阅读说明：本技术 一种FeSiAl基有机-无机双层核壳结构的制备方法 (Preparation method of FeSiAl-based organic-inorganic double-layer core-shell structure ) 是由 简贤 潘莹 田威 张兴中 刘一凡 于 2021-06-16 设计创作，主要内容包括：一种FeSiAl基有机-无机双层核壳结构的制备方法,属于新材料、微波隐身技术领域。包括：1)将FeSiAl粉料、无水乙醇和去离子水均匀混合,水浴加热,加入氨水调控其pH至9～10；2)加入正硅酸乙酯,搅拌,得到的混合液采用去离子水和无水乙醇交替洗涤,磁性分离,烘干；3)上步得到的样品分散在羟基丙烯酸树脂和乙酸丁酯的混合溶剂中,水浴加热；4)加入固化剂,搅拌,得到的混合液采用无水乙醇洗涤,磁性分离,烘干。本发明得到的FeSiAl复合材料,具有较好的包覆效果,制备方法简单易行,原位聚合的无机/有机双层结构使所得复合材料具备更好的耐腐蚀能力、电磁阻抗匹配特性以及较大的衰减常数。(A preparation method of a FeSiAl-based organic-inorganic double-layer core-shell structure belongs to the technical field of new materials and microwave stealth. The method comprises the following steps: 1) uniformly mixing FeSiAl powder, absolute ethyl alcohol and deionized water, heating in a water bath, and adding ammonia water to regulate the pH value to 9-10; 2) adding tetraethoxysilane, stirring, alternately washing the obtained mixed solution by using deionized water and absolute ethyl alcohol, performing magnetic separation, and drying; 3) dispersing the sample obtained in the previous step in a mixed solvent of hydroxy acrylic resin and butyl acetate, and heating in a water bath; 4) adding curing agent, stirring, washing the obtained mixed solution with absolute ethyl alcohol, magnetically separating, and drying. The FeSiAl composite material obtained by the invention has a good coating effect, the preparation method is simple and feasible, and the in-situ polymerized inorganic/organic double-layer structure ensures that the obtained composite material has better corrosion resistance, electromagnetic impedance matching property and larger attenuation constant.)

1. A preparation method of a FeSiAl-based organic-inorganic double-layer core-shell structure is characterized by comprising the following steps:

step 1, uniformly mixing 5-100 parts by weight of FeSiAl powder, 140-560 parts by weight of anhydrous ethanol and 20-140 parts by weight of deionized water, heating in a water bath at 25-60 ℃ for 0.2-0.5 h, and adding ammonia water to regulate the pH value to 9-10;

step 2, adding 7-140 parts of tetraethoxysilane into the mixed liquid A obtained in the step 1, and stirring for 0.5-8 hours; washing the obtained mixed solution B with deionized water and absolute ethyl alcohol for 6-8 times alternately, performing magnetic separation, and drying to obtain a single-layer inorganic SiO₂In-situ polymerizing a spherical FeSiAl sample;

step 3, weighing 1-20 parts of the sample obtained in the step 2, dispersing the sample in a mixed solvent of 0.1-5 parts of hydroxy acrylic resin and 4-200 parts of butyl acetate under the condition of stirring, and heating the mixture in a water bath at the temperature of 25-60 ℃ for 0.2-0.5 h to obtain a mixed solution C;

step 4, adding 0.04-2 parts of curing agent into the mixed liquid C obtained in the step 3, and stirring for 0.5-8 hours; washing the obtained mixed solution D with absolute ethyl alcohol for 6-8 times, performing magnetic separation, and drying to obtain the double-layer organic-inorganic PUA-SiO₂In-situ polymerized spherical FeSiAl composite material.

2. The method for preparing a FeSiAl-based organic-inorganic double-layer core-shell structure according to claim 1, wherein the weight ratio of the FeSiAl powder in the step 1 to the TEOS in the step 2 is 5: 7.

3. the preparation method of the FeSiAl-based organic-inorganic double-layer core-shell structure according to claim 1, wherein the weight part ratio of the hydroxyl acrylic resin to the butyl acetate in the step 3 is 1: 40.

