The 21st century is the century of military affairs. In future wars, humanity will engage in an unprecedented competition in space, centered on the development and utilization of space's abundant resources and the struggle for control of space, land, and sea. Military weapons and equipment will see rapid development. We have compiled the most cutting-edge military equipment, materials, and technologies for your reference. If there are any inaccuracies or shortcomings, please forgive us and feel free to correct them.
1,Carbon fiber: a material that military powers must compete for
Modern information-based warfare is not only a battle of high-tech equipment but also a battle of high-performance materials. Carbon fiber boasts outstanding properties, combining flexibility with strength, and possesses comprehensive characteristics such as electrical, thermal, and mechanical properties. It has high strength and good toughness, significantly enhancing the combat performance of modern weapon systems. It possesses a series of superior properties, including low density, high strength, high modulus, heat resistance, cold resistance, wear resistance, corrosion resistance, electrical conductivity, impact resistance, and excellent electromagnetic shielding effects. In addition to its widespread use in civilian industries (such as automobile manufacturing, mechanical components, sports equipment, high-speed rail parts, etc.), it is also an extremely important strategic material for military applications.
"Black gold" carbon fiber
The origins of carbon fiber can be traced back to 1860, when it was invented and patented by British scientist Joseph Swan during the development of electric light filaments. It is a fibrous carbon material, black in color, and extremely hard. It is a new type of material with outstanding comprehensive properties, including strength greater than steel, density lower than aluminum, corrosion resistance surpassing stainless steel, high-temperature resistance exceeding heat-resistant steel, and electrical conductivity comparable to copper. Due to its high manufacturing difficulty and significant practical value, it is hailed by the industry as "black gold."
Carbon fiber is "soft on the outside and strong on the inside," combining the inherent properties of carbon materials with the flexibility and processability of textile fibers, making it a new generation of high-performance reinforcing fibers. Carbon fibers, which are several times thinner than a human hair, are combined with resins, carbon, ceramics, metals, and other matrix materials through special composite forming processes to produce high-performance carbon fiber composite materials. These materials can be widely applied in aviation, aerospace, energy, transportation, military equipment, and other fields, making them an important material for both defense and military industries as well as civilian production and daily life.
Extremely challenging: complex and precise manufacturing processes
In the 1950s, to address key technical challenges such as high-temperature resistance and corrosion resistance in missile nozzles and warheads, the United States pioneered the development of viscose-based carbon fibers. In 1959, Japanese scientist Akira Kondo invented polyacrylonitrile-based carbon fibers. Due to the outstanding performance of carbon fibers in enhancing the capabilities of military equipment, they garnered significant attention from major military powers. Subsequently, some countries made significant investments, continuously developing carbon fibers with higher performance and a wider variety of types. Japan successively broke through a series of key technical challenges, such as achieving both high strength and high modulus, enabling the carbon fiber composites it developed to possess outstanding fatigue resistance and environmental adaptability, with its overall level consistently leading the field.
The Strongest of the Strong: A Radical Transformation of Defense Equipment
According to foreign media reports, the highly anticipated F-35 fighter jet has seen its maiden flight repeatedly delayed, with one major reason being its excessive weight. To address this challenge, Lockheed Martin adopted various solutions, ultimately incorporating up to 35% carbon fiber composite materials to significantly reduce the aircraft's weight. In this sense, it can be said that carbon fiber composite materials have made the F-35 fighter jet possible.
Today, carbon fiber composite materials have not only become an indispensable foundational material for achieving high stealth performance but also a key indicator of the advanced performance of weapon systems. For example, due to the higher proportion of carbon fiber composite materials used in aircraft such as the X-47B, Global Hawk, Global Observer, and Westwind, their payload capacity, endurance, and survivability have all achieved new breakthroughs.
The Best of the Best: A Matter of National Security Interests
Foreign militaries believe that modern information-based warfare is not only a battle of high-tech equipment but also a battle of high-performance materials. The development of modern weapon systems is characterized by trends toward stealth, low energy consumption, high mobility, and large payloads, leading to increasingly stringent requirements for the performance of carbon fiber and composite materials. Therefore, the development of carbon fiber with higher strength and modulus, along with matching high-performance combat systems, has become a key area of competition among military powers. Currently, developed countries are focusing their efforts on three key areas: carbon fiber, advanced resins, and manufacturing technology.
In recent years, to meet the needs of China's national defense development, carbon fiber and composite materials have been designated as national key support projects. Experts believe that, with an eye toward the future, building a complete, self-reliant, high-level industrial chain and striving to truly master core technologies related to national security interests is the inevitable path to realizing the Chinese Dream of national rejuvenation and military strength.
2,Metamaterials: Revolutionary Impact on the Military Industry
Metamaterials are materials that break through the limitations of certain apparent natural laws through the orderly design of structures at key physical dimensions of the material, thereby obtaining extraordinary properties that exceed the ordinary physical characteristics found in nature. Metamaterials are a cutting-edge technology field with significant military application value and broad application prospects, and will have a revolutionary impact on the future development of weapons and equipment and combat operations.
