Wave-absorbing film and preparation method and application thereof

Abstract

The invention relates to the technical field of semiconductor materials, and discloses a wave-absorbing film and a preparation method and application thereof. A porous structure is arranged on the wave-absorbing film, the porous structure is a periodic array structure, and the wave-absorbing film comprises a ferromagnetic material and a silicon material. The preparation method is simple and efficient, and the wave-absorbing film is prepared by firstly preparing the square film and pressing holes in the square film. The preparation process of the wave-absorbing film is simple, the effective bandwidth of the prepared wave-absorbing film is widened, and the wave-absorbing performance, adjustability, flexibility and stretchability are good.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor materials, and particularly relates to a microwave absorption thin film, a preparation method thereof, and an application thereof. Background Art

[0002] In modern information society, more and more electromagnetic pollution interferes with electronic devices and wireless communications, resulting in signal attenuation, distortion, and even interruption, affecting the performance of devices and the quality of communications. Electromagnetic pollution also interferes with the human nervous system, cardiovascular system, and reproductive system, posing potential risks to human health. Microwave absorption materials achieve absorption by converting electromagnetic wave energy into heat energy or other forms of energy, so as to avoid being detected, polluted, or interfered by the reflected wave of electromagnetic waves. Therefore, microwave absorption materials play an important role in military and civilian fields such as electromagnetic shielding, antennas, and stealth technologies. The increasingly complex electromagnetic environment and diverse microwave emission sources require microwave absorption materials to be applicable in a wider frequency band and achieve greater absorption. In summary, how to broaden the absorption bandwidth has become a research hotspot of microwave absorption materials at present.

[0003] Traditional microwave absorption materials often have limited wave absorption ability and are usually applicable to specific frequencies or limited wavelength ranges, restricting their applications in broadband environments. Metamaterials are a new type of microwave absorption materials composed of sub-wavelength-sized structural units, and can achieve efficient absorption of electromagnetic waves by designing the shape, size, structure, arrangement of geometric units, or changing the composition of materials. However, metamaterial absorbers are usually prepared by expensive, time-consuming, and complex micro-nano processing, such as electron beam lithography and nanoimprinting. In addition, both traditional microwave absorption materials and metamaterial absorbers have certain limitations in terms of tunability. Once manufactured, the absorption characteristics are difficult to adjust, which to a certain extent hinders their adaptability to environmental changes and application requirements. Summary of the Invention

[0004] In order to at least overcome one of the problems existing in the above prior art, one of the purposes of the present invention is to provide a microwave absorption thin film. Another purpose of the present invention is to provide a preparation method of the microwave absorption thin film. A third purpose of the present invention is to provide an application of the microwave absorption thin film. The microwave absorption thin film of the present invention is composed of ferromagnetic materials and silicon materials, and a microwave absorption thin film with a porous periodic array structure is prepared. The preparation process is simple, and the prepared microwave absorption thin film exhibits good wave absorption performance, tunability, flexibility, and stretchability.

[0005] For this reason, the present invention adopts the following technical solutions:

[0006] The first aspect of the present invention provides a microwave absorption thin film, wherein the microwave absorption thin film is provided with a porous structure; the porous structure is a periodic array structure; the composition of the microwave absorption thin film includes ferromagnetic materials and silicon materials.

[0007] Preferably, the microwave absorbing thin film is a square thin film with a length of 16 - 24 cm and a width of 16 - 24 cm. More preferably, the microwave absorbing thin film is a square thin film with a length of 16 - 20 cm and a width of 16 - 20 cm. Even more preferably, the microwave absorbing thin film is a square thin film with a length of 18 cm and a width of 18 cm.

[0008] Preferably, the thickness of the microwave absorbing thin film is 2 - 3 mm. More preferably, the thickness of the microwave absorbing thin film is 2 - 2.5 mm. Even more preferably, the thickness of the microwave absorbing thin film is 2 mm.

[0009] Preferably, the periodic array structure is located at the center of the microwave absorbing thin film, with a length of 8 - 12 cm and a width of 8 - 12 cm. More preferably, the periodic array structure is located at the center of the microwave absorbing thin film, with a length of 8 - 10 cm and a width of 8 - 10 cm. Even more preferably, the periodic array structure is located at the center of the microwave absorbing thin film, with a length of 9 cm and a width of 9 cm.

[0010] Preferably, the periodic array structure is one of a circular hole array, a square hole array, a triangular hole array, and a trapezoidal hole array. More preferably, the periodic array structure is one of a circular hole array, a square hole array, and a trapezoidal hole array. Even more preferably, the periodic array structure is one of a circular hole array and a square hole array.