4. the method for preparing a FeSiAl-based organic-inorganic double-layer core-shell structure according to claim 1, wherein the curing agent in the step 4 is isocyanate, pyridine, amino resin, resin with epoxy group or titanium tetraisopropoxide.

5. The preparation method of the FeSiAl-based organic-inorganic double-layer core-shell structure according to claim 1, wherein the drying temperature in the step 2 and the step 4 is 45-80 ℃, and the stirring in the step 2-4 is mechanical stirring.

6. Application of the FeSiAl-based organic-inorganic double-layer core-shell structure obtained by the method of any one of claims 1 to 5 as a wave-absorbing material.

Technical Field

The invention belongs to the technical field of new materials and microwave stealth, and particularly relates to a preparation method of an in-situ polymerized organic-inorganic double-layer structure on the surface of spherical FeSiAl and application of the in-situ polymerized organic-inorganic double-layer structure in a microwave stealth anticorrosive coating.

Background

With the application of wireless communication technology and the wide use of various electronic products and devices, the harm of electromagnetic radiation to electrical devices and human health is increasingly prominent, which has become a serious environmental pollution problem. The wave-absorbing material can convert electromagnetic energy of incident electromagnetic waves into mechanical energy, electric energy or heat energy to be dissipated. However, under extreme conditions (such as ocean, acid rain and damp and hot environments), the wave-absorbing material is corroded and faces the problems of corrosion and aging, so that the wave-absorbing function of the wave-absorbing material is reduced or even lost. How to meet the requirements of a high-performance wave-absorbing material with corrosion resistance, strong absorption, wide absorption bandwidth, small thickness and light weight is a great challenge faced by the wave-absorbing material. Therefore, it is imperative to develop a bifunctional material having good microwave absorption and corrosion resistance.

Modification treatments such as microstructure adjustment, doping, surface treatment and the like are carried out on the wave-absorbing material, which is an effective measure for realizing effective combination of all components of the composite wave-absorbing material and improving comprehensive performance of the absorber. Magnetic metals and alloys have attracted much attention in recent years as various wave-absorbing materials due to their advantages of high magnetic permeability and high dielectric constant. Spherical FeSiAl is a soft magnetic material and is widely used due to its excellent magnetic properties, high saturation magnetization and low cost. For example, chinese patent 201911029889.5 discloses a low dielectric composite FeSiAl powder material and a preparation method thereof, the preparation method is simple and easy, the problems of incomplete and uneven coating of the powder, weak adhesion of an inorganic coating layer and the like are solved, and the obtained composite FeSiAl powder material has moderate electromagnetic impedance matching. However, only the dielectric constant of the composite powder is reduced, the wave absorbing performance is not obviously improved, the reflection loss value is not increased much, and the corrosion resistance of the composite powder is not tested. Acrylic Polyurethane (PUA) is widely used in the paint industry because of its good solvent resistance, wear resistance, low temperature resistance, etc. For example, Chinese patent CN201110069944.0 discloses a highly weather-resistant highly wear-resistant acrylic polyurethane coating, which is prepared from nano SiO with hydroxyl₂The inorganic-organic interpenetrating network polymer structure formed by mixing the modified acrylate resin and the hexamethylene diisocyanate prepolymer curing agent with isocyanate can obviously improve the performances of the coating such as weather resistance, wear resistance, hardness, scratch resistance and the like. But the reaction temperature is regulated and controlled for many times in the preparation process, the preparation process is complex and difficult to control, and the wave-absorbing performance of the material is poor.

Disclosure of Invention

The invention aims to provide a preparation method of a FeSiAl-based organic-inorganic double-layer core-shell structure aiming at the defects in the background art. The FeSiAl composite material obtained by the invention has a good coating effect, the preparation method is simple and feasible, and the in-situ polymerized inorganic/organic double-layer structure ensures that the obtained composite material has better corrosion resistance, electromagnetic impedance matching property and larger attenuation constant.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a preparation method of a FeSiAl-based organic-inorganic double-layer core-shell structure is characterized by comprising the following steps:

step 1, uniformly mixing 5-100 parts by weight of FeSiAl powder, 140-560 parts by weight of anhydrous ethanol and 20-140 parts by weight of deionized water, heating in a water bath at 25-60 ℃ for 0.2-0.5 h, and adding ammonia water to regulate the pH value to 9-10;

