The material, developed by Zhi Lei, Daohai Zhang and colleagues, is built from two inexpensive and environmentally friendly ingredients: polyvinyl alcohol, a widely used water-soluble polymer, and gelatin, a natural biomass-derived protein. The researchers combined them into a semi-interpenetrating network in which the two polymer chains entangle during gelation and are further crosslinked by hydrogen bonds between abundant amino and hydroxyl groups. That molecular architecture produces a three-dimensional porous scaffold with high water content, and the same hydrophilic functional groups allow the gel to adhere to skin, paper, glass and metal through hydrogen bonding and intermolecular forces. Into this matrix the team dispersed composite nanoparticles made of carbon nanotubes decorated with ZIF-67, a cobalt-based metal-organic framework in which cobalt ions are coordinated by 2-methylimidazole ligands into a highly ordered porous crystal.

Each component of the hybrid filler plays a distinct role. Carbon nanotubes are lightweight and highly electrically conductive, so they raise the conductivity of the hydrogel dramatically, from 0.34 siemens per meter for the pristine polymer blend to 0.62 siemens per meter, an increase of 82.35 percent. ZIF-67, meanwhile, contributes cobalt centers that absorb electromagnetic waves, giving the composite dual loss mechanisms: dielectric loss from the conductive carbon network and magnetic loss from the cobalt ions. Together, the two phases dissipate incoming electromagnetic energy as heat rather than letting it pass through or bounce off. The porous hydrogel scaffold adds a third layer of defense, because its three-dimensional architecture provides anchoring sites for the nanoparticles and forces penetrating waves to undergo multiple internal reflections, each of which bleeds away more energy.

The synthesis relied on three complementary techniques. First, an in situ growth method deposited rhombic dodecahedral ZIF-67 crystals directly onto the surfaces of carboxylated multi-walled carbon nanotubes, with cobalt nitrate and nanotubes dispersed in methanol at controlled mass ratios and then added to a 2-methylimidazole solution under stirring for 24 hours. Second, a one-pot method dispersed the resulting CNTs@ZIF-67 particles uniformly into the aqueous PVA-gelatin precursor under ultrasonication. Third, cyclic freeze-thaw treatment physically crosslinked the polymers into a stable gel without any toxic chemical crosslinkers. Scanning electron microscopy confirmed that ZIF-67 had grown on the nanotubes and revealed how the fillers reshaped the gel’s internal pores.

Perhaps the most intriguing structural finding concerns electrostatics. When ZIF-67 alone was added, cobalt ions attracted electron-rich groups on the polymer chains, causing chain segments to bunch together and collapsing the gel’s three-dimensional network into a smoother, denser morphology. Carbon nanotubes alone infiltrated the pores and shrank them. But the combined CNTs@ZIF-67 particles produced hydrogels with more numerous and larger pores than either single filler. The researchers attribute this to an electrostatic confinement effect: oxygen anions on the nanotube surfaces neutralize the positive charge of the cobalt ions, weakening the electrostatic interactions between the composite and the polymer matrix and preserving the porous architecture that is so important for wave attenuation.

Spectroscopic analysis backed up the picture. X-ray diffraction peaks of the synthesized ZIF-67 matched the standard reference pattern at all expected crystal planes, indicating a complete lattice, while the hydrogels showed narrowed diffraction peaks consistent with grain-size changes induced by the cobalt-containing filler. Fourier transform infrared spectra showed no new functional groups after doping, meaning the nanoparticles disperse physically within the polymer framework rather than forming new chemical bonds. X-ray photoelectron spectroscopy, however, revealed subtle electronic interactions: the cobalt 2p binding energies shifted upward in the doped gels, suggesting that hydroxyl and carboxyl groups coordinate with cobalt ions and redistribute electron density at the interface.