New Materials: Revolutionizing Traditional Theory
Although the concept of metamaterials emerged around the year 2000, its origins can be traced back much further. In 1967, Soviet scientist Viktor Veselago proposed that if a material simultaneously possessed negative permittivity and negative permeability, the relationship between the electric field vector, magnetic field vector, and wave vector would no longer adhere to the "right-hand rule"-the foundation of classical electromagnetism-but instead exhibit the opposite "negative refractive index relationship." Such a material would revolutionize the field of optics, causing light waves to appear to flow backward and exhibiting behavior that defies conventional wisdom in many ways, such as negative refraction, "backward light waves," and anomalous Doppler effects. This concept was dismissed as "fantasy" by the scientific community upon its initial proposal. As the limitations of traditional material design concepts become increasingly evident, the difficulty of significantly enhancing material performance grows, and the reliance on scarce resources for high-performance materials intensifies. Developing new approaches to material design that surpass the performance limits of conventional materials has become a critical task in new material research and development.
In 2000, the first report on negative refractive index materials was published; in 2001, researchers at the University of California, San Diego, successfully fabricated metamaterials with both negative permittivity and negative permeability in the microwave frequency band; In 2002, researchers at the Massachusetts Institute of Technology theoretically confirmed the feasibility of negative refractive index materials; in 2003, due to the significant research achievements in metamaterials worldwide, they were selected by the American journal Science as one of the top ten major scientific and technological advancements of the year. Since then, metamaterials research has yielded numerous achievements worldwide, with many of Viktor Veselago's predictions being experimentally verified.
Miraculous functions reshape future warfare
Metamaterials have long been favored for their unique physical properties and hold significant application potential in the military field. In recent years, applications of metamaterials in stealth, electronic countermeasures, radar, and other areas have continuously emerged, demonstrating immense application potential and development prospects.
Stealth has been the most frequently discussed application of metamaterials in recent years and remains the primary focus of metamaterial technology research to date. For example, the U.S. F-35 fighter jet and DDG-1000 large destroyer both utilize metamaterial stealth technology. In the future, metamaterials hold immense potential for application in electromagnetic stealth, optical stealth, and acoustic stealth, and will be widely adopted in various aircraft, missiles, satellites, warships, and ground vehicles, revolutionizing military stealth technology. The distinction between metamaterial-based stealth and traditional stealth technologies lies in the fact that metamaterials cause incident electromagnetic waves, visible light, or sound waves to bypass the concealed object, thereby achieving true stealth in a technical sense.
In the field of electromagnetic stealth, in 2006, Duke University in the United States and Imperial College London collaborated to propose an electromagnetic stealth design scheme for the microwave frequency band. This design scheme consists of 10 concentric cylinders using a rectangular open-ring resonator unit structure. Experimental results confirmed that negative refractive index materials can be used for object stealth. In 2012, Northeastern University in the United States designed and tested a material with adjustable negative refractive index in the 33–44 GHz electromagnetic band using a combination of scandium-doped M-type barium ferrite thin films and copper wires. Raytheon Company developed "artificial composite skin materials with controllable wave transmission properties." This material employs metal microstructures with variable capacitors as frequency-selective surfaces. By controlling the bias voltage applied to the variable capacitors, the electromagnetic parameters of the frequency-selective surfaces can be altered, enabling artificial control of the material's wave transmission characteristics. This technology can be applied to various advanced radar systems and the intelligent stealth skins of next-generation stealth aircraft.
In the field of optical stealth, in 2012, Canadian company Ultra Stealth Bio-Tech invented a remarkable material called "Quantum Stealth." This material can cause surrounding light to refract and bend, thereby rendering the objects or people it covers completely invisible. It not only deceives the human eye but also successfully evades detection by military night vision goggles and infrared detectors. This material not only assists special forces in conducting daytime raids but also holds promise for application in next-generation stealth aircraft, ships, and tanks. In 2014, a research team at the University of Florida developed a metamaterial capable of achieving visible light stealth. The key to this technological breakthrough was the use of nano-transfer printing technology to create a multi-layered three-dimensional metamaterial. Nano-transfer printing technology can alter the surrounding refractive index of this metamaterial, causing light to bypass it and achieve invisibility.
In the field of acoustic invisibility, in 2011, a team led by Professor Kamal at Duke University developed a two-dimensional acoustic cloak capable of rendering a 10-centimeter-sized wooden block undetectable by sound waves. In March 2014, Duke University created the world's first three-dimensional acoustic cloak, an acoustic stealth device made from acoustic stealth metamaterials that allows incident sound waves to propagate along the cloak's surface without reflection or transmission, achieving stealth against detecting sound waves. The three-dimensional acoustic cloak consists of plastic plates with repeatedly arranged small holes, demonstrating perfect stealth performance at 3 kHz sound waves, thereby validating the feasibility of acoustic cloaks for active sonar countermeasures. Additionally, the U.S. Navy has independently developed a submarine acoustic stealth technology called "metal water," creating an aluminum material with a hexagonal unit cell structure and incorporating it into the sound-dampening material covering the submarine's hull to guide sound waves and achieve stealth. The development of acoustic stealth metamaterial technology will have a transformative impact on the stealth capabilities of submarines and other underwater equipment, potentially altering the "rules of the game" in future underwater warfare.
