Mechanical Properties Of Carbon Nanotubes Research Articles

Heat and mass transfer in MHD flow of SWCNT and graphene nanoparticles suspension in Casson fluid

AbstractThe exceptional mechanical properties of carbon nanotubes (CNTs) and graphene nanoparticles, particularly their high aspect ratio and flexibility, position them as highly promising materials for the next generation of armor technology. Their incorporation into protective wear, such as bullet‐proof vests, offers the potential for significant improvements in both performance and cost efficiency. By replacing traditional materials with CNTs and graphene, the durability and maintenance of these protective devices could be substantially enhanced, leading to more effective and sustainable solutions for personal safety. This study focuses on the complex phenomena of heat and mass transport within a suspension of CNTs and graphene nanoparticles dispersed in a Casson fluid, particularly under the influence of an applied magnetic field. The analysis begins by reformulating the governing equations using similarity variables to transform them into a dimensionless form to simplify the problem. The resulting dimensionless equations are then solved using the three‐stage Lobatto IIIa finite difference method, a robust numerical technique well‐suited for solving boundary value problems in fluid dynamics. The results of this investigation highlight a significant 78.41% reduction in skin friction when compared with traditional CNT‐water nanofluid systems. This considerable decrease in skin friction not only reveals the superior performance of the CNT‐graphene nanofluid suspension but also opens up new possibilities for the design and development of advanced protective materials. These findings contribute to the growing body of knowledge on nanofluid applications and offer valuable insights for future research in the field of advanced armor technology.

Impact of Dispersion Methods on Mechanical Properties of Carbon Nanotube (CNT)/Iron Oxide (Fe3O4)/Epoxy Composites

Integrating nanomaterials like carbon nanotubes (CNTs) and iron oxide (Fe3O4) into epoxy composites has attracted significant interest due to their potential to enhance mechanical properties. This study evaluates the impact of dispersion quality on the mechanical performance of CNT/Fe3O4/epoxy composites, comparing stirring and sonication methods at three different loadings: 0.1, 0.3, and 0.5 wt.%. Tensile testing revealed that sonicated composites consistently outperformed stirred composites, with a significant increase in the elastic modulus and ultimate tensile strength (UTS). However, fracture strain decreased in both composite types compared to pure epoxy, with sonicated composites experiencing a more significant reduction than stirred composites. These results underscore the importance of high-quality dispersion for optimizing mechanical properties.

Carbon nanotubes as a basis of metamaterials and nanostructures: Crafting via design optimization

Nanotruss structures made of carbon nanotubes are investigated in two conceptual applications: either as building blocks of metamaterials or for nanostructural applications. The nanotrusses are optimized for different purposes, including various loadings, boundary conditions, parameterizations, objectives and constraints used to formulate optimization problems. The procedure relies on a recently developed framework consisting of molecular dynamics simulations, neural networks and finite elements. This framework is now used in the design optimization of nanostructures and the performances of different popular heuristic optimization methods are compared. Five applications of nanotrusses made of carbon nanotubes are analyzed in detail to investigate the mechanical behavior of such structures and the efficiency of the optimizations. Besides an introductory example, the design of an energy trapping carbon nanotube nanotruss, an auxetic nanotruss, a cantilever nanotruss and the maximization of the compressive strength of a metamaterial are presented. It is shown that the exceptional mechanical properties of carbon nanotubes can indeed be exploited for the development of structures and materials with extraordinary mechanical properties. Although hampered by material and geometrical nonlinearity of the problem, most of the tested optimization methods have proven to be a good choice for the design of such materials and structures.

