Barium ferrite powder and nano-zirconia ceramic powder composite wave-absorbing stealth coating and preparation method

Abstract

The application provides a barium ferrite powder and nano ZrO2 ceramic powder composite wave-absorbing stealth coating and a preparation method. The weight ratio of the ZrO2 ceramic powder, the barium ferrite powder and the low-melting-point glass powder in the composite wave-absorbing stealth coating is 25-70:25-70:5-10, wherein the low-melting-point glass powder refers to a glass powder with a melting point of 100-400 DEG C, and the average particle size of the nano ZrO2 ceramic powder is 1-100 nm. The ZrO2 ceramic powder, the barium ferrite powder and the low-melting-point glass powder with the above ratio are mixed, and are coated on the surface of a coated machine body by using a plasma spraying technology, and the coating thickness ranges from 0.1 mm to 5 mm. The application has the beneficial effects that the application can not only significantly improve the radar stealth performance, but also can lead to a series of improvements of the overall performance of an airplane. Experimental detection shows that the ceramic has better radar absorption than the existing polymer, can absorb 99% or more energy from the radar, the material is waterproof, is harder than sand, and can better withstand harsh conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of invisible coating, and particularly relates to a barium ferrite powder and nano ZrO2 ceramic powder composite wave-absorbing invisible coating and a preparation method thereof. BACKGROUND

[0002] Traditional radar invisible coating is polymer, which can absorb up to 99% of radar energy, and with the optimization of body shape, the radar signal of the detected aircraft is very weak, which has very important military significance. However, the polymer radar absorbing material has great limitations. It is not very solid, and will be degraded or even peeled off when exposed to salt, moisture and abrasive environment, and will also be decomposed at a temperature higher than 250 degrees Celsius, resulting in two places of the jet aircraft becoming particularly hot. In a supersonic aircraft, the wing edge collides with the air at high speed, generating a large friction force, which may generate a heat spot of more than 250 degrees Celsius at the leading edge of the wing. Therefore, special designs have to be adopted to reduce the heat spot generated by friction, but these designs will affect the performance of the aircraft. The second high-temperature area is located at the rear of the aircraft. Even the coldest jet exhaust temperature is far higher than 250 degrees Celsius, which requires the stealth aircraft designer to make a particularly long and thick exhaust nozzle to avoid overheating of the wave-absorbing material on the surface of the exhaust nozzle. Unfortunately, the shape and weight of these nozzles will reduce the fuel efficiency of the aircraft, and the aircraft will fly slower and less maneuverable. SUMMARY

[0003] The present application aims at overcoming the deficiencies in the prior art, and provides a barium ferrite powder and nano ZrO2 ceramic powder composite wave-absorbing invisible coating and a preparation method thereof.

[0004] The present application aims at overcoming the deficiencies in the prior art, and provides a barium ferrite powder and nano ZrO2 ceramic powder composite wave-absorbing invisible coating and a preparation method thereof.

[0005] Further, the weight ratio of the ZrO2 ceramic powder, the barium ferrite powder and the low-melting-point glass powder is 70:25:5.

[0006] Further, the weight ratio of the ZrO2 ceramic powder, the barium ferrite powder and the low-melting-point glass powder is 25:70:5.

[0007] The application also provides a preparation method of the barium ferrite powder and nano ZrO2 ceramic powder composite wave-absorbing stealth coating.

[0008] The application can not only improve the radar stealth performance, but also improve the overall performance of the aircraft. The experimental detection shows that the ceramic has better radar absorption than the existing polymer, and can absorb 99% or more energy from the radar. The material is waterproof and harder than sand, and can better withstand harsh conditions. In addition, the material maintains its radar absorption characteristics at temperatures up to 1800℃ and negative 100℃. The combination of toughness and temperature elasticity will enable aerospace engineers to design better stealth bodies. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 The figure is a schematic diagram of the microwave loss curve of the coating of the application with frequency change. DETAILED DESCRIPTION

[0010] In order to enable those skilled in the art to better understand the technical solutions of the application, the preferred embodiments of the application are described below in combination with the drawings and specific embodiments. It should be understood that the drawings are only used for illustrative description, and cannot be understood as a limitation on the application. In order to better illustrate the embodiments, some components in the drawings may be omitted, enlarged or reduced, and do not represent the actual size of the product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationship described in the drawings is only used for illustrative description, and cannot be understood as a limitation on the application.