step 2, adding 7-140 parts of Tetraethoxysilane (TEOS) into the mixed solution A obtained in the step 1, and stirring for 0.5-8 hours; washing the obtained mixed solution B with deionized water and absolute ethyl alcohol for 6-8 times alternately, performing magnetic separation, and drying to obtain a single-layer inorganic SiO₂In-situ polymerizing a spherical FeSiAl sample;

step 3, weighing 1-20 parts of the sample obtained in the step 2, dispersing the sample in a mixed solvent of 0.1-5 parts of hydroxy acrylic resin and 4-200 parts of butyl acetate under the condition of stirring, and heating the mixture in a water bath at the temperature of 25-60 ℃ for 0.2-0.5 h to obtain a mixed solution C;

step 4, adding 0.04-2 parts of curing agent into the mixed liquid C obtained in the step 3, and stirring for 0.5-8 hours; washing the obtained mixed solution D with absolute ethyl alcohol for 6-8 times, performing magnetic separation,drying to obtain the double-layer organic-inorganic PUA-SiO₂In-situ polymerized spherical FeSiAl composite material.

Preferably, the weight part ratio of the FeSiAl powder in the step 1 to the TEOS in the step 2 is 5: 7.

preferably, the weight part ratio of the hydroxy acrylic resin to the butyl acetate in the step 3 is 1: 40.

further, in step 4, the curing agent is isocyanate (N3390), pyridine, amino resin, epoxy group-containing resin, titanium tetraisopropoxide, or the like.

Further, the drying temperature in the step 2 and the step 4 is 45-80 ℃, and in the step 2-4, the stirring is mechanical stirring, and magnetic stirring cannot be used because the FeSiAl powder has magnetism.

The invention also provides application of the FeSiAl-based organic-inorganic double-layer core-shell structure as a wave-absorbing material, and the FeSiAl-based organic-inorganic double-layer core-shell structure has good microwave absorption performance and corrosion resistance when being applied as the wave-absorbing material.

The invention provides a preparation method of a FeSiAl-based organic-inorganic double-layer core-shell structure, which has the following principle: adopting a traditional sol-gel method, firstly polymerizing a layer of inorganic SiO on the surface of spherical FeSiAl in situ at 25-60 DEG C₂A single-layer structure; then, the acrylic urethane (PUA) -SiO is subjected to a crosslinking reaction between the silicon hydroxyl bond in the coating layer, the isocyanate group in the curing agent N3390, and the hydroxyl group and the carboxyl group in the hydroxyacrylic resin₂The double-layer structure is polymerized on the surface of the spherical FeSiAl in situ. FeSiAl @ SiO prepared by the method₂The @ PUA has spherical microstructure, particle size of about 75 μm, and uniformly distributed fine fish scale-like flakes on the surface, and has structure compared with FeSiAl and FeSiAl @ SiO₂Is rougher, has good stability and hydrophobicity, and SiO is polymerized on the surface of FeSiAl in situ₂And the PUA has a double-layer structure, so that the microwave absorption performance and the corrosion resistance of the spherical FeSiAl magnetic powder are effectively improved.

Compared with the prior art, the invention has the beneficial effects that:

1. spherical FeSiAl @ SiO prepared by the invention₂The @ PUA has a larger reflection loss value and a larger water contact angle, so that the @ PUA has better wave-absorbing performance and corrosion resistance, and is favorable for application in practical engineering.

2. The preparation process has the advantages of mild conditions, low cost, convenient operation, realization of industrialization and good commercial value.

