CN111785470B - Magnetic bead powder and preparation method thereof, laminated magnetic bead and preparation method thereof - Google Patents
Magnetic bead powder and preparation method thereof, laminated magnetic bead and preparation method thereof Download PDFInfo
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- 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
- H01F1/12—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 soft-magnetic materials
- H01F1/14—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 soft-magnetic materials metals or alloys
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- H01F1/14708—Fe-Ni based alloys
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Abstract
The invention provides a preparation method of magnetic bead powder, which comprises the following steps: a) Mixing aluminum sulfate, potassium aluminate, sodium acetate and acetic acid in water to obtain a mixed solution; b) Immersing the magnetic metal particles subjected to acid washing into the mixed solution, adding sodium hydroxide, and reacting under stirring; c) Drying the solid product obtained in the step B) and calcining to obtain a base material with a core-shell structure; d) AlN, bi 2 O 3 、ZrO 2 、SiO 2 、MnO 2 And Co 3 O 4 Ball milling and mixing to obtain an additive; e) Mixing the base material with the additive to obtain the magnetic bead powder. Making metal magnetic material into M@Al 2 O 3 The core/shell structure material maintains the high magnetic permeability of the metal magnetic material, and has high impedance characteristic due to the existence of the insulating shell. The invention also provides magnetic bead powder, laminated magnetic beads and preparation methods thereof.
Description
Technical Field
The invention belongs to the technical field of electromagnetic materials, and particularly relates to magnetic bead powder and a preparation method thereof. Laminated magnetic beads and a preparation method thereof.
Background
The magnetic beads are widely used as elements and have the function of absorbing high-frequency harmonic waves in a circuit, the function of the magnetic beads is mainly to eliminate RF noise existing in a transmission line structure (circuit), RF energy is an AC sine wave component overlapped on a DC transmission level, and a DC component is a needed useful signal. To eliminate these unwanted signal energies, chip-type beads are used to act as high-frequency resistors (attenuators).
The magnetic beads have very high resistivity and permeability, which are equivalent to series connection of a resistor and an inductor, but the resistance value and the inductance value are changed along with the frequency. Compared with the common inductor, the inductor has better high-frequency filtering characteristic and is resistive at high frequency, so that higher impedance can be kept in a quite wide frequency range, and the frequency modulation filtering effect is improved.
The preparation material of the magnetic beads is required to have high magnetic permeability, high impedance and other performances, and at present, magnetic ferrite is mainly used as a main preparation material, and the ferrite is a ferrimagnetic material with a cubic lattice structure. Ferrite materials are iron-magnesium alloy or iron-nickel alloy, which have the problem of single preparation material and limit the further application of the magnetic beads. Fe, co, ni and their alloy materials, which are typical metal magnetic materials, have high magnetic permeability, but their resistance is low, so that they cannot be applied better in terms of magnetic bead preparation.
Disclosure of Invention
The invention aims to provide magnetic bead powder and a preparation method thereof. The laminated magnetic bead powder of the invention uses Fe, co, ni and alloy materials thereof as base materials, which not only maintains the special high magnetic permeability of the metal magnetic material, but also has higher impedance characteristic.
The invention provides a preparation method of magnetic bead powder, which comprises the following steps:
a) Mixing aluminum sulfate, potassium aluminate, sodium acetate and acetic acid in water to obtain a mixed solution;
the concentration of aluminum sulfate in the mixed solution is 0.003-0.2 mol/L, the concentration of potassium aluminate is 0.03-0.2 mol/L, the concentration of sodium acetate is 0.017-0.03 mol/L, and the concentration of acetic acid is 0.03-0.1 mol/L;
b) Immersing the magnetic metal particles subjected to acid washing into the mixed solution, adding sodium hydroxide, and reacting under stirring;
c) Drying the solid product obtained in the step B) and calcining to obtain a base material with a core-shell structure;
d) AlN, bi 2 O 3 、ZrO 2 、SiO 2 、MnO 2 And Co 3 O 4 Ball milling and mixing to obtain an additive;
e) Mixing the base material with the additive to obtain the magnetic bead powder.
Preferably, the magnetic metal particles are one or an alloy of any of iron, cobalt and nickel;
the particle size of the magnetic metal particles is 1-15 mu m.
