Carbon Nanotubes Content Research Articles

Electrostatic self-assembly effect of Fe3O4 nanoparticles on performance of carbon nanotubes in cement-based materials

Abstract The beneficial effect of carbon nanotubes (CNTs) to enhance the electrical conductivity and piezoresistivity of cement-based materials was highly contingent upon its dispersion. To achieve an appropriate dispersion of CNTs, ultrasonication, high-speed stirring, and chemical dispersion were commonly used, which raises the risk of structural damage of CNTs caused by the excessive energy. In this study, electrostatic self-assembly of Fe3O4 nanoparticles on CNTs was employed to efficiently disperse CNTs. To optimize the dispersion effect of conductive fillers in cement paste, the mix proportions including sodium dodecyl sulfate (SDS) concentration, CNTs concentration, and Fe3O4/CNTs ratios were adjusted. The dispersion degree and electrical property were evaluated by UV–vis absorption and zeta potential. In addition, the effect of self-assembled conductive filler dosage on the electrically conductive property of cement pastes was examined. The results show that the occurrence of electrostatic self-assembly was proved by the change of zeta potential, and the grape-bunch structure was observed by transmission electron microscopy. Further, the optimal proportions of self-assembled conductive fillers were 0.20 wt% SDS concentration, 0.05 wt% CNTs concentration, and 1:1 Fe3O4/CNTs ratio. The self-assembled conductive filler dosage between 0.02 and 0.10 wt% can effectively improve the electrical conductivity of cement paste with up to 68% reduction of resistivity.

Polymer Nanocomposites Based on Nanosized Substituted Ferrites (NiZn)1-xMnxFe2O4 on the Surface of Carbon Nanotubes for Effective Interaction with High-Frequency EM Radiation.

To create materials that interact effectively with electromagnetic (EM) radiation, new nanosized substituted ferrites (NiZn)1-xMnxFe2O4 (x = 0, 0.5, and 1) anchored on the surface of multi-walled carbon nanotubes (CNTs) have been synthesized. The concentration of CNTs in the (NiZn)1-xMnxFe2O4/CNT system was from 0.05 to 0.07 vol. fractions. The dielectric and magnetic characteristics of both pristine (NiZn)1-xMnxFe2O4 ferrites and (NiZn)1-xMnxFe2O4/CNT composite systems were studied. The introduction of (NiZn)1-xMnxFe2O4/CNT composites into the amorphous epoxy matrix allows to tailor absorbing properties at the high-frequency by effectively shifting the maximum peak values of the absorption and reflection coefficient to a region of lower frequencies (20-30 GHz). The microwave adsorption properties of (NiZn)1-xMnxFe2O4/0.07CNT-ER (x = 0.5) systems showed that the maximum absorption bandwidth with reflection loss below -10 dB is about 11 GHz.

A dual-crosslinking electroactive hydrogel based on gelatin methacrylate and dibenzaldehyde-terminated telechelic polyethylene glycol for 3D bio-printing

Gelatin was widely used as scaffold materials in 3D bio-printing due to its excellent bioactivity and availability and especially that their arginine–glycine–aspartic acid (RGD) sequences could efficiently promote cell adhesion and proliferation. In this study, an electroactive and 3D bio-printable hydrogel was prepared through a two-step chemical cross-linking process. Specifically, residual free amino groups of methacrylated gelatin (GelMA) were cross-linked with the aldehyde groups of dibenzaldehyde-terminated telechelic polyethylene glycol (DF-PEG) via Schiff base bonds, forming a gel at 37 °C. During the subsequent 3D bio-printing process, GelMA underwent UV curing, forming a secondary cross-linked network to the mechanical strength and stability of the printed structure. The uniform dispersion of carbon nanotubes (CNTs) in the GelMA/DF-PEG composite hydrogel significantly increased its conductivity. The optimized GelMA/DF-PEG composite hydrogel, i.e., 30% GelMA and 25% DF-PEG (G30D25-CNTs), exhibited superior bio-printability. When the content of CNTs was above 4%, the conductivity of G30D25-CNTs hydrogel exceeded 10–2 S/m, which satisfied the needs of cells for micro-current stimulation. Furthermore, the pore microstructures, swelling behavior, degradation ability and cell toxicity of G30D25-CNTs electroactive hydrogels were thoroughly evaluated. Thus, the G30D25-CNTs hydrogel with 4% MWCNTs could be considered for further application in electrical stimulation of tissue regeneration such as muscle and cardiac nerve tissue repair.

