阅读说明：本技术 一种磁性海泡石纳米晶磁芯及其制备方法 (Magnetic sepiolite nanocrystalline magnetic core and preparation method thereof ) 是由 邓毕力 潘振海 徐敏义 罗顶飞 王玉川 冯英杰 于 2021-09-26 设计创作，主要内容包括：本发明提供一种磁性海泡石纳米晶磁芯及其制备方法,按照重量份计,磁芯的制备原料包括：磁性铁氧体负载海泡石20份-30份；纳米晶Ni-Zn铁氧体晶粒15份-20份；聚丁二烯改性丙烯酸树脂25份-30份；甲基四氢苯酐5份-10份；硅烷偶联剂3份-6份。本申请通过自制备得到的磁性铁氧体负载海泡石和纳米晶Ni-Zn铁氧体晶粒两种磁性纳米级别颗粒作为原料制备磁芯,有效整合提高了最终制备得到的磁芯的磁性原料密度和晶粒尺寸,利用纳米晶Ni-Zn铁氧体晶粒的单磁畴结构,提高了原料界面上原子排列的无需度,降低了各晶粒间铁磁交换耦合,进而增强了其各向异性,最终提高了磁芯的磁导率、降低了其饱和磁化强度和矫顽力。(The invention provides a magnetic sepiolite nanocrystalline magnetic core and a preparation method thereof, wherein the preparation raw materials of the magnetic core comprise the following components in parts by weight: 20-30 parts of magnetic ferrite load sepiolite; 15-20 parts of nanocrystalline Ni-Zn ferrite grains; 25-30 parts of polybutadiene modified acrylic resin; 5-10 parts of methyl tetrahydrophthalic anhydride; 3-6 parts of a silane coupling agent. According to the magnetic core and the preparation method, two magnetic nano-grade particles, namely the magnetic ferrite load sepiolite and the nanocrystalline Ni-Zn ferrite crystal grain, which are obtained by self-preparation are used as raw materials to prepare the magnetic core, so that the magnetic raw material density and the crystal grain size of the magnetic core which is finally prepared are effectively integrated and improved, the unnecessary degree of atomic arrangement on a raw material interface is improved by using the single magnetic domain structure of the nanocrystalline Ni-Zn ferrite crystal grain, the ferromagnetic exchange coupling among the crystal grains is reduced, the anisotropy of the magnetic core is further enhanced, the magnetic conductivity of the magnetic core is finally improved, and the saturation magnetization intensity and the coercive force of the magnetic core are reduced.)

1. The magnetic sepiolite nanocrystalline magnetic core is characterized in that the magnetic core is prepared from the following raw materials in parts by weight:

2. a magnetic sepiolite nanocrystalline core according to claim 1, characterized in that the nanocrystalline Ni-Zn ferrite grains have a size of 15nm to 20 nm.

3. The magnetic sepiolite nanocrystalline magnetic core according to claim 1, characterized in that the nanocrystalline Ni-Zn ferrite grains are Ni-molecular formulas prepared by a spray-co-precipitation method_xZn_1-xFe₂O₄Ferrite grains, wherein x is more than or equal to 0.3 and less than or equal to 0.7.

4. The magnetic sepiolite nanocrystalline core according to claim 3, characterized in that the preparation method of the magnetic ferrite loaded sepiolite comprises the following steps:

1) FeCl is added₂·4H₂O、FeCl₃·6H₂Dissolving O in distilled water according to the molar ratio of x to 1-x to form a mixed iron salt solution;

2) immersing 30-40 parts of sepiolite in the mixed iron salt solution obtained in the step 1), and stirring at the rotating speed of 100-150 rpm in an inert atmosphere to obtain an iron-loaded sepiolite precursor solution;

3) adding alkali liquor into the iron-loaded sepiolite precursor solution obtained in the step 2), adjusting the pH to 10-12, heating for crystallization reaction to obtain a magnetic ferrite-loaded sepiolite precipitate with a three-dimensional space network structure with magnetic ferrite loaded on the pore surfaces and in the pore channels of the sepiolite;

4) washing the magnetic ferrite load sepiolite precipitate obtained in the step 3) for 3-5 times by using distilled water, and drying to obtain the magnetic ferrite load sepiolite.