Drawings

FIG. 1 is an SEM image of a spherical FeSiAl alloy of the present invention before and after coating; wherein (a) and (b) are SEM images of spherical FeSiAl alloy (M) before polymerization, and (c) and (d) are FeSiAl @ SiO obtained in example 1₂SEM pictures of (MS), (e) and (f) are FeSiAl @ SiO obtained in example 1₂SEM picture of @ PUA (MSP);

FIG. 2 shows a spherical FeSiAl (M) of the present invention, FeSiAl @ SiO obtained in example 1₂(MS) and FeSiAl @ SiO obtained in example 1₂XPS plots of @ PUA (MSP); wherein, (a) is M, MS and MSP full scan XPS spectrum, (b) is M Si 2p XPS spectrum, (C) is MS Si 2p XPS spectrum, (d), (e) (f) is MSP Si 2p, C1 s and N1s XPS spectrum;

FIG. 3 shows a spherical FeSiAl (M) of the present invention, FeSiAl @ SiO obtained in example 1₂(MS) and FeSiAl @ SiO obtained in example 1₂FTIR plots of @ PUA (MSP);

FIG. 4 shows FeSiAl @ SiO solid obtained in example 1 of the present invention₂Raman plots of @ PUA (MSP);

FIG. 5 shows a spherical FeSiAl (M) of the present invention, FeSiAl @ SiO obtained in example 1₂(MS) FeSiAl @ SiO obtained in example 1₂@ PUA (MSP) MSP, FeSiAl @ SiO obtained in example 2₂@ PUA (MSP-1.0) and FeSiAl @ SiO obtained in example 3₂The wave-absorbing performance diagram of @ PUA (MSP-1.5);

FIG. 6 shows FeSiAl @ SiO solid obtained in example 1 of the present invention₂(MS) and FeSiAl @ SiO obtained in example 3₂Contact angle plot of @ PUA (MSP-1.5);

FIG. 7 shows a spherical FeSiAl (M) of the present invention, FeSiAl @ SiO obtained in example 1₂(MS) and FeSiAl @ SiO obtained in example 3₂The corrosion performance test chart of @ PUA (MSP-1.5).

Detailed Description

The technical scheme of the invention is further detailed in the following by combining the drawings and the specific examples.

Example 1

A preparation method of an organic-inorganic double-layer core-shell structure in-situ polymerization spherical FeSiAl comprises the following steps:

uniformly mixing 50g of FeSiAl powder, 140g of anhydrous ethanol and 20g of deionized water, heating the mixture in a water bath at the temperature of 30 ℃ for 0.2h, and adding ammonia water to regulate the pH value to 9-10; adding 70g TEOS into the obtained mixed solution, stirring for 0.5h, alternately washing the obtained mixed solution with deionized water and absolute ethyl alcohol for 6 times, magnetically separating, and drying to obtain single-layer inorganic SiO₂In situ polymerization of a spherical FeSiAl sample, i.e., FeSiAl @ SiO₂Named MS; weighing FeSiAl @ SiO₂5g, dispersing the mixture in a mixed solvent of 0.5g of hydroxyl acrylic resin and 20g of butyl acetate under the stirring condition, and heating the mixture in a water bath at the temperature of 30 ℃ for 0.2h to obtain a component A; adding 0.2g N3390 curing agent into the component A, and stirring for 0.5 h; washing the obtained mixed solution with anhydrous ethanol for 6 times, performing magnetic separation, and drying in a 45 deg.C oven to obtain double-layer organic-inorganic PUA-SiO₂In-situ polymerized spherical FeSiAl composite material, i.e. FeSiAl @ SiO₂@ PUA, named MSP.

Example 2

This example is different from example 1 in that: weighing FeSiAl @ SiO₂5g, dispersing the mixture in a mixed solvent of 1g of hydroxyl acrylic resin and 40g of butyl acetate under the stirring condition, and heating the mixture in a water bath at the temperature of 30 ℃ for 0.2h to obtain a component A; 0.4g N3390 curing agent was added to component A and stirred for 0.5 h. The rest of the procedure was the same as in example 1. The obtained spherical FeSiAl @ SiO₂@ PUA is named MSP-1.0.

Example 3

This example is different from example 1 in that: weighing FeSiAl @ SiO₂5g, dispersing the mixture in a mixed solvent of 1.5g of hydroxyl acrylic resin and 60g of butyl acetate under the stirring condition, and heating the mixture in a water bath at the temperature of 30 ℃ for 0.2h to obtain a component A; 0.6g N3390 curing agent was added to component A and stirred for 0.5 h. The rest of the procedure was as in example 1The same is true. The obtained spherical FeSiAl @ SiO₂@ PUA is named MSP-1.5.