Mechanically, the composite gel proved remarkably robust. The pristine PVA-gelatin hydrogel withstood compressive stresses of 18.75 megapascals at 71.07 percent strain; the shielding version reached 19.67 megapascals at 66.33 percent strain, with its compressive modulus rising from 38.1 to 41.8 kilopascals as the fillers constrained chain mobility and increased crosslinking density. A cylinder of the composite hydrogel just half a centimeter in diameter could lift a 200-gram weight without fracturing, and the material stayed firmly attached to paper, iron rods and glass rods for extended periods. Differential scanning calorimetry showed the additives did not disturb the gel’s crystallization behavior, and water content remained high at 88.99 percent, with water absorption of 265.92 percent, so the shielding function came without sacrificing the hydration and flexibility that make hydrogels attractive for wearables.

The electromagnetic results were the study’s centerpiece. Measured with a vector network analyzer across the X-band from 8.2 to 12.4 gigahertz, the plain hydrogel achieved an average shielding effectiveness of 14.70 decibels. The optimized composite, designated PGZC1, reached 33.32 plus or minus 1.67 decibels, a 126.7 percent improvement that comfortably exceeds the 20-decibel threshold generally considered effective shielding. Analysis of the reflection, absorption and transmission coefficients showed near-zero transmission and absorption dominating over reflection, confirming that the material neutralizes waves by soaking up their energy rather than bouncing them back toward other devices, a crucial distinction for crowded electronic environments. Conductivity of the optimized gel measured 0.512 plus or minus 0.026 siemens per meter.

Intriguingly, more nanotubes were not always better. When the researchers increased the carbon nanotube proportion in the CNTs@ZIF-67 filler, shielding effectiveness progressively declined. The explanation lies in agglomeration: nanotubes have enormous surface area and strong van der Waals attraction, so at higher loadings they clump together, disrupting the synergistic interplay between the carbon and the ZIF-67 phase and damaging the gel’s porous structure, which reduces the surface area and active sites available for wave scattering. The finding underscores a recurring lesson in composite design, that uniform dispersion at modest loadings can outperform brute-force addition of conductive filler.

The researchers propose a clear shielding mechanism that ties the observations together. The PVA-gelatin network forms the structural scaffold, while well-dispersed CNTs@ZIF-67 particles build a conductive network and help generate relatively independent, complete spherical pores. When a wave strikes the surface, part is reflected and part penetrates, losing energy as it crosses the conductive walls; reflected components bounce between wall layers, attenuating further with each pass. Because absorption dominates, the energy ultimately dissipates as heat within the material. The authors suggest the gel’s combination of high shielding, toughness, adhesion, water retention and processability positions it for flexible electronics, wearable devices and stretchable sensors, offering a green, low-cost route to protecting both devices and people from the electromagnetic clutter of modern technology.

Subject of Research: CNTs@ZIF-67 composite nanoparticles enhancing electromagnetic interference shielding in tough PVA-gelatin organic hydrogels

Article Title: CNTs@ZIF-67 conductive composite nanoparticles enhance the electromagnetic shielding performance of tough organic hydrogels

Article References: Lei, Z., Zhang, D., Hu, Y., Zhou, T., Diao, K., Liu, D., Song, A., Zou, K., & Qin, S. (2026). CNTs@ZIF-67 conductive composite nanoparticles enhance the electromagnetic shielding performance of tough organic hydrogels. iScience, 29(11), Article 114635. https://doi.org/10.1016/j.isci.2026.114635

Image Credits: AI Generated

DOI: 10.1016/j.isci.2026.114635

Keywords: electromagnetic interference shielding, hydrogel, carbon nanotubes, ZIF-67, metal-organic framework, polyvinyl alcohol, gelatin, X-band, wearable electronics, dielectric loss, magnetic loss, conductive composites

The work, published in the Journal of Materials Science by Enyi He, Bo Song and colleagues at Huazhong University of Science and Technology and China Three Gorges University, centers on FeCoCrNiAl2, a five-element high-entropy alloy. Unlike conventional alloys built around a single dominant metal, high-entropy alloys mix several elements in roughly equal proportions, producing chaotic, distorted crystal lattices with unusual electronic and magnetic properties. In recent years these materials have attracted intense interest for electromagnetic applications precisely because that atomic disorder scatters and dissipates energy in ways ordinary alloys cannot.

