Novel compound wave-absorbing agent and preparation method and application thereof

Abstract

The invention discloses a novel compound wave-absorbing agent and a preparation method thereof. The novel compound wave-absorbing agent is of a core-shell structure, the core of the compound wave-absorbing agent is particles using an iron-nitrogen compound as the main phase, the shell of the compound wave-absorbing agent is a dielectric-material coating layer, the iron-nitrogen compound can be single-phase Fe4N or Fe3N or can be a compound phase using Fe4N or Fe3N as the main phase and comprising one or two of Fe, Fe3O4 and gamma-Fe2O3, and the shell coating layer is a dielectric material, with the dielectric constant being 2-10, such as SiO2, amorphous carbon and conductive polymer. The preparation method of the novel compound wave-absorbing agent is wide in adjustable range, capable of changing process parameters to acquire different shapes or sizes so as to allow the product to satisfy different application requirements, simple in steps, convenient to operate and high in practicality. The novel compound wave-absorbing agent has good impedance matching conditions and attenuation performance and has high application values in fields such as radar stealth materials and electromagnetic shielding.

Description

technical field

[0001] The invention belongs to the technical field of wave-absorbing materials, and in particular relates to a novel composite wave-absorbing agent, a preparation method and an application thereof. Background technique

[0002] In recent years, absorbing materials have been widely used in the fields of stealth, electromagnetic shielding and electromagnetic protection of weapons and equipment. The key to the development of absorbing materials lies in the development of absorbing agents. Commonly used materials for absorbers include magnetic metals such as Fe, Co, and Ni, ferrite, and conductive polymers. Among them, magnetic metal has the advantages of high saturation magnetization and high magnetic permeability, but its oxidation resistance and corrosion resistance are poor, and its dielectric constant is high, which easily causes the problem of difficult impedance matching; ferrite has high resistivity, It can avoid the skin effect of metal conductors at ...

Examples

preparation example Construction

[0039] The preparation method of above-mentioned novel composite wave-absorbing agent, with Fe 2 o 3 The powder is a precursor, which is prepared by a gas nitriding method after coating treatment.

[0040] The Fe 2 o 3 The precursor is prepared by hydrothermal method, and its shape and size are determined by the raw materials and process of hydrothermal synthesis.

[0041] The preparation steps of the hydrothermal method are as follows:

[0042] (1) Prepare FeCl with a concentration of 0.005-0.2mol / L 3 (ferric chloride) or K 3 [Fe(CN) 6 ] (potassium ferricyanide) aqueous solution, preferably adjust the pH value of the solution with ammonia or sodium hydroxide reagent;

[0043] (2) Put the above solution into an autoclave for reaction, the temperature is controlled at 120-180° C., and the holding time is 12-48 hours;

[0044] (3) After the reaction is completed, take out the reaction product after naturally cooling to room temperature, carry out centrifugation, wash (pr...

Embodiment 1

[0048] The steps of preparing the novel composite wave absorbing agent are as follows:

[0049] First, use deionized water to prepare FeCl with a concentration of 0.1mol / L 3 The aqueous solution, the pH value of this aqueous solution is adjusted greater than 14 with sodium hydroxide. Stir at room temperature for 10 minutes to become a clear solution. Pour 70ml of the solution into a 100ml stainless steel reaction kettle lined with polytetrafluoroethylene, tighten the lid of the reaction kettle, put the reaction kettle into an oven, and heat at 140°C. Reaction time 12 hours. After naturally cooling to room temperature, the reaction product was taken out, the obtained red precipitate was centrifuged, washed 5 times with deionized water and absolute ethanol, and dried at 60°C to obtain Fe 2 o 3 powder.

[0050] Weigh 1g Fe 2 o 3 Add to a solution of 80ml of absolute ethanol and 16ml of deionized water, and mechanically stir at a low speed for 15min. Then, 2 ml of tetraethy...

Embodiment 2

[0053] The steps of preparing the novel composite wave absorbing agent are as follows:

[0054] First, use deionized water to prepare FeCl with a concentration of 0.15mol / L 3 Aqueous solution, pH=2. Pour 70ml of the solution into a 100ml stainless steel reaction kettle lined with polytetrafluoroethylene, tighten the lid of the reaction kettle, put the reaction kettle into an oven, and keep the temperature at 150°C for 24 hours. After naturally cooling to room temperature, the reaction product was taken out, the resulting red precipitate was centrifuged, washed with deionized water and absolute ethanol five times each, and dried at 60°C to obtain Fe 2 o 3 powder.

