Natural mineral-based magnetic wave-absorbing coating and preparation method thereof

Abstract

The invention discloses a natural mineral-based magnetic wave-absorbing coating and a preparation method thereof, and relates to the technical field of electromagnetic wave absorbing materials. Weighing molybdenite powder and NiO powder, and fully grinding and mixing the molybdenite powder and the NiO powder in a mortar; placing the mixture in a container, carrying out heat treatment in a tubular furnace in an argon atmosphere, and naturally cooling to room temperature after heat treatment to obtain a powder material; and mixing the powder material with a water-based paint to obtain mixed slurry, and carrying out ball milling on the mixed slurry to obtain the natural mineral-based magnetic wave-absorbing paint. Natural molybdenite is used as a raw material, NiO is used as a doping substance and is subjected to an in-situ oxidation-reduction reaction with MoS2 in a heat treatment environment, comprehensive utilization of the wave absorbing agent and natural mineral resources is fully realized, and a new thought of preparing a MoS2 / MoO2 / Ni3S2 composite material by using the natural molybdenite as the raw material and using the MoS2 / MoO2 / Ni3S2 composite material as the wave absorbing agent is developed; the preparation method has the advantages of simple process, less investment equipment and lower cost.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic wave absorbing materials, and in particular to a natural mineral-based magnetic wave absorbing coating and a preparation method thereof. Background Art

[0002] Molybdenite is a disulfide mineral of molybdenum, an important molybdenum ore resource, and often contains rhenium, which is the main mineral for extracting molybdenum and rhenium. However, most molybdenite resources are mined and refined to obtain metals or their compounds, which is costly and rarely used directly.

[0003] With the development of science and technology, the application of electromagnetic wave absorbing materials is becoming more and more extensive, and the demand is gradually increasing. Its main material is MoS2. MoS2 has a unique two-dimensional layer structure and a large specific surface area, which makes it have good application potential. However, low conductivity and a small number of polar activation sites hinder its application as an electromagnetic wave absorbing material. Although molybdenite is a molybdenum disulfide mineral, it also contains a large number of other compounds and impurities. When it is directly used in the preparation of electromagnetic absorbing materials, there are problems such as unsatisfactory absorbing performance and limited bandwidth. Therefore, it is urgent to develop a natural mineral-based magnetic absorbing coating and its preparation method to improve the absorbing performance of absorbing materials and regulate the bandwidth of absorbing materials. Summary of the invention

[0004] The purpose of the present invention is to provide a natural mineral-based magnetic absorbing coating and a preparation method thereof, so as to solve the problem that the absorbing performance is not ideal when molybdenite is directly used for the preparation of absorbing materials.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solution: a method for preparing a natural mineral-based magnetic absorbing coating, characterized in that it comprises the following steps:

[0006] S1. Weigh the molybdenite powder and NiO powder and grind and mix them thoroughly in a mortar;

[0007] S2. The mixture in step S1 is placed in a container and heat treated in a tubular furnace under an argon atmosphere. After the heat treatment, the mixture is naturally cooled to room temperature to obtain a powder material, namely, a MoS2 / MoO2 / Ni3S2 composite material.

[0008] S3. Mix the powder material with the water-based coating to obtain a mixed slurry, and ball-mill the mixed slurry to obtain a natural mineral-based magnetic absorbing coating.

[0009] A further technical solution is that the particle size of the molybdenite powder in step S1 is 100-200 mesh, the particle size of the NiO powder is 100-200 mesh, and the molar ratio of MoS2 to NiO in the molybdenite powder is 1:3.

[0010] A further technical solution is that the grinding time in step S1 is 30 - 45 min.

[0011] A further technical solution is that in step S2, the heating rate of the tube furnace is 5 °C / min, the heat treatment temperature is 900 °C, and the heat preservation time is 6 h.

[0012] A further technical solution is that in step S3, the mass ratio of the powder material to the water-based coating is 2 - 4:1, the ball milling time is 8 - 12 h, and the ball milling rate is 200 rpm / min.

[0013] The present invention also discloses a natural mineral-based magnetic wave-absorbing coating, and the wave-absorbing material is prepared according to the preparation method of the above-mentioned natural mineral-based magnetic wave-absorbing coating.

