power is 1500W.
  • vacuum drying is used in the drying process, and the drying temperature is 70-90°C.
  • the above surface treatment method of the present invention is applicable to many types of rare earth magnetic powders, including but not limited to the same sex NdFeB magnetic powder (Nd-Fe-B), the opposite sex NdFeB magnetic powder (Nd-Fe-B), the same sex NdFeB magnetic powder, and the same sex NdFeB magnetic powder
  • Nd-Fe-B sex NdFeB magnetic powder
  • One or more of nitrogen magnetic powder Sm-Fe-N
  • anisotropic iron nitrogen magnetic powder Sm-Fe-N
  • Sm-Co samarium cobalt magnetic powder
  • a method for preparing an injection-molded rare earth magnetic material which includes the following steps: using the above-mentioned surface treatment method to carry out surface treatment on the rare earth magnetic powder; mixing the surface treated rare earth magnetic powder with a binder , and then extruded and granulated to obtain an injection-molded rare earth magnetic material.
  • Treating the rare earth magnetic powder with the surface treatment method provided by the present invention can significantly improve its oxidation resistance, and can protect the rare earth magnetic powder from being oxidized before and during subsequent injection granulation with the binder, and accordingly can prepare high-performance , High stability injection molding rare earth magnetic material.
  • the above binder can be nylon, such as nylon 6, nylon 12, nylon 11, nylon 66, etc., or polyphenylene sulfide PPS with better temperature resistance, or polyether ether ketone PEEK and other materials. These materials can be One or more combinations.
  • the amount of the binder is 8-15% by weight of the rare earth magnetic powder.
  • the extrusion granulation process adopts a twin-screw extruder, and the extrusion granulation temperature is 200-310°C.
  • an injection-molded rare earth magnetic material is also provided, which is prepared by the above-mentioned preparation method. Thanks to the good oxidation resistance of the rare earth magnetic powder after surface treatment, the injection molded rare earth magnetic material has more excellent magnetic properties and stability.
  • Rare earth magnetic powder same-sex NdFeB magnetic powder (15-9 magnetic powder from Magnequench, 92 parts);
  • Coupling agent silane coupling agent (KH550, 0.5 parts);
  • Binder Nylon 12 powder (Japan Ube Nylon 7.5 parts);
  • the surface-treated rare earth magnetic powder is mixed with a binder and granulated by a twin-screw extruder, and the granulation temperature is set at 200-220° C. to obtain a high-performance injection molded rare earth magnetic material.
  • Rare earth magnetic powder same-sex NdFeB magnetic powder (15-9 magnetic powder from Magnequench, 90 parts)
  • Coupling agent silane coupling agent (KH550, 0.5 parts);
  • Binder PPS powder (Tosoh 100#, 9.5 parts);
  • the surface-treated rare earth magnetic powder is mixed with a binder and granulated by a twin-screw extruder, and the granulation temperature is set at 290-310° C. to obtain a high-performance injection molded rare earth magnetic material.
  • Rare earth magnetic powder heterosexual Sm 2 F 17 Nx magnetic powder (D 50 is 2.5 ⁇ m, 91 parts);
  • Coupling agent silane coupling agent (KH550, 0.5 parts);
  • Binder Nylon 12 powder (Japan Ube Nylon 8.5 parts);
  • the surface-treated rare earth magnetic powder is mixed with a binder and granulated by a twin-screw extruder, and the granulation temperature is set at 200-220° C. to obtain a high-performance injection molded rare earth magnetic material.
  • Rare earth magnetic powder heterosexual Sm 2 F 17 Nx magnetic powder (D 50 is 2.5 ⁇ m, 89 parts);
  • Coupling agent silane coupling agent (KH550, 0.5 parts);
  • Binder PPS powder (Tosoh 100#, 10.5 parts);
  • the surface-treated rare earth magnetic powder is mixed with a binder and granulated by a twin-screw extruder, and the granulation temperature is set at 290-310° C. to obtain a high-performance injection molded rare earth magnetic material.
  • Example 1 The only difference from Example 1 is that acetic acid is selected as the weak acid, and KH560 is selected as the silane coupling agent.
  • acetic acid is selected as the weak acid
  • KH560 is selected as the silane coupling agent.
  • Example 1 The only difference from Example 1 is that carbonic acid is selected as the weak acid, and KH792 is selected as the silane coupling agent.
  • the amount of coupling agent added is 0.5% of the weight of rare earth magnetic powder, ultrasonic vibration, control power 2000W, after 15 minutes, vacuum dry the system at 90°C for 5h to obtain the surface-treated Rare earth magnetic powder.
  • the amount of coupling agent added is 1% of the weight of rare earth magnetic powder, ultrasonic vibration, control power 1200W, after 15 minutes, vacuum dry the system at 90°C for 7h to obtain the surface-treated Rare earth magnetic powder.
  • the weight parts of various raw materials and raw materials in this comparative example are as follows:
  • Rare earth magnetic powder same-sex NdFeB magnetic powder (15-9 magnetic powder from Magnequench, 92 parts)
  • Coupling agent silane coupling agent (KH550, 0.5 parts);
  • Phosphoric acid 0.5 parts
  • Binder Nylon 12 powder (7 parts of Ube Nylon, Japan);
  • the surface-treated rare earth magnetic powder is mixed with a binder and granulated by a twin-screw extruder, and the granulation temperature is set at 200-220° C. to obtain an injection-molded rare earth magnetic material.
  • Rare earth magnetic powder same-sex NdFeB magnetic powder (15-9 magnetic powder from Magnequench, 90 parts)
  • Coupling agent silane coupling agent (KH550, 0.5 parts);
  • Phosphoric acid 0.5 parts
  • Binder PPS powder (Tosoh 100#, 9 parts);
  • the surface-treated rare earth magnetic powder is mixed with a binder and granulated by a twin-screw extruder, and the granulation temperature is set at 290-310° C. to obtain an injection-molded rare earth magnetic material.
