A method for preparing a multilayer topological discontinuous cobalt-based magnetic particle

Abstract

The application discloses a preparation method of a multilayer topological discontinuous hollow gap structure Co-based magnetic particle, and comprises the following steps: S1, preparing an initial skeleton particle; S2, coating the initial skeleton particle with Co; S3, performing skeleton re-deposition on the particle in S2; S4, re-coating Co; S5, forming a multilayer Co coating layer containing the nano-skeleton particle; and S6, removing the skeleton metal to obtain the hollow gap structure Co particle. The multilayer topological discontinuous hollow gap structure makes electromagnetic waves reflect and absorb in the material cavity for multiple times, and effectively improves the microwave absorption performance of Co.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of magnetic wave-absorbing material preparation, and mainly relates to a preparation method of multilayer topological discontinuous hollow gap structure cobalt-based magnetic particles. BACKGROUND

[0002] Metallic magnetic wave-absorbing materials become an important part of microwave absorbing materials due to simple preparation process and affordable raw materials, among which iron and ferrite are most widely used. However, with the development of marine equipment technology, the traditional wave-absorbing materials are prone to corrosion in marine climate, and the maintenance cost is high, so it is urgent to develop a wave-absorbing material technology that can adapt to the service conditions of marine environment and has good corrosion resistance.

[0003] As a traditional magnetic metal material, cobalt has a high Curie temperature (1150℃) and a low standard electrode potential, and has good corrosion resistance, and will not be easily damaged even in an acid or alkaline environment, showing strong electrochemical stability and oxidation resistance, and is one of the ideal choices for marine climate-resistant wave-absorbing materials.

[0004] However, the effective absorption bandwidth of traditional cobalt particles for electromagnetic waves is narrow, which cannot fully meet the performance requirements of thin, light, wide and strong for wave-absorbing materials, and it is urgent to improve and enhance the wave-absorbing performance of magnetic cobalt particles. SUMMARY

[0005] The main purpose of the application is to design and prepare multilayer topological discontinuous hollow gap structure cobalt-based magnetic particles, to obtain corrosion-resistant cobalt-based particles with excellent wave-absorbing performance by designing and preparing the particles, and to form a wave-absorbing material with good corrosion resistance.

[0006] In order to achieve the above purpose, the application adopts the following technical scheme:

[0007] A preparation method of multilayer topological discontinuous hollow gap structure cobalt-based magnetic particles, comprising the following steps:

[0008] S1, preparing initial skeleton particles:

[0009] A certain concentration of metal salt solution is prepared by using deionized water, and a certain amount of complexing agent is mixed with the metal salt solution by slight stirring, and is heated in an ultrasonic water bath pot, and a certain concentration of reducing agent is configured, and the reducing agent is mixed with the salt solution under the action of ultrasonic stirring and reaction, the reaction rate is controlled by using the complexing agent, and the particle size of the initial particles is effectively controlled;

[0010] S2, coating the initial skeleton particles with Co:

[0011] A certain amount of Co salt solution is configured using deionized water, and a certain amount of complexing agent is mixed therewith, heated to a certain temperature, and then the particles in S1 are dispersed in deionized water and mixed with the Co salt solution, and a reducing agent is added, and under the conditions of ultrasonic stirring, Co is deposited on the surface of the metal skeleton to form a first layer of spherical shell;

[0012] S3, re-deposition of the skeleton on the particles in S2:

[0013] A certain concentration of metal salt solution is mixed with a complexing agent, heated, mixed with a reducing agent, and reacted under ultrasonic stirring, and the reaction rate is controlled by the complexing agent and the reducing agent to form a discontinuous nanometer metal phase on the particles in S2;

[0014] S4, re-coating of Co:

[0015] A certain concentration of Co salt solution is configured, mixed with a certain concentration of complexing agent, and then the particles containing a discontinuous nanometer phase in S3 are dispersed with deionized water, and the two are uniformly mixed, and a reducing agent is added, and the reaction rate is controlled to achieve re-coating of Co on the particles containing a discontinuous nanometer phase in S3;

[0016] S5, multi-layer metal Co coating layer containing nanometer skeleton particles:

[0017] The steps of S3 and S4 are repeated to prepare a multi-layer continuous metal Co coating layer containing nanometer skeleton particles according to design requirements;

[0018] S6, removing the skeleton metal to obtain a hollow gap structure Co particle:

[0019] A certain concentration of acid solution is configured, the particles obtained in S5 are placed in it, and the skeleton metal is corroded away by the acid under slow stirring to obtain a multi-layer topological discontinuous hollow gap structure cobalt-based magnetic particle.