[0011] Preferably, the holes of the circular hole array are circular holes with a diameter of 3 - 5 mm. More preferably, the holes of the circular hole array are circular holes with a diameter of 3 - 4 mm. Even more preferably, the holes of the circular hole array are circular holes with a diameter of 3.5 - 4 mm.

[0012] Preferably, the adjacent hole spacing of the circular holes is 7 - 11 mm. More preferably, the adjacent hole spacing of the circular holes is 7 - 10 mm. Even more preferably, the adjacent hole spacing of the circular holes is 8 - 10 mm.

[0013] Preferably, the holes of the square hole array are square holes with a length of 3 - 5 mm and a width of 3 - 5 mm. More preferably, the holes of the square hole array are square holes with a length of 3 - 4 mm and a width of 3 - 4 mm. Even more preferably, the holes of the square hole array are square holes with a length of 3 - 3.5 mm and a width of 3 - 3.5 mm.

[0014] Preferably, the adjacent hole spacing of the square holes is 7-11 mm. More preferably, the adjacent hole spacing of the square holes is 7-10 mm. Even more preferably, the adjacent hole spacing of the square holes is 8-9 mm.

[0015] Preferably, the holes in the triangular hole array are triangular holes, with side a having a length of 3-5 mm, side b having a length of 3-5 mm, side c having a length of 3-5 mm, and the side lengths of the triangle being equal. More preferably, the holes in the triangular hole array are triangular holes, with side a having a length of 3-4 mm, side b having a length of 3-4 mm, side c having a length of 3-4 mm, and the side lengths of the triangle being equal. Even more preferably, the holes in the triangular hole array are triangular holes, with side a having a length of 3-3.5 mm, side b having a length of 3-3.5 mm, side c having a length of 3-3.5 mm, and the side lengths of the triangle being equal.

[0016] Preferably, the adjacent hole spacing of the triangular holes is 7-11 mm. More preferably, the adjacent hole spacing of the triangular holes is 7-9 mm. Even more preferably, the adjacent hole spacing of the triangular holes is 7-8 mm.

[0017] Preferably, the holes in the trapezoidal hole array are trapezoidal holes, with the upper base being 2-4 mm, the lower base being 4-6 mm, and the height being 3-5 mm. More preferably, the holes in the trapezoidal hole array are trapezoidal holes, with the upper base being 2-3 mm, the lower base being 4-5 mm, and the height being 3-4 mm. Even more preferably, the holes in the trapezoidal hole array are trapezoidal holes, with the upper base being 2-2.5 mm, the lower base being 4-4.5 mm, and the height being 3-3.5 mm.

[0018] Preferably, the adjacent hole spacing of the trapezoidal holes is 7-11 mm. More preferably, the adjacent hole spacing of the trapezoidal holes is 7-9 mm. Even more preferably, the adjacent hole spacing of the trapezoidal holes is 8-9 mm.

[0019] Preferably, the ferromagnetic material is an organic ferromagnetic material. More preferably, the ferromagnetic material is an organic ferromagnetic material containing carboxyl groups. Even more preferably, the ferromagnetic material is carboxyl iron powder.

[0020] Preferably, the silicon material is an organosilicon material. More preferably, the silicon material is an organosilicon material containing -Si-O- groups. Even more preferably, the silicon material is silicone rubber.

[0021] Preferably, in the composition of the wave-absorbing thin film, the weight ratio of the ferromagnetic material to the silicon material is (16 - 22):(1 - 3). Further preferably, in the composition of the wave-absorbing thin film, the weight ratio of the ferromagnetic material to the silicon material is (16 - 20):(1 - 2.5). Even more preferably, in the composition of the wave-absorbing thin film, the weight ratio of the ferromagnetic material to the silicon material is (16 - 17):(1 - 2).

[0022] The second aspect of the present invention provides a method for preparing the wave-absorbing thin film according to the first aspect of the present invention, which is characterized by including the following steps:

[0023] (1) Mix the ferromagnetic material and the silicon material, form a film, and dry it to obtain a square thin film;

[0024] (2) Punch holes in the square thin film to obtain the wave-absorbing thin film.

[0025] Preferably, in step (1), the film forming is carried out by the casting method.

[0026] Preferably, in step (1), the drying temperature is 130 - 160 °C. Further preferably, in step (1), the drying temperature is 140 - 160 °C. Even more preferably, in step (1), the drying temperature is 140 - 150 °C.