  • the weight parts of various raw materials and raw materials in this comparative example are as follows:
  • Rare earth magnetic powder heterosexual Sm 2 F 17 Nx magnetic powder (D 50 is 2.5 ⁇ m, 91 parts);
  • Coupling agent silane coupling agent (KH550, 0.5 parts);
  • Phosphoric acid 0.5 parts
  • Binder Nylon 12 powder (8 parts of Ube Nylon, Japan);
  • the surface-treated rare earth magnetic powder is mixed with a binder and granulated by a twin-screw extruder, and the granulation temperature is set at 200-220° C. to obtain an injection-molded rare earth magnetic material.
  • the weight parts of various raw materials and raw materials in this comparative example are as follows:
  • Rare earth magnetic powder heterosexual Sm 2 F 17 Nx magnetic powder (D 50 is 2.5 ⁇ m, 89 parts);
  • Binder PPS powder (Tosoh 100#, 10.5 parts);
  • Coupling agent silane coupling agent (KH550, 0.5 parts);
  • the surface-treated rare earth magnetic powder is mixed with a binder and granulated by a twin-screw extruder, and the granulation temperature is set at 290-310° C. to obtain an injection-molded rare earth magnetic material.
  • Br, Hcj, and (BH)max are all important indicators of magnetic properties in permanent magnet materials. After rare earth permanent magnet materials are oxidized, their properties will decline, and these indicators will decrease accordingly. The more serious the oxidation, the more these indicators will decrease. It can be seen from the above table that the Br, Hcj, and (BH)max indexes of the injection-molded rare earth magnetic material prepared by using the rare earth magnetic powder treated by the surface treatment method in the embodiment of the present invention are all significantly improved, indicating that its oxidation resistance is stronger. Injection-molded rare earth magnetic materials have better magnetic properties. It should be noted that different binders have a large temperature difference during injection molding, and the preparation of magnetic powder at different temperatures will bring about a large difference.