[0020] As a further improvement of the technical solution: the multi-layer topological discontinuous hollow gap structure cobalt-based magnetic particle is a five-layer topological discontinuous nanometer hollow gap structure cobalt-based magnetic particle or an eight-layer topological discontinuous micrometer hollow gap structure cobalt-based magnetic particle.

[0021] As a further improvement of the technical solution: the S1, preparation of initial skeleton particles, specifically:

[0022] Take 15g of ferrous sulfate heptahydrate, add deionized water to prepare a 200ml solution, and take 7g of trisodium citrate and 3.4g of potassium sodium tartrate to prepare a 100ml solution, mix with the ferrous sulfate solution, heat to 70℃ in an ultrasonic water bath, and dissolve 14g of sodium hydroxide in deionized water to prepare a 50ml solution. Take 20ml of hydrazine hydrate and mix with sodium hydroxide to prepare a reducing agent. Mix the reducing agent with the ferrous sulfate solution under the conditions of 800HZ / min ultrasonic and 150r / min stirring, start the reaction, and take out the solution after 30min of reaction.

[0023] As a further improvement of the technical solution, S2, the initial framework particles are coated with Co, specifically:

[0024] Dissolve 15g of cobalt sulfate heptahydrate in deionized water to prepare a 200ml solution, and take 7g of trisodium citrate and 3.4g of potassium sodium tartrate to prepare a 100ml solution, mix with it, heat to 70℃, then mix solution 1 with the cobalt sulfate solution, and add 70ml of hydrazine hydrate reducing agent to it. Under the conditions of 800HZ / min ultrasonic and 150r / min stirring, wait for 30min for Co to deposit on the surface of Fe particles to form a spherical shell.

[0025] As a further improvement of the technical solution, S3, the framework is deposited again on the S2 particles, specifically:

[0026] Dissolve 5g of ferrous sulfate heptahydrate in deionized water to prepare a 100ml solution, mix the particle solution in step 2 with the ferrous sulfate solution, heat to 60℃, then mix with 70ml of hydrazine hydrate reducing agent, and under the conditions of 800HZ / min ultrasonic and 100r / min stirring, stop the reaction after 10min to form a non-continuous nano-Fe particle deposition on the Co shell.

[0027] As a further improvement of the technical solution, S4, re-coat Co, specifically:

[0028] Dissolve 20g of cobalt sulfate heptahydrate in deionized water to prepare a 200ml solution, mix with the same trisodium citrate and potassium sodium tartrate complexing agent 100ml, then mix the Co particle solution containing non-continuous nano-Fe particles in step 3 with it, and mix with 70ml of hydrazine hydrate reducing agent. Under the conditions of 800HZ / min ultrasonic and 150r / min stirring, coat Co for 30min, then take it out.

[0029] As a further improvement of the technical solution, S1, prepare the initial framework particles, specifically:

[0030] Take 50g of ferrous sulfate heptahydrate, add deionized water to prepare a 200ml solution, and take 25g of trisodium citrate and 10g of potassium sodium tartrate to prepare a 200ml solution, and mix with the ferrous sulfate solution under slight stirring, heat to 70℃ in an ultrasonic water bath, and take 30g of sodium hydroxide dissolved in deionized water to prepare a 100ml solution, take 30ml of hydrazine hydrate and mix with sodium hydroxide to prepare a reducing agent, mix the reducing agent with the ferrous sulfate solution under the conditions of 800HZ / min ultrasonic and 150r / min stirring, start the reaction, and take out the solution after 2 hours of reaction.