FIG. 1 is an SEM image of a spherical FeSiAl alloy of the present invention before and after coating; wherein (a) and (b) are SEM images of spherical FeSiAl alloy (M) before polymerization, and (c) and (d) are FeSiAl @ SiO obtained in example 1₂SEM pictures of (MS), (e) and (f) are FeSiAl @ SiO obtained in example 1₂SEM picture of @ PUA (MSP); as can be seen from FIG. 1, the surface of MS has SiO₂Spherical particles with an average particle size of 0.2 μm, with a significant lamellar coating on the MSP sample surface.

FIG. 2 shows a spherical FeSiAl (M) of the present invention, FeSiAl @ SiO obtained in example 1₂(MS) and FeSiAl @ SiO obtained in example 1₂XPS plots of @ PUA (MSP); wherein (a) is M, MS and MSP full scan XPS spectrum, (b) is M Si 2p XPS spectrum, (C) is MS Si 2p XPS spectrum, (d), (e) (f) is MSP Si 2p, C1 s and N1s XPS spectrum. Fig. 2(a) shows that the three samples all contain C, Si, Al, O elements, and the peak intensities of the Fe and Al elements in the M, MS and MSP samples decrease in sequence. In the M, MS and MSP samples, the peak intensity of the Si element increased and then decreased, indicating that the MS was coated with SiO₂And (3) a layer. Only the MSP contains N elements, indicating that the MSP sample has a surface with a layer of material that contains N but no Si. (b) Graphs (c) and (d) show that only the surface of the M sample contains a simple substance Si, the M, MS and the MSP sample surface are Si-O bonds, and the binding energy is gradually increased at 102.4eV, 103.3eV and 103.6eV respectively, which shows that Si loses electrons and the electron cloud density is reduced. (f) The MSP sample has C-C, C-N, C-O bonds on the surface, which are inherent groups of acrylic polyurethane, and the result is matched with the result obtained by infrared spectrum analysis. Evidence of SiO₂the/PUA double-layer structure is formed on the surface of FeSiAl, and can improve the microwave absorption and corrosion resistance of the composite material.

FIG. 3 shows a spherical FeSiAl (M) of the present invention, FeSiAl @ SiO obtained in example 1₂(MS) and FeSiAl @ SiO obtained in example 1₂FTIR plots of @ PUA (MSP); wherein (a) is M, MS and MSP is 500cm at 4000-^-1FTIR patterns in the range (b) M, MS and MSP at 2000-^-1FTIR patterns over a range; at 3436.6cm^-1The peak appears due to the sphereThe stretching vibration of the O-H bond on the surface of the FeSiAl. FIG. 3 shows 1215cm in MS samples^-1、1100cm^-1The peak is the stretching vibration of TEOS and C-O grafted with-OH on FeSiAl, 730cm^-1And 911cm^-1The peak at (A) is the stretching vibration of Si-O. 700cm in MSP^-1Peak at 1691cm^-1、1727cm^-1The peak indicates that the hydroxyl group of the acrylic resin in N3390 reacts with the isocyanate group to generate a strong stretching vibration of C ═ O in the urethane-O-C (O) -NH-unit, 1455cm^-1The peak at 1530cm is the vibration of C ═ C^-1、1378cm^-1The peak is antisymmetric stretching vibration and symmetric stretching vibration of C-N, 2736cm^-1Peak at is-CH₃3380cm, of^-1The peak at (A) is the oscillation of N-H. This fully confirms the spherical FeSiAl surface SiO₂Formation of inorganic organic materials of polyurethane acrylic (PUA).

FIG. 4 shows FeSiAl @ SiO solid obtained in example 1 of the present invention₂Raman plots of @ PUA (MSP); wherein (a) is MSP at 200-^-1Raman map within the range, (b) MSP at 1150-1800cm^-1Raman map within range. 1002cm^-1And 1032cm^-1Peak at 1194cm, which is the strong stretching vibration of Si-O-Si^-1The peak at (B) is the strong stretching vibration of C-O in the urethane-O-C (O) -NH-unit, 1308cm^-1、1448cm^-1And 1601cm^-1The peak at (A) is the asymmetric stretching vibration of C ═ O in the carboxylate unit, 1759cm^-1The peak at (a) is a strong stretching vibration of C ═ O in the saturated urethane-O-C (O) -NH-unit. This fully confirms the spherical FeSiAl surface SiO₂Formation of inorganic organic materials of polyurethane acrylic (PUA).