  • Fluidity refers to the melt flow rate of the finished product under a certain pressure in a certain molten state. Agglomeration of magnetic powder or irregular shape of magnetic powder will affect fluidity. It can be seen from the above table that the melt index of the injection-molded rare earth magnetic material prepared by using the rare earth magnetic powder treated by the surface treatment method in the embodiment of the present invention is significantly improved, indicating that the rare earth magnetic powder has a more regular appearance, and after surface treatment, it can be combined with the binder The compatibility between them is better.

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Abstract

一种稀土磁粉的表面处理方法、注塑稀土磁材料及其制备方法。上述表面处理方法包括：步骤S1，将稀土磁粉加入至弱酸溶液，以对稀土磁粉表面进行弱酸化处理，形成弱酸化磁粉；其中弱酸溶液中的弱酸，弱酸为酸度系数pKa值大于4.5的无机弱酸和/或酸度系数大于1.0的有机弱酸；步骤S2，采用磷化液对弱酸化磁粉进行磷化处理，形成磷化磁粉；步骤S3，将磷化磁粉与偶联剂混合，以对磷化磁粉进行偶联化处理，然后干燥，得到表面处理后的稀土磁粉。解决了现有技术中稀土磁粉抗氧化能力弱，导致注塑后的稀土磁材料磁性能差的问题。

Description

稀土磁粉的表面处理方法、注塑稀土磁材料及其制备方法 技术领域
本发明涉及稀土永磁领域，具体而言，涉及一种稀土磁粉的表面处理方法、注塑稀土磁材料及其制备方法。
背景技术
注塑磁体是由有机高分子树脂和磁性粉末一起熔融共混挤出造粒而成的。常用的高分子树脂有聚酰胺PA6、PA66、PA12、PA11、PA612系列还有耐温性更好的聚苯硫醚PPS、聚醚醚酮PEEK等；磁粉有性能较低的铁氧体(FeO)及性能较高的稀土类磁粉：钕铁硼(Nd-Fe-B)、衫铁氮(Sm-Fe-N)、钐钴(Sm-Co)等。随着市场的不断演化，对性能及产品小型化要求越来越高，注塑稀土磁性材料需求越来越大。但稀土磁粉不同于铁氧体粉末，稀土磁粉本身属于合金粉，在造粒加工过程中，由于需要较高的温度，磁粉极其容易被氧化，从而导致性能明显降低。尤其是粉末粒度较细的稀土粉，如异性SmFeN粉等。在制粉过程中，为了提高异性SmFeN粉的磁性能，厂家往往会通过调节粉末粒度的方法，导致会出现很多超细粉的存在，这些超细粉粒度往往只打到1-2μm，这些粉末极易被氧化，同时暴露的高温空气中甚至会出现自燃的情况。
因此，为了制备出高性能的注塑稀土磁原材料，通常需要先对稀土磁粉进行表面处理，给磁粉表面提供一层保护层，使磁粉在加工过程中能减少其氧化，保护其磁性能。目前，很多公司采用偶联化处理的方式对磁粉表面进行处理，偶联化的处理方式可以提高同粘结剂PA、PPS的结合性，在双螺杆挤出机中粘结剂溶解后包裹住磁粉后可以保护粘结剂内部磁粉不被氧化，但是在粘结剂完全包覆住磁粉前，磁粉还会存在很大程度上被氧化的可能性。专利CN201510454107.8专利上还提及了采用将磁粉浸泡在偶联剂、磷酸复合溶液中来处理稀土SmFeN磁粉的方法。通过磷酸溶液可以在粉末表面形成一定的磷化膜，从而提高磁粉耐高温性能，保护磁粉在造粒过程中不被氧化，磷酸通过在磁粉表面活性点上形成磷酸盐的晶核，然后晶核继续生长，形成稳定 的磷化膜。磷化膜的质量和完整度同磁粉表面活性点数量存在很大的相关性，若只是单纯的通过浸泡在磷酸溶液中，磁粉表面活性点很弱，很难形成稳定的高质量的磷化膜，导致后续高温造粒过程中，使处理后的稀土磁粉很大程度上还是存在被氧化的风险。
基于以上原因，有必要提供一种新的稀土磁粉的表面处理方法，以使其具有更好的抗氧化能力，进而改善其注塑后稀土磁材料的磁性能。
发明内容
本发明的主要目的在于提供一种稀土磁粉的表面处理方法、注塑稀土磁材料及其制备方法，以解决现有技术中稀土磁粉抗氧化能力弱，导致注塑后的稀土磁材料磁性能差的问题。
为了实现上述目的，根据本发明的一个方面，提供了一种稀土磁粉的表面处理方法，其包括以下步骤：步骤S1，将稀土磁粉加入至弱酸溶液，以对稀土磁粉表面进行弱酸化处理，形成弱酸化磁粉；其中弱酸溶液中的弱酸，弱酸为酸度系数pKa值大于4.5的无机弱酸和/或酸度系数大于1.0的有机弱酸；步骤S2，采用磷化液对弱酸化磁粉进行磷化处理，形成磷化磁粉；步骤S3，将磷化磁粉与偶联剂混合，以对磷化磁粉进行偶联化处理，然后干燥，得到表面处理后的稀土磁粉。
进一步地，弱酸为草酸、醋酸和碳酸的一种或多种；优选地，弱酸溶液的pH值为5～7；优选地，采用乙醇调节弱酸溶液的pH值；优选地，弱酸溶液与稀土磁粉的体积比为1.5～3:1。
进一步地，步骤S1中，在将稀土磁粉加入至弱酸溶液之后，进行第一超声波振动，以进行弱酸化处理；优选地，第一超声波振动的功率为1500～2500W，时长为2～5min。
进一步地，磷化液为锌系磷化液或锰系磷化液；优选地，待弱酸化处理结束后，直接向含有弱酸化磁粉的体系中加入磷化液，直至体系的pH值达到4～5，然后进行第二超声波振动，以进行磷化处理；优选地，第二超声波振动的功率为1000～1500W，时长为10～15min。
进一步地，偶联剂为硅烷偶联剂，优选为KH550、KH560、KH792中的一种或多种；优选地，待磷化处理结束后，直接向含有磷化磁粉的体系中加入偶联剂，然后进行第三超声波振动，以进行偶联化处理；优选地，偶联剂的加入量为稀土磁粉重量的0.5～1％；优选地，第三超声波振动的功率为1200～2000W，时长为10～15min；优选地，干燥过程采用真空干燥，干燥温度为70～90℃。