Preferably, the magnetic metal particles are pickled for 5 to 20 minutes by using an acid solution of 0.005 to 0.02 mol/L.
Preferably, in the step B), sodium hydroxide solution is slowly added into the mixed solution, wherein the concentration of the sodium hydroxide solution is 0.0015-4 mol/L, and the molar ratio of sodium hydroxide to aluminum sulfate is 1 (1-5).
Preferably, the calcination procedure in the step C) is as follows: under the vacuum state, the temperature is firstly increased to 200-500 ℃, the heat is preserved for 10-60 min, and the temperature is increased to 1000-1500 ℃ and the heat is preserved for 10-60 min.
Preferably, the mass of AlN is 1-3% of the total mass of the base material, bi 2 O 3 The mass of the ZrO is 0.5 to 2 percent of the total mass of the base material 2 The mass of the catalyst is 0.1 to 0.5 percent of the total mass of the base material, and SiO is the following mass 2 The mass of the catalyst is 0.1 to 0.5 percent of the total mass of the base material, mnO 2 The mass of the catalyst is 0.2 to 0.6 percent of the total mass of the base material, co 3 O 4 The mass of the (B) is 0.1-0.7% of the total mass of the base material.
Preferably, the ball-milled ball-material ratio in the step D) is (15-25): 1, the ball milling rotating speed is 200-500 r/min, and the ball milling time is 1-5 hours.
The invention provides a magnetic bead powder material, which is prepared according to the preparation method, wherein the base material in the magnetic bead powder material has a core-shell structure, the inner core is an alloy formed by one or more of iron, cobalt and nickel, and the outer shell is Al 2 O 3 。
The invention provides a laminated magnetic bead which is prepared by using the magnetic bead powder.
The invention provides a preparation method of laminated magnetic beads, which comprises the following steps:
the magnetic bead powder is made into a film through a tape casting process, a laminated structure is formed after screen printing, and terminal electrodes are formed on two sides of the laminated structure, so that laminated magnetic beads are obtained.
The invention provides a magnetic bead powderThe preparation method of the material comprises the following steps: a) Mixing aluminum sulfate, potassium aluminate, sodium acetate and acetic acid in water to obtain a mixed solution; the concentration of aluminum sulfate in the mixed solution is 0.003-0.2 mol/L, the concentration of potassium aluminate is 0.03-0.2 mol/L, the concentration of sodium acetate is 0.017-0.03 mol/L, and the concentration of acetic acid is 0.03-0.1 mol/L; b) Immersing the magnetic metal particles subjected to acid washing into the mixed solution, adding sodium hydroxide, and reacting under stirring; c) Drying the solid product obtained in the step B) and calcining to obtain a base material with a core-shell structure; d) AlN, bi 2 O 3 、ZrO 2 、SiO 2 、MnO 2 And Co 3 O 4 Ball milling and mixing to obtain an additive; e) Mixing the base material with the additive to obtain the magnetic bead powder. Making metal magnetic material into M@Al 2 O 3 A core/shell structure, wherein M: fe. Co, ni and alloys thereof, the shell/core structural material not only maintains the special high magnetic permeability of the metal magnetic material, but also has higher impedance characteristic due to the existence of the insulating shell, and completely meets the requirements of the magnetic bead preparation material. The material is used as a base material, and the mixed sintering is carried out by adding an additive, so that the material can be applied to the preparation of high-performance magnetic beads.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
FIG. 1 is a graph showing the impedance values of the base stock of example 1 of the present invention in the GHz operating frequency range;
FIG. 2 is a graph showing the attenuation constants of the base stock in example 1 of the present invention over the GHz operating frequency range.
Detailed Description
The invention provides a preparation method of magnetic bead powder, which comprises the following steps:
a) Mixing aluminum sulfate, potassium aluminate, sodium acetate and acetic acid in water to obtain a mixed solution;
the concentration of aluminum sulfate in the mixed solution is 0.003-0.2 mol/L, the concentration of potassium aluminate is 0.03-0.2 mol/L, the concentration of sodium acetate is 0.017-0.03 mol/L, and the concentration of acetic acid is 0.03-0.1 mol/L;
b) Immersing the magnetic metal particles subjected to acid washing into the mixed solution, adding sodium hydroxide, and reacting under stirring;
c) Drying the solid product obtained in the step B) and calcining to obtain a base material with a core-shell structure;
d) AlN, bi 2 O 3 、ZrO 2 、SiO 2 、MnO 2 And Co 3 O 4 Ball milling and mixing to obtain an additive;
e) Mixing the base material with the additive to obtain the magnetic bead powder.