But the alloy alone was not enough. The researchers combined it with reduced graphene oxide, or rGO, the defect-rich, electrically conductive form of graphene that has become a staple of microwave-absorption research. The critical variable turned out to be the ratio. When the mass ratio of FeCoCrNiAl2 to rGO was set at 3:1, the composite delivered its best performance, a balance the authors attribute to the synergistic interplay between the alloy’s magnetic losses and the graphene’s dielectric losses. Too much graphene and the material becomes overly conductive, reflecting waves at its surface instead of letting them in; too little and the dielectric loss pathway is starved.

The architecture is as important as the chemistry. Using a microemulsion technique, the team built spherical particles in which ethyl cellulose forms the outer shell framework and epoxy resin fills the inner core. The resulting microspheres are hollow and riddled with pores, and that internal void space does real electromagnetic work. Every boundary between air, polymer, alloy and graphene is a dielectric-magnetic heterointerface, a place where the material’s electrical and magnetic response changes abruptly. At each such boundary, incident microwaves are partially reflected, partially transmitted and partially absorbed, so a single wave entering a microsphere can bounce and scatter many times before it escapes, losing energy at every encounter.

The numbers reported in the study are striking. At a sample thickness of just 2 millimeters, the composite achieves an effective absorption bandwidth of 3.6 gigahertz, spanning 10.8 to 14.4 gigahertz, right in the heart of the X and Ku bands where military radars and satellite links operate. At a thinner 1.5 millimeters, the material reaches a minimum reflection loss of minus 40.48 decibels at 17.08 gigahertz. In practical terms, a reflection loss of minus 40 decibels means that more than 99.99 percent of the incident microwave energy at that frequency is absorbed rather than bounced back, which is the figure of merit that matters most for radar evasion and electromagnetic interference control.

Perhaps the most useful property is tunability. By simply varying the sample thickness between 1 and 5 millimeters, the composite can be adjusted to absorb efficiently anywhere across a broad range from 3.8 to 18 gigahertz, essentially covering the entire C, X and Ku bands. Thin absorbers typically struggle at lower frequencies because the quarter-wavelength matching condition demands thicker samples, so a material that can be tuned across nearly three octaves of radar spectrum by thickness alone gives designers a single filler that can serve many roles in one platform.

Underlying all of this is a cascade of dissipation mechanisms working in parallel. The researchers identify dipole and interfacial polarization, conductive loss, natural and exchange ferromagnetic resonance, and eddy current loss as the contributors. Dipole polarization arises when bound charges in the defective graphene and polymer matrix lag behind an oscillating field. Interfacial polarization, the Maxwell-Wagner-Sillars effect familiar from composite dielectrics, accumulates charge at the heterointerfaces created by the hollow porous structure. On the magnetic side, the iron- and cobalt-rich alloy undergoes natural ferromagnetic resonance, while exchange coupling between neighboring magnetic moments and eddy currents induced by the alternating field add further channels through which electromagnetic energy is converted into heat.

Impedance matching is the quiet hero of the story. An absorber fails if its surface impedance differs too much from that of free space, because the wave reflects before it ever penetrates the material. The hollow, porous architecture and the deliberate blending of magnetic alloy with dielectric graphene tune the composite’s permittivity and permeability into a regime where waves enter readily and are then dissipated inside. The abundant interfaces improve that matching while simultaneously multiplying the internal reflection pathways, which is why the authors credit the microspherical design, not just the constituent materials, for the enhanced performance.

The choice of ethyl cellulose and epoxy also carries practical weight. Both polymers are well established in microencapsulation technology, from controlled-release pharmaceuticals to self-healing coatings, and previous work has shown that polymer microcapsules filled with carbonyl iron or other functional powders can be incorporated into structural composites. A microwave absorber built from such microspheres could in principle be blended into resins, coatings or even 3D-printing feedstocks, and several of the authors have previously explored graphene and carbonyl iron microspheres for additive-manufactured absorbing composites. That processing heritage suggests a plausible route from laboratory measurement to real-world radomes, drone skins and electronics enclosures.