Rapid formation of carbon nanotubes–natural rubber films cured with glutaraldehyde for reducing percolation threshold concentration

Carbon nanotubes (CNTs) filled natural rubber (NR) composites with various CNT contents at 0, 1, 2, 3, 4 and 5 phr were prepared by latex mixing method using glutaraldehyde as curing agent. This work aims to improve the electrical and mechanical properties of CNT filled NR vulcanizates. The CNT dispersion of NR composites was clarified using dispersion grader, optical microscopy and scanning electron microscopy. The electrical properties of NR composites in the existing of CNT networks were studied by following the well-known percolation theory. It was observed that the NR composites exhibited low percolation threshold at 0.98 phr of CNT. Moreover, a three-dimensional network formation of CNT in the NR composites was observed and it is indicated by the t-value of 1.67. The mechanical properties of NR composites in terms of modulus, tensile strength and hardness properties were increased upon the addition of CNT to the optimum mechanical properties at 1 phr of CNT. Therefore, the present work is found the novelty of the study that the conductive rubber latex film can be produced using GA as low-temperature curing agent which enhanced good electrical properties. Moreover, this work is found to be beneficial in case of conductive rubber latex film that requires high modulus at low strain. The additional advantage of this system is the curing process occurs at low-temperature using GA and it can be easily processed.Graphical abstract

Enhanced rheological properties of carbon nanotubes reinforced natural rubber/butadiene rubber nanocomposites

AbstractEffects of carbon nanotubes (CNTs) content and the in situ surface modification via bis(triethoxysilylpropyl) disulfide (Si75) and (3‐aminopropyl) triethoxysilane (KH550) on the rheological properties of rubber nanocomposites are explored. Results from the strain sweep demonstrate that the filler network of the nanocomposite is enhanced when the hydroxylated CNT (HCNT) is incorporated. The promotion of filler–rubber interaction in nanocomposite reinforced with modified CNT is validated by both stress relaxation and strain sweep measurements. The die swell ratio (B) declines with increasing HCNT content and rises with a heightened shear rate. Compared to those without HCNT, B of the nanocomposites, which contained 5 phr HCNT, decreased by 5.4%, 7.0%, and 17.3% at 50, 200, and 500 s−1, respectively. The Si75‐modified HCNT and the carboxylated CNT (CCNT) reduce the B‐value of the extrudates at 500 s−1 by 3.7% and 3.0%, respectively. However, the extrudates filled with KH550‐modified HCNT or CCNT showed a larger B due to pre‐crosslinking, as demonstrated by stress relaxation and swelling tests. Furthermore, it is also found that the application of KH550 has an acceleration effect on the curing reaction, increasing the curing efficiency by 8.5%.Highlights The promotion of filler–rubber interaction is validated by RPA. The dimensional stability of the composites is improved after incorporating CNT. The extrudates with Si75 exhibit a reduced B and improved surface morphology. CNT content increase raises MH, ML, and shortens the t10 of the composite.

Study on the Mechanism of CNTs Regulating the Microstructures and Properties of Al–Cu–Mg Alloy

The purpose of this study was to investigate the effect of carbon nanotube addition on the microstructure and mechanical properties of Al–Cu–Mg alloy composites. By analyzing the XRD results, it was deduced that the extruded and heat-treated composites, after the addition of CNTs, were preferentially grown on the (220) crystal plane. In addition, the distribution of carbon nanotubes at α-Al grain boundaries was observed by SEM and TEM. The incorporation of carbon nanotubes leads to an increase in the degree of recrystallization in the composite. It is worth noting that according to the study of the four strengthening mechanisms of dislocation strengthening, grain refinement strengthening, load transfer strengthening, and second stage strengthening, when the carbon nanotube content is 1.5 wt.%, the tensile strength (480.4 MPa) and yield strength (456.68 MPa) are significantly improved.