[0014] A further technical solution is that the magnetic wave-absorbing coating is used for electromagnetic wave absorption. The magnetic wave-absorbing coating is evenly coated on the surface of the target material and can be used after the surface is dried.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1. Using natural molybdenite as the raw material and NiO as the doping substance, an in-situ redox reaction occurs between NiO and MoS2 in the heat treatment environment, which fully realizes the comprehensive utilization of the wave-absorbing agent and natural mineral resources, and opens up a new idea for preparing MoS2 / MoO2 / Ni3S2 composite materials using natural molybdenite as the raw material and using them as wave-absorbing agents. This preparation method has the advantages of simple process, less investment in equipment, and low cost;

[0017] 2. By adjusting the formulation ratio of the wave-absorbing agent - water-based coating and the ball milling mixing time, the RLmin and EAB of the wave-absorbing coating are effectively improved, and the frequency corresponding to the best wave-absorbing performance is concentrated in the X band, realizing the preparation of the natural mineral-based magnetic wave-absorbing coating; the present invention has a low cost and can obtain a good wave-absorbing effect. Description of the Drawings

[0018] Figure 1 It is the SEM diagram of the wave-absorbing agent obtained in Example 1.

[0019] Figure 2 It is the XRD diagram of the wave-absorbing agent obtained in Example 1.

[0020] Figure 3 It is the wave-absorbing performance curve of the product obtained in Example 1.

[0021] Figure 4 It is the wave-absorbing performance curve of the product obtained in Comparative Example 1.

[0022] Figure 5 It is the physical diagram of the product obtained in Example 1. Detailed Embodiments

[0023] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the following further details the invention in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] Example 1

[0025] A natural mineral-based magnetic wave-absorbing coating and its preparation method are carried out according to the following steps:

[0026] (1) Weigh 10 mmol of molybdenite powder and 30 mmol of NiO powder and mix them separately and evenly in a mortar;

[0027] (2) Place the mixture obtained in step (1) in a small porcelain boat respectively;

[0028] (3) Place the small porcelain boat obtained in step (2) in a tubular furnace under Ar atmosphere for heat treatment. The heat treatment temperature is 900 °C, the heating rate is adjusted to 5 °C / min, and the holding time is 6 h;

[0029] (4) Naturally cool the furnace in step (3) to room temperature, collect and label the powder material, and label it as: MoS2 / MoO2 / Ni3S2-3.0, thus obtaining the MoS2 / MoO2 / Ni3S2 wave-absorbing agent.

[0030] (5) Mix the MoS2 / MoO2 / Ni3S2 wave-absorbing agent obtained in step (4) with the water-based coating in a certain proportion (wave-absorbing agent: water-based coating = 3:1) to obtain a mixed slurry.

[0031] (6) Ball mill the mixed slurry obtained in step (5) for a certain time (12 h; 200 rpm / min) to achieve the preparation of the natural mineral-based magnetic wave-absorbing coating.

[0032] (7) Uniformly coat the natural mineral-based magnetic wave-absorbing coating obtained in step (6) on the surface of the required material, and wait for its surface to dry to obtain a composite material with electromagnetic wave absorption performance.

[0033] The water-based coating is a water-based alkyd antirust paint, color: iron red base color, origin: Jiangxi Copper Corporation (Dexing) Building Materials Co., Ltd.

[0034] The instrument used for ball milling is a vertical planetary ball mill of Miqi Company.

[0035] The scanning electron microscope (SEM) analysis of the obtained wave-absorbing agent is as Figure 1 shown. By Figure 1It can be seen that phase hybridization occurred in the MoS2 / MoO2 / Ni3S2-3.0 absorbent, and the surface of the matrix was gradually wrapped by the hybridized substances. This indicates that a "wrapped" heterostructure was formed between the hybridized substances and the matrix material. With MoS2 as the matrix, new substances MoO2 and Ni3S2 grew, and it was initially judged that the MoS2 / MoO2 / Ni3S2-3.0 absorbent powder was prepared.

[0036] The XRD pattern of the obtained absorbent is as Figure 2 shown. From Figure 2 it can be seen that the MoS2 phase of the sample is not obvious in the figure, and MoO2, Ni3S2, and Ni (PDF#04-0850) exist as new phases, and NiO exists as a precursor phase that did not participate in the reaction. This confirms the formation of the new phases of MoO2 and Ni3S2, and it can be determined that the MoS2 / MoO2 / Ni3S2-3.0 absorbent powder has been successfully prepared.

[0037] The microwave absorption properties of the obtained MoS2 / MoO2 / Ni3S2-3.0 absorbent powder and the water-based paint mixed coating sample are as Figure 3 shown: The microwave absorption properties of the MoS2 / MoO2 / Ni3S2-3.0 absorbent powder and the water-based paint mixed coating sample are good. The minimum reflection loss in the X band reaches -35.04 dB (f is 10.38 GHz, d is 1.8 mm), and the maximum EAB (4.34 GHz, 9.29 - 13.63 GHz) is exhibited at 1.7 mm. As d changes, the EAB of this composite coating covers the entire X and Ku bands.