进一步地，稀土磁粉为同性钕铁硼磁粉、异性钕铁硼磁粉、同性衫铁氮磁粉、异性衫铁氮磁粉、钐钴磁粉中的一种或多种。
根据本发明的另一方面，还提供了一种注塑稀土磁材料的制备方法，其包括以下步骤：采用上述表面处理方法对稀土磁粉进行表面处理；将表面处理后的稀土磁粉与粘结剂混合，然后挤出造粒，得到注塑稀土磁材料。
进一步地，粘结剂为尼龙、聚苯硫醚、聚醚醚酮中的一种或多种；优选地，粘结剂的用量为稀土磁粉重量的8～15％。
进一步地，挤出造粒过程采用双螺杆挤出机，挤出造粒的温度为200～310℃。
根据本发明的又一方面，还提供了一种注塑稀土磁材料，其由上述制备方法制备得到。
本发明提供了一种稀土磁粉的表面处理方法，其是依次对稀土磁粉进行了弱酸化处理、磷化处理和偶联化处理。弱酸化处理是磷化处理和偶联化处理的基础，其能够提高稀土磁粉表面的活性点数量，同时还可以将稀土磁粉表面不溶的亚铁、铁化合物杂质溶解，使其转化为弱酸亚铁。经弱酸化处理之后再进行磷化处理和偶联化处理，能够在稀土磁粉表面形成更完整、质量更高的磷化膜和偶联化保护层，从而使处理后的稀土磁粉具备更好的抗氧化性，在后续与粘结剂注塑造粒之前及进行过程中都能够保护稀土磁粉防止其被氧化，得到的注塑稀土磁材料相应具备更好的磁性能。
具体实施方式
需要说明的是，在不冲突的情况下，本申请中的实施例及实施例中的特征可以相互组合。下面将结合实施例来详细说明本发明。
正如背景技术部分所描述的，现有技术中的稀土磁粉抗氧化能力弱，导致注塑后的稀土磁材料磁性能较差。
为了解决这一问题，本发明提供了稀土磁粉的表面处理方法，其包括以下步骤：
步骤S1，将稀土磁粉加入至弱酸溶液，以对稀土磁粉表面进行弱酸化处理，形成弱酸化磁粉；其中弱酸溶液中的弱酸，弱酸为酸度系数pKa值大于4.5的无机弱酸和/或酸度系数大于1.0的有机弱酸；
步骤S2，采用磷化液对弱酸化磁粉进行磷化处理，形成磷化磁粉；
步骤S3，将磷化磁粉与偶联剂混合，以对磷化磁粉进行偶联化处理，然后干燥，得到表面处理后的稀土磁粉。
本发明提供了一种稀土磁粉的表面处理方法，其是依次对稀土磁粉进行了弱酸化处理、磷化处理和偶联化处理。弱酸化处理是磷化处理和偶联化处理的基础，其能够提高稀土磁粉表面的活性点数量，同时还可以将稀土磁粉表面不溶的亚铁、铁化合物杂质溶解，使其转化为弱酸亚铁。活性点数量的增多，能够提高稀土磁粉表面参与磷化反应和偶联化反应的位点数目，从而使磷化处理过程中的磷化度得以提高，偶联化处理也更为充分。亚铁、铁化合物等杂质溶解形成的弱酸亚铁因靠近或残留在稀土磁粉表面，能够在磷化过程中起到一定程度的磷化核的作用，也有利于磷化膜的生长形成。以上两方面的原因均有助于提高磷化膜的完整性和质量，偶联化保护层也相应更为完整。因此，经弱酸化处理之后再进行磷化处理和偶联化处理，能够在稀土磁粉表面形成更完整、质量更高的磷化膜和偶联化保护层，从而使处理后的稀土磁粉具备更好的抗氧化性，在后续与粘结剂注塑造粒之前及进行过程中都能够保护稀土磁粉防止其被氧化，得到的注塑稀土磁材料相应具备更好的磁性能。
此外，相比于采用磷化液和偶联剂复配进行处理的方式，本发明在弱酸化处理之后依次进行了磷化处理和偶联处理，这样能够时磷化膜生长更为完整，相应偶联化保 护层也更为完整，进一步有利于稀土磁粉抗氧化性的提高。与此同时，这样操作更有利于提高稀土磁粉后期混炼造粒过程中同高分子材料的相容性及结合力。
总之，使用本发明提供的表面处理方法处理稀土磁粉，能够明显改善其抗氧化性，相应能够制备出高性能、高稳定性的注塑稀土磁材料。
上述弱酸采用酸度系数pKa值大于4.5的无机弱酸和/或酸度系数大于1.0的有机弱酸，能够在不伤害稀土磁粉本体的基础上尽量增加磁粉表面的活性点数量，为使弱酸化处理更为有效，在一种优选的实施方式中，弱酸采用草酸、醋酸和碳酸的一种或多种。
优选地，弱酸溶液的pH值为5～7。将弱酸溶液的pH值控制在上述范围内，有利于控制弱酸化处理的稳定性，同时也促使弱酸化处理更充分，对于后续磷化膜和偶联化保护层的生长质量和完整性有进一步的促进作用。此外，为使稀土磁粉在弱酸溶液中更充分地分散和被包覆，优选地，可采用乙醇作为pH调节剂调节弱酸溶液的pH值至5～7。弱酸溶液中的具体溶剂包括但不限于异丙醇、乙醇、去离子水中的一种或多种。
上述弱酸溶液的加入量只要能够充分包覆稀土磁粉即可，考虑到进一步改善处理效果，在一种优选的实施方式中，弱酸溶液与稀土磁粉的体积比为1.5～3:1。
如前文所述，弱酸化处理还能够将稀土磁粉表面的亚铁、铁化合物杂质溶解，使其转化为弱酸亚铁。这些弱酸亚铁在磷化处理的过程中起到了一定程度的磷化核的作用，为了更充分地发挥该作用，在一种优选的实施方式中，步骤S1中，在将稀土磁粉加入至弱酸溶液之后，进行第一超声波振动，以进行弱酸化处理。通过超声波振动，能够将弱酸亚铁更均匀地分布在弱酸化磁粉的表面，进而使磷化膜的生长更为均匀完整，也有助于改善磷化处理的效率。与此同时，超声波振动过程中磁粉间轻微摩擦，还可以在微观程度上提高磁粉的形貌，使其更接近球形，从而提高后续产品的流动性，提高注塑产品的取向度，进一步改善注塑稀土磁材料的磁性能。优选地，第一超声波振动的功率为1500～2500W，时长为2～5min。在该功率和时长下，以上作用得以更充分发挥。优选功率为2000W。
在一种优选的实施方式中，磷化液为锌系磷化液或锰系磷化液(可购自爱尔斯姆)。采用上述磷化液能够对弱酸化磁粉进行更充分的磷化处理，形成的磷化膜质量更高，更为完整稳定。更优选地，采用锌系磷化液作为磷化液(如爱尔斯姆BW-231特种材料锌锰系磷化液)。