5. The magnetic sepiolite nanocrystalline core according to claim 4, characterized in that the heating temperature in step 3) is 45 ℃ to 75 ℃.

6. The magnetic sepiolite nanocrystalline magnetic core according to claim 4, characterized in that the alkaline solution used is a NaOH or KOH solution with a concentration of 1M to 1.5M.

7. The magnetic sepiolite nanocrystalline core according to claim 4, characterized in that the drying temperature in step 4) is 60 ℃ to 80 ℃.

8. The magnetic sepiolite nanocrystalline core according to claim 4, wherein the magnetic ferrite in the magnetic ferrite loaded sepiolite is Fe₃O₄、α-Fe₂O₃Or gamma-Fe₂O₃One kind of (1).

9. The magnetic sepiolite nanocrystalline core according to claim 1, characterized in that the silane coupling agent is one or more of 3-aminopropyltriethoxysilane, dimethyldimethoxysilane and vinyltriethoxysilane.

10. A method for preparing a magnetic sepiolite nanocrystalline core according to any of claims 1 to 9, characterized in that it comprises the following steps:

s1: dissolving the polybutadiene modified acrylic resin in the weight part in 300-500 ml of acetone, and uniformly stirring;

s2: adding the methyl tetrahydrophthalic anhydride serving as the curing agent in parts by weight, stirring at the rotating speed of 200-300 rpm, and continuously dropwise adding the silane coupling agent in parts by weight in the stirring process;

s3: adding the magnetic ferrite load sepiolite in parts by weight and the nanocrystalline Ni-Zn ferrite crystal grains in parts by weight into the mixture obtained in the step S2, uniformly mixing, drying at 100-150 ℃, granulating, performing single-side cold pressing to form a magnetic ring, and performing isostatic pressing high-temperature thermosetting molding under the conditions that the hot pressing pressure is 150-180 MPa, and the furnace body temperature is raised to the hot pressing temperature of 550-750 ℃ to obtain the magnetic sepiolite nanocrystalline core.

Technical Field

The invention belongs to the technical field of nanocrystalline magnetic cores, and particularly relates to a magnetic sepiolite nanocrystalline magnetic core and a preparation method thereof.

Background

At present, electronic power technology is developing towards low loss, high frequency, high power and small size, and many electronic devices need to install reactors, filters and anti-interference devices as much as possible in a limited space to ensure the working quality of the electronic devices. Because the iron-based nanocrystalline alloy has excellent soft magnetic performance, and the manufactured inductance element has the characteristics of good temperature stability, large inductance, high quality factor, small volume, strong anti-saturation capacity, high efficiency, energy conservation and the like, the iron-based nanocrystalline alloy has been widely applied to various devices such as satellite communication, precise measurement and control equipment, industrial rectifiers, various switching power supplies, inverter power supplies, computers and the like.

However, the magnetic core prepared by the prior art has too high saturation magnetization and too low magnetic permeability, and cannot meet the working requirements of the prior electrical devices. How to prepare a magnetic core with high magnetic permeability, lower saturation magnetization and low coercive force is a technical problem which needs to be solved urgently.

Disclosure of Invention

Aiming at the defects, the invention provides the magnetic sepiolite nanocrystalline magnetic core with high magnetic conductivity, lower saturation magnetization and low coercive force and the preparation method thereof.

The invention provides the following technical scheme: the magnetic sepiolite nanocrystalline magnetic core is prepared from sepiolite which is loaded by magnetic ferrite, and comprises the following components in parts by weight:

further, the size of the nanocrystalline Ni-Zn ferrite grains is 15nm-20 nm.

Furthermore, the nanocrystalline Ni-Zn ferrite crystal grain is prepared by adopting a jet-coprecipitation method, and the molecular formula of the nanocrystalline Ni-Zn ferrite crystal grain is Ni_xZn_1-xFe₂O₄Ferrite grains, wherein x is more than or equal to 0.3 and less than or equal to 0.7.