Beyond traditional stealth, recent breakthroughs have also been made in tactile invisibility using metamaterials. In 2014, researchers at the Karlsruhe Institute of Technology in Germany developed a tactile invisibility cloak using mechanical metamaterials. This is a novel stealth technology capable of deceiving human and sensor-based detection systems. The tactile invisibility cloak is made from metamaterial polymers with specially designed submicron-precision crystal structures. The crystals are composed of needle-shaped cones with their tips in contact, and the size of the contact points must be precisely calculated to meet the required mechanical properties. The invisibility cloak made from this metamaterial can block the tactile perception of instruments or the human body. For example, if an object protruding from a table is covered with the invisibility cloak, although the protrusion is visible, touching it with the hand will not feel the object's protrusion, just like touching a smooth table surface. Although this technology is still in the pure basic physics research stage, it will open up new avenues for defense applications in the coming years.
Antennas and antenna covers are another area where metamaterials can be applied. Numerous experiments abroad have shown that applying metamaterials to antennas on missiles, radars, spacecraft, etc., can significantly reduce antenna energy consumption, increase antenna gain, expand the antenna's operating bandwidth, and effectively enhance the antenna's focusing and directional properties.
In terms of antennas, Raytheon has developed a metamaterial dual-band miniaturized GPS antenna. Through precise artificial microstructure design, it can enhance the isolation between antenna units, reduce electromagnetic coupling between antenna components, and thus significantly expand the antenna's bandwidth. This technology can be applied to aircraft platforms and personal portable tactical navigation terminals with stringent requirements for antenna size.
In terms of radar antenna radomes, with the support of the U.S. Navy, an American company has successfully developed a metamaterial smart structure for radar radomes, which has been applied to the U.S. military's next-generation E-2 "Hawkeye" early warning aircraft, significantly enhancing its radar detection capabilities. By adopting the special design of metamaterials, this project addresses the issue of image distortion in traditional radar radomes. Additionally, this metamaterial electromagnetic structure is lightweight, facilitating post-installation modifications and maintenance, thereby greatly enhancing the overall performance of the E-2 "Hawkeye" early warning aircraft.
In the field of missile antenna radomes, Raytheon Company has developed a missile antenna radome based on metamaterials, enabling electromagnetic waves passing through the radome to avoid effective refraction, thereby significantly improving missile strike accuracy.
Metamaterials used for manufacturing optical lenses can be used to create lenses that are not limited by the diffraction limit, highly directional lenses, and high-resolution planar optical lenses. Lenses not limited by the diffraction limit are primarily applied in fields such as the detection of trace contaminants, medical diagnostic imaging, and single-molecule detection; highly directional lenses are primarily applied in fields such as lens antennas, miniaturized phased array antennas, and super-resolution imaging systems; high-resolution planar optical lenses are primarily used in fields such as optical guiding components for integrated circuits. In 2012, the University of Michigan completed research on a new type of metamaterial lens capable of observing objects smaller than 100 nm, with excellent performance across the spectrum from infrared to visible and ultraviolet light.
The significance of metamaterials lies not only in several key artificial materials but primarily in providing a new way of thinking-people can obtain "new materials" with extraordinary physical properties that are fundamentally different from those in nature, without violating the basic laws of physics. "A new generation of materials leads to a new generation of equipment." The emergence and development of innovative materials will inevitably give rise to new weapons systems and combat tactics. Will the "super material," which has already gained global acclaim shortly after its inception, become the next legend in new materials? This inevitably sparks endless imagination and anticipation.
3,Graphene: Leading the Frontier of Military Technology
Graphene is the thinnest and hardest known nanomaterial. It is almost completely transparent, lightweight, and possesses excellent flexibility and exceptional electrical and thermal conductivity. It holds immense application potential in high-tech military fields such as microelectronics, optoelectronics, and new materials. Developed countries like Europe and the US have invested heavily in strategic development of graphene in areas closely related to national defense, such as supercomputers, high-sensitivity sensors, portable electronic devices, and advanced protective materials, aiming to secure a leading position in cutting-edge military technology.
Smaller, more energy-efficient graphene chips with faster processing speeds
Graphene will enhance the storage and computational capabilities of computers, reduce their size, and lower energy consumption.
Computers are the core of weapon fire control systems, and their data processing and storage capabilities determine the accuracy of ballistic calculations and rapid strikes. Computers made with graphene devices are 1,000 times faster than silicon-based microprocessors, reaching terahertz speeds. This is significant for equipment design and manufacturing simulations, battlefield simulations, nuclear explosion simulations, and intelligence analysis. Additionally, graphene devices have the advantages of being small in size, low in energy consumption, and generating minimal heat. As a result, the U.S. Defense Advanced Research Projects Agency (DARPA) has already included the development of smaller, faster graphene-based microelectronic devices in its research plans.