Theoretical Model for the Stress–Strain Curve of CNT-Reinforced Concrete under Uniaxial Compression

The incorporation of carbon nanotubes (CNTs) can enhance the mechanical properties of concrete. The stress–strain curves of CNT-reinforced concrete under uniaxial compression are investigated through an experimental program with different CNT and steel fiber proportions considered. The test results demonstrate that CNTs can increase both peak stress and peak strain, and steel fibers can further enhance the effect of CNTs. Additionally, steel fibers can effectively enhance both the strength and ductility. Theoretical models for the peak strain, initial elastic modulus, toughness index and relative absorbed energy are established. A theoretical model for the uniaxial compressive constitutive relationship of CNT-reinforced concrete considering CNT and steel fiber content is developed. Finite element (FE) modelling is developed to simulate the axial compression behavior of CNT-reinforced concrete.

3D‐Printed Polyetheretherketone Smart Polymer Nanocomposite Scaffolds: Mechanical, Self‐Sensing, and Biological Attributes

This study demonstrates the mechanical, self‐sensing, and biological characteristics of carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs)‐engineered 3D‐printed polyetheretherketone (PEEK) composite scaffolds, utilizing custom‐made feedstocks. Microstructural analysis and macroscale testing reveal that the PEEK/CNT scaffolds with 6 wt% CNT content and 46% relative density achieve a gauge factor of up to 75, a modulus of 0.64 GPa, and a compressive strength of 64 MPa. The PEEK/CNT2.5/GNP2.5 scaffolds evince still better performance, at a relative density of 73%, reporting a modulus of up to 1.1 GPa and a compressive strength of 122 MPa. Importantly, stability in mechanical and piezoresistive performance up to 500 cycles is noted, indicating a durable and reliable performance under cyclic loading. Murine preosteoblast cells (MC3T3‐E1) are used to biologically characterize sulfonated scaffolds over 14 days. Cytotoxicity, DNA, and alkaline phosphatase (ALP) levels are quantified through in vitro assays, evaluating cell viability, proliferation, and osteogenic properties. Notably, PEEK/CNT 6 wt% scaffolds exhibit nearly 80% cytocompatibility, while PEEK/CNT2.5/GNP2.5 scaffolds reach nearly 100%. Both types of scaffolds support cell differentiation, as evidenced by elevated ALP levels. These findings carry significant promise in bone tissue engineering, paving the way for the development of adaptive, intelligent structural implants boasting enhanced biocompatibility and self‐sensing capabilities.

Analysis of low-velocity impact on FG-CNT reinforced cantilever sandwich beams: An FOSNDT approach

This study analyzes the low-velocity impact response of cantilever sandwich beams with foam cores and carbon nanotube (CNT) reinforced facesheets. Using the fifth-order shear and normal deformation theory, we explore three CNT distribution types through the thickness of the facesheets: uniformly distributed UD, functionally graded-V FG-V, and functionally graded-Λ FG-Λ. The contact force during impact is calculated according to Hertz contact law. Our findings indicate that the FG-V distribution offers the highest contact stiffness, resulting in reduced deflection compared to UD and FG-Λ distributions. Additionally, an increase in the core-to-face thickness ratio leads to decreased deflection and increased contact force, attributed to enhanced beam stiffness. The volumetric fraction of CNTs also plays a critical role, increased CNT content raises beam stiffness, decreasing deflection and enhancing contact force. Furthermore, the impactor’s initial velocity directly influences the deflection and contact force, with higher velocities leading to greater deflections due to increased kinetic energy. This comprehensive analysis underscores the significant effects of CNT distribution, volumetric fraction, and geometrical parameters on the dynamic response of sandwich beams under impact conditions.

Improvement of thermal conductivity and wear property of Gr/EP composites with CNTs/Cu foam as 3-dimensional reinforcing skeleton

The graphite-reinforced epoxy resin composite (Gr/EP) is considered one of the promising solid lubricating materials. However, the low thermal conductivity and correlated poor wear resistance cause limitations to its tribological applications. With the expectation to improve the thermal conductivity and wear property, carbon nanotube (CNT)-reinforced copper foams (CNTs/Cuf) are introduced as 3-dimensional skeletons to reinforce Gr/EP composites. Herein, comprehensive testing was conducted to assess the wear resistance, thermal conductivity, microstructure, and wear morphology of the composites. The results revealed that incorporating Cu or CNTs/Cu foams into the Gr/EP matrix significantly enhanced thermal conductivity and wear resistance, with only minor elevation of the friction coefficients, which showed a consistent decline trend with increasing CNTs contents. Notably, with the CNT content of 0.159 wt%, the composites reached the favorable combination of a 25.4 % improvement in thermal conductivity and a 34 % reduction in wear rate compared to pure copper foam-reinforced Gr/EP composites.