为使磷化处理过程效果更好，在一种优选的实施方式中，待弱酸化处理结束后，直接向含有弱酸化磁粉的体系中加入磷化液，直至体系的pH值达到4～5，然后进行第二超声波振动，以进行磷化处理。在具体实施过程中，第二超声波振动处理和第一超声波振动处理之间不间断，这样能够在持续振动的状态下进行磷化液的加料和磷化处理，效果更佳。优选地，第二超声波振动的功率为1000～1500W，时长为10～15min，更优选功率为1500W。
以上偶联剂可以采用本领域的常用类型，优选地，偶联剂为硅烷偶联剂。采用硅烷偶联剂能够在磷化磁粉表面形成更好的偶联化保护膜，且其在后续与粘结剂的注塑造粒过程中也能够进一步提高磁粉与粘结剂之间的融合性，使材料分布更为均一，最终材料的磁性能更佳。更优选地，偶联剂为KH550、KH560、KH792中的一种或多种。
为使偶联化处理效果更佳，在一种优选的实施方式中，待磷化处理结束后，直接向含有磷化磁粉的体系中加入偶联剂，然后进行第三超声波振动，以进行偶联化处理。具体实施过程中，第三超声波振动和第二超声波振动之间不间断，这样能够在持续振动的状态下进行偶联化处理，形成的偶联化保护层更为均匀完整。优选地，偶联剂的加入量为稀土磁粉重量的0.5～1％。将偶联剂的用量控制在上述范围，能够使其在磷化磁粉表面充分分布，更有利于提高磁粉的抗氧化性和注塑过程中和粘结剂之间的融合性，使得最终造粒得到的材料具有更好的磁性能和稳定性。优选地，第三超声波振动的功率为1200～2000W，时长为10～15min；优选功率为1500W。优选地，干燥过程采用真空干燥，干燥温度为70～90℃。
本发明上述表面处理方法适用于众多类型的稀土磁粉，包括但不限于稀土磁粉为同性钕铁硼磁粉(Nd-Fe-B)、异性钕铁硼磁粉(Nd-Fe-B)、同性衫铁氮磁粉(Sm-Fe-N)、异性衫铁氮磁粉(Sm-Fe-N)、钐钴磁粉(Sm-Co)中的一种或多种。
根据本发明的另一方面，还提供了一种注塑稀土磁材料的制备方法，其包括以下步骤：采用上述表面处理方法对稀土磁粉进行表面处理；将表面处理后的稀土磁粉与粘结剂混合，然后挤出造粒，得到注塑稀土磁材料。使用本发明提供的表面处理方法处理稀土磁粉，能够明显改善其抗氧化性，在后续与粘结剂注塑造粒之前及进行过程中都能够保护稀土磁粉防止其被氧化，相应能够制备出高性能、高稳定性的注塑稀土磁材料。
以上粘结剂可以是尼龙，如尼龙6、尼龙12、尼龙11、尼龙66等，也可以是耐温性更好的聚苯硫醚PPS，或者聚醚醚酮PEEK等材料，这些材料可以是一种或多种的组合使用。优选地，粘结剂的用量为稀土磁粉重量的8～15％。
在一种优选的实施方式中，挤出造粒过程采用双螺杆挤出机，挤出造粒的温度为200～310℃。
根据本发明的又一方面，还提供了一种注塑稀土磁材料，其由上述制备方法制备得到。得益于稀土磁粉表面处理后具有良好的抗氧化性，使得注塑稀土磁材料具有更加优异的磁性能和稳定性。
以下结合具体实施例进一步说明本发明的有益效果：
实施例1
本实施例中的各种原料及原料的重量份如下：
稀土磁粉：同性NdFeB磁粉(麦格昆磁公司15-9磁粉，92份)；
偶联剂：硅烷偶联剂(KH550，0.5份)；
粘结剂：尼龙12粉末(日本宇部尼龙7.5份)；
工艺步骤如下：
将0.01mol/L的草酸的异丙醇溶液溶解于无水乙醇中，调节pH值至5，形成弱酸溶液；向其中加入稀土磁粉，弱酸溶液能完全包覆住磁粉，其与磁粉的体积比为1.5:1；打开超声波振动，控制功率2000W，处理5分钟，形成含有弱酸化磁粉的体系。
向上述体系中加入爱尔斯姆的BW-231锌系磷化液，添加量以pH值为准，调节pH值至4，继续超声波振动，控制功率1500W，处理时间15分钟，形成含有磷化磁粉的体系。
继续向体系中加入偶联剂，超声波振动，控制功率1500W，10分钟后将体系在80℃条件下真空干燥5h，得到表面处理后的稀土磁粉。
将表面处理后的稀土磁粉和粘结剂混合并用双螺杆挤出机造粒，造粒温度设定在200～220℃，得到高性能注塑稀土磁材料。
按照IEC 60404-8-1相关测试标准，对注塑稀土磁材料样品进行性能测试，结果如下：Br＝0.58T，Hcj＝737KA/m，(BH)m＝52KJ/m 3，熔融指数为306g/10min。
实施例2
本实施例中的各种原料及原料的重量份如下：
稀土磁粉：同性NdFeB磁粉(麦格昆磁公司15-9磁粉，90份)
偶联剂：硅烷偶联剂(KH550，0.5份)；
粘结剂：PPS粉末(日本东曹100#，9.5份)；
工艺步骤如下：
将0.01mol/L的草酸的异丙醇溶液溶解于无水乙醇中，调节pH值至7，形成弱酸溶液；向其中加入稀土磁粉，弱酸溶液能完全包覆住磁粉，其与磁粉的体积比为2:1；打开超声波振动，控制功率2000W，处理5分钟，形成含有弱酸化磁粉的体系。
向上述体系中加入爱尔斯姆的BW-231锌系磷化液，添加量以pH值为准，调节pH值至5，继续超声波振动，控制功率1500W，处理时间15分钟，形成含有磷化磁粉的体系。
继续向体系中加入偶联剂，超声波振动，控制功率1500W，10分钟后将体系在80℃条件下真空干燥5h，得到表面处理后的稀土磁粉。
将表面处理后的稀土磁粉和粘结剂混合并用双螺杆挤出机造粒，造粒温度设定在290～310℃，得到高性能注塑稀土磁材料。
按照IEC 60404-8-1相关相关测试标准，对注塑稀土磁材料样品进行性能测试，结果如下：Br＝0.54T，Hcj＝709KA/m，(BH)m＝49KJ/m 3，熔融指数为183g/10min。
实施例3
本实施例中的各种原料及原料的重量份如下：
