CN111799051A - Nano gamma-Fe2O3Coated nano silicon dioxide composite material, preparation method thereof and high-frequency anti-interference magnetic core - Google Patents
Nano gamma-Fe2O3Coated nano silicon dioxide composite material, preparation method thereof and high-frequency anti-interference magnetic core Download PDFInfo
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- CN111799051A CN111799051A CN202010486806.1A CN202010486806A CN111799051A CN 111799051 A CN111799051 A CN 111799051A CN 202010486806 A CN202010486806 A CN 202010486806A CN 111799051 A CN111799051 A CN 111799051A
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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
- H01F1/0036—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties showing low dimensional magnetism, i.e. spin rearrangements due to a restriction of dimensions, e.g. showing giant magnetoresistivity
- H01F1/0045—Zero dimensional, e.g. nanoparticles, soft nanoparticles for medical/biological use
- H01F1/0054—Coated nanoparticles, e.g. nanoparticles coated with organic surfactant
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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
- H01F1/10—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 non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
Abstract
The invention discloses a nano gamma-Fe2O3A coated nano silicon dioxide composite material and a preparation method thereof and a high-frequency anti-interference magnetic core are provided, wherein nano silicon dioxide is used as a core in the composite material, and the diameter of the nano silicon dioxide is 30-60 nm. gamma-Fe2O3Is a shell which is uniformly coated on the surface of the nano silicon dioxide, the thickness of the shell is 100-200 nm, and the shell is gamma-Fe2O3The grain size is about 10 nm. The magnetic core made of the composite material has very small impedance at low frequency and large impedance at the frequency of 200 MHz-2 GHz, and can be used as a high-frequency anti-interference magnetic core material.
Description
Technical Field
The invention belongs to the field of material preparation, and relates to nano gamma-Fe2O3Coated nano silicon dioxide composite material, preparation method and high-frequency anti-interference magnetic core, wherein the material has the function of ensuring that the material has good magnetic properties in the field of high-frequency anti-interference magnetic coresThe use value is high.
Background
The power line can transmit interference of an external power grid and noise of the switching power supply to the line of the equipment. The ferrite anti-interference magnetic cores are arranged at the outlet of the power supply and the inlet of the power supply of the printed board, so that the high-frequency interference transmission between the power supply and the printed board can be inhibited, and the mutual interference of high-frequency noise between the printed boards can be inhibited.
At present, the anti-interference magnetic ring mainly adopts ferrite materials. Different ferrites have different optimum rejection frequency ranges, with manganese zinc ferrites being more suitable for use at low frequencies, such as 30MHz or lower; while nickel zinc ferrite is suitable for high frequency applications, such as 25MHz to 200MHz, or higher. However, with the increase of the frequency of the current circuit, the existing manganese zinc ferrite and nickel zinc ferrite can not meet the frequency requirement. The suppression of interference signals above 200MHz is an anti-interference frequency which is urgently needed to be solved at present.
At present, the use frequency of ferrite is mainly improved by doping of ferrite. However, the magnitude of the increase is not great. The frequency of ferrite can be improved by preparing nano particles, but how to prepare nano ferrite with low cost and high stability is continuously researched. The nano magnetic iron oxide only contains iron metal elements, so the material is low in price and has little pollution to the environment. However, the preparation cost is high, and the method is only used for the biological magnetic material. Nanoparticles have also been studied as interference-free. However, the problem of industrial production has not been effectively solved. In the preparation of the iron oxide and silicon oxide composite material, although many researches on preparing silicon oxide on the surface of iron oxide are reported, at present, no report exists on depositing nano iron oxide on the surface of nano silicon dioxide, and no report exists on the application of the composite material in a high-frequency anti-interference magnetic core. The nano iron oxide is prepared on the surface of the silicon oxide, and is deposited on the surface of the silicon oxide due to the substrate action of the silicon oxide, so that agglomeration is not easy to generate. However, silica is chemically stable and thus is not easily deposited on its surface.
The invention content is as follows:
aiming at the defects of the prior art, the invention discloses nano gamma-Fe2O3A composite material coated with nano silicon dioxide, its preparing process and high-frequency anti-interference magnetic core are disclosed, which uses nano silicon dioxide as core and gamma-Fe2O3Is a shell which is uniformly coated on the surface of the nano silicon dioxide. The material has good inhibition effect on interference signals at frequencies of 200M to 2G.
In order to solve the technical problems in the prior art, the technical scheme of the invention is as follows:
nano gamma-Fe2O3Coating nano silicon dioxide composite material, uniformly coating a layer of nano gamma-Fe on the surface of nano silicon dioxide core2O3A shell, wherein the diameter of the nano silicon dioxide core is 30-60 nm; nano gamma-Fe2O3The shell thickness is 100-200 nm, and the size of the shell is 10nm of gamma-Fe2O3And (4) grain composition.