Graphene will enhance sensor sensitivity and promote miniaturization
Graphene possesses outstanding optical properties and, after processing, can also exhibit high-sensitivity magnetic, thermal, and mechanical characteristics, making it the most promising material for developing new lightweight sensors.
Developed countries such as Europe and the United States place high importance on the research and development of military graphene sensors. The Soldier Nanotechnology Laboratory at the Massachusetts Institute of Technology has set the development of a new generation of infrared night vision systems with high sensitivity, adjustable spectral selectivity, and rapid response characteristics using graphene technology as a research goal. In 2014, researchers at the University of Michigan sandwiched graphene between lenses to create a sensor capable of capturing visible light and infrared radiation. The lenses can be made smaller than a fingernail and integrated into contact lenses, enabling soldiers to gain night vision capabilities in the future. In July 2015, the U.S. Defense Advanced Research Projects Agency (DARPA) and the Army Research Laboratory funded Northeastern University to prepare a boron, nitrogen, and oxygen-doped graphene-based two-dimensional material, endowing graphene with thermosensitivity and ultra-sensitivity, which aids in the development of smaller, more portable infrared thermal imagers and ultra-sensitive light detectors. In August 2015, researchers at the Swiss Federal Institute of Technology in Lausanne announced they were developing a graphene ultra-sensitive detector capable of detecting a single photon. This detector responds to a broad spectrum ranging from near-infrared to X-rays, with sensitivity millions of times higher than conventional silicon-based photodetectors. It could be used in military night vision systems, space telescopes, and even optical quantum computers.
Graphene will enhance the protective performance and stealth capabilities of equipment.
Graphene possesses superior mechanical properties and holds significant potential for applications in ballistic protection. In 2014, researchers at Rice University in the United States conducted graphene impact resistance studies with support from the Defense Threat Reduction Agency. They found that when subjected to high-speed impacts from silica spheres, graphene rapidly disperses the impact force, absorbing incident energy at a rate ten times that of steel and twice that of Kevlar fiber. Combining graphene with other lightweight, high-strength materials could lead to the development of high-performance lightweight armor systems. In May 2015, researchers at the University of Trento in Italy discovered that graphene significantly enhances the strength of spider silk, with composite fibers reaching 3.5 times the strength of natural spider silk, making it a high-performance material for body armor.
Given graphene's lightweight, high-strength properties and thermal and electrical characteristics, it can also be used in stealth protection applications. In 2013, researchers at the University of California developed a graphene-based infrared stealth coating that achieves infrared stealth by altering the wavelength of reflected light. This material can be applied over large areas on structural surfaces and platforms to achieve military camouflage. Additionally, the European Defense Agency held a specialized workshop in June 2015 focusing on the application potential of graphene in composite material protection systems and adaptive camouflage coatings.
Graphene bulletproof vests are lighter and offer stronger protection
4,Armor Protection Materials: Military Equipment "Bulletproof Vests"
Modern warfare has reached an unprecedented level of intensity. High-performance weapons such as long-range attacks, battlefield stray bullets, and pre-positioned fragments create all-around, three-dimensional, high-density fragment attacks that cause severe vehicle damage and casualties. To adapt to the changing patterns of modern warfare, the demand for enhanced protection levels in military vehicles is growing. Research into military vehicle armor protection technology and improving battlefield protection capabilities for military vehicles is of utmost importance.
Armor Protection Materials: Performance and Applications Armor protection materials used in military equipment worldwide primarily include bulletproof glass, bulletproof steel plates, bulletproof ceramics, bulletproof high-strength fiberglass, bulletproof aramid fibers, and bulletproof PE fibers.
Bulletproof Glass
Currently, bulletproof glass is primarily composed of inorganic glass and organic materials. The main types include:
Laminated composite of float glass and PVB interlayer film. This method involves bonding multiple layers of float glass with polyvinyl butyral (PVB) interlayer film using high-temperature and high-pressure processing to form a transparent, integrated structure with bulletproof capabilities. The advantages of this bulletproof glass include excellent optical performance, good impact resistance, high environmental stability, resistance to aging, long service life, low cost, and ease of maintenance. The disadvantages include large volume and weight, making it suitable for installation in fixed locations.
Laminated glass combined with organic transparent panels: This type of bulletproof glass comes in two forms. One involves placing an organic transparent panel behind a layer of laminated glass, with the laminated glass positioned in front of the organic transparent panel as the impact layer-this is the layered method; The other involves directly bonding glass with polycarbonate sheets (PC sheets) to form bulletproof glass, using polyurethane film (PU film) as the adhesive material. The production process is similar to the PVB laminated method.
