Temperature-resistant resin-based radar wave-absorbing coating and design method and application thereof

Abstract

The invention belongs to the technical field of stealth materials, and particularly discloses a temperature-resistant resin-based radar wave-absorbing coating and a design method and application thereof, and the design method comprises the following steps: 1) constructing a formula database according to component data of a wave-absorbing material; 2) screening components of the wave-absorbing coating in the wave-absorbing material database according to service index requirements; 3) designing an orthogonal test, and determining the optimal ratio of the wave-absorbing coating to obtain a formula; 4) acquiring thermal expansion data of the base material to be coated; 5) preparing the wave-absorbing coating according to the formula, and judging whether the thermal expansion coefficient needs to be adjusted so as to determine the structure of the wave-absorbing coating; and (6) finally, through performance testing, whether the designed wave-absorbing coating structure and formula meet service index requirements or not is determined. The optimal proportion is determined through scientific material selection and orthogonal test design, the test amount is greatly reduced, the efficiency is improved, the coating can be well matched with the base material, the requirements for wave absorption and high temperature resistance are completely met, and the coating can be used in multiple fields.

Description

Technical Field

[0001] This invention belongs to the field of stealth materials technology, specifically relating to a heat-resistant resin-based radar absorbing coating, its design method, and its application. Background Art

[0002] With the rapid development of communication, electronic equipment, and aerospace technology, electromagnetic pollution is becoming increasingly severe. Today, communication technologies are constantly upgrading, electronic devices are becoming more widespread and their performance is continuously improving, and aerospace activities are becoming more frequent. All of these factors contribute to the increasingly complex distribution of electromagnetic waves in the environment, causing serious pollution. Under these circumstances, the research on strong absorbing coatings has become extremely crucial.

[0003] Against this backdrop, the development of strong radar-absorbing coatings is particularly crucial, especially in the aerospace field. With the continuous development of this field, the value of stealth technology is becoming increasingly prominent, and radar-absorbing coatings, as a key element, are of great significance in reducing the probability of targets being detected by radar. Currently, with the continuous increase in aircraft speed, the problem of heat accumulation during flight is becoming increasingly serious. High-temperature areas such as engine exhaust nozzles place higher demands on the dual performance of radar-absorbing coatings, requiring both high-temperature resistance and radar absorption capabilities.

[0004] However, based on the current state of research in China, most existing microwave absorbing coatings are designed for room temperature conditions. Although these coatings possess a certain microwave absorption capacity at room temperature, they often struggle to maintain both good absorption performance and stable physicochemical properties under high-temperature conditions. In other words, they lack high-temperature resistance. This limitation significantly restricts the application of microwave absorbing coatings in high-temperature components and related applications in aerospace.

[0005] Based on the above, and according to the properties of the absorber and the matrix, the design and research of high-temperature absorbing coatings for different temperature ranges, aiming to make the absorbing coatings possess both absorbing and high-temperature resistance properties, has become one of the key directions in my country's radar absorbing material research field. However, at present, the design of high-temperature absorbing coatings mainly relies on a large number of experiments to explore suitable coating formulations. This approach has the following drawbacks:

[0006] First, there is a lack of effective data integration mechanisms. When selecting the material composition for microwave absorbing coatings, the process is often done blindly, without a systematic database or data integration method to provide a scientific basis for material selection, making it extremely difficult to screen suitable components from a large number of materials.

[0007] Secondly, there is a lack of scientific experimental design methods for determining the composition ratio of the microwave absorbing coating. The only option is to conduct numerous experiments, which not only results in a huge workload and a long testing period, but also leads to a significant waste of raw materials, severely impacting research and development efficiency.

[0008] Furthermore, insufficient consideration has been given to the compatibility between the absorbing coating and the substrate. In practical applications, differences in factors such as the coefficient of thermal expansion between the coating and the substrate may lead to damage to the coating, thereby affecting the performance and service life of the absorbing coating.

[0009] In view of this, this invention is hereby proposed. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-temperature resistant resin-based radar absorbing coating, its design method, and its application. This invention primarily addresses a series of problems faced by existing technologies in the design of high-temperature absorbing coatings. Specifically, it includes how to use a more scientific and reasonable design method to reduce experimental workload, shorten the R&D cycle, and reduce material waste, while ensuring that the designed absorbing coating possesses excellent absorption performance and good high-temperature resistance in different temperature ranges (especially high-temperature ranges), and can achieve good compatibility with the substrate, thus guaranteeing the stability and longevity of the absorbing coating in practical applications.