[0031] As a further improved scheme of the technical solution, the S5, the multi-layer metal Co coating layer containing nanoskeleton particles, is specifically:

[0032] Repeat step 3 / 4 for 4 times, and collect the prepared particles with a magnet.

[0033] As a further improved scheme of the technical solution, the S5, the multi-layer metal Co coating layer containing nanoskeleton particles, is specifically:

[0034] Repeat step 3 / 4 for 4 times, and collect the prepared particles with a magnet.

[0035] As a further improved scheme of the technical solution, the S6, removing the skeleton metal to obtain a hollow gap structure Co particle, is specifically:

[0036] Prepare 400ml of 1% hydrochloric acid solution, put the Fe and Co composite particles obtained in S4 into the solution, and slightly stir to corrode Fe, then take out and clean with a magnet after 20min, and dry in a freeze dryer for 24h to obtain a multi-layer topological non-continuous micrometer hollow gap structure cobalt-based magnetic particle.

[0037] Compared with the prior art, the beneficial effects of the present application are:

[0038] The present application improves the microwave absorption performance of cobalt by multiple reflection and absorption of electromagnetic waves in the material cavity through the multi-layer topological non-continuous hollow gap structure.

[0039] The above description is only a summary of the technical solution of the present application, in order to more clearly understand the technical means of the present application, and the content of the specification can be implemented, the following preferred embodiments of the present application are described in detail with the help of the drawings. The specific embodiments of the present application are given in detail by the following examples and their drawings. BRIEF DESCRIPTION OF DRAWINGS

[0040] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

[0041] Figure 1 Preparation of multi-layer topological non-continuous nanometer hollow gap structure Co particles and final structure schematic diagram. DETAILED DESCRIPTION

[0042] Example 1 Preparation of five-layer topological non-continuous nanometer hollow gap structure cobalt-based magnetic particles

[0043] 1. Preparation of nanometer Fe particles as an initial skeleton

[0044] Take 15 g of ferrous sulfate heptahydrate, add deionized water to prepare a 200 ml solution, and take 7 g of trisodium citrate and 3.4 g of potassium sodium tartrate to prepare a 100 ml solution. Mix the ferrous sulfate solution with slight stirring, heat to 70°C in an ultrasonic water bath, and dissolve 14 g of sodium hydroxide in deionized water to prepare a 50 ml solution. Take 20 ml of hydrazine hydrate and mix with sodium hydroxide to prepare a reducing agent. Mix the reducing agent with the ferrous sulfate solution under the conditions of 800 HZ / min ultrasonic and 150 r / min stirring, start the reaction, and take out the solution after 30 min of reaction.

[0045] 2. Primary coating of nanometer Fe with Co

[0046] Dissolve 15 g of cobalt sulfate heptahydrate in deionized water to prepare a 200 ml solution, and take 7 g of trisodium citrate and 3.4 g of potassium sodium tartrate to prepare a 100 ml solution. Mix them, heat to 70°C, then mix the solution with the cobalt sulfate solution, and add 70 ml of the same hydrazine hydrate reducing agent. Under the conditions of 800 HZ / min ultrasonic and 150 r / min stirring, wait for 30 min for Co to deposit on the surface of the Fe particles to form a spherical shell.

[0047] 3. Secondary deposition of Fe on the particles

[0048] Dissolve 5 g of ferrous sulfate heptahydrate in 100 ml, mix the particle solution in 2 with the ferrous sulfate solution, heat to 60°C, then mix with 70 ml of hydrazine hydrate reducing agent. Under the conditions of 800 HZ / min ultrasonic and 100 r / min stirring, stop the reaction after 10 min to form a non-continuous nanometer Fe particle deposition on the Co shell.

[0049] 4. Secondary coating of the Co shell

[0050] Take 20 g of seven hydrated cobalt sulfate dissolved in deionized water to configure 200 ml solution, configure the same citric acid and sodium tartrate complexing agent 100 ml mixed with it, and then mix the non-continuous nano Fe particle containing Co particle solution in 3 with it, and then configure the same hydrazine hydrate reducing agent 70 ml, and perform Co coating under the conditions of 800 HZ / min ultrasonic and 150 r / min stirring, and take out after 30 min.