Engineered nanomaterials display a variable interaction with anoxygenic photoelectrogenic biofilm for pharmaceutical pollutants degradation

Engineered nanomaterials (ENMs) have been reported to facilitate extracellular electron transfer (EET) by increasing the electrical conductivity of electroactive biofilms. However, the mechanisms between different ENMs and anoxygenic photoelectrogenic bacteria for degrading organic pollutants remain unclear. In this study, we investigated the mechanism of metronidazole (MNZ) degradation by different concentrations of carbon nanotubes (CNTs), Iron (III) oxide (Fe3O4) NPs, and titanium dioxide (TiO2) NPs in Rhodopseudomonas palustris based photoelectrogenic biofilms. At low concentrations, CNTs enhanced the electrochemical activity and EET capacity of the biofilm, possibly by increasing the DNA concentration and cellular activity in the cathodic biofilm. However, the ecological toxicity of CNTs at high concentrations damaged the activity of R. palustris, resulting in a decline in the MNZ degradation rate (0.29179 h−1 at 185 μg/L and 0.27801 h−1 at 370 μg/L). A high TiO2 NPs concentration (370 μg/L) significantly boosted the MNZ degradation rate (133 % increase) via photocatalytic activity. But it affected the biofilm activity and EET. Overall, Fe3O4 NPs demonstrated superior performance. At 185 μg/L, the photosynthetic current and MNZ degradation rate increased by 138 % and 142 %, respectively. Despite a slowdown in the utilization rate of Fe (III) and EET at high concentrations, the biofilm exhibited sustained high activity, indicating that Fe3O4 NPs can significantly enhance the metabolism of R. palustris. These findings were not only important for optimizing the performance of anoxygenic photoelectrogenic biofilms but also for regulating the ecological impact of ENMs in natural environments.

Scalable fabrication of lightweight carbon nanotube aerogel composites for full X-band electromagnetic wave absorption

Electromagnetic waves (EMWs) from advanced electronic devices can hinder normal operation of other electronic equipment, negatively affecting their performance and cause harmful impacts on human health by breaking down DNA strands and causing cancer. In this study, we thrivingly prepared new lightweight EMW absorbing aerogel composites by first blending polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), carbon nanotube (CNT), reduced graphene oxide (rGO), and carbonyl iron (CI), followed by freeze-drying. The materials are promising for up-scale production with the current pilot-scale samples sizing 35 cm × 35 cm. The effects of CNT types, CNT, rGO, CI, and crosslinker contents on EMW absorption ability are comprehensively investigated. The obtained aerogel composites exhibit a 3D porous structure with low densities (0.088–0.210 g/cm3), high thermal stability (227 °C), and high Young's modulus (670.9 kPa) compared to past aerogels. Notably, the materials with 3.0–3.5 mm in thickness achieve the minimum reflection loss (RLmin) of up to −42 dB (99.99 % EMW energy lost) and provide coverage across the entire X-band (8.2–12.4 GHz) with RL < −10 dB, indicating a 90 % attenuation of EMW energy. Compared to commercial Ni/CNT and other existing composites, our materials boast a broader effective bandwidth of 1.2–2.2 GHz. These properties make our aerogel composites highly promising for valuable commercial use, offering lightweight, durable, and efficient EMW absorption capabilities.

Efficient energy harvesting enabled by large-area piezoelectric PVDF-based composite film enhanced by carbon nanotubes

Considerable attention has been drawn to the use of flexible piezoelectric energy harvesting devices for powering smart wearable technology. Herein, we employed a melt extrusion casting process to prepare large-area PVDF-based piezoelectric composite films and achieved continuous production. The films were prepared by adding 15 wt% lead zirconate titanate powder modified with a titanium coupling agent (PZT@UP15) and different content of carbon nanotubes (CNTs) exhibiting high conductivity into the PVDF matrix. The addition of CNTs in moderate amounts significantly enhanced the mechanical, dielectric, and piezoelectric properties of the composite films. Remarkably, the composite film containing 0.06 wt% CNTs achieved a d33 value of 28 pC/N, generated an open circuit voltage of 16.85 V, and a maximum power density of 0.46 μW/cm2 in the bending-releasing mode. Furthermore, the film exhibited relatively stable output performance even after 1500 cycles. The enhanced performances of the piezoelectric composite films can be attributed to the factors that the CNTs can effectively promote PVDF polarization by inducing dipole alignment and building an internal electric field, and further improve the piezoelectric performance and the electrostrictive performance. This work shows that the prepared piezoelectric composite film holds great potential as an energy harvesting device to provide power for wearable electronic devices.

