阅读说明：本技术 一种新型陶瓷吸波微球材料及其制备方法 (Novel ceramic wave-absorbing microsphere material and preparation method thereof ) 是由 温广武 侯永昭 仲诚 刘芸 朱楠楠 杨国威 于 2020-12-21 设计创作，主要内容包括：本发明提供了一种新型陶瓷吸波微球材料及其制备方法。所述制备方法包括以下步骤：磁性粉末与PSA液体的混合,混合物连续相中乳化；乳液固化；前体微球与连续相的分离；磁性聚合物的陶瓷化处理。本发明实施例示例的新型陶瓷吸波微球材料的制备方法,工艺简单,易于在简易的条件下制备,同时可以实现大规模工业化生产。本发明实施例示例的新型陶瓷吸波微球材料的制备方法制备得到的吸波材料具有良好的球形形貌,聚硅乙炔具有活性反应位点,成分结构可调,可与磁性物质反应交联,通过调节磁性物质的成分和含量形成不同的微观结构,改变制备得到的吸波材料对电磁波的吸收和反射能力。(The invention provides a novel ceramic wave-absorbing microsphere material and a preparation method thereof. The preparation method comprises the following steps: mixing magnetic powder and PSA liquid, and emulsifying in the mixture continuous phase; solidifying the emulsion; separation of the precursor microspheres from the continuous phase; and (3) carrying out ceramic treatment on the magnetic polymer. The preparation method of the novel ceramic wave-absorbing microsphere material disclosed by the embodiment of the invention is simple in process, easy to prepare under a simple condition and capable of realizing large-scale industrial production. The wave-absorbing material prepared by the preparation method of the novel ceramic wave-absorbing microsphere material disclosed by the embodiment of the invention has a good spherical shape, the poly-silicon acetylene has active reaction sites, the component structure is adjustable, the poly-silicon acetylene can react and crosslink with a magnetic substance, different microstructures are formed by adjusting the components and the content of the magnetic substance, and the absorption and reflection capacities of the prepared wave-absorbing material on electromagnetic waves are changed.)

1. A preparation method of a novel ceramic wave-absorbing microsphere material is characterized by comprising the following steps: the method comprises the following steps: adding magnetic powder into PSA liquid, and then dropping the mixture into simethicone to stir and emulsify; curing the emulsion in an oven; then separating the precursor microspheres from the dimethyl silicon oil; and (3) carrying out ceramic treatment on the magnetic polymer.

2. The method of claim 1, wherein: the magnetic substance is selected from more than one of ferric chloride, cobalt chloride, nickel chloride, ferric nitrate, cobalt nitrate, nickel nitrate, ferric acetylacetonate, cobalt acetylacetonate, nickel acetylacetonate and iron cobalt nickel metal powder.

3. The method of claim 1, wherein: the mass ratio of the iron acetylacetonate, the cobalt acetylacetonate and the nickel acetylacetonate in the polyethylacetylene solution is 1-20%.

4. The method of claim 1, wherein: the polysilane can be replaced by polycarbosilane and polysiloxane.

5. The method of claim 1, wherein: the emulsification comprises the following specific steps: the continuous phase can be simethicone and glycerol, the viscosity of the simethicone is 350-.

6. The method of claim 1, wherein: the emulsion curing method comprises the following specific steps: heating and curing the mixed emulsion, wherein the curing temperature is selected to be 180-300 ℃, and preserving heat for 2-6 hours.

7. The method of claim 1, wherein: the precursor microsphere and dimethyl silicon oil are separated by the following specific steps: dissolving and dispersing the precursor microsphere and the emulsion of the simethicone in a normal hexane solution, a tetrahydrofuran solution or a xylene solution, ultrasonically dispersing for 30-60 minutes, centrifuging for 5-20 minutes at the rotating speed of 5000-10000 r/min to take the lower layer of powder, and repeating the process for 2-5 times to obtain the magnetic polymer microsphere.

8. The method of claim 1, wherein: the magnetic polymer microsphere ceramic comprises the following specific steps: dispersing the polymer microspheres in a normal hexane or tetrahydrofuran solution, carrying out ultrasonic treatment for 10-20 minutes, drying, and sintering in a nitrogen or argon atmosphere at the sintering temperature of 800-1400 ℃, keeping the temperature for 1-4 hours, wherein the heating rate is 1-5 ℃/min.

9. A novel ceramic wave-absorbing microsphere material prepared by the preparation method of any one of claims 1 to 8.

Technical Field

The invention relates to a ceramic wave-absorbing material and a preparation method thereof, in particular to a novel ceramic wave-absorbing microsphere material and a preparation method thereof.

Background

With the development of modern technology, electromagnetic waves are widely used in the technical fields of wireless communication systems, data transmission, satellite transmission and radar stealth. However, the electromagnetic pollution caused by electromagnetic waves seriously threatens the health, work and life of human beings. Therefore, effective shielding or absorption of electromagnetic waves is a problem that needs to be solved urgently in current informatization. Meanwhile, the application of electromagnetic absorption materials has become a major direction in the military field. Therefore, the development of advanced absorbing materials with significant electromagnetic absorption and wide operating frequencies is pressing and of great significance.