[0051] 5. Repeat step 4 of 3 / 4 four times, and use a magnet to clean and collect the prepared particles.

[0052] 6. Remove Fe to obtain multi-layer topological non-continuous nano hollow gap structure cobalt-based magnetic particles

[0053] Configure 1% hydrochloric acid solution 100 ml, put the Fe / Co composite particles obtained in 4 into it, and slightly stir to corrode Fe, take out and clean after 4 min using a magnet, and dry in a freeze dryer for 24 h to obtain multi-layer topological non-continuous nano hollow gap structure cobalt-based magnetic particles.

[0054] Preparation of eight-layer topological non-continuous micro hollow gap structure cobalt-based magnetic particles

[0055] 1. Preparation of micro Fe particles as initial skeleton

[0056] Take 50 g of seven hydrated ferrous sulfate, add deionized water to configure 200 ml solution, and take 25 g of citric acid and 10 g of sodium tartrate to configure 200 ml solution, and mix with the ferrous sulfate solution under slight stirring, and place it in an ultrasonic water bath to heat to 70°C. Take 30 g of sodium hydroxide dissolved in deionized water to configure 100 ml solution, and take 30 ml of hydrazine hydrate and mix with sodium hydroxide to configure a reducing agent, and mix the reducing agent with the ferrous sulfate solution under the conditions of 800 HZ / min ultrasonic and 150 r / min stirring, start the reaction, and take out the solution after 2 hours of reaction.

[0057] 2. Primary coating of micro Fe with Co

[0058] Dissolve 15 g of seven hydrated cobalt sulfate in deionized water to configure 200 ml solution, and take 7 g of citric acid and 3.4 g of sodium tartrate to configure 100 ml solution, mix with it, heat to 70°C, then mix the solution 1 with the cobalt sulfate solution, configure 70 ml of the same hydrazine hydrate reducing agent, and add it under the conditions of 800 HZ / min ultrasonic and 150 r / min stirring for 30 min to wait for Co to deposit on the surface of the Fe particles to form a shell.

[0059] 3. Secondary deposition of Fe on the particles

[0060] 5g of ferrous sulfate heptahydrate is configured to 100ml, the particle solution in 2 is mixed with the ferrous sulfate solution, and after being heated to 60 DEG C, 70ml of hydrazine hydrate reducing agent is configured and mixed therewith, under the condition of 800HZ / min ultrasonic and 100r / min stirring, the reaction is stopped after 10min, and the deposition of non-continuous nano Fe particles on the Co shell is formed.

[0061] 4, Co shell is coated again

[0062] 20g of cobalt sulfate heptahydrate is dissolved in deionized water to configure 200ml solution, the same trisodium citrate and potassium sodium tartrate complexing agent 100ml is mixed, and the non-continuous nano Fe particle-containing Co particle solution in 3 is mixed, and the same hydrazine hydrate reducing agent 70ml is configured, and the Co coating is carried out under the condition of 800HZ / min ultrasonic and 150r / min stirring, and the Co coating is carried out under the condition of 800HZ / min ultrasonic and 150r / min stirring.

[0063] 5, the steps 3 / 4 are repeated 8 times, and the prepared particles are washed and collected by a magnet.

[0064] 6, Fe is removed, and multi-layer topological non-continuous micrometer hollow gap structure cobalt-based magnetic particles are obtained

[0065] 400ml of 1% hydrochloric acid solution is configured, the Fe / Co composite particles obtained in 4 are placed therein, and the acid is corroded under slight stirring, 20min later, the magnet is used to take out and wash, and the drying is carried out in a freeze dryer for 24h, and multi-layer topological non-continuous micrometer hollow gap structure cobalt-based magnetic particles are obtained.

[0066] The principle of the application is:

[0067] Research shows that when the magnetic particles have a hollow inside, the wave absorption performance of the particles can be effectively improved, because electromagnetic waves can form reflection in the hollow position inside the particles, accelerating the attenuation of electromagnetic waves. However, the hollow cobalt particles are wrapped by a continuous shell layer, and the wave absorption performance of the position of the shell layer as a continuous structure is equivalent to that of a traditional solid particle, and cannot be effectively improved, which seriously restricts the improvement of the electromagnetic wave absorption performance of the particles.