Further, the preparation method of the magnetic ferrite loaded sepiolite comprises the following steps:

1) FeCl is added₂·4H₂O、FeCl₃·6H₂Dissolving O in distilled water according to the molar ratio of x to 1-x to form a mixed iron salt solution;

2) immersing 30-40 parts of sepiolite in the mixed iron salt solution obtained in the step 1), and stirring at the rotating speed of 100-150 rpm in an inert atmosphere to obtain an iron-loaded sepiolite precursor solution;

3) adding alkali liquor into the iron-loaded sepiolite precursor solution obtained in the step 2), adjusting the pH to 10-12, heating for crystallization reaction to obtain a magnetic ferrite-loaded sepiolite precipitate with a three-dimensional space network structure with magnetic ferrite loaded on the pore surfaces and in the pore channels of the sepiolite;

4) washing the magnetic ferrite load sepiolite precipitate obtained in the step 3) for 3-5 times by using distilled water, and drying to obtain the magnetic ferrite load sepiolite.

Further, the heating temperature in the step 3) is 45-75 ℃.

Further, the alkali liquor is NaOH or KOH solution with the concentration of 1M-1.5M.

Further, the drying temperature of the step 4) is 60-80 ℃.

Further, the magnetic ferrite in the magnetic ferrite load sepiolite is Fe₃O₄、α-Fe₂O₃Or gamma-Fe₂O₃One kind of (1).

Further, the silane coupling agent is one or more of 3-aminopropyltriethoxysilane, dimethyldimethoxysilane and vinyltriethoxysilane.

The invention also provides a preparation method of the magnetic sepiolite nanocrystalline magnetic core, which comprises the following steps:

s1: dissolving the polybutadiene modified acrylic resin in the weight part in 300-500 ml of acetone, and uniformly stirring;

s2: adding the methyl tetrahydrophthalic anhydride serving as the curing agent in parts by weight, stirring at the rotating speed of 200-300 rpm, and continuously dropwise adding the silane coupling agent in parts by weight in the stirring process;

s3: adding the magnetic ferrite load sepiolite in parts by weight and the nanocrystalline Ni-Zn ferrite crystal grains in parts by weight into the mixture obtained in the step S2, uniformly mixing, drying at 100-150 ℃, granulating, performing single-side cold pressing to form a magnetic ring, and performing isostatic pressing high-temperature thermosetting molding under the conditions that the hot pressing pressure is 150-180 MPa, and the furnace body temperature is raised to the hot pressing temperature of 550-750 ℃ to obtain the magnetic sepiolite nanocrystalline core.

The invention has the beneficial effects that:

1. according to the magnetic core, two magnetic nano-grade particles, namely the magnetic ferrite load sepiolite and the nanocrystalline Ni-Zn ferrite crystal grain, which are obtained by self-preparation are used as raw materials to prepare the magnetic core, so that the density and the size of the magnetic raw materials of the magnetic core which is finally prepared are effectively integrated and improved, the unnecessary degree of atomic arrangement on the interface of the raw materials for preparing the magnetic core is improved by using the single magnetic domain structure of the nanocrystalline Ni-Zn ferrite crystal grain, the ferromagnetic exchange coupling among the crystal grains is reduced, the anisotropy of the magnetic core is further enhanced, the magnetic conductivity of the magnetic core is finally improved, and the saturation magnetization intensity and the coercive force of the magnetic core are reduced.

2. According to the preparation method, the methyl tetrahydrophthalic anhydride is a curing agent for the resin which is heat-resistant, chemically stable, excellent in physical and electrical properties, high in melting point, small in sublimation phenomenon and small in environmental influence, and is beneficial to reducing the internal stress of magnetic ferrite load sepiolite and nanocrystalline Ni-Zn ferrite grains of the magnetic core synthetic raw materials, so that the magnetic conductivity of the magnetic core is improved, and the saturation magnetization intensity and the coercive force of the magnetic core are reduced.

3. Through the isostatic pressing effect, the magnetic ordering in the magnetic core is inhibited to a certain extent in the whole heat treatment process, the magnetocrystalline anisotropy is reduced, the saturation magnetization intensity, the magnetic conductivity and the remanence ratio of the material are improved, and the comprehensive soft magnetic properties such as the coercive force are reduced.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The reagents adopted by the invention are all commercially available.

Example 1

In this embodiment, the magnetic core is made of sepiolite, which is a magnetic ferrite made of Fe₃O₄The loaded magnetic core is prepared from the following raw materials in parts by weight:

the nanocrystalline Ni-Zn ferrite grain adopted in the embodiment is prepared by adopting a spray-coprecipitation method, and the molecular formula of the nanocrystalline Ni-Zn ferrite grain is Ni_0.35Zn_0.65Fe₂O₄Ferrite grains.