The broader context is a fast-moving field. High-entropy materials, from alloys to diborides and carbides, are being systematically explored for wave absorption, with recent studies reporting broadband performance at extreme temperatures and low-frequency absorption through engineered exchange interactions. Graphene-based hybrids with ferrites, carbonyl iron and molybdenum disulfide have pushed reflection losses deeper and bandwidths wider for a decade. What distinguishes the new work is the combination of a high-entropy magnetic filler, a two-dimensional conductive filler and a hollow polymer-templated architecture in a single lightweight particle, with each element contributing a distinct loss mechanism. The researchers, funded by the State Key Laboratory of Materials Processing and Die and Mould Technology, describe their strategy as a new route toward high-performance, wideband electromagnetic absorbers. If the fabrication scales beyond the laboratory, materials like these could quietly become the skin of the next generation of stealthy aircraft, satellites and electronic devices, absorbing the very signals that would otherwise give them away.

Subject of Research: Microwave absorption properties of FeCoCrNiAl2-rGO high-entropy alloy and graphene composite microspheres

Article Title: Fabrication and enhanced microwave absorption properties of high-performance FeCoCrNiAl2-rGO composite materials

Article References: Fabrication and enhanced microwave absorption properties of high-performance FeCoCrNiAl2-rGO composite materials. (n.d.). https://doi.org/10.1007/s10853-026-13276-9

Image Credits: AI Generated

DOI: 10.1007/s10853-026-13276-9

Keywords: high-entropy alloy, reduced graphene oxide, microwave absorption, FeCoCrNiAl2, composite microspheres, impedance matching, radar stealth, electromagnetic interference, ethyl cellulose, epoxy resin, dielectric loss, magnetic loss

The research, published in the journal Advanced Composites and Hybrid Materials, was led by Nayeong Kim and Inseok Baek, who contributed equally, along with colleagues at the Korea Institute of Materials Science in Changwon, Pusan National University, and Oak Ridge National Laboratory in Tennessee. Corresponding authors Youngseok Oh and Jinsu Kim of KIMS guided the study, which was supported by the National Research Foundation of Korea and the Korea Institute of Materials Science, with additional authorship under the U.S. Department of Energy’s contract with UT-Battelle at Oak Ridge. The work addresses a fundamental tension in induction welding of carbon fiber-reinforced thermoplastics, known as CFRTPs: effective joining demands both a rapid temperature rise at the weld line and a temperature field that is spatially uniform across the entire bond area.

The difficulty stems from the physics of induction heating itself. When an alternating magnetic field passes through an electrically conductive material, it induces eddy currents that dissipate energy as Joule heat. In a carbon fiber composite, however, the conductive network is formed by fibers that may not create continuous current loops in the right places, and the magnetic field generated by the induction coil is inherently non-uniform, strongest near the coil and weaker farther away. The result is localized hot spots and cold zones, which translate directly into incomplete melting, poor polymer impregnation, and weak welds. Achieving both rapid heating and uniform heating simultaneously has therefore been a persistent challenge, because the strategies that accelerate heating often intensify the non-uniformity.

The Korean-American team’s answer is a synergistic heating medium: a powdered aerogel composed of carbon nanotubes, iron oxide (Fe3O4) nanoparticles, and polyamide 6. Each component plays a distinct role. The carbon nanotubes form continuous conductive pathways throughout the aerogel, enabling efficient Joule heating when eddy currents are induced, and they also improve heat transfer through the weld interface. The Fe3O4 particles, meanwhile, respond rapidly to the alternating magnetic field through magnetic loss mechanisms, including hysteresis loss, acting as countless nanoscale heat sources distributed throughout the material. Because these magnetic heat sources are dispersed rather than concentrated, they compensate for the non-uniformity of the external field, warming regions that eddy-current heating alone would leave cold.

The aerogel architecture is central to the design. Aerogels are ultralight, highly porous solids, and in this powdered form the nanocomposite can be sprinkled or placed at the weld interface between two CFRTP parts. The porosity and the interconnected CNT network maximize the material’s interaction with the electromagnetic field while allowing the molten polymer to flow and impregnate the layer during welding. Crucially, the carbon nanotubes do more than generate heat: they also act as nanoscale mechanical pins that bridge the two composite surfaces, reinforcing the joint at the molecular level and enhancing interfacial weld strength beyond what thermal fusion alone can achieve.