[0011] The objective of this invention is achieved through the following technical solution:

[0012] In a first aspect, the present invention provides a design method for a heat-resistant resin-based radar absorbing coating, comprising the following steps:

[0013] S1. Obtain the composition data of multiple sets of microwave absorbing materials to construct a microwave absorbing material database;

[0014] S2. Based on the service performance requirements, the composition of the absorbing coating is initially screened in the absorbing material database constructed in S1.

[0015] S3. Based on the components of the microwave absorbing coating initially screened in S2, design an orthogonal experiment to determine the ratio of the microwave absorbing coating and obtain the formula of the microwave absorbing coating.

[0016] S4. Obtain data of the substrate to be coated, wherein the substrate data includes the coefficient of thermal expansion of the substrate.

[0017] S5. Based on the thermal expansion coefficient of the substrate described in S4, determine whether the thermal expansion coefficient of the absorbing coating prepared from the formulation of the absorbing coating described in S3 needs to be adjusted. If adjustment is required, add the fiber mesh to the absorbing coating and cure it to form a heat-resistant resin-based radar absorbing coating. If adjustment is not required, the heat-resistant resin-based radar absorbing coating is directly formed after curing.

[0018] S6. Test the performance of the heat-resistant resin-based radar absorbing coating formed in S5, and determine whether the heat-resistant resin-based radar absorbing coating meets the performance requirements; if yes, then end; if no, then proceed to S2.

[0019] Furthermore, the components of each group of absorbing materials in S1 include an absorber and a resin binder, and the component data includes the electromagnetic parameters of the absorber and the maximum operating temperature of the resin binder.

[0020] Furthermore, the specific process for determining the formulation of the microwave absorbing coating in step S3 is as follows:

[0021] S31. Design multiple groups of absorbents and multiple groups of resin binders with gradually increasing content;

[0022] S32. Conduct cross-tests between any one group of absorbents and each group of resin binders in the multiple groups of absorbents.

[0023] S33. Test the performance of each group of cross-test results;

[0024] S34. Based on the test results, determine the ratio of absorber to resin binder in the microwave absorbing coating.

[0025] Furthermore, the substrate in S4 includes aluminum alloy, magnesium alloy or titanium alloy.

[0026] Furthermore, the process of adding the fiber mesh between the absorbing coatings in step S5 to form a heat-resistant resin-based radar absorbing coating is as follows:

[0027] S51. Weigh the absorber and resin binder according to the ratio of the microwave absorbing coating determined in step S3.

[0028] S52. Add the weighed absorbent and resin binder to the solvent, stir evenly, and prepare the microwave absorbing slurry.

[0029] S53. The microwave absorbing slurry is coated onto the surface of the substrate by air spraying or brushing to form a microwave absorbing coating, and fiber mesh is added to the microwave absorbing coating.

[0030] S54. The prepared radar-absorbing coating is placed in a heat treatment furnace and cured to form a heat-resistant resin-based radar-absorbing coating.

[0031] Furthermore, in S53, fiber mesh is added at 1 / 3 and 2 / 3 of the thickness of the microwave absorbing coating, respectively.

[0032] Furthermore, the parameters for the curing process in S54 are set as follows: temperature is 220℃~270℃, and time is 30min~100min.

[0033] Furthermore, the performance testing of the temperature-resistant resin-based radar absorbing coating in S6 includes appearance testing, thickness testing, adhesion testing, reflectivity testing, areal density testing, and temperature resistance testing.

[0034] Secondly, the present invention provides a heat-resistant resin-based radar absorbing coating, which is obtained by the above-described design method.