Bulletproof steel plates
Metal bulletproof materials (including bulletproof steel, aluminum alloy, titanium alloy, etc.) have been widely used in military (tanks, armored vehicles, etc.) and civilian protective applications (armored cash transport vehicles, armed police, public security anti-riot vehicles, and bulletproof sedans) from the past to the present. As the requirements for armor protection materials' penetration resistance, impact resistance, and fragmentation resistance continue to increase due to advancements in weaponry and ammunition, metal ballistic materials have evolved from ordinary steel armor to high-hardness steel armor, dual-hardness steel composite armor, and even titanium alloy armor, with continuously improving protective capabilities. Armor steel materials primarily consist of the Cr2Ni2Mo alloy series of armor steel. By adjusting the carbon content, the hardness of the armor steel plates can be modified. Armor steel plates are classified based on their hardness value (HRC50). Those with hardness values of 24C, 28C, and 30C are less than or equal to HRC50 and are categorized as high-hardness armor steel; 39C and 44C have hardness values greater than HRC50, classified as ultra-high-hardness armor steel.
Traditional metallic armor materials, such as steel plates, have high density. Weapons with high destructive power and explosive force require armor to reach a certain thickness. However, using overly thick and heavy steel plate armor necessitates sacrificing the vehicle's, ship's, or aircraft's payload capacity. Additionally, the excessive weight of the armor material makes it difficult to maneuver, reduces flexibility, and increases engine failure rates.
Bulletproof ceramics
In 1918, it was discovered that coating a thin, hard layer of enamel on metal surfaces could enhance their bulletproof properties, leading to the adoption of this technology during World War I for tank armor. In the 1960s, composite armor was developed using Al₂O₃ ceramic panels bonded to aluminum or fiberglass backing plates, capable of withstanding high-velocity projectiles. Subsequently, other ceramic armor materials such as B₄C, SiC, and Si₃N₄ were introduced. Ceramics are brittle materials that are prone to breaking when subjected to impact. They are typically not used alone as armor but are combined with metal and other fiber materials to form composite armor. The ceramics used in composite armor are often modified into ceramic blocks, so that even if one block is shattered by a projectile, the others remain effective. Ceramic materials are primarily used in armor systems designed to counter medium- and large-caliber long-rod armor-piercing projectiles, which primarily rely on ablation-based destruction mechanisms. They are also used in bulletproof vests, where ceramic materials are combined with composite backing materials to provide the required protective capability. In engineering applications, ceramic composite armor is widely used in the protective armor of tanks, armored vehicles, and other equipment. However, ceramic materials have poor plasticity, low fracture strength, and are prone to brittle fracture. They cannot provide secondary ballistic protection. Additionally, their成型 dimensions are small, production efficiency is low, and due to their extremely high hardness and brittleness, secondary forming and processing are extremely difficult, particularly the processing of forming holes, resulting in high production costs and significant limitations in application.
Currently, the three main ceramic materials used for ballistic protection are aluminum oxide, silicon carbide, and boron carbide. Aluminum oxide is more widely used in ballistic protection due to its low cost, but it has the lowest ballistic protection rating and the highest density; boron carbide offers the best ballistic performance and lowest density, but it is the most expensive. It was first used in the 1960s as a material for designing ballistic vests; Silicon carbide ceramic materials fall between the two in terms of cost, ballistic performance, and density. Therefore, it is most likely to become the next-generation replacement for aluminum oxide ballistic ceramics.
Bulletproof High-Strength Fiberglass
As early as World War II, the United States began researching fiberglass armor and successfully developed fiberglass/polyester armor materials. With the emergence of S-2 high-strength fiberglass, high-performance fiberglass composite materials became the first generation of composite armor materials as a relatively inexpensive bulletproof armor material. Their bulletproof capability can reach more than three times that of steel. Fiberglass is also used as a composite armor structural material for armed helicopters, transport aircraft, and communication helicopters.
Ballistic-resistant aramid fibers
The United States was the first to develop aramid composite materials into ballistic-resistant helmets and body armor, and subsequently combined aramid fiber laminates with ceramic or steel plates for tank armor. For example, the U.S. M1 Main Battle Tank employs a "steel + Kevlar + steel" composite armor configuration, which can withstand neutron bullets and anti-tank missiles with armor-piercing capabilities of approximately 700 mm, while also reducing the instantaneous pressure effects caused by armor-piercing rounds within the driver's compartment. The critical internal structural components of the U.S. M113 armored personnel carrier are also equipped with Kevlar linings, providing secondary armor protection against the impact and penetration of armor-piercing rounds, high-explosive anti-tank rounds, and fragmentation rounds. The composite armor composed of bulletproof composite material backplates and ceramic panels used in the U.S. V-22 Osprey military aircraft and military helicopters is the ideal lightweight armor for helicopters.
Ballistic PE fiber
Ultra-high molecular weight polyethylene fiber composite materials (known as Dyneema in the Netherlands and Spectra in the United States) are high-performance fibers with excellent comprehensive properties. Their characteristics include high strength, high modulus, low elongation, and low density (lighter than water), as well as excellent corrosion resistance, UV resistance, cut resistance, and wear resistance. Additionally, they have low moisture absorption and are unaffected by environmental conditions. Furthermore, their high hydrogen content provides excellent neutron and gamma ray protection.