[0011] The application provides a barium ferrite powder and nano ZrO2 ceramic powder composite wave-absorbing stealth coating. The weight ratio of ZrO2 ceramic powder, barium ferrite powder and low-melting-point glass powder is 25-70:25-70:5-10. The molecular formula of the barium ferrite powder is BaO6Fe2O3. The low-melting-point glass powder refers to a glass powder with a melting point of 100-400℃, which acts as a binder for the nano ZrO2 ceramic powder and the barium ferrite powder. The average particle size of the nano ZrO2 ceramic powder is 1-100 nanometers, and the density is about 8wt%.

[0012] Another aspect of the present application provides a method for preparing a composite wave-absorbing stealth coating of barium ferrite powder and nano-ZrO2 ceramic powder, which comprises mixing the ZrO2 ceramic powder, barium ferrite powder and low-melting-point glass powder in the above-mentioned proportions, and coating the mixture onto the surface of a coated body by means of plasma spraying technology, and coating the mixture onto a 180X180 mm aluminum plate by means of plasma spraying technology and testing the microwave reflectivity by means of a vector network analyzer. The prepared coating has excellent properties such as wear resistance, oxidation resistance and thermal shock resistance.

[0013] The coating thickness is the most important factor for wave-absorbing shielding. The coating thickness ranges from 0.1 mm to 5 mm. The thicker the coating thickness, the greater the weight gain, which is not conducive to the structure of the body. Experimental results show that the coating thickness affects the magnitude of microwave reflectivity. In order to ensure a larger microwave reflectivity, the optimal coating thickness is about 1.5 mm. On the basis of the coating thickness, the coating thickness tolerance is required to be within the range of + / - 0.1-0.5 mm.

[0014] The ZrO2 ceramic powder must have an average particle size of 1-100 nm. If the ZrO2 ceramic powder with an average particle size of microns is used instead of the nano-ZrO2 ceramic powder, the plasma-sprayed coating has poor strength and micro-cracks.

[0015] Example 1: The weight proportion of the ZrO2 ceramic powder, barium ferrite powder and low-melting-point glass powder is 70:25:5. Experimental results show that the low-melting-point glass powder melts at a hot-pressing temperature of 680°C to show a bright coating surface, which proves that the low-melting-point glass powder has an effective bonding effect on the high-melting-point nano-ZrO2 ceramic powder and barium ferrite powder. The microwave absorption rate of the composite wave-absorbing stealth coating is greater than 99%. The curve of the microwave loss of the coating with respect to the frequency is shown in Fig. 1. The reflection loss reaches -23 db at 17 GHz. Figure 1

[0016] Example 2: The difference from Example 1 is that the weight proportion of the ZrO2 ceramic powder, barium ferrite powder and low-melting-point glass powder is 25:70:5.

[0017] Example 3: The difference from Example 1 is that the weight proportion of the ZrO2 ceramic powder, barium ferrite powder and low-melting-point glass powder is 40:55:5.

[0018] It can be understood that equivalent replacements or changes of the technical solutions and inventive concepts of the present application made by those skilled in the art shall fall within the protection scope of the claims appended to the present application.​

Claims

1. A composite microwave absorbing stealth coating of barium ferrite powder and nano-ZrO2 ceramic powder, characterized in that: The weight ratio of ZrO2 ceramic powder, barium ferrite powder, and low-melting-point glass powder is 25-70:25-70:5-10. Among them, low-melting-point glass powder refers to glass powder with a melting point of 100℃ to 400℃, and the average particle size of nano ZrO2 ceramic powder is 1-100 nanometers.

2. The composite microwave absorbing stealth coating of barium ferrite powder and nano-ZrO2 ceramic powder according to claim 1, characterized in that: The weight ratio of ZrO2 ceramic powder, barium ferrite powder, and low-melting-point glass powder is 70:25:

5.

3. The composite microwave absorbing stealth coating of barium ferrite powder and nano-ZrO2 ceramic powder according to claim 1, characterized in that: The weight ratio of ZrO2 ceramic powder, barium ferrite powder, and low-melting-point glass powder is 25:70:

5.

4. A method for preparing a composite microwave absorbing stealth coating of barium ferrite powder and nano-ZrO2 ceramic powder as described in any one of claims 1-3, characterized in that: The ZrO2 ceramic powder, barium ferrite powder and low melting point glass powder in the above proportions are mixed and applied to the surface of the machine body using plasma spraying technology. The coating thickness ranges from 0.1 to 5 mm.

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