稀土磁粉：异性Sm 2F 17Nx磁粉(D 50为2.5μm，91份)；
偶联剂：硅烷偶联剂(KH550，0.5份)；
粘结剂：尼龙12粉末(日本宇部尼龙8.5份)；
工艺步骤如下：
将0.01mol/L的草酸的异丙醇溶液溶解于无水乙醇中，调节pH值至7，形成弱酸溶液；向其中加入稀土磁粉，弱酸溶液能完全包覆住磁粉，其与磁粉的体积比为3:1；打开超声波振动，控制功率2000W，处理5分钟，形成含有弱酸化磁粉的体系。
向上述体系中加入爱尔斯姆的BW-231锌系磷化液，添加量以pH值为准，调节pH值至5，继续超声波振动，控制功率1500W，处理时间15分钟，形成含有磷化磁粉的体系。
继续向体系中加入偶联剂，超声波振动，控制功率1500W，10分钟后将体系在80℃条件下真空干燥5h，得到表面处理后的稀土磁粉。
将表面处理后的稀土磁粉和粘结剂混合并用双螺杆挤出机造粒，造粒温度设定在200～220℃，得到高性能注塑稀土磁材料。
按照IEC 60404-8-1相关相关测试标准，对注塑稀土磁材料样品进行性能测试，结果如下：Br＝0.64T，Hcj＝725KA/m，(BH)m＝65KJ/m 3，熔融指数为142g/10min。
实施例4
本实施例中的各种原料及原料的重量份如下：
稀土磁粉：异性Sm 2F 17Nx磁粉(D 50为2.5μm，89份)；
偶联剂：硅烷偶联剂(KH550，0.5份)；
粘结剂：PPS粉末(日本东曹100#，10.5份)；
工艺步骤如下：
将0.01mol/L的草酸的异丙醇溶液溶解于无水乙醇中，调节pH值至6，形成弱酸溶液；向其中加入稀土磁粉，弱酸溶液能完全包覆住磁粉，其与磁粉的体积比为1.5:1；打开超声波振动，控制功率2000W，处理5分钟，形成含有弱酸化磁粉的体系。
向上述体系中加入爱尔斯姆的BW-231锌系磷化液，添加量以pH值为准，调节pH值至5，继续超声波振动，控制功率1500W，处理时间15分钟，形成含有磷化磁粉的体系。
继续向体系中加入偶联剂，超声波振动，控制功率1500W，10分钟后将体系在80℃条件下真空干燥5h，得到表面处理后的稀土磁粉。
将表面处理后的稀土磁粉和粘结剂混合并用双螺杆挤出机造粒，造粒温度设定在290～310℃，得到高性能注塑稀土磁材料。
按照IEC 60404-8-1相关相关测试标准，对注塑稀土磁材料样品进行性能测试，结果如下：Br＝0.59T，Hcj＝695KA/m，(BH)m＝59KJ/m 3，熔融指数为108g/10min。
实施例5
与实施例1的区别仅在于：弱酸选用醋酸，硅烷偶联剂选用KH560。按照IEC60404-8-1相关相关测试标准，对注塑稀土磁材料样品进行性能测试，结果如下：Br＝0.58T，Hcj＝726KA/m，(BH)m＝52KJ/m 3，熔融指数为312g/10min。
实施例6
与实施例1的区别仅在于：弱酸选用碳酸，硅烷偶联剂选用KH792。按照IEC60404-8-1相关相关测试标准，对注塑稀土磁材料样品进行性能测试，结果如下：Br＝0.59T，Hcj＝724KA/m，(BH)m＝53KJ/m 3，熔融指数为300g/10min。
实施例7
与实施例1的区别仅在于：
用乙醇调节弱酸溶液的pH值至7，弱酸溶液与稀土磁粉的体积比为3:1；第一次超声波振动的功率为1500W，处理2分钟；
锌系磷化液加入至含有弱酸化磁粉的体系，调节pH值至5，继续超声波振动，控制功率1000W，处理时间10分钟，形成含有磷化磁粉的体系；
继续向体系中加入偶联剂，偶联剂的加入量为，稀土磁粉重量的0.5％，超声波振动，控制功率2000W，15分钟后将体系在90℃条件下真空干燥5h，得到表面处理后的稀土磁粉。
按照IEC 60404-8-1相关测试标准，对注塑稀土磁材料样品进行性能测试，结果如下：Br＝0.59T，Hcj＝753KA/m，(BH)m＝53KJ/m 3，熔融指数为275g/10min。
实施例8
与实施例1的区别仅在于：
用乙醇调节弱酸溶液的pH值至6，弱酸溶液与稀土磁粉的体积比为2:1；第一次超声波振动的功率为2500W，处理4分钟；
锌系磷化液加入至含有弱酸化磁粉的体系，调节pH值至5，继续超声波振动，控制功率1500W，处理时间15分钟，形成含有磷化磁粉的体系；
继续向体系中加入偶联剂，偶联剂的加入量为，稀土磁粉重量的1％，超声波振动，控制功率1200W，15分钟后将体系在90℃条件下真空干燥7h，得到表面处理后的稀土磁粉。
按照IEC 60404-8-1相关测试标准，对注塑稀土磁材料样品进行性能测试，结果如下：Br＝0.58T，Hcj＝706KA/m，(BH)m＝51KJ/m 3，熔融指数为328g/10min。
对比例1
本对比例中的各种原料及原料的重量份如下：
稀土磁粉：同性NdFeB磁粉(麦格昆磁公司15-9磁粉，92份)
偶联剂：硅烷偶联剂(KH550，0.5份)；
磷酸：0.5份；
粘结剂：尼龙12粉末(日本宇部尼龙7份)；
工艺步骤如下：
将硅烷偶联剂和磷酸溶解在适量的无水乙醇中，向其中加入稀土磁粉，无水乙醇用量以能完全包覆磁粉，其与磁粉的体积比为1.5:1；然后向该溶液加入稀土磁粉充分搅拌混合均匀，然后在80℃真空干燥5h，得到表面处理的稀土磁粉。
将表面处理后的稀土磁粉和粘结剂混合并用双螺杆挤出机造粒，造粒温度设定在200～220℃，得到注塑稀土磁材料。
按照相关测试标准，对注塑稀土磁材料样品进行性能测试，结果如下：Br＝0.56T Hcj＝716KA/m，(BH)m＝48KJ/m 3，熔融指数为264g/10min。
对比例2
本对比例中的各种原料及原料的质量百分比如下：
稀土磁粉：同性NdFeB磁粉(麦格昆磁公司15-9磁粉，90份)