[0035] Thirdly, the present invention provides an application of the above-mentioned heat-resistant resin-based radar absorbing coating, which is used in the fields of communications, electronics, aerospace, surface protection of military equipment, and stealth protection of radar facilities.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The microwave absorbing coating design method provided by this invention, in terms of material selection and formulation, involves preliminary screening of components through a constructed microwave absorbing material database, and determining the optimal ratio of absorber to resin binder within a small number of experiments using orthogonal experiments, thereby reducing the number of experiments, shortening the experimental cycle, and improving R&D efficiency. Regarding compatibility and structure, the thermal expansion coefficient of the substrate is considered to ensure compatibility; if necessary, fiber mesh is added to the microwave absorbing coating and cured to optimize the structure, enhance stability, and extend lifespan. In terms of performance and application, comprehensive performance testing ensures coating quality, and the coating can be widely used in fields such as communications, electronics, aerospace, military equipment, and radar facilities, meeting the requirements for microwave absorption and high-temperature resistance. Attached Figure Description

[0038] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a flowchart of the design method for the heat-resistant resin-based radar absorbing coating of the present invention;

[0041] Figure 2 This is a schematic diagram of the electromagnetic parameters of the absorber in the microwave absorbing material of the present invention;

[0042] Figure 3 This is a schematic diagram of a structure of the heat-resistant resin-based radar absorbing coating of the present invention;

[0043] Figure 4 This is another structural schematic diagram of the heat-resistant resin-based radar absorbing coating of the present invention.

[0044] in:

[0045] 1 is the substrate; 2 is the microwave absorbing coating; 3 is the fiber mesh. DETAILED DESCRIPTION

[0046] Exemplary embodiments will now be described in detail. The embodiments described below are not representative of all embodiments consistent with this invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.

[0047] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0048] like Figure 1 As shown in the figure, the design method of a heat-resistant resin-based radar absorbing coating provided by the present invention specifically includes the following steps:

[0049] 1) Obtain composition data of multiple sets of microwave absorbing materials to construct a microwave absorbing material database.

[0050] In this process, it is necessary to clarify that the main components of each group of absorbing materials are absorbers and resin binders. The related component data covers two key indicators: the electromagnetic parameters of the absorber and the maximum operating temperature of the resin binder. Furthermore, this invention does not specifically limit the methods for obtaining this data. For example, historical records of the electromagnetic parameters of the absorber and the operating temperature of the resin binder used in previous absorbing coating preparation experiments can be systematically reviewed and summarized to obtain a large amount of data on absorbing materials. Various information channels can also be utilized, such as consulting domestic and international literature in related fields or browsing professional online information platforms, to extract and organize data on multiple groups of absorbing materials. This provides rich and accurate data support for building an absorbing material database. This diversified data acquisition method ensures the comprehensiveness and reliability of the database content, laying a solid foundation for subsequent absorbing coating design work.

[0051] Specifically, this invention collected the electromagnetic parameters of four absorbers and the operating temperatures of four resin binders to establish a microwave absorbing material database. The electromagnetic parameters of the four absorbers are as follows: Figure 2 As shown in Table 1 below, the maximum service temperatures of the four resin adhesives are as follows:

[0052] Table 1-4 Operating Temperatures of Resin Adhesives

[0053]

[0054] 2) Based on the service performance requirements, the components of the absorbing coating are initially screened in the absorbing material database constructed in step 1).

[0055] The service performance requirements of this invention are as follows: the operating temperature is required to be around 450°C, and the radar reflectivity in the 8-18 GHz frequency band is ≤-6.5 dB. Based on these service performance requirements, the components of the absorbing coating are initially screened in the constructed absorbing material database, including absorber A and resin binder a.

[0056] 3) Based on the components of the microwave absorbing coating initially screened in step 2), design an orthogonal experiment to determine the optimal ratio of the microwave absorbing coating and obtain the formulation of the microwave absorbing coating.

[0057] The specific process for this step is as follows:

[0058] 3.1) Design multiple groups of absorbents and multiple groups of resin binders with gradually increasing content. The composition of the absorbents is shown in Table 2 below, and the composition of the resin binders is shown in Table 3 below:

[0059] Table 2 Composition ratio of absorbent

[0060]

[0061] Table 3 Composition ratio of resin adhesive

[0062]

[0063] 3.2) Cross-tests were conducted according to the component ratios designed in Tables 2 and 3, resulting in a total of 9 test schemes, as shown in Table 4 below:

[0064] Table 4-9 Experimental Design

[0065]

[0066]

[0067] 3.3) After conducting 9 sets of cross-tests, the coating adhesion and reflectivity were tested. The test results are shown in Table 5 below:

[0068] Table 5. Coating performance test results under different test schemes

[0069]

[0070] 3.4) As shown in Table 5, the coating adhesion of schemes in groups 1, 2, 3, 6, 7, and 9 is less than 10 MPa. In scheme group 5, the coating reflectivity is relatively low. Therefore, only schemes in groups 4 and 8 meet the service performance requirements, with scheme group 8 showing better performance than group 4. Therefore, after comprehensive consideration, scheme group 8 is selected as the optimal ratio of absorber and resin binder components to obtain the formulation of the microwave absorbing coating.