Mechanical properties of carbon nanotube (CNT) reinforced polymers using electron‐deficient aromatics as additives

AbstractIn initial experiments the effects of aromatic model substances on carbon nanotube (CNT) dispersions in dimethylformamide (DMF) were investigated. Electron‐deficient aromatics interact strongly with CNTs, causing increased agglomeration and sedimentation. Conversely, electron‐donating aromatics stabilize CNT dispersions in DMF. Polymers with electron‐deficient aromatics, such as polydinitrostyrene (PDNS), exhibit a concentration‐dependent effect: low concentrations lead to stabilization of dispersions, while higher concentrations lead to sedimentation. This suggests that such polymers can enhance attraction between the matrix of CNT‐reinforced polymers as well as stabilize the dispersed CNTs. Polycarbonate, modified with polydinitrocarbonate (PDNC) and reinforced with CNTs showed improved mechanical properties. The addition of 6 wt.% CNTs and 6 wt.% PDNC resulted in a notable improvement with a 22% increase in tensile strength, a 29% increase in flexural strength, a 39% increase in Young's modulus and a 47% increase in flexural modulus. This enhancement resulted in an overall mechanical performance comparable to the high‐performance polymer polyetherimide. However, there must be noted, that the addition of PDNC increases the CNT particle size, which can negatively affect mechanical properties. The results highlight the additive's dual role in enhancing adhesive interactions while potentially increasing CNT agglomerate sizes.Highlights Interactions of CNTs dispersed in DMF and various aromatics were investigated. Polydinitrocarbonate (PDNC) was synthesized as a new additive for CNT‐composites. Polycarbonate/CNT‐composites were obtained using extrusion. Test specimens with CNT contents up to 6 wt.% were obtained. Mechanical properties of polycarbonate reached the level of polyetherimide.

Studying quantum effects of fine scaling on the buckling behavior of CNTs under torsional loading using the density functional theory and molecular mechanics approach

In this study, we introduce a comprehensive investigation into the buckling behavior of carbon nanotubes (CNTs) using a combined approach of quantum mechanics and molecular mechanics methods. A novel aspect of our research lies in the exploration of the quantum effects of fine scaling on the buckling behavior of finite‐length nanotubes across various dimensions and chiralities. Specifically, we analyze the critical buckling strain variations in CNTs with distinct lengths, diameters, and chiralities, revealing pronounced differences influenced by atomic arrangement and the type of structure used in nanotube construction. Our findings elucidate that at smaller dimensions, nanotubes exhibit a higher critical buckling strain than other chiralities, while zigzag atomic arrangements demonstrate greater resistance to torsional loading at larger diameters. Additionally, we compare the buckling behavior of nanotubes obtained by wrapping armchair and zigzag nanosheets, highlighting differential resistance trends. This research not only underscores the critical role of quantum effects in determining nanotube buckling but also provides valuable insights into the nuanced influences of atomic arrangement and nanosheet type on the mechanical properties of CNTs. Thus, our work contributes a novel perspective to the field, bridging the gap between quantum mechanics and the mechanical behavior of nanostructures, which has significant implications for the design and application of nanoscale materials

Characterization and Evaluation of Mechanical Properties of Carbon Nanotube Filler Epoxy Composite

The outstanding mechanical properties of carbon nanotubes (CNT) have made them the focus of extensive investigation. To characterize and study the effects of the different volume fraction of multi walled carbon nanotubes (MWCNTs) on the mechanical properties of the nanocomposites attempted. The purpose of this work is to use experimental techniques to ascertain the mechanical characteristics of the nanocomposite. Tests on mechanical tensile strength were conducted to see how the MWCNT filler content affected the reinforced epoxy nanocomposite. The result of altered percentage of MWCNTs on the mechanical properties of the composites had been inspected. Results showed that 0.2 wt% MWCNT addition has the best effect on the mechanical properties of the matrix.

Enhancing the Interaction of Carbon Nanotubes by Metal–Organic Decomposition with Improved Mechanical Strength and Ultra-Broadband EMI Shielding Performance

HighlightsA strategy based on metal-organic decomposition is proposed to enhance the tube-tube interactions of carbon nanotubes (CNTs).The robust tube-tube interactions of CNTs enhance both EMI shielding performance and mechanical properties of CNT film.This innovative approach provides an effective way to obtain high-performance CNT film.