The researchers fabricated nanocomposites with varying ratios of CNTs to Fe3O4 and experimentally identified the optimal composition, systematically balancing electrical conductivity against magnetic loss. The performance gains were striking. The nanocomposite-enabled welding system exhibited an initial heating rate of 148.7 degrees Celsius per second, which is 94.6 percent higher than that achieved with carbon fiber composite alone. That figure demonstrates that the dual heating mechanism does not merely redistribute heat; it dramatically accelerates the entire process, a property that matters enormously in industrial settings where cycle time determines economic viability.

Speed, however, would mean little without joint quality, and here too the results were compelling. The interfacial shear strength of welds made with the nanocomposite interlayer increased by 30.8 percent compared with conventional induction welding. Fracture-surface analysis of the broken joints revealed why: the weld areas showed more uniform melting and more effective impregnation of the polymer across the full bond area, rather than the patchy fusion characteristic of overheated-and-underheated regions. In a well-made thermoplastic weld, the polymer chains from each surface interdiffuse and entangle as the interface melts; uniform melting maximizes the area over which this healing occurs, and the CNT pinning adds mechanical interlocking on top.

The implications for manufacturing are considerable. Thermoplastic composites are prized because, unlike thermoset composites, they can be remelted, reshaped, and welded, opening the door to faster production of aircraft structures, automotive body panels, battery enclosures, and hydrogen storage vessels. Induction welding is already used to join thermoplastic aircraft components, but its reliability has been limited by temperature non-uniformity, forcing manufacturers to weld slowly or accept weaker joints. A consumable interlayer material that guarantees rapid, even heating could reduce energy consumption, shorten cycle times, and improve the structural integrity of welded assemblies, all without requiring changes to the induction equipment itself.

The study also highlights a broader trend in materials science: the deliberate combination of multiple physical mechanisms within a single nanostructured material to overcome the limitations of each. Joule heating and magnetic loss heating are complementary responses to the same electromagnetic field, and by embedding both in one aerogel, the researchers created a system in which the weaknesses of one mechanism are offset by the strengths of the other. The mechanical reinforcement provided by the CNT network is a bonus that no purely thermal approach could offer. The authors suggest that this nanocomposite represents a promising strategy for achieving both rapid and spatially uniform interfacial heating, leading to improved mechanical performance in the induction welding of CFRTPs.

Published as an open-access article on 2 September 2026, the paper invites further exploration of composition optimization, scalability of aerogel production, and long-term durability of the welded joints under fatigue and environmental exposure. For now, it stands as a vivid demonstration that sometimes the key to a better industrial process is not a new machine but a smarter material placed precisely where it is needed, a whisper-thin layer of nanotubes and magnetic particles that turns a patchy, uneven weld into a fast, strong, and uniform bond.

Subject of Research: Nanocomposite aerogel interlayers for rapid and uniform induction welding of carbon fiber-reinforced thermoplastic composites

Article Title: Synergistic heating effect via CNT/Fe3O4 nanocomposite aerogels enabling uniform and rapid induction welding with high bond strength in CFRTPs

Article References: Kim, N., Baek, I., Park, B., Kim, D., Jeong, C., Lee, J., Kim, J.-S., Joo, G., Kim, S., Kumar, V., Oh, Y., & Kim, J. (2026). Synergistic heating effect via CNT/Fe3O4 nanocomposite aerogels enabling uniform and rapid induction welding with high bond strength in CFRTPs. Advanced Composites and Hybrid Materials. https://doi.org/10.1007/s42114-026-02040-x

Image Credits: AI Generated

DOI: 10.1007/s42114-026-02040-x

Keywords: induction welding, CFRTP, carbon nanotubes, Fe3O4, nanocomposite aerogel, Joule heating, magnetic loss, hysteresis loss, interfacial shear strength, thermoplastic composites, polyamide 6, aerogels