A simple strategy for the construction of bi-supported triazine-based covalent organic frameworks as high-performance capacitive materials

A series of hybrid materials with different carbon nanotube contents TD-COF@CNTx (x = 0.05, 0.25, 0.45, and 0.65) were successfully prepared by using a one-pot method, where x represents the mass of carbon nanotubes added during the preparation process.

Effects of iron oxide and carbon nanotube contents on mechanical properties and shape memory behavior of biocompatible and biodegradable shape memory polymers

AbstractThe shape memory polymers (SMPs) is a potential alternative material for conventional shape memory alloys (SMAs) in various fields. Previous studies have focused on the application of SMPs materials as an alternative to SMAs. However, considering problems such as the poor mechanical properties, its application has been limited. This study developed a biodegradable, magnetically responsive SMPs material that can be used for medical implants with shape memory behavior under magnetic force and improved mechanical properties by adding nanoparticles. Moreover, effect of the added nanoparticle was investigated due to contents ratio. Nanocomposite was synthesized with polycaprolactone which has shape memory properties, Fe3O4 that generates heat under magnetic field, and carbon nanotubes with reinforcing effect. The morphology analysis confirmed the homogeneous dispersion of the Fe3O4/Carbon‐nanotubes (CNTs) in polymer matrix. The tensile test shows that tensile strength (14.9–17.6 MPa) increased when Fe3O4 (0–20 wt%) was included and that it did not increase significantly when CNTs (0–0.8 wt%) were included. The shape memory test result confirmed that developed composite had a shape memory under a magnetic field. It was confirmed that even if Fe3O4 was incorporated into polycaprolactone, did not lose its exothermic properties under magnetic field. The developed polymer showed high shape memory ratio (91%–98%) in all the nanoparticle content rates. With regard to biodegradability, weight loss occurred over time in the phosphate‐buffered saline solution. Therefore, the biocompatible, biodegradable, magnetic response shape memory polymer developed in this study might applied to various medical implant as advanced shape memory materials.

Investigation on the enhancement of heat transfer in counterflow double-pipe heat exchanger using nanofluids

Particles less than 100 nanometers in size are suspended in a base fluid such as water, oil, and ethylene glycol. These nanoparticles are floating in the nanofluid. The purpose of this study is to research the operation of a counter-flowing, double-pipe heat exchanger using two distinct nanofluids as cooling media. Titanium carbide and carbon nanotubes combine to form alkaline water, a basic fluid. The purpose of this research was to assess the performance of a counterflow double-pipe heat exchanger using water with different concentrations of titanium carbide and carbon nanotubes. Alkaline water had a particle volume concentration of 0.06, and its nanofluid-flow rate was 0.03. Using a heat exchanger, water is heated to 65?C while nanofluids are heated to 35?C, both at a constant input velocity. The speed of both fluids is constant. The findings demonstrate that nanofluid outperforms water in heat absorption across a broad range of flow speeds. Heat exchangers benefit from the improved thermal characteristics of nanoscale fluids.

Synthesis, and antimicrobial activity of polyazomethine-pyrazole/multi-walled carbon nanotubes nanocomposite materials

A novel series of bioactive polymer nanocomposites was recently created using the polycondensation method in conjunction with ultrasonic radiation. These nanocomposites comprise multi-wall carbon nanotubes and polyazomethine, which is based on the pyrazole moiety with various derivatives. The polyazomethine polymer was supplemented with a 2% concentration of multi-wall carbon nanotubes. The produced polymer nanocomposites were identified by Fourier-transform infrared spectroscopy and characterized by common characterization tools including X-ray diffraction, Scanning electron microscopy, and Transmission electron microscopy. The thermal stability was measured by thermogravimetric analysis and differential thermal gravimetry. The results of the X-ray diffraction patterns indicate that the multi-wall carbon nanotubes are really in the polymer matrix. The thermal analysis of these polymer nanocomposites shows high thermal stability. The agar diffusion technique was used to assess the antibacterial properties of the freshly synthesized polymer nanocomposites against various bacterial and fungal species. The chosen bacteria and fungi were susceptible to varying degrees of antimicrobial and antifungal activity in the polymer nanocomposites that were evaluated. Moreover, the antibacterial properties of the fabricated Polymer nanocomposites were assessed through colony forming units against Escherichia coli bacteria and showed good effectiveness of all tested polymer nanocomposites. All samples showed an effect on bacterial growth after 12 h by 22%–35%. After 24 h, the percent inhibition of E. coli in the presence of the prepared polymer nanocomposites was highest; it showed 45%–60%.