[0055] 2.4g of prepared Fe 2 o 3 Disperse the powder in 100ml of hydrochloric acid (20mmol / L) and stir for 30min, add 5.75g of PVP, and stir for 30min; then add 0.05mol / L aniline solution, and stir the mixture for 1h; according to the formula of ammonium persulfate:aniline=1.1:1 Add ammonium persulfate proporti...

technical field

[0001] The invention belongs to the technical field of wave-absorbing materials, and in particular relates to a novel composite wave-absorbing agent, a preparation method and an application thereof. Background technique

[0002] In recent years, absorbing materials have been widely used in the fields of stealth, electromagnetic shielding and electromagnetic protection of weapons and equipment. The key to the development of absorbing materials lies in the development of absorbing agents. Commonly used materials for absorbers include magnetic metals such as Fe, Co, and Ni, ferrite, and conductive polymers. Among them, magnetic metal has the advantages of high saturation magnetization and high magnetic permeability, but its oxidation resistance and corrosion resistance are poor, and its dielectric constant is high, which easily causes the problem of difficult impedance matching; ferrite has high resistivity, It can avoid the skin effect of metal conductors at ...

Examples

preparation example Construction

[0039] The preparation method of above-mentioned novel composite wave-absorbing agent, with Fe 2 o 3 The powder is a precursor, which is prepared by a gas nitriding method after coating treatment.

[0040] The Fe 2 o 3 The precursor is prepared by hydrothermal method, and its shape and size are determined by the raw materials and process of hydrothermal synthesis.

[0041] The preparation steps of the hydrothermal method are as follows:

[0042] (1) Prepare FeCl with a concentration of 0.005-0.2mol / L 3 (ferric chloride) or K 3 [Fe(CN) 6 ] (potassium ferricyanide) aqueous solution, preferably adjust the pH value of the solution with ammonia or sodium hydroxide reagent;

[0043] (2) Put the above solution into an autoclave for reaction, the temperature is controlled at 120-180° C., and the holding time is 12-48 hours;

[0044] (3) After the reaction is completed, take out the reaction product after naturally cooling to room temperature, carry out centrifugation, wash (pr...

Embodiment 1

[0048] The steps of preparing the novel composite wave absorbing agent are as follows:

[0049] First, use deionized water to prepare FeCl with a concentration of 0.1mol / L 3 The aqueous solution, the pH value of this aqueous solution is adjusted greater than 14 with sodium hydroxide. Stir at room temperature for 10 minutes to become a clear solution. Pour 70ml of the solution into a 100ml stainless steel reaction kettle lined with polytetrafluoroethylene, tighten the lid of the reaction kettle, put the reaction kettle into an oven, and heat at 140°C. Reaction time 12 hours. After naturally cooling to room temperature, the reaction product was taken out, the obtained red precipitate was centrifuged, washed 5 times with deionized water and absolute ethanol, and dried at 60°C to obtain Fe 2 o 3 powder.

[0050] Weigh 1g Fe 2 o 3 Add to a solution of 80ml of absolute ethanol and 16ml of deionized water, and mechanically stir at a low speed for 15min. Then, 2 ml of tetraethy...

Embodiment 2

[0053] The steps of preparing the novel composite wave absorbing agent are as follows:

[0054] First, use deionized water to prepare FeCl with a concentration of 0.15mol / L 3 Aqueous solution, pH=2. Pour 70ml of the solution into a 100ml stainless steel reaction kettle lined with polytetrafluoroethylene, tighten the lid of the reaction kettle, put the reaction kettle into an oven, and keep the temperature at 150°C for 24 hours. After naturally cooling to room temperature, the reaction product was taken out, the resulting red precipitate was centrifuged, washed with deionized water and absolute ethanol five times each, and dried at 60°C to obtain Fe 2 o 3 powder.

[0055] 2.4g of prepared Fe 2 o 3 Disperse the powder in 100ml of hydrochloric acid (20mmol / L) and stir for 30min, add 5.75g of PVP, and stir for 30min; then add 0.05mol / L aniline solution, and stir the mixture for 1h; according to the formula of ammonium persulfate:aniline=1.1:1 Add ammonium persulfate proporti...

Images