The invention also discloses nano gamma-Fe2O3The preparation method of the coated nano silicon dioxide composite material comprises the following steps:
step 1: measuring DMF (dimethyl formamide) and distilled water in a volume ratio of 8:2, and uniformly mixing to obtain a mixed solvent;
step 2: weighing a certain amount of nano silicon dioxide, adding the nano silicon dioxide into the mixed solvent, and uniformly dispersing the nano silicon dioxide in the solvent after carrying out ultrasonic treatment for 10 minutes to obtain nano silicon dioxide dispersion liquid; wherein the concentration of the nano silicon dioxide in the mixed solution is 0.5-2 mg/mL;
and step 3: weighing ferrous chloride tetrahydrate, ethylene glycol and anhydrous sodium acetate, adding the ferrous chloride tetrahydrate, the ethylene glycol and the anhydrous sodium acetate into the nano silicon dioxide dispersion liquid, and magnetically stirring the mixture in a water bath at 90 ℃ for 2 hours, wherein the concentration of the ferrous chloride tetrahydrate relative to the concentration of the mixed solution is 8-12 mg/mL, the volume ratio of the ethylene glycol relative to the mixed solvent is 0.002: 1-0.008: 1, and the molar concentration ratio of the anhydrous sodium acetate relative to the ferrous chloride tetrahydrate is 2: 1-5: 1;
and 4, step 4: cooling, centrifugally cleaning and collecting the product, and drying to obtain the nano gamma-Fe2O3A composite material coated with nano-silica;
in the step 3, the surface of the silicon dioxide adsorbs the glycol through the action of oxygen ions. Iron ions, DMF and water form a complex, the iron ion complex and ethylene glycol on the surface of silicon dioxide are adsorbed on the surface of the silicon dioxide through molecular force, and the complex forms gamma-Fe through decomposition and oxidation2O3A nanoparticle layer.
The invention also discloses a high-frequency anti-interference magnetic core which is prepared by adopting the composite material of claim 1 or 2, has impedance of more than 70 omega at the frequency of 200 MHz-2 GHz, and has impedance of less than 1 omega at the frequency below 2 MHz.
By adopting the technical scheme of the invention, the invention has the following technical effects:
1. in the present invention, the surface of silica adsorbs ethylene glycol by the action of oxygen ions. Iron ions, DMF and water form a complex, the iron ion complex and ethylene glycol on the surface of silicon dioxide are adsorbed on the surface of the silicon dioxide through molecular force, and the complex forms gamma-Fe through decomposition and oxidation2O3A nanoparticle layer.
2. The invention adopts nano silicon oxide as a substrate to prepare nano gamma-Fe on the nano silicon oxide2O3Nanoparticles, gamma-Fe2O3Can retain nano-particles, gamma-Fe2O3Is not easy to generate agglomeration. Compared with the preparation of silicon dioxide on the surface of ferric oxide, the method has the characteristic of simple preparation process. And can make gamma-Fe2O3Smaller particle size. The nanometer silicon oxide has poor conductivity, so that the resistivity of the composite material can be improved, the generation of eddy current is inhibited, and the frequency of an interference signal is inhibited from moving towards a high frequency direction.
3. In the invention, the silicon oxide is nano-particles, and can be nano gamma-Fe2O3The proportion of magnetic substances is improved as much as possible under the condition that the shell has a certain thickness, so that the magnetic performance and the anti-interference effect of the composite material are guaranteed; at the same time, gamma-Fe2O3The composite material can keep good magnetic performance through magnetic coupling effect, and the influence of the nano silicon oxide on the magnetic performance is eliminated.
4. In the present invention,γ-Fe2O3has a small particle size of gamma-Fe2O3Has good paramagnetic performance, therefore, under the condition of low frequency, the magnetic loss is not easy to generate, thereby improving the gamma-Fe2O3Performance at high frequencies. The nanoparticles may facilitate the absorption of high frequency signals.
5. The composite material is simple in preparation process, is suitable for industrial production, and has a good inhibition effect on interference signals at frequencies from 200M to 2G.
Drawings
FIG. 1 is a schematic structural view of a composite material according to the present invention;
FIG. 2 is an XRD pattern of a composite material prepared according to example 1 of the present invention;
FIG. 3 is a scanning electron micrograph of a composite material prepared in example 1 of the present invention;
FIG. 4 is an impedance spectrum of a composite material prepared in example 1 of the present invention;
Detailed Description
The technical solution provided by the present invention will be further explained with reference to the accompanying drawings.