[0038] Control Example 1

[0039] The differences from Example 1 are carried out according to the following steps:

[0040] (1) Weigh 10 mmol of molybdenite powder and 30 mmol of NiO powder and mix them evenly in a mortar respectively;

[0041] (2) Place the mixture obtained in step (1) in a small porcelain boat respectively;

[0042] (3) Place the small porcelain boat obtained in step (2) in a tubular furnace under Ar atmosphere for heat treatment. The heat treatment temperature is 900 °C, the heating rate is adjusted to 5 °C / min, and keep the temperature for 6 h;

[0043] (4) Naturally cool the furnace in step (3) to room temperature, collect and label the sample, labeled as: MoS2 / MoO2 / Ni3S2-3.0, and thus obtain the MoS2 / MoO2 / Ni3S2 absorbent.

[0044] (5) Mix the MoS2 / MoO2 / Ni3S2 wave-absorbing agent obtained in step (4) with the water-based coating in a certain ratio (wave-absorbing agent: water-based coating = 1:1) to obtain a mixed slurry.

[0045] (6) Ball-mill the mixed slurry obtained in step (5) for a certain period of time (6 h; 200 rpm / min) to achieve the preparation of the natural mineral-based magnetic wave-absorbing coating.

[0046] (7) Uniformly apply the natural mineral-based magnetic wave-absorbing coating obtained in step (6) on the surface of the required material, and wait for its surface to dry to obtain a composite material with electromagnetic wave absorption performance.

[0047] Example 2

[0048] A natural mineral-based magnetic wave-absorbing coating and its preparation method are carried out according to the following steps:

[0049] (1) Weigh 10 mmol of molybdenite powder and 30 mmol of NiO powder and mix them evenly in a mortar respectively;

[0050] (2) Place the mixtures obtained in step (1) in small porcelain boats respectively;

[0051] (3) Place the small porcelain boats obtained in step (2) in a tubular furnace under an Ar atmosphere for heat treatment. The heat treatment temperature is 900 °C, the heating rate is adjusted to 5 °C / min, and the holding time is 6 h;

[0052] (4) Naturally cool the furnace in step (3) to room temperature, collect and label the samples, labeled as: MoS2 / MoO2 / Ni3S2-3.0, to obtain the MoS2 / MoO2 / Ni3S2 wave-absorbing agent.

[0053] (5) Mix the MoS2 / MoO2 / Ni3S2 wave-absorbing agent obtained in step (4) with the water-based coating in a certain ratio (wave-absorbing agent: water-based coating = 2:1) to obtain a mixed slurry.

[0054] (6) Ball-mill the mixed slurry obtained in step (5) for a certain period of time (8 h; 200 rpm / min) to achieve the preparation of the natural mineral-based magnetic wave-absorbing coating.

[0055] (7) Uniformly apply the natural mineral-based magnetic wave-absorbing coating obtained in step (6) on the surface of the required material, and wait for its surface to dry to obtain a composite material with electromagnetic wave absorption performance.

[0056] Example 3

[0057] A natural mineral-based magnetic wave-absorbing coating and its preparation method are carried out according to the following steps:

[0058] (1) Weigh 10 mmol of molybdenite powder and 30 mmol of NiO powder, and mix them evenly in a mortar respectively;

[0059] (2) Place the mixtures obtained in step (1) into small porcelain boats respectively;

[0060] (3) Place the small porcelain boats obtained in step (2) in a tubular furnace under Ar atmosphere for heat treatment. The heat treatment temperature is 900 °C, the heating rate is adjusted to 5 °C / min, and keep the temperature for 6 h;

[0061] (4) Naturally cool the furnace in step (3) to room temperature, collect and label the samples, label as: MoS2 / MoO2 / Ni3S2-3.0, and thus obtain the MoS2 / MoO2 / Ni3S2 wave-absorbing agent.

[0062] (5) Mix the MoS2 / MoO2 / Ni3S2 wave-absorbing agent obtained in step (4) with the water-based coating in a certain proportion (wave-absorbing agent: water-based coating = 4:1) to obtain a mixed slurry.

[0063] (6) Ball mill the mixed slurry obtained in step (5) for a certain time (12 h; 200 rpm / min) to prepare the natural mineral-based magnetic wave-absorbing coating.