The magnetic bead powder comprises a base material and an additive, wherein the base material is a metal material with a core-shell structure, the inner core is metal Fe, co and Ni or alloys thereof, and the outer shell is Al 2 O 3 。
The base material is prepared according to the following steps:
firstly, mixing aluminum sulfate, potassium aluminate, sodium acetate and acetic acid in water to obtain a mixed solution, preferably, firstly preparing the aluminum sulfate, the potassium aluminate, the sodium acetate and the acetic acid into an aluminum sulfate solution, a potassium aluminate solution, a sodium acetate solution and an acetic acid solution respectively, then mixing the above solutions, and uniformly stirring to obtain the mixed solution.
In the present invention, the concentration of the aluminum sulfate solution is preferably 0.01 to 0.5mol/L, more preferably 0.05 to 0.4mol/L, and most preferably 0.1 to 0.3mol/L; specifically, in the embodiment of the present invention, it may be 0.1mol/L or 0.01mol/L.
The concentration of the potassium aluminate solution is preferably 0.1 to 0.6mol/L, more preferably 0.2 to 0.5mol/L, and most preferably 0.3 to 0.4mol/L; specifically, in embodiments of the present invention, it may be 0.4mol/L or 0.6mol/L.
In the invention, aluminum sulfate generates aluminum hydroxide and sulfuric acid in weak alkaline solution, potassium aluminate reacts with water to generate aluminum hydroxide and sodium hydroxide, and sulfuric acid and sodium hydroxide can play a role in neutralization.
The concentration of the sodium acetate solution is preferably 0.1 to 0.2mol/L, and specifically, in the embodiment of the invention, may be 0.1mol/L or 0.2mol/L;
the concentration of the acetic acid solution is preferably 0.1 to 0.5mol/L, more preferably 0.2 to 0.5mol/L, most preferably 0.3 to 0.4mol/L, and particularly, in an embodiment of the present invention, may be 0.4mol/L or 0.5mol/L.
In the invention, the acetic acid and sodium acetate have the function of forming a buffer solution, so that the large fluctuation of the pH value caused by the subsequent addition of sodium hydroxide is avoided.
After the solutions of the raw materials with the concentrations are prepared, the solution is prepared according to the following aluminum sulfate solution: potassium aluminate solution: sodium acetate solution: acetic acid solution 1: (0.5-2): (0.1-1): (0.1-1) to obtain a mixed solution, preferably, the volume ratio of the aluminum sulfate solution, the potassium aluminate solution, the sodium acetate solution and the acetic acid solution is preferably 1: (1-1.5): (0.5-0.8): (0.5-0.8). Specifically, in the embodiment of the present invention, it may be 1:1:0.5:0.5.
then adding the magnetic metal particles after acid washing into the mixed solution, firstly cleaning the magnetic metal particles in a diluted acid solution to remove surface oxide skin and impurities, and simultaneously forming uneven etching pits on the surfaces of the particles to form the etching pits mainly aiming at inducing the aluminum hydroxide particles to form nuclei at the positions for growth because the etching pits can provide surface energy for the nucleation growth of the aluminum hydroxide and reduce the nucleation growth difficulty of the aluminum hydroxide. And more evenly distributed such pits on the surface of the magnetic particles contribute to the formation of a uniform aluminum hydroxide layer. In addition, alumina is generated in the subsequent calcination process, and the existence of the etching pits increases the mechanical bonding area of the alumina and the magnetic metal particles, so that the bonding strength of the alumina and the magnetic metal particles is increased. The bonding strength of the bulk material is increased in the subsequent process of sintering and forming the magnetic beads.
In the present invention, the magnetic metal particles are preferably any one or an alloy of any of Fe, co, and Ni, and the particle diameter of the magnetic metal particles is preferably 1 to 15 μm.
The acid solution is preferably a strong acid solution such as hydrochloric acid, sulfuric acid, nitric acid, etc., the concentration of the acid solution is preferably 0.005 to 0.02mol/L, more preferably 0.01mol/L, and the pickling time is preferably 5 to 20 minutes, more preferably 10 to 15 minutes.
