Porous, multi-stage, multi-phase, lightweight, broadband absorbing new material

Nano absorbing materialsThe transmissivity and absorptivity of electromagnetic waves are much higher than those of micro Rice noodles. Nanomaterials have excellent absorption properties, as well as wide bandwidth, good compatibility, small mass, and thin thickness. Countries such as the United States, Russia, France, Germany, and Japan have studied and explored nanomaterials as a new generation of stealth materials. Currently, developed military countries around the world are researching nano composite materials that cover wavelengths such as centimeter wave, millimeter wave, infrared, and visible light.

　　Polycrystalline iron fiber stealth coatingIn the mid to late 1980s, countries such as the United States and Japan vigorously conducted research on polycrystalline iron fiber absorbing coatings. Research has shown that this coating has the advantages of wide absorption band, low density, and good absorption performance.

It is reported that the coating has been used on French strategic missiles and re-entry vehicles. The absorbing coating developed by 3M Company in the United States uses polycrystalline iron fibers with a diameter of 0.26 μ m and a length of 6.5 μ m. Polycrystalline carbonyl iron fiber absorbent materials have been applied, and corrosion-resistant polycrystalline carbonyl iron fiber absorbent coatings have been used on F/A-18E/F and A/F-117X aircraft.

　　Conductive polymer absorbing coatingThe research on high polymers with microwave electrical and magnetic loss properties has attracted increasing attention from countries around the world. At present, Hunstvills Company in the United States has developed a transparent absorbing coating composed of a mixture of aniline and cyanate whiskers. The characteristic of this coating is that the absorbing material is evenly distributed within the coating, and there is no need to increase the thickness to improve the absorption bandwidth, making it particularly suitable for stealth retrofitting of old aircraft. In addition, this absorbing coating is transparent and suitable for stealth of cabin covers, missile transparent windows, and electromagnetic windows of night vision infrared devices, reducing radar echoes.

　　High temperature resistant absorbing materialUsually, certain special parts of aircraft and weapons, such as nose cones, engine intakes, and nozzles, require high temperature and high-speed thermal airflow resistance. To meet the stealth requirements of these special parts, high-temperature absorbing materials are currently being actively developed both domestically and internationally.

In recent years, a series of ceramic fibers have been developed abroad, mainly including silicon carbide fibers, aluminum oxide fibers, silicon nitride, and aluminum silicate fibers. Among them, silicon carbide fibers have developed the fastest.

According to reports, absorbing materials and structures made of ceramic based composite materials in the United States can withstand high temperatures of 1093 ℃ when added to the tail nozzle of the F-117 stealth aircraft. Alcole, a French company, uses ceramic composite fibers composed of glass fiber, carbon fiber, and aramid fiber to manufacture unmanned stealth aircraft.

Carbon carbon materials are also excellent high-temperature absorbing materials with excellent absorbing properties, which can reduce infrared and radar wave signals. Using carbon carbon materials to manufacture engine intake ducts can absorb radar waves entering the ducts.

Visible light, infrared, and radar compatible stealth coatings. With the emergence of advanced detection equipment such as infrared detectors, meter wave radars, millimeter wave radars, and laser radars, stealth materials are developing towards a multi spectral direction that can be compatible with multi band electromagnetic wave stealth, including meter wave, centimeter wave, millimeter wave, infrared, and laser.

Advanced multifunctional stealth materials from abroad have made significant progress in the integration of visible light, near-infrared, far-infrared, 8mm, and 3mm five bands.

The direction of unified development of materials and weapons

　　Hand drawn absorbing coatingHand drawn absorbing coatings are a new type of absorbing material developed in recent years, consisting of a matrix and a chiral medium doped with one or more different characteristic parameters. The United States, France, and Russia attach great importance to the research of chiral materials and have made significant progress in the study of microscopic mechanisms, and have confirmed the characteristics of rotational waves through experiments. At present, thin film samples with an area of 0.1 μ m2 and a thickness of 0.005mm can be produced in the laboratory, and the film thickness is uniform. We are currently trying to manufacture films with larger areas.

Intelligent absorbing materials and structures are a new type of high-tech material developed and highly valued in the 1980s. They can sense and analyze various active detection signals reaching the surface of aircraft from different directions, instantly adjust the electromagnetic and optical properties of the surface, and achieve stealth effects. The US Air Force recently proposed to connect multiple layers of thin films with different conductivities together to obtain a skin structure that is functionally similar to layered dielectric absorbing coatings, and embed various airborne electronic devices, sensors, etc. into the skin to replace traditional radar antennas, thus forming an intelligent skin. In this way, the surface of the aircraft can not only withstand loads and maintain its appearance, but also have functions such as communication, stealth, electronic countermeasures, fire control, flight control, etc., partially or completely replacing the original discrete electronic devices, increasing functionality, reducing weight, and improving survivability.

New Technologies in Aerospace Weapon Systems

Plasma stealth technology is one of the new technologies that applies stealth technology to aerospace weapon systems. Russia began researching plasma drag reduction technology in the mid-1990s. By deploying plasma generators around the aircraft body, the release of plasma during flight can not only reduce drag by more than 30%, but also have a significant stealth effect. In the late 1990s, this technology completed experiments and is currently accelerating the development of third-generation plasma generator systems.

The stealth effect of plasma increases with the increase of radar wavelength, while the stealth effect of coating stealth materials decreases with the increase of wavelength. This stealth technology not only solves the limitations of absorbing coating thickness and quality, but also has the advantages of absorbing frequency bandwidth, high absorption rate, simple use, and long time. It can also meet the high reflection local requirements, especially suitable for missile stealth