5,A Comprehensive Overview of Stealth Coating Technology
Stealth coatings are a mysterious member of the coatings family. They are not the "invisibility" depicted in science fiction, but rather a combination of techniques and technologies used in military terminology to control the observability of a target or its characteristic signals. Target signature signals are a set of characteristics that describe how easily a weapon system can be detected, including six types of signature signals: electromagnetic (primarily radar), infrared, visible light, acoustic, smoke, and exhaust trails. According to statistics, 80% to 90% of aircraft losses in air combat are due to detection. Reducing a platform's signature signals lowers the probability of detection, identification, and tracking, thereby enhancing survivability. Reducing platform signature signals is not only aimed at countering radar detection but also at reducing the likelihood of being detected by other detection devices. Stealth involves increasing the difficulty for enemies to detect, track, guide, control, and predict the spatial position of a platform or weapon, significantly reducing the accuracy and completeness of information obtained by enemies, and lowering their ability to successfully employ various weapons in combat, thereby achieving measures to enhance one's own survivability.
Stealth coatings are materials used on the exteriors of aircraft, warships, tanks, and other equipment to counter radar detection and prevent electromagnetic wave leakage or interference. Stealth materials and stealth design are organically integrated to form a new technology known as stealth technology. Stealth technology requires the concealment of light, electricity, magnetism, sound, and infrared radiation, making it a comprehensive technology. Modern stealth technology is primarily divided into electromagnetic wave stealth technology and acoustic wave stealth technology.
Stealth Coatings Classification
Stealth coatings can be classified into radar stealth coatings, infrared stealth coatings, visible light stealth coatings, laser stealth coatings, sonar stealth coatings, and multi-functional stealth coatings based on their functions. Stealth coatings must possess chemical stability over a wide temperature range; excellent frequency band characteristics; low surface density and lightweight; high adhesion strength; and resistance to certain temperatures and environmental changes. (1) Radar Stealth Coatings Radar stealth coatings refer to materials that can absorb and attenuate incident electromagnetic waves, converting electromagnetic energy into thermal energy through dielectric oscillation, eddy currents, and magnetostriction of the absorber, thereby dissipating the energy or causing the electromagnetic waves to disappear due to interference. Radar stealth coatings aim to minimize the likelihood of being detected by radar. Research on radar stealth technology primarily focuses on structural design and absorptive materials. Currently, absorptive coatings are widely used in aircraft, such as ferrite absorptive coatings, which are cost-effective; carbonyl iron absorptive coatings, which have strong absorptive capabilities but high surface density; and ceramic absorptive coatings, which have lower density; radioisotope absorptive coatings, which are thin, lightweight, and capable of withstanding high-speed aerodynamic forces, making them an ideal absorptive coating for aircraft; and conductive polymer absorptive coatings, which are thin and easy to maintain. Additionally, nano-absorptive coatings have emerged as a new highlight in stealth coatings, capable of covering electromagnetic waves, microwaves, and infrared radiation, while enhancing corrosion protection, exhibiting excellent weather resistance, and offering superior coating performance. (2) Infrared stealth coatings The purpose of infrared stealth is to reduce or alter a target's infrared radiation characteristics to achieve low detectability. By improving structural design and applying infrared physical principles to attenuate or absorb a target's infrared radiation energy, infrared detection equipment finds it difficult to detect the target. Infrared stealth coatings feature a simple production process, easy application, durability, and low cost, making them the most important type of stealth coating currently available. They are special functional coatings designed to reduce the infrared characteristics of weapon systems to meet stealth technology requirements. They primarily target infrared thermal imaging reconnaissance, aiming to reduce the brightness of aircraft in the infrared spectrum, conceal or distort the shape of equipment in infrared thermal imaging, and lower the probability of detection and identification. The primary resin in infrared stealth coatings is a single-component rubber resin, which has excellent compatibility with chlorinated polyvinyl chloride coatings, epoxy iron oxide primers, and polyurethane coatings. (3) Laser Stealth Coatings Since the 1980s, stealth technology-particularly radar and infrared stealth technology-has reached a very high level of development. For example, the low-observable aircraft developed by the United States, such as the F-117 stealth fighter and the B-2 stealth bomber, have achieved excellent performance in radar and infrared stealth capabilities. However, with the rapid advancement of laser technology, its application in weapon systems and other fields has been increasing. The process of laser stealth is similar to that of radar stealth, primarily aiming to reduce the target's surface reflectivity, decrease the echo power detected by laser sensors, and lower the performance of laser sensors, thereby preventing or making it difficult for the enemy to conduct laser detection, thus achieving the goal of laser stealth. The primary approaches to achieving laser stealth technology include shape technology and material technology. Shape technology involves reducing the target's radar cross-section (RCS) through unconventional shape design; while material technology involves using materials that absorb lasers or applying absorptive coatings to the surface to increase laser absorption and reduce reflection, thereby achieving stealth. Since shape design can only scatter approximately 30% of radar waves and it is difficult to find a shape that optimally balances LRCS and aerodynamics, achieving complete stealth ultimately relies on stealth materials. Laser stealth materials primarily include three types: laser-absorbing materials, light-guiding materials, and transmissive materials. Among these, transmissive materials allow laser light to pass through the target surface without reflection. In principle, a laser beam termination medium should follow the transmissive material; otherwise, reflection or scattering of laser light may still occur. Light-guiding materials redirect laser beams incident on the target surface through certain channels to other directions, thereby reducing direct reflection echoes. These two types of stealth functional materials present significant challenges in their implementation as laser stealth materials. Therefore, exploring new technologies, methods, and actively researching new stealth mechanisms and novel multifunctional stealth materials-particularly new coating-based multifunctional, multi-spectrum compatible stealth materials-has become a new research hotspot and challenge. (4) Visible Light Stealth Coatings Visible light stealth coatings, also known as video stealth technology, address the shortcomings of radar stealth and infrared stealth. They are stealth technologies designed to counter human visual observation, photography, and videography. Their purpose is to reduce the target characteristics of the aircraft itself, minimize the brightness, color, and motion contrast between the target and its background, and control the visual signals of the target to reduce the probability of detection by visible light detection systems.