[0027] Preferably, in step (1), the drying time is 30 - 50 min. Further preferably, in step (1), the drying time is 30 - 40 min. Even more preferably, in step (1), the drying time is 30 - 35 min.

[0028] The third aspect of the present invention provides the application of the wave-absorbing thin film according to the first aspect of the present invention or the wave-absorbing thin film prepared by the method for preparing the wave-absorbing thin film according to the second aspect of the present invention in the field of composite materials.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] (1) The wave-absorbing thin film of the present invention has excellent absorption performance, and is effectively absorbed (greater than 10 dB) in the range of 1 - 18 GHz, and the maximum absorption reaches 53 dB.

[0031] (2) The wave-absorbing thin film of the present invention has magnetic field tunability. Increasing the magnetic field shifts the frequency of the maximum absorption from 3.36 GHz to 15.18 GHz, and the maximum absorption value increases from 53 dB to 65 dB, and the effective bandwidth is broadened.

[0032] (3) The manufacturing process of the present invention is simple, and it has the conditions for industrial production, and the application prospect is very broad. Description of the Drawings

[0033] The present invention will be further described below in conjunction with the accompanying drawings and embodiments, where:

[0034] Figure 1 It is a schematic plan view of the wave-absorbing thin film prepared in Example 1.

[0035] Figure 2 It is a schematic three-dimensional view of the wave-absorbing thin film prepared in Example 1. Specific embodiments

[0036] The content of the present invention will be further described in detail below through specific embodiments, but it is not limited to all the descriptions and data.

[0037] Among the raw materials, the silicone rubber is the silicone rubber of model CMT305AB from Shenzhen Dazhou Material Technology Co., Ltd.

[0038] It should be particularly emphasized that, unless otherwise specified, the raw materials, reagents or devices in the present invention can be obtained from conventional commercial channels unless otherwise specified.

[0039] Example 1:

[0040] A wave-absorbing thin film is provided with a hole-like structure, and the hole-like structure is a periodic array structure. Among them, the raw material composition of the wave-absorbing thin film is a ferromagnetic material and a silicon material.

[0041] A method for preparing a wave-absorbing thin film includes the following steps:

[0042] (1) Prepare a square thin film

[0043] A mixture of carbonyl iron powder and silicone rubber with a weight ratio of 17:2 is mixed in a planetary gravity vacuum mixer at 1 Kpa and a rotation speed of 650 r / min for 40 s to obtain a precursor for preparing a wave-absorbing thin film. On the basis of the precursor, a wet film with a thickness of 2.15 mm is obtained by the casting method, and the wet film is placed in an oven at 150 °C for 30 min to cure to obtain a square thin film with a thickness of 2 mm.

[0044] (2) Prepare a wave-absorbing thin film

[0045] A periodic circular hole array with a diameter of 3.5 mm and an adjacent hole spacing of 8 mm is pressed in a 9 cm × 9 cm square area in the center of the square thin film using a hollow mold to obtain a 18 cm × 18 cm wave-absorbing thin film.

[0046] Example 2:

[0047] A method for preparing a wave-absorbing thin film, the step (1) is the same as the step (1) of Example 1, the difference is that in the preparation method of Example 2, the step (2) is as follows:

[0048] (2) Preparation of microwave-absorbing thin film

[0049] Use a hollow mold to press a periodic square hole array with a side length of 3 mm and an adjacent hole spacing of 8 mm in a 9 cm×9 cm square area at the center of the square thin film, and obtain a 18 cm×18 cm microwave-absorbing thin film.

[0050] Example 3:

[0051] A preparation method of a microwave-absorbing thin film, the step (1) is the same as the step (1) of Example 1, the difference is that in the preparation method of Example 3, the step (2) is as follows:

[0052] (2) Preparation of microwave-absorbing thin film

[0053] Use a hollow mold to press a periodic equilateral triangle hole array with a side length of 3 mm and an adjacent hole spacing of 8 mm in a 9 cm×9 cm square area at the center of the square thin film, and obtain a 18 cm×18 cm microwave-absorbing thin film.

[0054] Example 4:

[0055] A preparation method of a microwave-absorbing thin film, the step (1) is the same as the step (1) of Example 1, the difference is that in the preparation method of Example 4, the step (2) is as follows:

[0056] (2) Preparation of microwave-absorbing thin film

[0057] Use a hollow mold to press a periodic trapezoidal hole array with an upper base of 2 mm, a lower base of 4 mm, a height of 3 mm and an adjacent hole spacing of 8 mm in a 9 cm×9 cm square area at the center of the square thin film, and obtain a 18 cm×18 cm microwave-absorbing thin film.