Magnetic ferrite Fe₃O₄The preparation method of the loaded sepiolite comprises the following steps:

1) FeCl is added₂·4H₂O、FeCl₃·6H₂Dissolving O in distilled water according to the molar ratio of 0.35:0.65 to form a mixed iron salt solution;

2) immersing 30 parts of sepiolite in the mixed iron salt solution obtained in the step 1), and stirring at the rotating speed of 100rpm under the inert atmosphere of argon gas to obtain an iron-loaded sepiolite precursor solution;

3) adding NaOH alkali solution with the concentration of 1M into the iron-loaded sepiolite precursor solution obtained in the step 2), adjusting the pH to 10, heating at 45 ℃ for crystallization reaction to obtain Fe ferrite with magnetic property₃O₄Magnetic ferrite Fe with three-dimensional space network structure loaded on sepiolite pore surfaces and pore channels₃O₄Loading sepiolite precipitate;

4) washing the magnetic ferrite load sepiolite precipitate obtained in the step 3) for 3-5 times by using distilled water, and drying at 60 ℃ to obtain magnetic ferrite Fe₃O₄And loading sepiolite.

The embodiment also provides a preparation method of the magnetic sepiolite nanocrystalline magnetic core, which comprises the following steps:

s1: dissolving 25 parts of polybutadiene modified acrylic resin in 300ml of acetone, and uniformly stirring;

s2: adding 5 parts of methyl tetrahydrophthalic anhydride as a curing agent, stirring at the rotating speed of 200rpm, and continuously dropwise adding 3 parts of 3-aminopropyltriethoxysilane in the stirring process;

s3: adding 20 parts of magnetic ferrite Fe to the mixture obtained in the step S2₃O₄Uniformly mixing the loaded sepiolite and 15 parts of nanocrystalline Ni-Zn ferrite grains with the size of 15nm, drying at 100 ℃, granulating, cold pressing the single surface of the mixture to form a magnetic ring, and then carrying out isostatic pressing high-temperature thermosetting molding under the conditions that the hot pressing pressure is 150Mpa and the furnace body temperature is raised until the hot pressing temperature reaches 550 ℃ to obtain the magnetic sepiolite nanocrystalline magnetic core.

Through experiments, the magnetic core provided by the embodiment has the magnetic permeability of 85MHz, the saturation magnetization of 0.73T and the coercive force of 3.01A/m.

Example 2

In this embodiment, the magnetic core is made of sepiolite, which is a magnetic ferrite γ -Fe core, and the raw material for making the magnetic core contains sepiolite₂O₃The loaded magnetic core is prepared from the following raw materials in parts by weight:

the nanocrystalline Ni-Zn ferrite grain adopted in the embodiment is prepared by adopting a spray-coprecipitation method, and the molecular formula of the nanocrystalline Ni-Zn ferrite grain is Ni_0.5Zn_0.5Fe₂O₄Ferrite grains.

Magnetic ferrite gamma-Fe₂O₃The preparation method of the loaded sepiolite comprises the following steps:

1) FeCl is added₂·4H₂O、FeCl₃·6H₂Dissolving O in distilled water according to the molar ratio of 1:1 to form a mixed iron salt solution;

2) immersing 35 parts of sepiolite in the mixed iron salt solution obtained in the step 1), and stirring at the rotating speed of 130rpm in the inert atmosphere of nitrogen to obtain an iron-loaded sepiolite precursor solution;

3) adding KOH alkaline liquor with the concentration of 1.2M into the iron-loaded sepiolite precursor solution obtained in the step 2), adjusting the pH to 11, heating at 60 ℃ for crystallization reaction to obtain the magnetic ferrite gamma-Fe₂O₃Magnetic ferrite gamma-Fe with three-dimensional space network structure loaded on sepiolite pore surfaces and pore channels₂O₃Loading sepiolite precipitate;

4) subjecting the magnetic ferrite gamma-Fe obtained in the step 3)₂O₃Washing the sepiolite-loaded precipitate with distilled water for 4 times, and drying at 70 deg.C to obtain magnetic ferrite gamma-Fe₂O₃And loading sepiolite.