Condicionamento fisiológico de sementes em Clitoria ternatea L. com nanotubos de carbono de paredes múltiplas: Uma abordagem físico-química e morfológica

Abstract Clitoria ternatea L. is valued for its ornamental characteristics, medicinal properties, and culinary uses. However, efficient production of this species is constrained by seed coat dormancy, which impedes germination and seedling production. This study aimed to explore the physicochemical and morphological aspects of C. ternatea seeds, focusing on overcoming dormancy by applying multi-walled carbon nanotubes (MWCNTs) functionalized with carboxylic acid. The seeds were characterized by their physical, chemical, and mineral composition. Characterization included color dominance, geometry, thousand seed weight, and moisture content analyses. The seeds were treated with different concentrations (0, 100, 200, 400, 800 mg L-1) of multi-walled carbon nanotubes (MWCNT) during 24 hours of soaking. Then the germination rates were evaluated and morphological analysis was performed using scanning electron microscopy. Regarding the morphometry of the seeds, they were characterized by an oblong shape, a predominance of black tegument coloration, high levels of proteins, carbohydrates, lipids, fibers, and the presence of minerals such as potassium, magnesium, iron, and calcium. Seeds soaked in MWCNTs at a concentration of 200 mg L-1 exhibited an increase in germination percentage and the formation of normal seedlings compared to the control group (seeds soaked in water). The results suggest that MWCNTs can help to overcome seed dormancy and improve the quality of the resulting seedlings. Image analysis and scanning electron microscopy were crucial in understanding the physicochemical characteristics of the seeds and their changes upon exposure to MWCNTs.

Comportamento reológico, hidratação e propriedades mecânicas de sistemas LC3 com a incorporação de nanotubos de carbono de paredes múltiplas funcionalizados

Abstract Alternatives to conventional Portland cement with a more sustainable appeal are increasingly recurrent. Among these are the Limestone Calcined Clay (LC3) systems, characterized by high replacement percentages of Portland clinker by calcined clay and limestone, materials widely available worldwide. A complete understanding of the rheological behavior of LC3 systems is necessary for the practical application of this type of cement to be consolidated. Furthermore, although not yet investigated, the incorporation of nanomaterials stands out as a promising alternative for accelerating reactions and enhancing the mechanical performance of these systems at early ages. This study investigated the incorporation of carbon nanotubes (CNT) contents from 0.05 to 0.125% in an LC3 system through rotational rheometry, isothermal calorimetry, compressive strength at 7 and 28 days, and X-ray diffraction. Although the CNT incorporation increased the dynamic yield stress and equivalent viscosity of the LC3 pastes, the content of 0.1 wt.% slightly increased and anticipated the occurrence of the main peak of the aluminates. Increases of up to 13.5% in compressive strength at 7 and 28 days of hydration were observed for a CNT content of 0.1 wt.%.

Enhanced microwave absorption performance of Fe3Al flakes by optimizing the carbon nanotube coatings.

Fe3Al is a good magnetic loss absorber for microwave absorption. However, due to the relatively high density and poor impedance matching ratio, the potential of Fe3Al cannot be fully released. Herein, a dielectric loss absorber of carbon nanotubes (CNTs) is coupled with Fe3Al to form Fe3Al/CNTs composite absorbers. CNTs are randomly tangled and coated on the surface of the Fe3Al flakes, forming a connecting conductive network. By carefully tuning the content of CNTs, the optimized Fe3Al/CNTs composite absorber with 1.5% of CNTs can combine both magnetic loss and dielectric loss mechanisms, thus achieving an impedance matching ratio close to 1 while keeping strong attenuation for enhanced microwave absorption. As a result, an effective absorption bandwidth (RL ≤ -10 dB) of 4.73 GHz at a thickness of 2 mm is achieved.