The defining trick of a high entropy alloy lies in its name. Where a conventional alloy is dominated by a single base metal doped with trace additions, an HEA dissolves five or more elements at concentrations of roughly 5 to 35 atomic percent, typically with atomic radii differing by less than 15 percent. The authors note that the field has converged on a second, thermodynamic definition as well: a genuine HEA must possess a configurational entropy of at least 1.5R, where R is the gas constant, meaning the sheer number of possible atomic arrangements is large enough to stabilise simple solid solution phases instead of brittle intermetallic compounds. The result is a material whose structure and properties can be tuned not by tweaking a trace element but by redesigning the entire elemental recipe.

The review organises the field around four so-called core effects, first outlined by Jien-Wei Yeh and completed by S. Ranganathan in 2003. The high entropy effect favours stable, disordered solid solutions; sluggish diffusion slows the rate at which atoms move and phases transform; severe lattice distortion arises because every atom is surrounded by neighbours of different sizes, straining the crystal; and the cocktail effect captures the surprising composite behaviours that emerge when many elements interact at once. Crucially, each of these effects has a direct electromagnetic consequence. Lattice distortion bends electronic energy bands, splits energy levels and creates localised states between the valence and conduction bands, modulating conductivity and dielectric response in ways conventional alloys cannot easily replicate.

That structural disorder translates into an unusually rich toolbox of electromagnetic loss mechanisms. When a microwave strikes an HEA, energy is dissipated through electronic polarisation, as electron clouds shift against their nuclei in the local electric fields created by chemically distinct atoms; through interfacial polarisation, as charges pile up at grain and phase boundaries; through magnetic loss, as magnetic domains in ferromagnetic alloys containing iron, cobalt, nickel or manganese respond and resonate; and through conductive loss, as free electrons oscillate and convert wave energy into heat via Ohmic heating. The challenge, the authors stress, is balance: too much conductivity turns an absorber into a mirror, and a large mismatch between the material’s impedance and that of free space causes most of the wave to reflect away before it can be absorbed.

Impedance matching is therefore the central design problem, and here HEAs offer unusual flexibility. Because complex permittivity and complex permeability can both be adjusted through composition, HEAs can be engineered to bring the material impedance closer to that of ambient space, minimising the reflection coefficient while maximising the attenuation constant that governs how quickly the wave’s amplitude decays inside the absorber. The quantitative payoff is striking. Reported reflection losses for HEA-based materials span from about minus 10 decibels, the threshold below which 90 percent of incident power is absorbed, down to roughly minus 70 decibels, depending on composition, thickness and frequency. The reviewed literature includes an FeCoNiMnCu0.5 alloy with a reflection loss of minus 71.0 decibels at 6.79 gigahertz from a layer just 2.93 millimetres thick, and boron-doped FeCoNiCr alloys reaching minus 62.5 decibels at 2.11 millimetres.

Getting there, however, takes careful processing. Because pure HEAs tend to be strongly metallic and conductive, the review describes several engineering strategies for taming them. Mechanical alloying, particularly high-energy ball milling, flattens spherical particles into high aspect ratio flakes that promote multiple polarisation events and tune the complex electromagnetic parameters. Annealing then sharpens crystallinity and boosts saturation magnetisation: FeCoNiAlCr0.9 powders improved from minus 26.88 to minus 47.55 decibels after heat treatment, while FeCoNiMn0.5Al0.2 annealed at 500 degrees Celsius delivered minus 44.425 decibels over a 3.825 gigahertz bandwidth. Surface modifications do impressive work too. Phosphating FeCoNiMn flakes produced a protective layer that lifted performance to minus 62.4 decibels at 10.7 gigahertz while adding corrosion and oxidation resistance, and dealloying, which leaches aluminium out of FeCoNiCuAl surfaces, enhanced impedance matching and pushed losses past minus 56 decibels at two separate frequencies.