Slowly adding sodium hydroxide solution into the mixed solution with the magnetic metal particles, reacting, continuously stirring the solution in the adding process, and continuously stirring for 5-20 min after the sodium hydroxide solution is added.
In the present invention, the concentration of the sodium hydroxide solution is preferably 0.0003 to 4mol/L, more preferably 0.001 to 3mol/L, most preferably 0.01 to 2mol/L, and in particular, in the embodiment of the present invention, may be 0.01mol/L or 1mol/L; the ratio of the concentration of the sodium hydroxide solution to the concentration of the aluminum sulfate solution is preferably (0.1 to 20): 1, more preferably (1 to 15): 1, most preferably (5 to 10): 1, a step of; the molar ratio of sodium hydroxide to aluminum sulfate is preferably 1: (1 to 5), more preferably 1: (2-4), most preferably 1: (2-3).
In the present invention, the temperature of the reaction is preferably 20 to 30 ℃, more preferably 25 ℃, and the time of the reaction is preferably 30 to 90 minutes, more preferably 40 to 80 minutes, and most preferably 50 to 60 minutes.
After the reaction is finished, collecting a solid reaction product, washing the solid reaction product with deionized water for 3-5 times, washing the solid reaction product with absolute ethyl alcohol for 3-5 times, and finally drying the solid reaction product in vacuum for standby.
In the present invention, the temperature of the vacuum drying is preferably 40 to 90 ℃, more preferably 50 to 80 ℃, and most preferably 60 to 70 ℃; the time for the vacuum drying is preferably 1 to 9 hours, more preferably 2 to 8 hours, and most preferably 3 to 5 hours.
Finally, the reaction product dried in vacuum is subjected to vacuum calcination to obtain the base material with a core/shell structure.
In the present invention, the vacuum calcination process is as follows:
under vacuum state, the temperature is raised to 200-500 ℃, preferably 300-400 ℃, kept for 10-60 min, preferably 20-50 min, most preferably 30-40 min, then raised to 1000-1500 ℃, preferably 1100-1400 ℃, more preferably 1200-1300 ℃, kept for 10-60 min, preferably 20-50 min, most preferably 30-40 min, and cooled to room temperature after the end.
In the vacuum calcination process, the heating rate is preferably 1 to 10 ℃/min, more preferably 3 to 8 ℃/min, most preferably 5 to 6 ℃/min, and the cooling rate is preferably 1 to 10 ℃/min, more preferably 3 to 8 ℃/min, most preferably 5 to 6 ℃/min.
The invention prepares the additive according to the following steps:
the additives are prepared according to the following adding proportion by weight of the base material:
AlN:1 to 3%, preferably 1.5 to 2.5%, more preferably 2%; bi (Bi) 2 O 3 :0.5 to 2%, preferably 1 to 1.5%; zrO (ZrO) 2 :0.1 to 0.5%, preferably 0.2 to 0.4%, more preferably 0.3%; siO (SiO) 2 :0.1 to 0.5%, preferably 0.2 to 0.4%, more preferably 0.3%; mnO (MnO) 2 :0.2 to 0.6%, preferably 0.3 to 0.5%, more preferably 0.4%; co (Co) 3 O 4 : from 0.1 to 0.7%, preferably from 0.2 to 0.6%, more preferably from 0.3 to 0.5%, most preferably 0.4%.
In the present invention, the AlN, bi 2 O 3 、ZrO 2 、SiO 2 、MnO 2 And Co 3 O 4 The particle size of (C) is preferably 1 to 20. Mu.m.
The traditional additives mainly play a role of an adhesive in the preparation process of the magnetic beads, like glue, bind the base materials, the traditional method is that the base materials and the additives are directly mixed and then sintered, the dispersion degree of the additives in the base materials depends on the mixing effect, and if the mixing effect is poor, the additives can not be capable of completely and completely binding the base materials in the binding process, so that the improvement of the integral binding strength of the magnetic beads is not favored.
