Composites have revolutionized the field of aeronautics with its intriguing properties including high strength to weight ratio, low weight, chemical and weather resistance, flexible design and low cost of installation. Also, composites are used as radar absorbing materials (RAMs) in the manufacturing of stealth aircraft. Stealth technology (ST) uses a combination of RAMs and geometry to minimize the reflection of electromagnetic waves back to a radar system. In this review article, working principle and basic constituents of ST are examined along with RAMs types in the light of composites. Moreover, recently developed carbonaceous‐based polymer composites are critically discussed in terms of RAMs for stealth applications. A carbonaceous‐based composite provides a high flexibility for the design and properties control. Carbon black particles, carbon fibers, carbon nanotubes (CNTs), and graphene are used in composites to tailor the wave's absorption properties of a composite. Multilayered structures are also recommended by researchers to extend the absorption band for better stealth application. Optimized absorption properties were achieved from composites containing carbon fiber as filler. Also, CNTs are preferred due to its smaller loading (0.35%) to get conductivity equal to higher concentration of carbon black (20%), which consequently improves the ST. Enhanced electromagnetic absorption properties can be achieved form the graphene‐based RAMs along with incorporating the magnetic particles of different microstructures, particle size, and electromagnetic characteristics. This review will intensively cover the methodology of ST and different composites including carbon‐based composites as RAMs for the use in stealth technology.

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This study reports on the electrical conductivity, dielectric, and electromagnetic interferenc (EMI) shielding properties of conductive epoxy/PAni blend containing various concentrations. Polyaniline (PAni) was synthesized using oxidative chemical polymerization technique and then dispersed into epoxy resin using a sonication bath. Infrared spectra confirm the curing of composites. Increasing the aspect ratio of PAni in epoxy increased the electrical conductivity and improves the microwave absorption properties of composites in the microwave range (0.1 GHz–20 GHz). Electrical conductivity was measured by using the four-probe method, and the maximum conductivity of the composite was achieved 3.51 × 10−13 Scm−1 with 30 wt% of PAni. The maximum porosity of the composite with 30 wt% of PAni was 15.5%. EMI shielding was measured by a vector network analyzer (VNA) in the microwave region (0.1 GHz–20 GHz), which gives the maximum value of 63 dB. IR shielding was measured by IR spectroscopy and less than 0.5% transmission was observed in NIR (700 nm–2500 nm) region. The average particle size of PAni is found to be 113 nm. These composites were used as a potential candidate for conductive coatings, EMI shielding purposes, and electronic applications.

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Magnetic and electrically conductive polymeric nanocomposites were fabricated using polystyrene (PS) as matrix, Nickel Ferrites (NiFe) as magnetic nanofiller and polyaniline (PANI) as electrically conductive nanofiller. Electromagnetic interference (EMI) shielding and infrared (IR) blocking are the main application of these nanocomposites. PANI and NiFe were successfully prepared by chemical and co-precipitation methods respectively. The successful fabrication of nanofillers was confirmed by the X-ray diffraction technique. DC conductivity and dielectric properties were first analyzed and a huge increase in both dielectric constant and DC conductivity was observed. Dielectric Constant seemed to be increased from 2.2 for PS to 5.5 for PS/PANI/NiFe composite. For the measurement of EMI shielding effectiveness (SE), Vector Network Analyzer was used in 0.1-20 GHz frequency range. IR spectroscopy was used to measure IR transmission in near-infrared (NIR) region of 700-2500 nm wavelength range. PS film is transparent for both NIR waves and microwaves, by observing almost 90% transmission in the NIR range and about − 3 dB SE in the microwave region. IR transmission reduces to less than 0.5% for PS/PANI/NiFe composite in the whole NIR range. Also, in the microwave region, − 3 dB shielding enhanced to less than − 35 dB in a broad range of frequency from 0.1 to 20 GHz.

Carbon fabric‐reinforced polymer (CFRP) composites were incorporated with novel, environment‐friendly and, low‐cost inorganic flame‐retardant (FR) materials. Synergistic properties of potash alum (KA) and magnesium hydroxide (MH) were obtained by infusing these materials in the carbon woven fabric with diglycidial ether of bisphenol‐A epoxy (EP) matrix through resin infusion technology. Composite samples EP80%MH20% and EP80%MH15%KA5% showed Underwriter Laboratories 94 (UL94) V‐2 rating, EP80%MH10%KA10% and EP80%MH5%KA15% showed UL94 V‐1 rating, and EP80%KA20% showed UL94 V‐0 rating. Flame retardancy of EP was improved with increasing concentration of KA up to UL94 V‐0 while a high concentration of MH improved flame retardancy only up to UL94 V‐2 rating, which is not suitable for the material. Flexural modulus and flexural strength of EP were decreased with increasing concentration of KA and MH because both FR created the distance between the EP chains and hence imparted ductility. Thermogravimetric analysis showed an increase in char residue with increasing KA concentration. The char residue of EP100% (without FR materials) was 16.5 wt%, which increased to 71.2 wt% for EP80%KA20%. CFR samples were prepared with the given FR materials and it was seen that reduction in mechanical properties was compensated with the help of CFRP.