Visible light stealth coatings typically employ camouflage techniques to render aircraft invisible, such as protective camouflage, imitation camouflage, and deformable camouflage. One type of visible light stealth technology is camouflage screening, where the screening material mimics the electromagnetic radiation characteristics of the background, enabling the target to blend in and merge with the environment. This is the primary method for stationary and stationary moving targets, and camouflage coatings are a crucial component of this technology. In summary, visible light stealth coatings have widespread applications, are easy to use, and cost-effective, making them a relatively mature technology in the development of aircraft stealth coatings.
Exploration of New Stealth Coatings
(1) Multi-band Absorbing Materials
With the continuous development of multi-mode composite guidance technology and the increasing diversity of detection methods, battlefield weapon systems may face threats from multiple detection methods such as radar, infrared, laser, and visible light. Therefore, the development of multi-band composite stealth materials has long been a focus of attention and research by experts and relevant researchers. How to make the coating compatible across several bands will be one of the primary research directions in the future.
(2) Nanocoating Materials
In recent years, nanoscale absorptive coatings have emerged as a new highlight in stealth coatings. This is a highly promising coating material, typically composed of inorganic nanomaterials combined with organic polymers. By precisely controlling the uniform dispersion of inorganic nanoparticles within a polymer matrix, novel coatings with superior performance can be prepared. They exhibit good mechanical properties, low surface density, and are highly efficient broadband absorptive coatings capable of covering electromagnetic waves, microwaves, and infrared radiation. They enhance corrosion protection, have excellent weather resistance, and offer superior coating performance. Based on these advantages, countries are competing to invest human and material resources in research and development in this field.
(3) Chiral Absorbing Materials
Chirality refers to a substance that lacks geometric symmetry with its mirror image and cannot be made to coincide with its mirror image through any operation. Chiral absorbing coatings are a newly developed type of absorbing material. Compared to conventional absorbing coatings, they offer advantages such as higher absorbing frequencies and broader absorbing bandwidths. By adjusting chiral parameters, their absorbing characteristics can be improved, demonstrating significant potential for enhancing absorbing performance and expanding the absorbing bandwidth.
(4) Conductive Polymer Materials
This material has emerged in recent years and has garnered significant attention from the scientific community due to its structural diversity, low density, and unique physical and chemical properties. By combining conductive polymers with inorganic magnetic loss materials or ultra-fine particles, it is anticipated that a new type of lightweight, wide-band microwave absorber material can be developed.
(5) Plasma stealth technology
Plasma is the fourth state of matter, following solids, liquids, and gases. Plasma possesses stealth capabilities because it refracts and absorbs radar waves. Plasma stealth technology differs from existing shape and material stealth technologies in that it offers numerous advantages: wide absorption frequency band, high absorption rate, excellent stealth performance, ease of use, long service life, and low cost; it does not require changes to aircraft design and does not affect flight performance; and the absence of absorptive materials or coatings significantly reduces maintenance costs. Additionally, wind tunnel tests conducted in Russia have shown that plasma-based stealth technology can reduce an aircraft's aerodynamic drag by over 30%. However, achieving stealth for weapons using plasma technology also presents significant challenges and issues. The development of military detection and guidance technologies has driven the advancement of stealth materials, from early visible light stealth materials to current laser stealth materials, with research and development in this field continuing uninterrupted. Regardless of the type of stealth material, future development trends will focus on lightweight, broadband, high-efficiency, and durable materials. Furthermore, with the advancement of multi-mode technology, traditional materials with single stealth functions can no longer simultaneously evade multiple detection methods, making multi-band compatible stealth materials a future trend. As scientific research continues to deepen, new stealth coatings will continue to emerge. However, due to the high level of military sensitivity and technological confidentiality, the development and application of stealth coatings remain shrouded in mystery. Meanwhile, various anti-stealth technologies and methods are being actively developed. The competition between stealth and anti-stealth technologies will undoubtedly become a highlight of military struggles in the new century.
6,3D Printing: The Rising Star in the Defense and Military Industry
In today's world, "3D printing technology" has become a frequently used term in science and technology news reports, and has even been predicted by The Economist magazine in the UK to "drive the arrival of a new industrial revolution." Due to its advanced 'replication' capabilities in terms of digitization and intelligence, this technology has gained widespread favor. While being adopted for civilian use, it has also gradually become a popular "newcomer" in the defense and military industries.