The silicon dioxide used in the additive reacts with the alumina with the core-shell structure in the subsequent sintering process to generate aluminum silicate, and the reaction product is helpful for enhancing the bonding strength between the magnetic bead powder materials. And the alumina is uniformly and completely coated around the magnetic particles in the form of a shell, and the aluminum silicate generated by the method is also coated around the core structure in a completely and uniformly manner. This method is much more uniform than the conventional direct mixing method.
And ball-milling and mixing the AlN and other raw material powder according to the adding proportion to obtain the additive.
In the invention, the ball-milling ball-material ratio is preferably (15-25): 1, more preferably 20:1, a step of; the rotation speed of the ball milling is preferably 200-500 r/min, more preferably 300-400 r/min, and the time of the ball milling is preferably 1-5 hours, more preferably 2-4 hours, and most preferably 3 hours.
And uniformly mixing the base material and the additive to obtain the magnetic bead powder.
The invention also provides a magnetic bead powder, which comprises a base material and an additive, wherein the base material has a core-shell structure, the inner core is an alloy formed by one or more of iron, cobalt and nickel, and the outer shell is Al with the thickness of 1-5 mu m 2 O 3 。
The invention also provides a laminated magnetic bead, which is prepared by taking the magnetic bead powder as a raw material.
The invention also provides a preparation method of the laminated magnetic beads, which comprises the following steps:
the magnetic bead powder is made into a film through a tape casting process, a laminated structure is formed after screen printing, and terminal electrodes are formed on two sides of the laminated structure, so that laminated magnetic beads are obtained.
In the present invention, the method for preparing the laminated magnetic beads from the magnetic bead powder, such as a casting process for preparing a thin film, a screen printing process for preparing a laminated structure and a process for forming a terminal electrode, are all common methods in the art, and the present invention is not repeated herein.
Compared with the prior art, the invention has the following advantages:
(1) The base material of the invention designs the typical metal magnetic material into a shell-core structure, which has high magnetic permeability and high impedance performance of the metal magnetic material;
(2) Because the core structure material is selected to be a high-conductivity material, the core-insulating layer-core structure is of a capacitor-like structure, and has dielectric loss under the action of high-frequency electromagnetic waves, and the property does not exist in the ferrite magnetic beads;
(3) The shell-core structure has a large number of interfaces, and interfaces exist between the shell-core structures, so that the dielectric loss of the interfaces of the high-frequency electromagnetic waves is improved, and the magnetic particles themselves magnetically lose the high-frequency electromagnetic waves, so that a double-loss mechanism is finally formed;
(4) The addition material designed by the invention contains a certain proportion of AlN material, so that the overall heat conductivity of the magnetic bead can be improved;
(5) Simple process, low cost and obvious effect.
In order to further illustrate the invention, the following examples are provided for a magnetic bead powder and a preparation method thereof. The laminated magnetic beads and the preparation method thereof are described in detail, but are not to be construed as limiting the scope of the present invention.
Example 1
(A) Preparation of base Material (about 10g base Material preparation is taken as an example)
(1) 200mL of 0.01mol/L aluminum sulfate solution is prepared; 200mL of potassium aluminate with the concentration of 0.4mol/L; 100mL of sodium acetate with the concentration of 0.1mol/L and 100mL of acetic acid with the concentration of 0.4mol/L are mixed into 600mL of solution and stirred uniformly;
(2) 10g of Co metal particles having a particle size of 5 μm were weighed. Washing the weighed magnetic metal in hydrochloric acid solution with the dilution concentration of 0.01mol/L for 10min, removing surface oxide skin and impurities, and forming uneven etching pits on the surface of the particles;
(3) Placing the magnetic metal particles in the step (2) into the solution prepared in the step (1);
(4) 20mL of the sodium hydroxide solution slowly added in the above (3) had a concentration ratio of 0.1:1, continuously stirring the solution in the process, wherein the reaction temperature is 25 ℃, and continuously stirring for 10min after the sodium hydroxide solution is added;
(5) After the reaction is finished, collecting reactants, washing the reactants with deionized water for three times, washing the reactants with absolute ethyl alcohol for three times, and finally drying the reactants in vacuum for standby;
(6) Calcining the reactant in the step (5) in vacuum, wherein the vacuum calcining process comprises the steps of firstly, preserving the temperature at 300 ℃ for 30min; then the temperature is raised to 1200 ℃, the temperature is kept for 30min, and the room temperature is reached after the end. Wherein the heating and cooling rate is 5 ℃/min, and the whole process is kept in a vacuum state;
(7) And collecting the calcined product, namely the base material with the shell/core structure.