Tailored twisted CNT bundle with improved inter-tube slipping performances

The exceptional mechanical properties of carbon nanotubes (CNTs) have encouraged the development of high-performance synthetic fibers in composite materials. To understand the effect of twisting on the mechanical and slipping performances of CNT bundles, molecular dynamics simulation is applied to investigate the tensile performances, failure modes, and pull-out responses of twisted CNT bundles. A molecular model comprising nineteen parallel aligned single-walled carbon nanotubes (SWCNTs) is twisted into bundles at angles of 0°, 10°, and 20°, and further tensile and pull-out simulations are performed. The tensile simulation indicates that compared with the non-twisted CNT bundle showing a tensile strength of about 82 GPa with obvious inter-tube slipping, the 10°-twisted bundle exhibits a tensile strength of approximately 70 GPa with SWCNTs fracture as the main failure mode, which indicates that twisting improves the inter-tube slipping performance without causing excessive strength reduction. Comparatively, when the twisting angle is 20°, no inter-tube slipping is observed and the tensile strength of the CNT bundle is measured to be 55 GPa, which decreases by approximately 32.9 %. The pull-out simulations further reveal that the pull-out forces increase as the twisting angle increases and the weakened bundle strength of twisted bundle is attributed to the repulsive van der Waals forces caused by the reduced distances between inter-tubes. Essentially, twisting is unfavorable for the overall mechanical strength while torsional densification mitigates the inter-tube slipping, which indicates that a trade-off need to be achieved. This paper provides insights into the tensile and slipping performances of twisted CNT bundles and forms a basis for enhancing the assembled CNTs bundle as the next-generation reinforcing phase in composite materials.

Dispersion mechanism of nanoparticles and its role on mechanical, thermal and electrical properties of epoxy nanocomposites - A Review

The combined effect of nano-reinforcements on the mechanical performance of nanocomposites, which are a novel class of epoxy matrix hybrid nanocomposites containing multiwall carbon nanotubes (MWCNT), graphene, and nanodiamonds (NDs), is drawing substantial attention from many research communities. The discussion concentrates on the dispersion techniques adopted for the preparation of epoxy composites containing different types of nanoparticles (3-D fillers, nanofibers, nanotubes, and plate-like fillers). This review paper covers the electrical, thermal, and mechanical properties of carbon nanotubes (CNTs), graphene, and nanodiamond-reinforced epoxy nanocomposites and correlates them with the topographical features, morphology, weight fraction, dispersion state, and surface functionalization of CNTs, graphene, and nanodiamond. This review paper also summarises recent developments in the dispersion method of different carbon nanoparticles in epoxy matrix.

Damage mechanism and mechanical properties of carbon nanotubes induced by He2+ ion irradiation: Molecular dynamics simulations and experiments

Carbon nanotubes (CNTs) are expected to play a pivotal role in future space device applications owing to their exceptional material properties. To ensure the reliability and safety of CNTs in such applications, meticulous assessment and understanding of their structural integrity under ions irradiation is imperative. In this study, the mechanisms of damage to 1–5 wall CNTs caused by the irradiation of He2+ ions in the 1–100 keV energy range were investigated by conducting molecular dynamics (MD) simulations. The mechanisms of damage induced by He2+ ion irradiation exhibited notable distinctions between single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). SWCNTs easily conducted the kinetic energy of the He2+ irradiation out of the CNTs with cascade collisions, thereby reducing the damage they incurred, whereas the interlayer structure of the MWCNTs resulted in the irradiation energy being confined inside the tubes, leading to an increase in defects. The MD simulations revealed the irradiation swelling phenomenon of the MWCNTs in relation to the kinetic energy of irradiation and the cumulative fluence and indicated that swelling occurred simultaneously inward and outward along the radial direction of the CNTs. Irradiation-induced swelling was observed in experiments involving vertical array carbon nanotubes (VACNTs) irradiated with 540 keV He2+ ions. The results from scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterization, along with the Raman analysis, indicate that the damage observed in CNTs due to He2+ ion irradiation closely resembles the findings obtained through MD simulations. Both experimental and MD simulation studies demonstrated that increasing the dosage of He2+ ion irradiation increased the CNT defects, causing a transition from the ordered graphite structure to amorphous C. Additionally, the compressive mechanical properties and surface adhesion mechanics of the irradiated VACNTs were examined by performing nanoindentation experiments. The tensile mechanical properties of the irradiated CNTs were evaluated using MD simulations. The combined results indicated that high-energy, high-fluence ion irradiation degraded the mechanical properties of the CNTs. This study comprehensively investigated the mechanisms of damage to CNTs under He2+ ion irradiation and the subsequent impacts on the mechanical properties of the CNTs. The findings of this research provide essential insights for comprehending the irradiation responses of CNTs and for designing composite CNT materials with enhanced radiation resistance.