Referring to FIG. 1, a schematic structural diagram of the composite material of the present invention, nano-gamma-Fe, is shown2O3Coating nano silicon dioxide composite material, uniformly coating a layer of nano gamma-Fe on the surface of nano silicon dioxide core2O3A shell, wherein the diameter of the nano silicon dioxide core is 30-60 nm; nano gamma-Fe2O3The shell thickness is 100-200 nm, and the size of the shell is 10nm of gamma-Fe2O3And (4) grain composition.
The preparation process and performance test of the above composite material are described in detail by the following examples.
Example 1
Step 1: measuring DMF (dimethyl formamide) and distilled water in a volume ratio of 8:2, and uniformly mixing to obtain a mixed solvent;
step 2: weighing a certain amount of nano silicon dioxide (the diameter is about 30 nm) and adding the nano silicon dioxide into the mixed solvent, and performing ultrasonic treatment for 10 minutes to uniformly disperse the nano silicon dioxide in the solvent to obtain nano silicon dioxide dispersion liquid; wherein the concentration of the nano silicon dioxide in the mixed solution is 2 mg/mL;
and step 3: weighing ferrous chloride tetrahydrate and anhydrous sodium acetate, adding the ferrous chloride tetrahydrate and the anhydrous sodium acetate into the nano silicon dioxide dispersion, and magnetically stirring the mixture in a water bath at 90 ℃ for 2 hours, wherein the concentration of the ferrous chloride tetrahydrate relative to the concentration of the mixed solution is 10mg/mL, the volume ratio of ethylene glycol relative to the mixed solvent is 0.002:1, and the molar concentration ratio of the anhydrous sodium acetate relative to the ferrous chloride tetrahydrate is 2: 1;
and 4, step 4: cooling, centrifugally cleaning and collecting the product, and drying to obtain the nano gamma-Fe2O3A composite material coated with nano silicon dioxide.
Example 2
Step 1: measuring DMF (dimethyl formamide) and distilled water in a volume ratio of 8:2, and uniformly mixing to obtain a mixed solvent;
step 2: weighing a certain amount of nano silicon dioxide (with the diameter of about 50 nm) and adding the nano silicon dioxide into the mixed solvent, and performing ultrasonic treatment for 10 minutes to uniformly disperse the nano silicon dioxide in the solvent to obtain nano silicon dioxide dispersion liquid; wherein the concentration of the nano silicon dioxide in the mixed solution is 0.5 mg/mL;
and step 3: weighing ferrous chloride tetrahydrate and anhydrous sodium acetate, adding the ferrous chloride tetrahydrate and the anhydrous sodium acetate into the nano silicon dioxide dispersion, and magnetically stirring the mixture for 2 hours in a water bath at the temperature of 90 ℃, wherein the concentration of the ferrous chloride tetrahydrate relative to the concentration of the mixed solution is 8mg/mL, the volume ratio of ethylene glycol relative to the mixed solvent is 0.005:1, and the molar concentration ratio of the anhydrous sodium acetate relative to the ferrous chloride tetrahydrate is 3: 1;
and 4, step 4: cooling, centrifugally cleaning and collecting the product, and drying to obtain the nano gamma-Fe2O3A composite material coated with nano silicon dioxide.
Example 3
Step 1: measuring DMF (dimethyl formamide) and distilled water in a volume ratio of 8:2, and uniformly mixing to obtain a mixed solvent;
step 2: weighing a certain amount of nano silicon dioxide (with the diameter of about 60 nm) and adding the nano silicon dioxide into the mixed solvent, and performing ultrasonic treatment for 10 minutes to uniformly disperse the nano silicon dioxide in the solvent to obtain nano silicon dioxide dispersion liquid; wherein the concentration of the nano silicon dioxide in the mixed solution is 1.5 mg/mL;
and step 3: weighing ferrous chloride tetrahydrate and anhydrous sodium acetate, adding the ferrous chloride tetrahydrate and the anhydrous sodium acetate into the nano silicon dioxide dispersion, and magnetically stirring the mixture in a water bath at 90 ℃ for 2 hours, wherein the concentration of the ferrous chloride tetrahydrate relative to the concentration of the mixed solution is 12mg/mL, the volume ratio of ethylene glycol relative to the mixed solvent is 0.008:1, and the molar concentration ratio of the anhydrous sodium acetate relative to the ferrous chloride tetrahydrate is 5: 1;
and 4, step 4: cooling, centrifugally cleaning and collecting the product, and drying to obtain the nano gamma-Fe2O3A composite material coated with nano silicon dioxide.
The composite material prepared in example 1 was examined for XDR as shown in FIG. 2, which shows diffraction peaks of all γ -Fe2O3The diffraction peak of (1). Gamma-Fe can be observed in the figure2O3The diffraction peak width was very broad, and thus, gamma-Fe was found2O3The grain size of (2) is very small. Since the nano silicon dioxide is amorphous, no diffraction peak of the silicon dioxide is shown in an XRD diffraction pattern. FIG. 3 shows an electron microscope image of the composite material, in which the diameter of the composite particles is about 220 nm and gamma-Fe on the shell is observed2O3The particle size is less than 10 nm.