(B) Preparation of additives
(1) Weighing the additive components according to the proportion, wherein the proportion is calculated according to the total amount of the base materials: alN:1% of Bi 2 O 3 :0.5%、ZrO 2 :0.1%、SiO 2 0.1%、MnO 2 :0.2%、Co 3 O 4 :0.1 percent of the particles with the particle size of 1-20 microns;
(2) Ball milling and mixing the additives in the step (1), wherein the ball material ratio is 20:1, the rotating speed is 300r/min, and the ball milling time is as follows: 3h;
(3) And (3) collecting the mixture in the step (2) to obtain the additive.
And (3) uniformly mixing the base material in the step (A) and the additive in the step (B) to obtain the laminated magnetic bead powder. When preparing laminated magnetic beads, powder can be made into a film through a tape casting process, a laminated structure is formed after screen printing, and terminal electrodes are formed on two sides of the laminated structure, so that the laminated magnetic beads are required.
Example 2
(A) Preparation of base Material (about 10g base Material preparation is taken as an example)
(1) 200mL of 0.1mol/L aluminum sulfate solution is prepared; 200mL of potassium aluminate with the concentration of 0.6mol/L; 100mL of sodium acetate with the concentration of 0.2mol/L and 100mL of acetic acid with the concentration of 0.5mol/L are mixed into 600mL of solution and stirred uniformly;
(2) 10g of Fe particles having a particle diameter of 10 μm were weighed. Washing the weighed magnetic metal in hydrochloric acid solution with the dilution concentration of 0.01mol/L for 10min, removing surface oxide skin and impurities, and forming uneven etching pits on the surface of the particles;
(3) Placing the magnetic metal particles in the step (2) into the solution prepared in the step (1);
(4) 20mL of the sodium hydroxide solution slowly added in the above (3), the concentration ratio of which to the aluminum sulfate concentration was 10:1, continuously stirring the solution in the process, wherein the reaction temperature is 25 ℃, and continuously stirring for 10min after the sodium hydroxide solution is added;
(5) After the reaction is finished, collecting reactants, washing the reactants with deionized water for three times, washing the reactants with absolute ethyl alcohol for three times, and finally drying the reactants in vacuum for standby;
(6) Calcining the reactant in the step (5) in vacuum, wherein the vacuum calcining process comprises the steps of firstly, preserving the temperature at 300 ℃ for 30min; then the temperature is raised to 1200 ℃, the temperature is kept for 30min, and the room temperature is reached after the end. Wherein the heating and cooling rate is 5 ℃/min, and the whole process is kept in a vacuum state;
(7) And collecting the calcined product, namely the base material with the shell/core structure.
(B) Preparation of additives
(1) Weighing the additive components according to the proportion, wherein the proportion is calculated according to the total amount of the base materials: alN:3%, bi 2 O 3 :2%、ZrO 2 :0.5%、SiO 2 :0.5%、MnO 2 :0.6%、Co 3 O 4 :0.7 percent of the particles with the particle size of 1-20 microns;
(2) Ball milling and mixing the additives in the step (1), wherein the ball material ratio is 20:1, the rotating speed is 300r/min, and the ball milling time is as follows: 3h;
(3) And (3) collecting the mixture in the step (2) to obtain the additive.
And (3) uniformly mixing the base material in the step (A) and the additive in the step (B) to obtain the laminated magnetic bead powder. When preparing laminated magnetic beads, powder can be made into a film through a tape casting process, a laminated structure is formed after screen printing, and terminal electrodes are formed on two sides of the laminated structure, so that the laminated magnetic beads are required.
The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.