偶联剂：硅烷偶联剂(KH550，0.5份)；
磷酸：0.5份；
粘结剂：PPS粉末(日本东曹100#，9份)；
工艺步骤如下：
将硅烷偶联剂和磷酸溶解在适量的无水乙醇中，向其中加入稀土磁粉，无水乙醇用量以能完全包覆磁粉，其与磁粉的体积比为2:1；然后向该溶液加入稀土磁粉充分搅拌混合均匀，然后在80℃真空干燥5h，得到表面处理的稀土磁粉。
将表面处理后的稀土磁粉和粘结剂混合并用双螺杆挤出机造粒，造粒温度设定在290～310℃，得到注塑稀土磁材料。
按照相关测试标准，对注塑稀土磁材料样品进行性能测试，结果如下：Br＝0.51T Hcj＝674KA/m，(BH)m＝46KJ/m 3，熔融指数为152g/10min。
对比例3
本对比例中的各种原料及原料的重量份如下：
稀土磁粉：异性Sm 2F 17Nx磁粉(D 50为2.5μm，91份)；
偶联剂：硅烷偶联剂(KH550，0.5份)；
磷酸：0.5份；
粘结剂：尼龙12粉末(日本宇部尼龙8份)；
工艺步骤如下：
将硅烷偶联剂和磷酸溶解在适量的无水乙醇中，向其中加入稀土磁粉，无水乙醇用量以能完全包覆磁粉，其与磁粉的体积比为3:1；然后向该溶液加入稀土磁粉充分搅拌混合均匀，然后在80℃真空干燥5h，得到表面处理的稀土磁粉。
将表面处理后的稀土磁粉和粘结剂混合并用双螺杆挤出机造粒，造粒温度设定在200～220℃，得到注塑稀土磁材料。
按照相关测试标准，对注塑稀土磁材料样品进行性能测试，结果如下：Br＝0.58T Hcj＝684KA/m，(BH)m＝59KJ/m 3，熔融指数为138g/10min。
对比例4
本对比例中的各种原料及原料的重量份如下：
稀土磁粉：异性Sm 2F 17Nx磁粉(D 50为2.5μm，89份)；
粘结剂：PPS粉末(日本东曹100#，10.5份)；
偶联剂：硅烷偶联剂(KH550，0.5份)；
工艺步骤如下：
将硅烷偶联剂和磷酸溶解在适量的无水乙醇中，向其中加入稀土磁粉，无水乙醇用量以能完全包覆磁粉，其与磁粉的体积比为1.5:1；然后向该溶液加入稀土磁粉充分搅拌混合均匀，然后在80℃真空干燥5h，得到表面处理的稀土磁粉。
将表面处理后的稀土磁粉和粘结剂混合并用双螺杆挤出机造粒，造粒温度设定在290～310℃，得到注塑稀土磁材料。
按照相关测试标准，对注塑稀土磁材料样品进行性能测试，结果如下：Br＝0.52T Hcj＝625KA/m，(BH)m＝52KJ/m 3，熔融指数为117g/10min。
表1
Figure PCTCN2021129091-appb-000001
Br、Hcj、(BH)max都是永磁材料中磁性能的重要指标，稀土永磁材料氧化后，性能下降，这些指标会跟着下降，氧化越严重，这些指标下降越多。由上表可知，采用本发明实施例中的表面处理方法处理的稀土磁粉，所制备的注塑稀土磁材料的Br、Hcj、(BH)max指标均有明显提高，表明其抗氧化能力更强，注塑稀土磁材料的磁性能更好。需要说明的是不同粘结剂，注塑时温度差异很大，磁粉在不同温度下制备会带来较大差异，因此，上述实施例1至4制备的稀土磁粉注塑材料的性能之间差异明显，但将其分别与对比例1至4进行比较，同一种粘结剂或者同一种磁粉对应的注塑材料性能明显提高，足以表明本发明表面处理方法所带来的有益效果。
流动性指的是成品在一定熔融状态下，在一定压力下的溶体流速。磁粉团聚或者磁粉形貌不规则都会影响流动性。由上表可知，采用本发明实施例中的表面处理方法处理的稀土磁粉，所制备的注塑稀土磁材料的熔融指数均明显提高，表明稀土磁粉形貌更规则，经表面处理后与粘结剂之间的相容性更好。
以上仅为本发明的优选实施例而已，并不用于限制本发明，对于本领域的技术人员来说，本发明可以有各种更改和变化。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (10)

  1. 一种稀土磁粉的表面处理方法，其特征在于，包括以下步骤：
    步骤S1，将稀土磁粉加入至弱酸溶液，以对所述稀土磁粉表面进行弱酸化处理，形成弱酸化磁粉；其中所述弱酸溶液中的弱酸，所述弱酸为酸度系数pKa值大于4.5的无机弱酸和/或酸度系数大于1.0的有机弱酸；
    步骤S2，采用磷化液对所述弱酸化磁粉进行磷化处理，形成磷化磁粉；
    步骤S3，将所述磷化磁粉与偶联剂混合，以对所述磷化磁粉进行偶联化处理，然后干燥，得到表面处理后的所述稀土磁粉。
  2. 根据权利要求1所述的表面处理方法，其特征在于，所述弱酸为草酸、醋酸和碳酸的一种或多种；
    优选地，所述弱酸溶液的pH值为5～7；
    优选地，采用乙醇调节所述弱酸溶液的pH值；
    优选地，所述弱酸溶液与所述稀土磁粉的体积比为1.5～3:1。
  3. 根据权利要求1或2所述的表面处理方法，其特征在于，所述步骤S1中，在将所述稀土磁粉加入至所述弱酸溶液之后，进行第一超声波振动，以进行所述弱酸化处理；
    优选地，所述第一超声波振动的功率为1500～2500W，时长为2～5min。
  4. 根据权利要求1至3中任一项所述的表面处理方法，其特征在于，所述磷化液为锌系磷化液或锰系磷化液；
    优选地，待所述弱酸化处理结束后，直接向含有所述弱酸化磁粉的体系中加入所述磷化液，直至体系的pH值达到4～5，然后进行第二超声波振动，以进行所述磷化处理；
    优选地，所述第二超声波振动的功率为1000～1500W，时长为10～15min。
  5. 根据权利要求4所述的表面处理方法，其特征在于，所述偶联剂为硅烷偶联剂，优选为KH550、KH560、KH792中的一种或多种；