[0071] 4) Obtain the data of the substrate to be coated, including the coefficient of thermal expansion of the substrate.

[0072] This invention allows for the acquisition of relevant data on the substrate by consulting relevant literature or web information. The substrates that can be used with the design method of this invention include metallic substrates such as aluminum alloys, magnesium alloys, and titanium alloys. It is also applicable to composite substrates such as carbon fiber reinforced composites and glass fiber reinforced composites, or ceramic substrates such as silicon nitride ceramics and alumina ceramics. In this embodiment, TA15 titanium alloy is used as the substrate. The coefficient of thermal expansion of TA15 titanium alloy is approximately (9.41~10.03)×10. -6 / ℃.

[0073] 5) Based on the coefficient of thermal expansion of the TA15 titanium alloy substrate in step 4), determine whether the coefficient of thermal expansion of the absorbing coating prepared by the formulation in step 3) needs to be adjusted. If adjustment is required, add the fiber mesh to the absorbing coating and cure it to form a heat-resistant resin-based radar absorbing coating. If adjustment is not required, the heat-resistant resin-based radar absorbing coating is directly formed after curing.

[0074] The above tests show that the coefficient of thermal expansion of the coating prepared by the eighth scheme is 100 × 10⁻¹⁰. -6 The coefficient of thermal expansion of the absorbing coating differs significantly from that of TA15 titanium alloy at ℃, thus requiring adjustment of the coefficient of thermal expansion. Without adjustment, a thermal stress mismatch will exist between the absorbing coating and the TA15 titanium alloy, causing the coating to crack or peel off due to thermal expansion, ultimately leading to the stealth failure of the absorbing coating.

[0075] The specific adjustment process is as follows:

[0076] 5.1) Based on the microwave absorbing coating formulation of the 8th group of schemes determined in step 3), weigh absorber a3 and resin binder b2;

[0077] 5.2) Add the weighed absorbent a3 and resin binder b2 to the solvent xylene, stir evenly, and prepare the microwave absorbing slurry;

[0078] 5.3) The microwave absorbing slurry is coated onto the surface of a TA15 titanium alloy substrate using an air spraying method to form a microwave absorbing coating. Fiber mesh is then added at 1 / 3 and 2 / 3 of the coating's thickness. Figure 3 As shown;

[0079] 5.4) The prepared radar-absorbing coating is placed in a heat treatment furnace and kept at 220℃~270℃ for 30min~100min to cure and form a heat-resistant resin-based radar-absorbing coating.

[0080] It should be noted that if the coefficient of thermal expansion of the coating is the same as or close to that of the TA15 titanium alloy (meaning the coefficients are on the same order of magnitude and the error is generally controlled within ±5, and at most not exceeding ±10), then it can be cured directly to form a heat-resistant resin-based radar-absorbing coating without adjustment. Figure 4 As shown.

[0081] 6) Test the performance of the heat-resistant resin-based radar absorbing coating formed in step 5) and determine whether the heat-resistant resin-based radar absorbing coating meets the performance requirements; if yes, then end; if no, then proceed to step 2) to re-determine.

[0082] Specifically, the performance tests of the heat-resistant resin-based radar absorbing coating included appearance testing, thickness testing, adhesion testing, reflectivity testing, areal density testing, and temperature resistance testing. The test results are shown in Tables 6 and 7 below:

[0083] Table 6. Performance Test Results of Heat-Resistant Resin-Based Radar Absorbing Coating

[0084]

[0085] Table 7 Average reflectivity of heat-resistant resin-based radar absorbing coating at different wavelengths

[0086]

[0087] After comparing the performance test results in Tables 6 and 7 with the service performance requirements, the heat-resistant resin-based radar absorbing coating designed in this embodiment of the invention fully meets the performance requirements, and therefore the design is complete.