The base versus tip growth mode of carbon nanotubes by catalytic hydrocarbon cracking: Review, challenges and opportunities

Hydrogen gas production using catalytic hydrocarbon cracking on metal nanoparticles has become a vital bridge technology, as this process, unlike the traditional methane-based reforming process, does not co-produce carbon gasses (e.g., CO, CO2). The major benefit of direct catalytic methane cracking using a nanostructured catalyst is the formation of solid carbon in high-value products, such as carbon nanotubes (CNTs) or filaments. This solid carbon can then be removed physically and valorized. However, it is challenging to design a catalyst capable of sustaining its activity after solid carbon has started to deposit and grow, meanwhile preventing the formation of coke. For CNTs, in particular, the base growth mode of CNTs is the desired pathway, as the catalyst can then be regenerated and re-used. If the CNTs are formed under the tip-growth mode, the catalyst particle will be lifted off the support of the regeneration and reusability is lost. Therefore, the study of CNTs growth modes is a vital topic, both experimentally and theoretically, of designing appropriate catalysts. To date, enormous efforts have been made to investigate conditions where the CNTs base growth mode can be maintained during the carbon deposition process. Several possible correlations and mechanisms regarding the base growth mode have been explored and established. Theoretical calculations and numerical simulations across length scales were conducted to investigate the nucleation mechanism and growth of CNTs. Density functional theory (DFT), classical and quantum-based molecular dynamics (MD) and Monte Carlo (MC) simulations were also carried out to study the initial CNT cap formation and its encapsulation during the catalytic hydrocarbon cracking process. A thermodynamics-based nucleation formula of CNTs for both the base and tip growth modes was also established. However, there is still no consensus on what determines the CNT growth modes and what the roles are of the various influencing factors such as the nanoparticle size, the oxidation state of the catalyst, the mechanical properties of CNT, and the catalyst-support interaction. This paper reviews the current status of CNT's growth mechanism development. The benefits and limitations of theory and modeling approaches concerning CNT growth modes are discussed.

Superior crack propagation inhibitory effectiveness of MWCNT reinforced SBS toward improving oil/gas well cement integrity

The brittleness and low cracking resistance of oil- and gas-well cement threaten its integrity, specially under the high stress concentrations at bottom-hole conditions. Fortunately, the excellent mechanical properties of carbon nanotubes and elastomers motivate researchers to utilize them as versatile candidates that can positively modify the breakage behaviors of cement-based materials. Herein, we investigated the hybridization effects of multi-walled carbon nanotubes (MWCNTs) and styrene–butadiene–styrene (SBS) on the mechanical properties and breakage behaviors of oil- and gas-well cements. MWCNTs and SBS were synthesized and then, characterized with a wide range of techniques, signifying successful syntheses of these two materials. Afterward, SBS was dry mixed with cement powder and then added to the aqueous suspension of MWCNT prepared via sonication method. The mechanical testing (e.g., uniaxial, triaxial, and Brazilian tests), numerical simulation, and imaging analysis showed that incorporation of the SBS into the cement matrix promoted the ductility and macro-scale cracking resistance. The introduction of MWCNTs improved the cohesion, micro-scale cracking resistance, and strength properties of the cement matrix. Thereupon, the hybridization of 0.075 wt% of MWCNT and 9 wt% of SBS endowed great mechanical behavior and cracking resistance to the conventional oil-well cement in both micro and macro structures. These specifications can maintain cement’s durability under the critical thermal and mechanical stress concentrations at various bottom hole conditions. This improvement contains the increasing of strain energy, tensile strength, cohesion, and Poisson’s ratio by 219.27%, 141.17%, 750% and 100%, respectively and reducing the elastic modulus by 41.67%. Fourier Transform Infrared Spectroscopy (FTIR) analysis exhibited that these enhancements can be attributed to favorable interactions between MWCNT and SBS in the cement matrix.