Modern absorption materials are moving towards dielectric and magnetic lightweight composites. The comprehensive performance meets the requirements of thin, wide, light and strong absorption materials. Magnetic metal/alloy particles are recognized as the most promising candidates for electromagnetic wave absorption (EMA) due to their excellent electromagnetic properties. At a temperature higher than the curie point, the magnetic properties of ferrite and carbonyl iron-based magnetic absorbents are lost, and the electromagnetic absorption properties are also lost. In addition, they cannot be used at high frequencies due to their lower ferromagnetic resonance frequency. As an alternative to ferrites, magnetic alloys have a high Curie point to ensure activity even at high temperatures, such as Co-Fe, Fe-Si and Co-Si alloys. Ceramic materials have the potential for electromagnetic absorption due to their thermal stability, radiation resistance and good mechanical properties, especially Polymer Derived Ceramics (PDC). With PDC, the electromagnetic absorbing material has great variability in composition, morphology and structure. Compared with other ceramics, the SiCO ceramics have proper impedance matching, good mechanical properties and higher thermal stability even at 1000 ℃ in air.

Disclosure of Invention

The invention aims to provide a novel ceramic wave-absorbing microsphere material and a preparation method thereof, the ceramic wave-absorbing microsphere material is prepared by emulsifying a mixture of poly-silicon-acetylene and a magnetic substance, the wave-absorbing material prepared by using the poly-silicon-acetylene as a SiCO ceramic precursor has better high-temperature stability, the prepared microsphere wave-absorbing material has good spherical morphology and provides good interface effect, the magnetic loss of the material is improved by introducing magnetic components, and the prepared magnetic ceramic microsphere has stronger wave-absorbing performance.

In a first aspect, an embodiment of the present application provides a preparation method of a novel ceramic wave-absorbing microsphere material, including the following steps: adding magnetic powder into PSA liquid, and then dropping the mixture into simethicone to stir and emulsify; curing the emulsion in an oven; then separating the precursor microspheres from the dimethyl silicon oil; and (3) carrying out ceramic treatment on the magnetic polymer.

Preferably: the magnetic substance is selected from more than one of ferric chloride, cobalt chloride, nickel chloride, ferric nitrate, cobalt nitrate, nickel nitrate, ferric acetylacetonate, cobalt acetylacetonate, nickel acetylacetonate and iron cobalt nickel metal powder.

Preferably: the mass ratio of the iron acetylacetonate, the cobalt acetylacetonate and the nickel acetylacetonate in the polyethylacetylene solution is 1-20%.

Preferably: the polysilane can be replaced by polycarbosilane and polysiloxane.

Preferably: the emulsification comprises the following specific steps: the continuous phase can be simethicone and glycerol, the viscosity of the simethicone is 350-.

Preferably: the emulsion curing method comprises the following specific steps: heating and curing the mixed emulsion, wherein the curing temperature is selected to be 180-300 ℃, and preserving heat for 2-6 hours.

Preferably: the precursor microsphere and dimethyl silicon oil are separated by the following specific steps: dissolving and dispersing the precursor microsphere and the emulsion of the simethicone in a normal hexane solution, a tetrahydrofuran solution or a xylene solution, ultrasonically dispersing for 30-60 minutes, centrifuging for 5-20 minutes at the rotating speed of 5000-10000 r/min to take the lower layer of powder, and repeating the process for 2-5 times to obtain the magnetic polymer microsphere.

Preferably: the magnetic polymer microsphere ceramic comprises the following specific steps: dispersing the polymer microspheres in a normal hexane or tetrahydrofuran solution, carrying out ultrasonic treatment for 10-20 minutes, drying, and sintering in a nitrogen or argon atmosphere at the sintering temperature of 800-1400 ℃, keeping the temperature for 1-4 hours, wherein the heating rate is 1-5 ℃/min.

In a second aspect, the embodiment of the application provides a ceramic wave-absorbing microsphere material prepared by any one of the above preparation methods.

In summary, the invention provides a precursor-converted silicon carbide ceramic and a preparation method thereof. The scheme of the invention has the following advantages:

1. the preparation method of the novel ceramic wave-absorbing microsphere material disclosed by the embodiment of the invention is simple in process, easy to prepare under simple conditions and capable of realizing large-scale industrial production;

2. the wave-absorbing microspheres prepared by the preparation method of the ceramic wave-absorbing microspheres disclosed by the embodiment of the invention have good spherical morphology and can provide better interface effect;

3. the polysilane provided by the embodiment of the invention has good fluidity and solubility, and can be dissolved in n-hexane, absolute ethyl alcohol and tetrahydrofuran;

4. the poly-silicon acetylene disclosed by the embodiment of the invention has active reaction sites, the component structure is adjustable, the poly-silicon acetylene can react and crosslink with a magnetic substance, different microstructures are formed by adjusting the components and the content of the magnetic substance, and the absorption and reflection capacities of the prepared wave-absorbing material to electromagnetic waves are changed.