[0088] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0089] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A design method for a heat-resistant resin-based radar absorbing coating, characterized in that: The following steps are involved: S1. Acquire composition data of multiple groups of absorbing materials to construct an absorbing material database; S2. Preliminarily screen the composition of the absorbing coating in the absorbing material database constructed in S1 according to the service index requirements; S3. Designing an orthogonal experiment based on the components of the absorbing coating preliminarily screened in S2 to determine the ratio of the absorbing coating to obtain a formula of the absorbing coating; S4, obtaining data of the substrate to be coated, wherein the substrate data includes a thermal expansion coefficient of the substrate; S5. According to the thermal expansion coefficient of the substrate in S4, it is determined whether the radar absorbing coating prepared by the formula of the radar absorbing coating in S3 needs to be adjusted in thermal expansion coefficient; if adjustment is required, a fiber mesh is added to the radar absorbing coating, and a curing treatment is performed to form a heat-resistant resin-based radar absorbing coating; If no adjustment is required, a heat-resistant resin-based radar absorbing coating is directly formed after curing; S6, testing the performance of the heat-resistant resin-based radar absorbing coating formed in S5, and determining whether the heat-resistant resin-based radar absorbing coating meets the performance requirements; if so, ending; if not, entering S2.

2. The design method of the heat-resistant resin-based radar absorbing coating according to claim 1, characterized in that: The components of each group of absorbing materials in S1 include an absorbent and a resin binder, and the component data include electromagnetic parameters of the absorbent and the maximum operating temperature of the resin binder.

3. The design method of the heat-resistant resin-based radar absorbing coating according to claim 2, characterized in that: The specific process of determining the ratio of the absorbing coating in S3 is as follows: S31, respectively designing multiple groups of absorbents and multiple groups of resin binders with gradually increasing contents; S32, performing a cross test on any one of the multiple groups of absorbents and each group of resin binders in the multiple groups of resin binders; S33, testing the performance of each group of cross-test results; S34. Determine the ratio of the absorber to the resin binder in the absorbing coating according to the test results.

4. The design method of the heat-resistant resin-based radar absorbing coating according to claim 1, characterized in that: The substrate in S4 includes aluminum alloy, magnesium alloy or titanium alloy.

5. The design method of the heat-resistant resin-based radar absorbing coating according to claim 2, characterized in that: The process of adding the fiber mesh cloth between the radar absorbing coatings to form the heat-resistant resin-based radar absorbing coating in S5 is as follows: S51, weighing the absorbent and the resin binder according to the ratio of the absorbing coating determined in step S3; S52, adding the weighed absorbent and resin binder into the solvent, stirring evenly, to prepare a microwave absorbing slurry; S53, coating the absorbing slurry on the surface of the substrate by air spraying or brushing to form an absorbing coating, and adding a fiber mesh cloth to the absorbing coating; S54, placing the prepared radar absorbing coating in a heat treatment furnace and subjecting it to a curing treatment to form a heat-resistant resin-based radar absorbing coating.

6. The design method of the heat-resistant resin-based radar absorbing coating according to claim 5, characterized in that: In the S53, fiber mesh is added at 1 / 3 and 2 / 3 of the thickness of the absorbing coating respectively.

7. The design method of the heat-resistant resin-based radar absorbing coating according to claim 5, characterized in that: The parameters of the curing process in S54 are set as follows: the temperature is 220° C. to 270° C., and the time is 30 min to 100 min.

8. The design method of the heat-resistant resin-based radar absorbing coating according to claim 1, characterized in that: The performance test of the heat-resistant resin-based radar absorbing coating in S6 includes an appearance test, a thickness test, an adhesion test, a reflectivity test, a surface density test and a temperature resistance test.

9. A heat-resistant resin-based radar absorbing coating, characterized in that: The heat-resistant resin-based radar absorbing coating is obtained by adopting the design method as described in any one of claims 1 to 8.

10. An application of the heat-resistant resin-based radar absorbing coating according to claim 9, characterized in that: The heat-resistant resin-based radar absorbing coating is used in the fields of communications, electronics, aviation and aerospace, surface protection of military equipment, and stealth protection of radar facilities.

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