[0068] The scheme is proposed in this background. In view of the limited wave absorption performance of the corrosion-resistant magnetic cobalt particles, the hollow structure can effectively improve the wave absorption performance of the cobalt particles, but the continuous shell structure restricts the performance of the particles. The hollow gap structure design and preparation of the corrosion-resistant magnetic cobalt particles are carried out by using a chemical reduction composite template method, and the hollow gap structure cobalt particles with a hollow spherical shell and a multi-layer topological non-continuous hole are obtained. Through the multi-layer topological non-continuous hollow gap structure, electromagnetic waves are reflected and absorbed in the material cavity for many times, and the microwave absorption performance of cobalt is effectively improved.

[0069] The above merely describes preferred embodiments of the present application, and is not intended to limit the present application in any form; any person skilled in the art can easily implement the present application according to the drawings and the above description; however, any person skilled in the art can make some changes, modifications and equivalent changes within the scope of the technical solutions of the present application, and the equivalent embodiments of the present application are still within the protection scope of the technical solutions of the present application.

Claims

1. A method for preparing a multilayer topological non-continuous hollow gap Co-based magnetic particle, characterized in that, The method comprises the following steps: S1, preparing initial skeleton particles: A metal salt solution with a certain concentration is prepared using deionized water, and a certain amount of complexing agent is mixed with the metal salt solution under slight stirring, heated in an ultrasonic water bath, and a reducing agent with a certain concentration is prepared, which is mixed with the salt solution under the action of ultrasonic stirring and reaction. The reaction rate is controlled by using the complexing agent, thereby effectively controlling the particle size of the initial particles; S2, coating the initial skeleton particles with Co: A Co salt solution with a certain amount is prepared using deionized water, and a certain amount of complexing agent is mixed therewith, heated to a certain temperature, and then the particles in S1 are dispersed in deionized water and mixed with the Co salt solution, and a reducing agent is added, and under the condition of ultrasonic stirring, Co is deposited on the surface of the metal skeleton to form a first layer of spherical shell; S3, re-deposition of the skeleton on the particles in S2: A metal salt solution with a certain concentration is mixed with a complexing agent, heated, mixed with a reducing agent, and reacted under ultrasonic stirring. The reaction rate is controlled by the complexing agent and the reducing agent to form a non-continuous nano-metal phase on the particles in S2. Specifically, 5g of ferrous sulfate heptahydrate is prepared into 100ml, the particle solution in S2 is mixed with the ferrous sulfate solution, heated to 60℃, and then 70ml of hydrazine hydrate reducing agent is mixed therewith, and under the condition of 800HZ / min ultrasonic stirring and 100r / min stirring, the reaction is stopped after 10min to form a non-continuous nano-Fe particle deposition on the Co shell S4, re-coating with Co: A Co salt solution with a certain concentration is prepared, a certain concentration of complexing agent is added and mixed, and then the particles containing non-continuous nano-phase in S3 are dispersed with deionized water, and the two are uniformly mixed, and a reducing agent is added. By controlling the reaction rate, the non-continuous nano-phase in S3 is re-coated with Co; S5, multi-layer Co-coated layer of nano-skeleton particles: Repeat steps S3 and S4 to prepare a multi-layer continuous Co-coated layer of nano-skeleton particles according to design requirements; S6, removing the skeleton metal to obtain a hollow gap structure Co particle: A certain concentration of acid solution is prepared, the particles obtained in S5 are placed therein, and the skeleton metal is corroded away by slow stirring to obtain a multi-layer topological non-continuous hollow gap structure cobalt-based magnetic particle.

2. A process for the preparation of a multilayer topological non-continuous Co- based magnetic hollow gap structure particle as claimed in claim 1, wherein, The multi-layer topological non-continuous hollow gap structure cobalt-based magnetic particle is a five-layer topological non-continuous nano-hollow gap structure cobalt-based magnetic particle or an eight-layer topological non-continuous micro-hollow gap structure cobalt-based magnetic particle.