Carbon Nanotube Based Broadband Solar Thermal Absorber Coatings

Radiant energy conversion and storage eliminate the mass transfer process induced power output limitation, and open a new vista for energy utilization. An effective system for harvesting radiant energy from both solar and thermal radiation will be beneficial for further radiant energy utilization. On the other hand, space observatory missions require low-reflectivity surfaces/coatings for space-borne instruments, such as seeker telescopes, optical sensors, etc., to minimize stray and reflected light on targeted telescope and baffle materials and construction. The excellent optical, thermal, and mechanical properties of carbon nanotubes (CNTs) make them as ideal coating materials for absorbing the broadband spectrum across UV-Vis-IR regions.In this presentation, Faraday Technology will discuss an innovative electrophoretic deposition (EPD) manufacturing process, based on the use of pulsed electric fields, for controlled, reproducible, scalable deposition of a wide variety of carbon nanotube based coatings across a broad range of substrates, geometries and sizes (Figure 1 a). The effects of waveforms, electrolytes, substrates, etc. on the formation of robust and uniform coating will be discussed in this talk. The optical properties, and environmental survivability of carbon nanotube coatings will be demonstrated via a variety of testing or characterizations. The CNT coatings show the total hemispherical reflection of 0.5% - 1% across UV-Vis to near infrared (NIR) wavebands, which is much lower than the reflectance of the typically used Z306 black paint (Figure 1 b). These CNT coatings also withstood simulated launch conditions vibrational tests, and demonstrated no weight loss and optical degradation. Furthermore, the CNT coatings were evaluated for atomic oxygen erosion resistance in a simulated low earth orbit (LEO) environment, and showed enhanced resilience when compared to Kapton and HOPG. Faraday will also introduce their applications in low-reflective coatings and solar thermal absorbers for radiant energy harvesting and conversion.In summary, a scalable EPD manufacturing process for fabricating carbon nanotube based coatings have been developed at Faraday for the applications in the field of low-reflective coatings and broadband solar thermal absorbers.Acknowledgements: The financial support from NASA SBIR program through contracts No. 80NNSC18P2062 & 80NSSC19C0177, DARPA SBIR program through grant No. W31P4Q-22-C-0014, DOD MDA STTR program through grant No. HQ0147-19-C-7065, and DOD Air Force SBIR program through grant No. FA9550-22-P-0015 are acknowledged. Figure 1

Optimization of electrical and mechanical properties of a single-walled carbon nanotube composite using a three-roll milling method

In this study, the electrical and mechanical properties of carbon nanotube (CNT)/polydimethylsiloxane (PDMS) composites were optimized using a three-roll milling dispersion method. Depending on the number of CNT walls, such as single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs), the three-roll milling conditions required to optimize the electrical conductivity of CNT/PDMS composites are quite different. In addition, the mechanical properties of the CNT/PDMS composites depend on the dispersion time. These properties were improved under an appropriate three-roll milling time but gradually deteriorated after excessive processing time. To demonstrate and optimize this phenomenon, various mechanical, electrical, and thermal properties of the CNT/PDMS composites were measured with respect to the type of CNT, milling time, and filler weight fraction. Morphological and structural analyses were also conducted on the CNT fillers and composites after milling.

Effect of induced vacancy defects on the mechanical behavior of wavy single-walled carbon nanotubes

This study utilized molecular dynamics simulations to assess the influence of structural alterations, such as waviness and vacancy defects, on the mechanical properties of carbon nanotubes. This work utilizes the LAMMPS simulation environment to compare models of carbon nanotubes, thus enabling the observation of fracture properties at an atomistic level. A comparative analysis was conducted on pristine straight carbon nanotubes and their wavy and defective counterparts. The study was divided into two stages: the initial stage revealed that straight carbon nanotubes exhibited superior mechanical strength when subjected to tensile loading. However, introducing waviness along the axis of the carbon nanotubes resulted in a significant reduction in strength. Subsequently, in the second stage, vacancy defects were introduced to the carbon nanotube structure, which were quantified by defect densities and plotted against the tensile strength of the carbon nanotubes. This analysis allowed for a deeper understanding of the correlation between the defect density and tensile strength of carbon nanotube structure. Finally, a relationship between the strain energy and temperature variation in carbon nanotubes was established, emphasizing the importance of temperature control in the applications and manufacturing processes of carbon nanotubes. Overall, this study provides valuable insights into the factors that can affect the mechanical properties of carbon nanotubes.