8% of PVA binder is added into the composite material obtained in the example 1, and after the mixture is uniformly stirred, the mixture is pressed into an anti-interference magnetic core with the diameter of 12mm multiplied by 5mm multiplied by 7mm (the outer diameter multiplied by the inner diameter multiplied by the height). A wire is passed through the core and the impedance of the interference-resistant core is detected in the range of 1M-3G by an impedance analyzer. Figure 4 shows that the composite has more than 70 omega in the 200M-2GHz range. And the impedance at frequencies below 2MHz is less than 1 omega.
The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (5)
1. Nano gamma-Fe2O3The coating nano silicon dioxide composite material is characterized in that: uniformly coating a layer of nano gamma-Fe on the surface of a nano silicon dioxide core2O3A shell, wherein the diameter of the nano silicon dioxide core is 30-60 nm; nano gamma-Fe2O3The shell thickness is 100-200 nm, and the size of the shell is 10nm of gamma-Fe2O3And (4) grain composition.
2. A method of making the composite material of claim 1, wherein: the method comprises the following steps:
step 1: measuring DMF (dimethyl formamide) and distilled water in a volume ratio of 8:2, and uniformly mixing to obtain a mixed solvent;
step 2: weighing a certain amount of nano silicon dioxide, adding the nano silicon dioxide into a mixed solvent, and uniformly dispersing the nano silicon dioxide in the solvent after ultrasonic treatment to obtain nano silicon dioxide dispersion liquid; wherein the concentration of the nano silicon dioxide in the mixed solution is 0.5-2 mg/mL;
and step 3: weighing ferrous chloride tetrahydrate, ethylene glycol and anhydrous sodium acetate, adding the ferrous chloride tetrahydrate, the ethylene glycol and the anhydrous sodium acetate into the nano silicon dioxide dispersion liquid, and stirring the mixture in a constant-temperature water bath for uniform reaction; wherein the concentration of the ferrous chloride tetrahydrate is 8-12 mg/mL relative to the concentration in the mixed solution, the volume ratio of the ethylene glycol to the mixed solvent is 0.002: 1-0.008: 1, and the molar concentration ratio of the anhydrous sodium acetate to the ferrous chloride tetrahydrate is 2: 1-5: 1;
and 4, step 4: cooling, centrifugally cleaning and collecting the product, and drying to obtain the nano gamma-Fe2O3A composite material coated with nano silicon dioxide.
3. The composite material of claim 2The preparation method is characterized by comprising the following steps: in step 3, ethylene glycol is adsorbed on the surface of the silicon dioxide through the action of oxygen ions, iron ions, DMF and water form a complex, the iron ion complex and the ethylene glycol on the surface of the silicon dioxide are adsorbed on the surface of the silicon dioxide through the action of molecular force, and the complex is decomposed and oxidized to form gamma-Fe2O3A nanoparticle layer.
4. A method for preparing a composite material according to claim 2, characterized in that: in step 3, the mixed solution was magnetically stirred in a water bath at 90 ℃ for 2 hours.
5. High frequency anti-interference magnetic core, its characterized in that: the magnetic core is obtained by pressing the composite material obtained in the claim 1 or the composite material prepared by the method in any one of the claims 2-4, and has impedance of more than 70 omega in the frequency of 200 MHz-2 GHz, and impedance of less than 1 omega in the frequency below 2 MHz.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1662256A1 (en) * | 2004-11-25 | 2006-05-31 | Spinomix S.A. | Tailored magnetic particles and method to produce same |
| CN101815774A (en) * | 2007-09-28 | 2010-08-25 | 纳米技术有限公司 | Core shell nanoparticles and preparation method thereof |
| CN104399465A (en) * | 2014-11-12 | 2015-03-11 | 石河子大学 | Core-shell catalyst and preparation method and application thereof |
| CN108249482A (en) * | 2017-12-28 | 2018-07-06 | 杭州电子科技大学 | Magnetic Fe2O3The preparation method of nano particle and its method compound with nano-carbon material |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1662256A1 (en) * | 2004-11-25 | 2006-05-31 | Spinomix S.A. | Tailored magnetic particles and method to produce same |
| CN101815774A (en) * | 2007-09-28 | 2010-08-25 | 纳米技术有限公司 | Core shell nanoparticles and preparation method thereof |
| CN104399465A (en) * | 2014-11-12 | 2015-03-11 | 石河子大学 | Core-shell catalyst and preparation method and application thereof |
| CN108249482A (en) * | 2017-12-28 | 2018-07-06 | 杭州电子科技大学 | Magnetic Fe2O3The preparation method of nano particle and its method compound with nano-carbon material |
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