The embodiment also provides a preparation method of the magnetic sepiolite nanocrystalline magnetic core, which comprises the following steps:

s1: dissolving 28 parts of polybutadiene modified acrylic resin in 400ml of acetone, and uniformly stirring;

s2: adding 7.5 parts of methyl tetrahydrophthalic anhydride as a curing agent, stirring at the rotating speed of 250rpm, and continuously dropwise adding 4.5 parts of vinyl triethoxysilane in the stirring process;

s3: and (2) adding the magnetic ferrite load sepiolite in parts by weight and 17 parts of nanocrystalline Ni-Zn ferrite crystal grains with the size of 18nm into the mixture obtained in the step S2, uniformly mixing, drying at 120 ℃, granulating, performing cold pressing on a single surface to form a magnetic ring, and then performing isostatic pressing high-temperature thermosetting molding under the conditions that the hot pressing pressure is 165Mpa and the furnace body temperature is raised to 650 ℃ to obtain the magnetic sepiolite nanocrystalline core.

Through experiments, the magnetic core provided by the embodiment has the magnetic permeability of 97MHz, the saturation magnetization of 0.64T and the coercive force of 2.53A/m.

Example 3

The magnetic sepiolite nanocrystalline magnetic core provided by the embodiment of the invention comprises sepiolite in preparation raw materials, wherein the sepiolite is loaded by magnetic ferrite, and the preparation raw materials of the magnetic core comprise the following components in parts by weight:

the nanocrystalline Ni-Zn ferrite grain is prepared by adopting a jet-coprecipitation method, and the molecular formula of the nanocrystalline Ni-Zn ferrite grain is Ni_0.7Zn_0.3Fe₂O₄Ferrite grains.

Magnetic ferrite alpha-Fe₂O₃The preparation method of the loaded sepiolite comprises the following steps:

1) FeCl is added₂·4H₂O、FeCl₃·6H₂Dissolving O in distilled water according to the molar ratio of 0.7:0.3 to form a mixed iron salt solution;

2) immersing 40 parts of sepiolite in the mixed iron salt solution obtained in the step 1), and stirring at the rotating speed of 150rpm under the inert atmosphere of argon gas to obtain an iron-loaded sepiolite precursor solution;

3) adding NaOH alkali solution with the concentration of 1.5M into the iron-loaded sepiolite precursor solution obtained in the step 2), adjusting the pH to 12, heating at 75 ℃ for crystallization reaction to obtain the magnetic ferrite alpha-Fe₂O₃Three loaded on sepiolite pore surface and pore channelMagnetic ferrite alpha-Fe with dimensional space network structure₂O₃Loading sepiolite precipitate;

4) subjecting the magnetic ferrite alpha-Fe obtained in the step 3)₂O₃Washing the sepiolite-loaded precipitate with distilled water for 3-5 times, and drying at 80 deg.C to obtain magnetic ferrite alpha-Fe₂O₃And loading sepiolite.

The embodiment also provides a preparation method of the magnetic sepiolite nanocrystalline magnetic core, which comprises the following steps:

s1: dissolving 30 parts of polybutadiene modified acrylic resin in 500ml of acetone, and uniformly stirring;

s2: adding 10 parts of methyl tetrahydrophthalic anhydride as a curing agent, stirring at the rotating speed of 300rpm, and continuously dropwise adding 6 parts of dimethyl dimethoxysilane in the stirring process;

s3: adding 30 parts of magnetic ferrite alpha-Fe to the mixture obtained in the step S2₂O₃Uniformly mixing the loaded sepiolite and 20 parts of nanocrystalline Ni-Zn ferrite grains with the size of 20nm, drying at 150 ℃, granulating, cold pressing the single surface of the mixture to form a magnetic ring, and then carrying out isostatic pressing high-temperature thermosetting molding under the conditions that the hot pressing pressure is 180Mpa and the furnace body temperature is raised until the hot pressing temperature reaches 750 ℃ to obtain the magnetic sepiolite nanocrystalline magnetic core.

Through experiments, the magnetic core provided by the embodiment has the magnetic permeability of 118MHz, the saturation magnetization of 0.58T and the coercive force of 2.06A/m.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Furthermore, those skilled in the art will appreciate that while some embodiments herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the claims above, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.