Claims (7)
1. The preparation method of the magnetic bead powder comprises the following steps:
a) Mixing aluminum sulfate, potassium aluminate, sodium acetate and acetic acid in water to obtain a mixed solution;
the concentration of aluminum sulfate in the mixed solution is 0.003-0.2 mol/L, the concentration of potassium aluminate is 0.03-0.2 mol/L, the concentration of sodium acetate is 0.017-0.03 mol/L, and the concentration of acetic acid is 0.03-0.1 mol/L;
b) Pickling magnetic metal particles for 5-20 min by using an acid solution with the concentration of 0.005-0.02 mol/L, immersing the pickled magnetic metal particles in the mixed solution, slowly adding a sodium hydroxide solution into the mixed solution, and reacting under the stirring condition;
the concentration of the sodium hydroxide solution is 0.0015-4 mol/L, and the molar ratio of the sodium hydroxide to the aluminum sulfate is 1 (1-5);
c) Drying the solid product obtained in the step B) and calcining to obtain the product with a core-shell structure and an outer shell of Al 2 O 3 Is a base material of (2);
the calcination procedure in step C) is as follows: heating to 200-500 ℃ under vacuum, preserving heat for 10-60 min, heating to 1000-1500 ℃ and preserving heat for 10-60 min;
d) AlN, bi 2 O 3 、ZrO 2 、SiO 2 、MnO 2 And Co 3 O 4 Ball milling and mixing to obtain an additive;
e) Mixing the base material with the additive to obtain the magnetic bead powder.
2. The method according to claim 1, wherein the magnetic metal particles are an alloy of one or more of iron, cobalt and nickel;
the particle size of the magnetic metal particles is 1-15 mu m.
3. The preparation method according to claim 1, wherein the AlN has a mass of 1 to 3% of the total mass of the base material, bi 2 O 3 Is the mass of the total mass of the base material0.5~2%,ZrO 2 The mass of the catalyst is 0.1 to 0.5 percent of the total mass of the base material, and SiO is the following mass 2 The mass of the catalyst is 0.1 to 0.5 percent of the total mass of the base material, mnO 2 The mass of the catalyst is 0.2 to 0.6 percent of the total mass of the base material, co 3 O 4 The mass of the (B) is 0.1-0.7% of the total mass of the base material.
4. The method according to claim 1, wherein the ball-milled ball-material ratio in the step D) is (15 to 25): 1, the ball milling rotating speed is 200-500 r/min, and the ball milling time is 1-5 hours.
5. A magnetic bead powder prepared by the preparation method according to any one of claims 1 to 4, wherein the base material in the magnetic bead powder has a core-shell structure, the inner core is an alloy formed by one or more of iron, cobalt and nickel, and the outer shell is Al 2 O 3 。
6. A laminated magnetic bead prepared by using the magnetic bead powder as claimed in claim 5.
7. A preparation method of laminated magnetic beads comprises the following steps:
the magnetic bead powder in claim 5 is made into a film by a tape casting process, a laminated structure is formed after screen printing, and terminal electrodes are formed on two sides of the laminated structure, so that laminated magnetic beads are obtained.
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CN104028749A (en) * | 2014-06-05 | 2014-09-10 | 浙江大学 | High-thermal-stability insulated coating treatment method of metal soft magnetic composite material |
CN108597711A (en) * | 2018-04-17 | 2018-09-28 | 浙江工业大学 | A kind of method of soft magnetic metal powder surface in-stiu coating alundum (Al2O3) insulating layer |
CN109754979A (en) * | 2019-01-25 | 2019-05-14 | 同济大学 | A kind of multilayer coating structure soft-magnetic composite material and preparation method thereof |
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JP5065960B2 (en) * | 2008-03-28 | 2012-11-07 | 株式会社東芝 | High-frequency magnetic material and method for producing the same. |
US8988301B2 (en) * | 2009-03-27 | 2015-03-24 | Kabushiki Kaisha Toshiba | Core-shell magnetic material, method for producing core-shell magnetic material, device, and antenna device |
FR3030478B1 (en) * | 2014-12-18 | 2017-01-27 | Ifp Energies Now | PROCESS FOR THE PREPARATION OF ALUMINA BALLS BY SHAPING THE SHAPE OF A VERY DISPERSIBLE GEL |
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JPS6461324A (en) * | 1987-08-28 | 1989-03-08 | Toda Kogyo Corp | Magnetic particulate powder and production thereof |
CN104028749A (en) * | 2014-06-05 | 2014-09-10 | 浙江大学 | High-thermal-stability insulated coating treatment method of metal soft magnetic composite material |
CN108597711A (en) * | 2018-04-17 | 2018-09-28 | 浙江工业大学 | A kind of method of soft magnetic metal powder surface in-stiu coating alundum (Al2O3) insulating layer |
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