Enhancing the Electrochemical Properties and Processing Techniques of Carbon Nanotubes for Bio pharmacological Applications: A Research Perspective

Compared with other biopharmaceutical technologies, carbon nanotubes not only have unique structure, but also have strong electrochemical properties, which occupy an important position in the fields of chemistry, physics, biopharmaceutics and materials science, and have played an active role in promoting the development of biopharmaceutics and chemical industry in China. Carbon nanotubes (CNTs) are mainly used in the field of biopharmacology for the determination of small biological molecules and drug molecules, the determination of dopamine and thrombin, the determination of high concentrations of ascorbic acid, and the detection of drug formulations. Although carbon nanotubes (CNTs) have many advantages in the field of biopharmaceutics, there are certain limitations that limit the scope of application of carbon tubes, which are mainly the following: one is the high cost of the carbon nanotube material itself and the high technical difficulty of its preparation; the other is that the smooth surface of the material is not conducive to the loading of other particles; finally, although the carbon nanotubes are modified with different groups after treatment, the structure of the material itself is damaged. Finally, although carbon nanotubes are modified with different groups after treatment, their own material structure is destroyed, which reduces their conduction performance. Although the above defects can affect the performance of carbon nanotubes, they can be solved by optimizing the structure of carbon nanotubes, enhancing the plastic mechanical properties of carbon nanotubes and corrosion resistance, in order to give full play to the role of carbon nanotubes in the field of biopharmaceuticals. In this regard, the author briefly analyzes the electrochemical properties of carbon nanotubes in biopharmacology and the application of treatment methods based on relevant literature and work experience, hoping to provide reference value for related scholars and researchers.

Characterization and application of flexible, highly conductive freestanding films of SWCNT and PMMA nanocomposite prepared by facile solution method

The aim of this work was to prepare single-walled carbon nanotube (SWCNT)-embedded polymethyl methacrylate (PMMA) freestanding polymer films and investigate their mechanical and electrical properties. PMMA is widely used in various applications; however, its poor mechanical and electrical properties limit its use. The electrical and mechanical performance of PMMA can be effectively improved by producing nanoparticle-reinforced PMMA composites. Carbon nanotubes (CNTs) are highly attractive nanoparticles used to develop polymer nanocomposite films with novel properties useful for diverse technological applications. The superior electrical and mechanical properties of CNTs can enhance the corresponding properties of the CNT/PMMA nanocomposite. The SWCNT/PMMA nanocomposite films were prepared with a simple sonication technique by employing ethanol and water as solvents. The prepared films were characterized by X-ray diffraction, photoluminescence, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, and scanning electron microscopy analysis to examine the structural, morphological, and optical properties as well as chemical composition of the films. In addition, nanoindentation and current vs. voltage studies were also conducted. Further, the hydrogen evaluation reaction effect of the prepared electrode was evaluated to investigate the catalytic activity of the films. This technologically attractive SWCNT/PMMA nanocomposite freestanding film prepared first time via a simple low-cost technique showed good conductivity, photosensitivity and flexibility with catalytic property.