FIG. 5 shows (a) spherical FeSiAl (M) according to the invention and (b) FeSiAl @ SiO obtained in example 1₂(MS) and (c) FeSiAl @ SiO solid obtained in example 1₂@ PUA (MSP) MSP, (d) FeSiAl @ SiO obtained in example 2₂@ PUA (MSP-1.0) and (e) FeSiAl @ SiO obtained in example 3₂The wave-absorbing performance diagram of @ PUA (MSP-1.5). As shown in FIGS. a-b, pure FeSiAl and FeSiAl @ SiO₂Exhibits similar, poor absorption capacity, with a minimum RL value of less than-15 dB at 12GHz at a thickness of 2.5 mm.As shown in FIGS. c-e, the minimum reflection loss values of MSP, MSP-1.0 and MSP-1.5 increase with increasing prepolymer content after in situ polymerization of the inorganic/organic layers on FeSiAl. The frequency corresponding to the lowest reflection loss of the three samples increases in sequence. In practical applications, an RL value of less than-10 dB means that 90% of the electromagnetic waves are absorbed. The MSP-1.5 has an absorber layer thickness of 2.5mm and an Effective Absorption Bandwidth (EAB) (less than-10 dB) of up to 7.8GHz (10.21-18GHz), covering the entire Ku band (12-18GHz), but at the same thickness the EAB of the original FeSiAl is only 6GHz (8.9-14.9GHz) (FIG. 7 a). In-situ polymerization of SiO on FeSiAl surface₂The value of the minimum reflection loss of the sample increases after the/PUA bilayer structure. This fully demonstrates that the FeSiAl sample has better wave-absorbing performance after being coated.

FIG. 6 shows FeSiAl @ SiO solid obtained in example 1 of the present invention₂(MS) and FeSiAl @ SiO obtained in example 3₂Contact angle plot of @ PUA (MSP-1.5); FeSiAl @ SiO obtained in example 3₂@ PUA has a water contact angle after coating acrylic polyurethane, which is higher than that of FeSiAl @ SiO₂Obviously increased and hydrophobic property improved, which shows that the formed SiO₂PUA bilayer structure compared to SiO alone₂The layer can more effectively prevent the corrosive medium from contacting with the FeSiAl wave absorbing agent, thereby having certain corrosion resistance.

FIG. 7 shows a spherical FeSiAl (M) of the present invention, FeSiAl @ SiO obtained in example 1₂(MS) and FeSiAl @ SiO obtained in example 3₂The corrosion performance test chart of @ PUA (MSP-1.5). Wherein (a), (b) and (c) correspond to side views of M, MS and MSP-1.5, respectively, immersed in a 5.0 wt.% NaCl solution at pH 3 for more than 120 h; (d) side views of (f) and (h) immersed in 5.0 wt.% NaCl solution at pH 12 for 3930h, corresponding to M, MS and MSP-1.5, respectively; (e) bottom views of (i), (g) and (i) immersed in 5.0 wt.% NaCl solution at pH 12 for 3930h, corresponding to M, MS and MSP-1.5, respectively. Among them, as can be seen from fig. 7a-c, the liquid soaked in M is dark in color due to excessive corrosion of M in the solution. The liquid immersion in MS is shallow. In contrast, the liquid in which the MSP-1.5 is immersed is still clear and transparent, which shows that the double-layer coating has an effect of improving the corrosion resistance of the composite material. It can be seen from fig. 7d-e that pure fesai is corroded. From FIGS. 7f-g can be seenTo see that only one layer of SiO is coated₂The sample showed slight corrosion, while from fig. 7h-i it can be seen that the MSP-1.5 powder coated with the inorganic/organic bilayer structure was not discolored yet. This corrosion phenomenon is fully explained by the SiO coating on the FeSiAl surface₂the/PUA composite double-layer structure can effectively prevent a corrosive medium from contacting with the FeSiAl wave absorbing agent.