3D printing technology has been applied to expensive fighter jets
3D printing technology applied to carrier-based aircraft
3D printing technology has been applied to the military and aerospace fields, and even expensive fighter jets and carrier-based aircraft can now be "printed." So, how has 3D printing helped the military industries of various countries?
3D Printing for Upgrading Aging Components of U.S. Warplanes
Tinker Air Force Base in Oklahoma is home to the Oklahoma City Air Logistics Center (OC-ALC) and serves as the management and maintenance hub for aircraft, engines, missiles, software, and avionics under the U.S. Air Force Materiel Command (AFMC). Its responsibilities include managing the development of aircraft and technology for the U.S. military fleets, including various components, developing combat aircraft programs, testing equipment, and industrial automation software. In simple terms, the Air Force Logistics Center is responsible for ensuring that any military aircraft or related equipment continues to fly safely.
USA: 3D printing aids combat logistics support
Exterior view of the American B-52 bomber
To maintain aircraft and enhance their combat capabilities, the US Air Force and OC-ALC are currently developing a strategic plan to integrate 3D printing technology into their current air force, maintaining every aspect of their missions. OC-ALC will utilize 3D printing technology to optimize workflows, including additive manufacturing of aircraft engine components and 3D printing of modern electronic components designed by the 76th Software Maintenance Group.
3D printing used to improve aging parts of US B-52 fighter jets
The Application of 3D Printing in Military Aircraft Components in South Korea
When it comes to South Korea, a country that is often overlooked in military circles, it has also made significant strides in 3D printing. In June 2015, the engine of an F-15K fighter jet used by the South Korean Air Force was damaged, requiring repairs to the titanium alloy turbine shroud and cobalt alloy air seal. The goal was to find a durable and reliable method to upgrade the components without compromising quality. For this repair, the South Korean Air Force opted to use 3D printing technology. They partnered with a German 3D printer manufacturer, which employed specialized DMT technology to swiftly complete the repair of the engine casing and seal. The DMT technology operates by using a high-power laser to melt metal powder, and is considered one of the latest and most promising 3D printing technologies, capable of nearly instantly repairing components of South Korean military aircraft.
F-15K fighter jets used by the South Korean Air Force
DMT technology repairs F-15K fighter jet parts
The working principle of DMT technology is mainly to melt metal powder using high-power lasers
Russia's 3D-printed drone "Water Duck"
When it comes to Russia's military strength, almost everyone knows that it has inherited 70% of the former Soviet Union's military strength, and its 3D printing technology capabilities are also not to be overlooked.
In June 2015, Russia Today reported that the state-owned Russian Technologies Corporation had manufactured a drone prototype using 3D printing technology. The drone weighed 3.8 kilograms, had a wingspan of 2.4 meters, could fly at speeds of up to 100 kilometers per hour, and had a flight endurance of 1 to 1.5 hours. The company achieved the leap from concept to prototype in just two and a half months, with actual production taking only 31 hours and manufacturing costs totaling less than 200,000 rubles. The unique feature of this drone is that it requires no special takeoff or landing facilities and can operate on any surface, whether snow-covered ground or drainage ditches. At an altitude of 6,000 meters, its control range reaches 2,500 kilometers, with a payload capacity of 300 kilograms, capable of carrying 2–3 passengers or luggage, or transporting detection and monitoring equipment. The drone's air cushion can be recovered in flight mode, enabling it to deliver supplies to hard-to-reach disaster zones or support military operations, such as carrying small guided missiles, precision-guided bombs, and other offensive weapons, as well as conducting reconnaissance missions.
China's 3D-printed "large aircraft" components
3D printing technology has played a significant role in the manufacturing of high-end, complex, and precision-structured critical components for key sectors such as national defense and aviation, providing a supportive platform for their application. China is not lagging behind other developed countries in this field; on the contrary, it even leads in some high-tech military sectors. For instance, some of the domestically produced fighter jets displayed at the military parade commemorating the 70th anniversary of the victory in the War of Resistance against Japan on September 3, 2015, featured components manufactured using 3D printing technology.
Applications of 3D Printing in Warfare
As is well known, logistics and supply chains are the most vulnerable and easily targeted weak links on the battlefield. During the Afghanistan War, the U.S. military deployed significant combat forces to ensure uninterrupted supply lines and protect personnel safety. The U.S. military believed that if 3D printers had been integrated with battlefield networks, unmanned transport helicopters, or vehicles at the time, this issue could have been completely resolved. By using 3D printing technology to produce food, medicine, and equipment on-site to meet actual needs, a revolutionary transformation in logistics support could have been achieved.
It is evident that, provided the technology is sufficiently advanced, 3D printing can almost meet all the needs of future battlefields. With this "mobile arsenal" capable of "cloning" logistical supplies, combat consumables can be rapidly replenished during wartime.
Source: Materials Circle, Composite Materials People. All rights reserved to the original author.