Carbon nanotube‐based polymer nanocomposites: Evaluation of barrier, hydrophobic, and mechanical properties for aerospace applications

AbstractThe anticorrosive and mechanical properties of carbon nanotubes (CNTs) in epoxy resin (EP) coatings have been improved by the integration of molybdenum disulfide (MoS2) and 3‐aminopropyltrimethoxysilane (APTMS) for surface modification based on CNTs. SEM/EDX, TEM, TGA/XRD, XPS, and XRD techniques were used to characterize the composites for the various formulations, including APTMS/CNTs, CNTs/MoS2, and APTMS/CNTs‐MoS2. By including APTMS/CNTs‐MoS2 composite, the EP coating exhibits improved anticorrosive and mechanical performance, as demonstrated by electrochemical methods and mechanical testing. Superior hydrophobic property of EP‐APTMS/CNTs‐MoS2 is confirmed by its WCA of 167°. Additionally, it was discovered that the EP‐APTMS/CNTs‐MoS2 had a resistance that was significantly larger (17,421 kΩ.cm2) than the plain epoxy (102 kΩ.cm2), and its hardness (1695 MPa), adhesion (19.7 MPa), and tensile (237 MPa) properties all are improved significantly. Therefore, the newly developed EP‐APTMS/CNTs‐MoS2 could act as the vital material for coating AA7475 aluminum alloy used in aerospace applications.

Effects of functionalized CNTs in improving the dielectric, corrosion protection, and mechanical properties of epoxy nanocomposites for automotive/aircraft components

ABSTRACT Excellent mechanical, thermal, electrical, electrochemical, and optical properties can be found in carbon nanotubes (CNTs). The anticorrosive and mechanical properties of CNTs in epoxy resin (EP) coatings have been improved by the integration of zirconium disulfide (ZrS2) and 2-amino−5-(4-methoxyphenyl)−1, 3, 4-thiadiazole (AMPT) for surface modification based on CNTs. The structural, morphological, and dielectric behaviors of the films were characterized for the different formulations of coatings such as EP, EP/CNTs, EP-AMPT/CNTs, EP-CNTs/ZrS2, and EP-AMPT/CNTs-ZrS2 by means of SEM/EDX, TEM, TGA/XRD, XPS, XRD, and contact angle (CA) measurement. As a result, with the addition of only 0.3% AMPT/CNTs-ZrS2, the dielectric constant of EP was increased by 87-fold at 1 Hz. The electrochemical techniques and mechanical testing confirmed that AMPT/CNTs-ZrS2 composite exhibit enhanced anticorrosive and mechanical performance of the EP coating. Superior hydrophobic property of EP-AMPT/CNTs-ZrS2 is confirmed by its WCA of 161º. Furthermore, the resistance of the EP-AMPT/CNTs-ZrS2 was found to be much higher (20.870 MΩ.cm2)] than that of the pure EP (0.112 MΩ.cm2) and the microhardness and tensile strength of EP-AMPT/CNTs-ZrS2 were increased sharply. Therefore, the newly developed EP-AMPT/CNTs-ZrS2 nanocomposite could act as the vital material for coating AA8014 aluminum alloy used in aerospace applications.

An investigation on the effect of Al4C3 on microstructure and mechanical properties of carbon nanotube reinforced aluminum composite

In carbon nanotube (CNT) reinforced metal-matrix composites, a strong interface between CNTs and the matrix is essential for an effective load transfer. Otherwise, the excellent qualities of CNTs would virtually remain unexploited. The aim of this study is to investigate the effect of Al4C3 formation on the mechanical properties of CNT/Al composites. Composite powders were produced through a three-stage process; First, CNTs were sufficiently crushed via high-energy milling of 20 h. Then, the crushed CNTs were ultrasonically mixed with raw CNTs (in an ethanol medium) followed by a wet milling process. Finally, different amounts of the obtained reinforcing agent (0.5, 1, 1.5, 2, and 3 wt.%) were milled with aluminum powders. Composite powders were subsequently consolidated using spark plasma sintering (SPS) process at two different temperatures (500 and 550 °C) For each sample, the amount of carbide was calculated in a semi-quantitative manner using Raman spectroscopy. The results of phase analysis and mechanical-behavior evaluations showed that Al4C3 formation, due to the consumption of highly-activated crushed CNTs, could improve the interface bonding state while maintaining CNTs structural integrity. Moreover, mechanical and wear tests revealed that the optimum properties were obtained for the composite reinforced by 1wt.% processed carbon nanotubes (PCNTs) and SPSed at 550 °C for 10 min. These findings can open up a window toward the realm of design and processing of CNT/Al composites.