3. The method for preparing multilayer topological discontinuous hollow interstitial cobalt-based magnetic particles according to claim 1, characterized in that, S1, preparation of initial skeleton particles, specifically: take 15g of ferrous sulfate heptahydrate, add deionized water to prepare a 200ml solution, and take 7g of trisodium citrate and 3.4g of potassium sodium tartrate to prepare a 100ml solution, mix with the ferrous sulfate solution, place in an ultrasonic water bath and heat to 70℃, and take 14g of sodium hydroxide dissolved in deionized water to prepare a 50ml solution, take 20ml of hydrazine hydrate and mix with sodium hydroxide to prepare a reducing agent, mix the reducing agent with the ferrous sulfate solution under the conditions of 800HZ / min ultrasonic and 150r / min stirring, start the reaction, and take out the solution after 30min of reaction.

4. The method for preparing multilayer topological discontinuous hollow interstitial cobalt-based magnetic particles according to claim 1, characterized in that, S2, coating the initial skeleton particles with Co, specifically: dissolve 15g of cobalt sulfate heptahydrate in deionized water to prepare a 200ml solution, mix with 7g of trisodium citrate and 3.4g of potassium sodium tartrate to prepare a 100ml solution, heat to 70℃, then disperse the particles in S1 into deionized water and mix with the cobalt sulfate solution, prepare 70ml of the same hydrazine hydrate reducing agent and add it, wait for 30min under the conditions of 800HZ / min ultrasonic and 150r / min stirring for Co to deposit on the surface of the Fe particles to form a spherical shell.

5. The method for preparing multilayer topological discontinuous hollow interstitial cobalt-based magnetic particles according to claim 1, characterized in that, S4, coating Co again, specifically: take 20g of cobalt sulfate heptahydrate dissolved in deionized water to prepare a 200ml solution, prepare the same trisodium citrate and potassium sodium tartrate complexing agent 100ml and mix with it, then mix the Co particle solution containing non-continuous nano Fe particles in S3 with it, and prepare the same hydrazine hydrate reducing agent 70ml, coat Co under the conditions of 800HZ / min ultrasonic and 150r / min stirring, and take out after 30min.

6. The method for preparing multilayer topological discontinuous hollow interstitial cobalt-based magnetic particles according to claim 1, characterized in that, S1, preparation of initial skeleton particles, specifically: take 15g of ferrous sulfate heptahydrate, add deionized water to prepare a 200ml solution, and take 7g of trisodium citrate and 3.4g of potassium sodium tartrate to prepare a 100ml solution, mix with the ferrous sulfate solution, place in an ultrasonic water bath and heat to 70℃, and take 14g of sodium hydroxide dissolved in deionized water to prepare a 50ml solution, take 20ml of hydrazine hydrate and mix with sodium hydroxide to prepare a reducing agent, mix the reducing agent with the ferrous sulfate solution under the conditions of 800HZ / min ultrasonic and 150r / min stirring, start the reaction, and take out the solution after 30min of reaction.

7. The method for preparing multilayer topological discontinuous hollow interstitial cobalt-based magnetic particles according to claim 1, characterized in that, S5, multiple layers of metal Co coating containing nano skeleton particles, specifically: repeat step 3 / 4 4 times, and collect the prepared particles using a magnet.

8. The method for preparing multilayer topological discontinuous hollow interstitial cobalt-based magnetic particles according to claim 1, characterized in that, S5, multiple layers of metal Co coating containing nano skeleton particles, specifically: repeat step 3 / 4 8 times, and collect the prepared particles using a magnet.

9. The method for preparing multilayer topological discontinuous hollow interstitial cobalt-based magnetic particles according to claim 1, characterized in that, The S6 removes the skeleton metal to obtain the hollow gap structure Co particles, specifically: 400ml of 1% hydrochloric acid solution is configured, the Fe and Co composite particles obtained in the S4 are placed in the solution, the acid is used to corrode the Fe under slight stirring, the Fe is taken out after 20min using a magnet and is cleaned, and is dried in a freeze dryer for 24h to obtain the multi-layer topological discontinuous micrometer hollow gap structure cobalt-based magnetic particles.

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