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Porous Fe3O4/Fe/SiO2 core-shell nanorod absorbing high-frequency electromagnetic waves and a preparation method

A technology of nano-rods and electromagnetic waves, applied in the field of nano-materials, can solve the problems of low width, only -12.28dB, etc., and achieve the effect of strong absorption characteristics and simple operation

Inactive Publication Date: 2009-08-26
HARBIN ENG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The nanomaterial can absorb electromagnetic waves, but when the ZnO concentration is 7wt%, and the film thickness is 1mm, the absorption of electromagnetic waves is only -12.28dB
At the same time, the width of the absorption frequency is low, and the frequency range of greater than -10dB absorption is less than 2GHz

Method used

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  • Porous Fe3O4/Fe/SiO2 core-shell nanorod absorbing high-frequency electromagnetic waves and a preparation method
  • Porous Fe3O4/Fe/SiO2 core-shell nanorod absorbing high-frequency electromagnetic waves and a preparation method
  • Porous Fe3O4/Fe/SiO2 core-shell nanorod absorbing high-frequency electromagnetic waves and a preparation method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] (1) 40 milliliters of 0.5mol / L FeCl 3 The solution was placed in a 50ml stainless steel sealed autoclave. Keep in an oven at 120°C for 12 hours;

[0021] (2) After the autoclave is naturally cooled to room temperature, the precipitate in the autoclave is washed with water and ethanol several times. β-FeOOH nanorods were obtained after drying at 80°C;

[0022] (3) Hydrolyze the β-FeOOH nanorods obtained above in 60 ml tetraethyl orthosilicate / isopropanol solution to obtain β-FeOOH / SiO 2 Core-shell nanorods. Wherein, the volume ratio of ethyl tetrasilicate / isopropanol is 60:1;

[0023] (4)β-FeOOH / SiO 2 Core-shell nanorods were annealed in air at 500 °C for 2.5 h to obtain α-Fe 2 o 3 / SiO 2 Core-shell nanorods. α-Fe 2 o 3 / SiO 2 Core-shell nanorods are porous structures, and their morphology and microstructure are characterized by transmission electron microscopy, as shown in figure 1 shown;

[0024] (5) α-Fe 2 o 3 / SiO 2 Core-shell nanorods in N 2 / H 2 ...

Embodiment 2

[0027] (1) 40 milliliters of 1.0mol / L FeCl 3 The solution was placed in a 50ml stainless steel sealed autoclave. Keep in the oven at 100°C for 12 hours;

[0028] (2) After the autoclave is naturally cooled to room temperature, the precipitate in the autoclave is washed with water and ethanol several times. β-FeOOH nanorods were obtained after drying at 80°C;

[0029] (3) Hydrolyze the β-FeOOH nanorods obtained above in tetraethyl orthosilicate / isopropanol solution to obtain β-FeOOH / SiO 2 Core-shell nanorods. Wherein, the volume ratio of ethyl tetrasilicate / isopropanol is 60:1;

[0030] (4)β-FeOOH / SiO 2 Core-shell nanorods were annealed in air at 500 °C for 2.5 h to obtain α-Fe 2 o 3 / SiO 2 Core-shell nanorods;

[0031] (5) α-Fe 2 o 3 / SiO 2 Core-shell nanorods in N 2 / H 2 (8% / H 2 ) atmosphere, annealed at 400 ° C for 7 hours, and finally obtained porous Fe 3 o 4 / Fe / SiO 2 Nano stave.

Embodiment 3

[0033] (1) 40 milliliters of 0.25mol / L FeCl 3 The solution was placed in a 50ml stainless steel sealed autoclave. Keep in an oven at 110°C for 12 hours;

[0034] (2) After the autoclave is naturally cooled to room temperature, the precipitate in the autoclave is washed with water and ethanol several times. β-FeOOH nanorods were obtained after drying at 80°C;

[0035] (3) Hydrolyze the β-FeOOH nanorods obtained above in tetraethyl orthosilicate / isopropanol solution to obtain β-FeOOH / SiO 2 Core-shell nanorods. Wherein, the volume ratio of ethyl tetrasilicate / isopropanol is 60:1;

[0036] (4)β-FeOOH / SiO 2 Core-shell nanorods were annealed in air at 500 °C for 2.5 h to obtain α-Fe 2 o 3 / SiO 2 Core-shell nanorods;

[0037] (5) α-Fe 2 o 3 / SiO 2 Core-shell nanorods in N 2 / H 2 (8% / H 2 ) atmosphere, annealed at 400 ° C for 7 hours, and finally obtained porous Fe 3 o 4 / Fe / SiO 2 Nano stave.

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Abstract

The invention provides a porous Fe3O4 / Fe / SiO2 core-shell nanorod absorbing high-frequency electromagnetic waves and a preparation method. FeCl3 liquid of 0.25 to 1.0 mol is poured into a stainless steel sealed autoclave, and is maintained for 12 hours in an oven under 100 and 120 DEG C; after the autoclave is naturally cooled to the room temperature, the precipitation in the autoclave is washed by water and ethanol, and dried under 80 DEG C to obtain a beta-FeOOH nanorod; the beta-FeOOH nanorod is hydrolyzed in ethyl orthosilicate / isopropanol solution to obtain a beta-FeOOH / SiO2 core-shell nanorod; the beta-FeOOH / SiO2 core-shell nanorod is annealed for 2.5 hours in the air under 500 DEG C to obtain an alpha-Fe2O3 / SiO2 core-shell nanorod; then the alpha-Fe2O3 / SiO2 core-shell nanorod is annealed for 7 hours under 400 DEG C in the N2 / H2 atmosphere, of which the volume of H2 accounts for 8 percent to finally obtain the porous Fe3O4 / Fe / SiO2 core-shell nanorod. The method of the invention has the advantages of simple operation, and suitability for industrial production; moreover, the obtained product has strong absorption characteristic to the high-frequency electromagnetic waves.

Description

(1) Technical field [0001] The invention relates to a nanometer material with strong absorption characteristics for high-frequency electromagnetic waves, and also relates to a preparation method of the nanometer material with strong absorption characteristics for high-frequency electromagnetic waves. (2) Background technology [0002] With the development of information technology and electronic instruments, electromagnetic waves are more and more widely used in communication and other fields, especially electromagnetic waves in the high frequency range. For example, electromagnetic waves with a frequency of 1-75 GHz are widely used in mobile communications, radar systems, ground microwave communication relay stations, electron spin resonance instruments, and other intelligent transmission systems. Since these systems and instruments all use high-frequency electromagnetic waves, on the one hand they are extremely susceptible to interference from external fields and cannot wo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K3/00
Inventor 陈玉金朱春玲
Owner HARBIN ENG UNIV
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