Doping and compositing broaden the palette further. Adding small amounts of non-metals such as carbon, nitrogen or boron introduces ionic character and dipole oscillations that feed dielectric loss; boron-doped FeCoNiCr alloys achieved a maximum bandwidth of 5.78 gigahertz while retaining mechanical strength and oxidation resistance. Encapsulating HEA nanoparticles in graphitic carbon shells, via routes from arc discharge in methane to metal-organic chemical vapour deposition, simultaneously improves impedance matching and reduces radar cross-section, with one carbon-coated FeCoNiCuMn composite reaching minus 65.8 decibels and an absorption width of 7.68 gigahertz. Pairing HEAs with polymers, oxides or ceramics blends the alloy’s magnetic loss and structural stability with the partner phase’s dielectric loss, as in FeNiCrMn-polylactic acid composites printable by fused deposition modelling, and FeCoNi(Si0.6Al0.2B0.2) powders embedded in paraffin, which the review singles out as among the most versatile performers, combining thin 1.2 to 2.0 millimetre layers with reflection losses down to minus 44.1 decibels in the X and Ku bands.

Measuring all this in a way that matters outside the laboratory is its own discipline, and the review devotes detailed attention to it. Vector network analysers paired with horn antennas measure scattering parameters such as S11 and S21 in free-space fixtures, from which shielding effectiveness and reflection loss are derived; HEA-reinforced carbon fibre composites tested this way achieved total shielding of about 45.9 decibels at 4 gigahertz. Open area test sites, with calibrated ground planes and antennas separated by 3 to 30 metres, serve compliance testing of large enclosures, while indoor anechoic chambers lined with pyramidal absorbers provide reflection-free environments for monostatic and bistatic radar cross-section measurements across controlled angles, polarisations and frequency sweeps. The review reports HEA composite radar cross-section reductions of roughly 10 to 30 decibels in chamber tests, and notes that such measurements bridge laboratory-grade shielding data and real-world electromagnetic detectability.

Obstacles remain before these alloys fly on actual aircraft. The authors highlight the absence of standardised testing protocols across frequency bands and environments, which makes comparing studies difficult; edge effects and sample size limits that hamper scaling VNA results to full components; interfacial stability and oxidation concerns when HEAs are coupled with polymers; and early-stage cost and manufacturability. Even the frequency coverage is lopsided: most HEA research targets the C and X bands central to military radar and communications, leaving S-band and Ku-band coverage comparatively underexplored. The review calls for quantitative assessment of absorption mechanisms, a firmer physical understanding of lattice distortion, scalable synthesis, multi-scale modelling and durability testing under extreme conditions as the priorities that will determine whether laboratory spectacles become fielded technologies.

The most transformative possibility, the authors argue, lies in merging HEA chemistry with additive manufacturing. Because 3D printing can control composition, microstructure and geometry simultaneously, it promises lightweight graded structures whose electromagnetic response is designed in from the melt, capable of surviving high temperatures and corrosive atmospheres while retaining their absorption performance. From stealth platforms and radar-visible UAV signatures to telecommunications, energy storage and even healthcare electronics, the combination of chaotic multielement chemistry and precision manufacturing offers something conventional absorbers cannot: a single material family whose dielectric and magnetic personalities can be tuned almost at will. If the remaining manufacturing and standardisation hurdles fall, the alloys once prized mainly for their strength and heat resistance may quietly become the invisible backbone of an electromagnetically cleaner, harder-to-detect world.

Subject of Research: High entropy alloys as electromagnetic wave absorbing materials for stealth and shielding applications

Article Title: A review on high entropy alloys as an absorber of electromagnetic radiation

Article References: Gowda, N. R., Setupathy, A., Raj, A. A. B., & Thangaraju, S. (2026). A review on high entropy alloys as an absorber of electromagnetic radiation. Journal of Materials Science: Metallurgy, 1(1), Article 5. https://doi.org/10.1007/s44492-026-00006-0

Image Credits: AI Generated

DOI: 10.1007/s44492-026-00006-0

Keywords: high entropy alloys, electromagnetic wave absorption, stealth technology, radar cross section, impedance matching, magnetic loss, dielectric loss, radar absorbing materials, electromagnetic interference shielding, mechanical alloying, additive manufacturing, lattice distortion