    优选地，待所述磷化处理结束后，直接向含有所述磷化磁粉的体系中加入所述偶联剂，然后进行第三超声波振动，以进行所述偶联化处理；
    优选地，所述偶联剂的加入量为所述稀土磁粉重量的0.5～1％；
    优选地，所述第三超声波振动的功率为1200～2000W，时长为10～15min；
    优选地，所述干燥过程采用真空干燥，干燥温度为70～90℃。
  6. 根据权利要求1至3中任一项所述的表面处理方法，其特征在于，所述稀土磁粉为同性钕铁硼磁粉、异性钕铁硼磁粉、同性衫铁氮磁粉、异性衫铁氮磁粉、钐钴磁粉中的一种或多种。
  7. 一种注塑稀土磁材料的制备方法，其特征在于，包括以下步骤：
    采用权利要求1至6中任一项所述的表面处理方法对稀土磁粉进行表面处理；
    将表面处理后的所述稀土磁粉与粘结剂混合，然后挤出造粒，得到所述注塑稀土磁材料。
  8. 根据权利要求7所述的制备方法，其特征在于，所述粘结剂为尼龙、聚苯硫醚、聚醚醚酮中的一种或多种；优选地，所述粘结剂的用量为所述稀土磁粉重量的8～15％。
  9. 根据权利要求7所述的制备方法，其特征在于，所述挤出造粒过程采用双螺杆挤出机，所述挤出造粒的温度为200～310℃。
  10. 一种注塑稀土磁材料，其特征在于，由权利要求7至9中任一项所述的制备方法制备得到。
PCT/CN2021/129091 2021-10-27 2021-11-05 稀土磁粉的表面处理方法、注塑稀土磁材料及其制备方法 WO2023070735A1 (zh)

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5013411A (en) * 1988-06-02 1991-05-07 Shin-Etsu Chemical Co., Ltd. Method for producing a corrosion resistant rare earth-containing magnet
JP2002008911A (ja) * 2000-06-22 2002-01-11 Nichia Chem Ind Ltd 希土類−鉄−窒素系磁粉の表面処理方法及びそれを用いたプラスチック磁石
JP2003142308A (ja) * 2001-11-07 2003-05-16 Sumitomo Metal Mining Co Ltd 樹脂結合型磁石用組成物及びそれを用いてなる樹脂結合型磁石
CN1808648A (zh) * 2006-01-19 2006-07-26 北京科技大学 一种稀土粘结磁体的制备方法
CN102605361A (zh) * 2011-01-24 2012-07-25 北京中科三环高技术股份有限公司 一种烧结钕铁硼磁性材料的表面处理方法
CN106349686A (zh) * 2015-07-16 2017-01-25 车声雷 一种高性能聚酰胺/钐铁氮磁性复合材料及其制备方法
CN107603220A (zh) * 2017-09-14 2018-01-19 横店集团东磁股份有限公司 一种pps‑稀土永磁注塑用颗粒母料及其制备方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104637667B (zh) * 2015-01-16 2018-02-09 浙江和也健康科技有限公司 一种防氧化的柔性粘贴NdFeB磁条及其制备方法
JP7201565B2 (ja) * 2019-09-27 2023-01-10 日亜化学工業株式会社 磁性粉末の製造方法
JP6760470B2 (ja) * 2019-10-24 2020-09-23 日亜化学工業株式会社 表面処理された希土類系磁性粉末及びその製造方法並びにボンド磁石及びその製造方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5013411A (en) * 1988-06-02 1991-05-07 Shin-Etsu Chemical Co., Ltd. Method for producing a corrosion resistant rare earth-containing magnet
JP2002008911A (ja) * 2000-06-22 2002-01-11 Nichia Chem Ind Ltd 希土類−鉄−窒素系磁粉の表面処理方法及びそれを用いたプラスチック磁石
JP2003142308A (ja) * 2001-11-07 2003-05-16 Sumitomo Metal Mining Co Ltd 樹脂結合型磁石用組成物及びそれを用いてなる樹脂結合型磁石
CN1808648A (zh) * 2006-01-19 2006-07-26 北京科技大学 一种稀土粘结磁体的制备方法
CN102605361A (zh) * 2011-01-24 2012-07-25 北京中科三环高技术股份有限公司 一种烧结钕铁硼磁性材料的表面处理方法
CN106349686A (zh) * 2015-07-16 2017-01-25 车声雷 一种高性能聚酰胺/钐铁氮磁性复合材料及其制备方法
CN107603220A (zh) * 2017-09-14 2018-01-19 横店集团东磁股份有限公司 一种pps‑稀土永磁注塑用颗粒母料及其制备方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP4199016A4

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