Drawings

Fig. 1 is an infrared image of the wave-absorbing microspheres of the embodiment of the invention after thermal curing.

Fig. 2 is an XRD pattern of the ceramic wave-absorbing microsphere after adding iron acetylacetonate, cobalt acetylacetonate, and nickel acetylacetonate in the embodiment of the present invention.

Fig. 3 is a wave-absorbing performance diagram of a cobalt-containing ceramic wave-absorbing microsphere in an example of the invention.

Detailed Description

In order to better explain the technical scheme of the invention, the following describes the preparation of the ceramic wave-absorbing microspheres of the invention in detail with reference to the accompanying drawings and specific examples.

Example 1

Iron acetylacetonate powder (1 g) was added to a polysilyne liquid (9 g) with the addition of an appropriate amount of tetrahydrofuran to completely dissolve the iron acetylacetonate powder and mixed by stirring. The mixture was dropped into dimethylsilicone oil and stirred at 1000 rpm. Stirring for 2 hours, curing for 4 hours in an oven at 200 ℃, and separating precursor microspheres from dimethyl silicon oil by centrifugation;

the infrared pattern of the iron-containing resin microspheres obtained after separation is shown in FIG. 1 and is at 2165cm^-1 2040 cm^-1Peaks at (D) are peaks of-Si-H bond and-C.ident.C-stretching vibration, 1260 cm^-1And 1420 cm^-1Due to Si-CH3 vibrations. In particular, the Si-H bond of PSA reacts with the iron acetylacetonate to form a new Si-O-Fe bond corresponding to 1023 to 1016 cm^-1In a range of-Si-O-at 1037 cm^-1The peak at (a) is broadened while being at 2165cm^-1The Si-H bond at the position is weakened at 1571 cm^-1the-C = O bond of acetylacetone at the same time appears.

Example 2

First, nickel acetylacetonate powder (1 g) was added to PSA liquid (9 g) while adding an appropriate amount of tetrahydrofuran to completely dissolve the nickel acetylacetonate powder and mixed by stirring. The mixture was dropped into dimethylsilicone oil and stirred at 1000 rpm. After stirring for 2 hours, the emulsion was cured in an oven according to the following steps: the temperature is kept at 180 ℃ for 1 hour, at 200 ℃ for 1 hour and at 220 ℃ for 2 hours. The precursor microspheres were then separated from the dimethylsilicone oil by centrifugation. After separation, the polymer was pyrolyzed in an ultra-high purity nitrogen atmosphere in a high temperature alumina tube furnace. The tube furnace was heated from room temperature to 1000 ℃ at a heating rate of 3 ℃/min and held for an additional 2 hours. The XRD pattern of the prepared ceramic wave-absorbing microspheres is shown in figure 2. The sample showed peaks of SiC phase at 35.54 °, 59.92 ° and 71.69 °, corresponding to lattice planes (111), (220) and (311), respectively. Fe₃Peaks of Si at 27.33 DEG and 45.30 DEG, respectively, corresponding to the lattice planes (II) ((III))111) And (220).

Example 3

First, cobalt acetylacetonate powder (2 g) was added to PSA liquid (8 g) while adding an appropriate amount of acetone to completely dissolve the cobalt acetylacetonate powder and mixed by stirring. The mixture was dropped into dimethylsilicone oil and stirred at 1000 rpm. After stirring for 2 hours, the emulsion was cured in an oven according to the following steps: the temperature is kept at 160 ℃ for 1 hour, 190 ℃ for 1 hour and 200 ℃ for 2 hours. The precursor microspheres were then separated from the dimethylsilicone oil by centrifugation. After separation, the polymer was pyrolyzed in a high purity nitrogen atmosphere in a high temperature alumina tube furnace. The tube furnace was heated from room temperature to 1200 ℃ at a heating rate of 5 ℃/min and held for an additional 4 hours. The wave-absorbing property of the prepared ceramic wave-absorbing microspheres is shown in figure 3.

Example 4

In the first step, cobalt acetylacetonate powder (2 g) is added to polysiloxane liquid (8 g) and simultaneously an appropriate amount of acetone solution is added to completely dissolve the cobalt acetylacetonate powder in acetone and uniformly stir. The mixture was added dropwise to glycerol and stirred at 800 rpm. After stirring for 2 hours, the emulsion was cured in an oven according to the following steps: the temperature is kept at 90 ℃ for 2 hours and at 100 ℃ for 2 hours. And then mixing and stirring the emulsion and water, and separating the precursor microspheres from the glycerol by a suction filtration method. After separation, the pyrolysis of the polymer is carried out under an oxygen atmosphere. The tube furnace was heated from room temperature to 800 ℃ at a heating rate of 3 ℃/min and held for an additional 2 hours.

The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as devised in the present application is not limited to the specific combination of features described above, but also covers other embodiments having any combination of features described above or of features together without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.