[0058] Material property test:

[0059] The performance tests of the microwave-absorbing thin film are as follows:

[0060] (1) Reflection loss test: Use the GJB 2038-94 bow method to test the reflection loss of the microwave-absorbing thin films of Examples 1 to 4 in the range of 1-18 GHz.

[0061] (2) Magnetic field tunability test: Use a Lake Shore 642 electromagnet as the power supply of the magnetic field generating device, place the sample in the Helmholtz coil, fix the incident wave frequency and scan the magnetic field strength (0-2500 Oe), fix the magnetic field strength and scan the frequency (1-18 GHz), and test the influence of the magnetic field strength on the absorption performance of the microwave-absorbing thin film of Example 1.

[0062] (3) Flexural modulus: Perform a flexural test using ASTM D790.

[0063] (4) Elongation at break: Tensile testing is carried out using a universal testing machine.

[0064] The reflection loss data are shown in Table 1 below.

[0065] Table 1 Reflection loss data of the microwave absorption films of Examples 1 - 4 (unit: dB)

[0066] Frequency band Example 1 Example 2 Example 3 Example 4 2 - 4 GHz -53 -50 -45 -49 8 - 12 GHz -47 -45 -40 -44 15 - 18 GHz -32 -30 -25 -29

[0067] In the test of the magnetic field tunability of the microwave absorption film of Example 1, when the magnetic field increased from 500 Oe to 2500 Oe, the maximum absorption peak moved from 3.36 GHz to 15.18 GHz, the maximum absorption value increased from 53 dB to 65 dB, and the effective bandwidth was broadened.

[0068] It is obtained through experiments that the flexural modulus of the microwave absorption film of Example 1 ≤ 1 MPa, and the elongation at break ≥ 200%. It can be seen that the microwave absorption film of the present invention performs well in terms of flexibility and stretchability.

[0069] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications within the scope of the technical solution of the present invention by using the technical content prompted above as equivalent embodiments of equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A microwave absorbing film, characterized in that: The absorbing film is provided with a hole structure; The pore structure is a periodic array structure; The wave-absorbing film comprises ferromagnetic material and silicon material.

2. The absorbing film according to claim 1, characterized in that: The wave-absorbing film is a square film with a length of 16 to 24 cm and a width of 16 to 24 cm.

3. The absorbing film according to claim 1, characterized in that: The thickness of the wave-absorbing film is 2 to 3 mm.

4. The absorbing film according to claim 1, characterized in that: The periodic array structure is located at the center of the wave-absorbing film, and has a length of 8 to 12 cm and a width of 8 to 12 cm.

5. The absorbing film according to claim 1, characterized in that: The periodic array structure is one of a circular hole array, a square hole array, a triangle hole array, and a trapezoidal hole array.

6. The absorbing film according to claim 5, characterized in that: The holes of the circular hole array are circular holes with a diameter of 3 to 5 mm and a distance between adjacent holes of 7 to 11 mm; And / or, the holes of the square hole array are square holes, which are 3 to 5 mm in length, 3 to 5 mm in width, and the distance between adjacent holes is 7 to 11 mm; And / or, the holes of the triangular hole array are triangular holes, the length of side a is 3 to 5 mm, the length of side b is 3 to 5 mm, the length of side c is 3 to 5 mm, the sides of the triangle are equal, and the distance between adjacent holes is 7 to 11 mm; And / or, the holes of the trapezoidal hole array are trapezoidal holes, with an upper base of 2 to 4 mm, a lower base of 4 to 6 mm, a height of 3 to 5 mm, and a distance between adjacent holes of 7 to 11 mm.

7. The absorbing film according to claim 1, characterized in that: The ferromagnetic material is an organic ferromagnetic material; And / or, the silicon material is an organic silicon material.

8. The absorbing film according to claim 1, characterized in that: In the composition of the wave-absorbing film, the weight ratio of the ferromagnetic material to the silicon material is (16-22):(1-3).

9. The method for preparing the microwave absorbing film according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) Mixing ferromagnetic material and silicon material, forming a film, and drying to obtain a square film; (2) Punch holes in a square film to produce a microwave-absorbing film.

10. Use of the absorbing film according to any one of claims 1 to 8 or the absorbing film prepared by the method for preparing the absorbing film according to claim 9 in the semiconductor field.

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