[0064] (7) Uniformly coat the natural mineral-based magnetic wave-absorbing coating obtained in step (6) on the surface of the required material, and wait for its surface to dry to obtain a composite material with electromagnetic wave absorption performance.

[0065] Wave Absorbing Performance

[0066] Take the wave-absorbing agent powder and the water paint mixed coating of Example 1 and Comparative Example 1 as samples, and use a vector network analyzer (VNA, Agilent N5234A, 1-18 GHz) to analyze the dielectric properties and electromagnetic properties of the materials. The specific method is as follows: Dry the mixed slurry of the wave-absorbing agent powder and the water paint into a thin sheet, and cut it into a coaxial ring with inner and outer diameters of 3.04 mm and 7.00 mm respectively, and a thickness of about 2.00 mm. Use the vector network analyzer to simulate and test the wave-absorbing performance of samples with different thicknesses. The wave-absorbing performance of the MoS2 / MoO2 / Ni3S2-3.0 wave-absorbing agent powder and the water paint mixed coating sample obtained in Example 1 is shown by Figure 3It can be seen that the MoS2 / MoO2 / Ni3S2-3.0 absorbent powder and water paint mixed coating sample has good microwave absorption performance. The minimum reflection loss in the X-band reaches -35.04 dB (f = 10.38 GHz, d = 1.8 mm), and it exhibits the maximum effective absorption bandwidth (EAB) at 1.7 mm (4.34 GHz, 9.29 - 13.63 GHz). As d changes, the EAB of this composite coating covers the entire X and Ku bands. Comparing with the microwave absorption performance of the MoS2 / MoO2 / Ni3S2-3.0 absorbent powder and water paint mixed coating sample obtained in Comparative Example 1, it can be seen from Figure 4 that the MoS2 / MoO2 / Ni3S2-3.0 absorbent powder and water paint mixed coating sample has poor microwave absorption performance. The minimum reflection loss in the X-band reaches -4.23 dB, which is an ineffective microwave absorption performance. This is due to the relatively small content of the absorbent powder, the short ball milling time, and the uneven mixing of the slurry. The coating physical map of the MoS2 / MoO2 / Ni3S2-3.0 absorbent powder and water paint mixed coating sample obtained in Example 1 is shown in Figure 5 It can be seen that the coating is bright red in color, has strong slurry fluidity, can be evenly coated on the surface of the material, and can be used as an absorbing coating in the field of microwave absorption.

[0067] Although the present invention has been described herein with reference to various illustrative embodiments of the invention, it should be understood that those skilled in the art can design many other modifications and embodiments that will fall within the scope of the disclosure of this application.

Claims

1. A method for preparing a natural mineral-based magnetic absorbing coating, characterized in that The steps include: S1. Weigh the molybdenite powder and NiO powder and grind and mix them thoroughly in a mortar; S2. placing the mixture in step S1 in a container, and heat treating it in a tube furnace under an argon atmosphere, and naturally cooling it to room temperature after the heat treatment to obtain a powder material; S3. Mix the powder material with the water-based coating to obtain a mixed slurry, and ball-mill the mixed slurry to obtain a natural mineral-based magnetic absorbing coating.

2. The method for preparing a natural mineral-based magnetic absorbing coating according to claim 1, characterized in that: step The particle size of the molybdenite powder in S1 is 100-200 mesh, the particle size of the NiO powder is 100-200 mesh, and the molar ratio of MoS2 to NiO in the molybdenite powder is 1:

3.

3. The method for preparing a natural mineral-based magnetic absorbing coating according to claim 1, characterized in that: step The grinding time in S1 is 30 to 45 minutes.

4. The method for preparing a natural mineral-based magnetic absorbing coating according to claim 1, characterized in that: The heating rate of the tubular furnace in step S2 is 5°C / min, the heat treatment temperature is 900°C, and the holding time is 6h.

5. The method for preparing a natural mineral-based magnetic absorbing coating according to claim 1, characterized in that: In step S3, the mass ratio of the powder material to the water-based coating is 2-4:1, the ball milling time is 8-12 hours, and the ball milling rate is 200 rpm / min.

6. A natural mineral-based magnetic absorbing coating, characterized in that: The absorbing material is prepared according to the preparation method of the natural mineral-based magnetic absorbing coating according to any one of claims 1 to 5.

7. The natural mineral-based magnetic absorbing paint according to claim 6, characterized in that: The magnetic wave-absorbing paint is used for electromagnetic wave absorption. The magnetic wave-absorbing paint is evenly coated on the surface of the target material and waits for the surface to dry.

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