Effect Of Carbon Nanotube Addition Research Articles

Physico-chemical studies and development of water-based drilling fluid formulations with carbon nanotube additives

The paper offers a comprehensive experimental study on the effect of carbon nanotube additives on the features of water-based drilling fluids. A similar study for this fluid has not been carried out before. Nanotubes were used to modify the drilling fluids. Weight concentration of nanomaterials in slurries was from 0.1 to 0.5 %. The formulation of stable drilling slurries modified by carbon nanotube were developed and refined. The study is focused on investigation of rheology, filtration and antifriction properties, temperature and colloidal stability of drilling fluids modified with carbon nanotubes. It is shown that carbon nanotube additives even in small concentrations can significantly change the features of water-based drilling fluids. A comparison was made between the effects of single- and multi-walled carbon nanotubes (SWCNT and MWCNT) on the characteristics of water-based drilling fluids. The study has shown that both types of nano-additives considerably change in the properties of the base fluid. Nevertheless, it was determined that in order to achieve a comparable effect on solution properties, an order of magnitude greater amount of MWCNT additives is required in comparison to single-walled carbon nanotubes.

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.

An experimental investigation of the effect of carbon nanotubes addition and shot peening process on the ballistic limit of fiber-metal laminates

The present research has experimentally investigated the effect of adding multi-walled carbon nanotubes (MWCNTs) and shot peening operations on the ballistic behavior of fiber-metal laminates (FMLs). The unreinforced and reinforced FMLs with 0.2 wt.%, 0.4 wt.%, and 0.6 wt.%. of MWCNTs were manufactured by hand lay-up method and subjected to shot peening operations. Finally, the specimens were exposed to the ballistic impact test using a cylindrical projectile with a conical head. The best result was obtained for 0.4 wt.% of MWCNTs, in which the ballistic limit and absorbed energy increased by 6.80% and 13.75% for non-shotted and by 8.50% and 17.45% for shotted samples, respectively. This demonstrates the positive effect of shot peening in increasing the ballistic limit through a combination of work hardening and compressive residual stresses in the aluminum layers. However, mechanical performance decreased in samples containing 0.6 wt.% of MWCNTs due to nanoparticle agglomeration. The fracture surfaces of the samples were also analyzed by scanning electron microscopy, and the results indicated an improvement in the adhesion properties at the interface between the fibers and matrix in the reinforced samples, achieved through mechanisms such as crack bridging and MWCNTs pull-out.

Effects of carbon nanotube addition on the microstructures, martensitic transformation, and internal friction of Cu–Al–Ni shape-memory alloys

In this study, we analyze the influences of carbon nanotube (CNT) addition on the martensite transformation and internal friction of Cu–Al–Ni shape-memory alloys (SMAs). X-ray diffraction and differential scanning calorimetry results demonstrate that Cu–13.5Al–4Ni–xCNT (x = 0, 0.2, 0.4, 0.6, and 0.8 wt%) SMA/CNT composites exhibit a β1(DO3)⇄β1′(18R)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\upbeta }_{1}({\\mathrm{DO}}_{3})\\rightleftarrows {\\upbeta }_{1}^{\\mathrm{^{\\prime}}}(18\\mathrm{R})$$\\end{document} martensitic transformation. The martensitic transformation temperatures and transformation enthalpies of the martensitic transformation peaks for the Cu–13.5Al–4Ni–xCNT (x = 0–0.8 wt%) composites gradually decrease with the increase in the amount of CNT addition. Compared to the Cu–13.5Al–4Ni SMA, the Cu–13.5Al–4Ni–xCNT (x = 0.2–0.8 wt%) SMA/CNT composites exhibit significant improvements in the amount of dissipation of energy (storage modulus (E′))\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${E}^{\\prime}))$$\\end{document} and mechanical strength. However, the tan δ of the internal friction peak gradually decreases with the increase in the CNT content above 0.6 wt%. The reduction in tan δ is attributed to the decrease in the magnitude of the austenite-to-martensite transformation and precipitation of γ2 (Cu9Al4) phase particles, which impede the interface motion in between the parent/martensitic phase and martensitic phase.

Self‐healing polymers containing nanomaterials for biomedical engineering applications: A review

AbstractMaterials that can recover the function of lost or damaged parts, called self‐healing materials, have attracted attention due to their wide usage in different fields such as water refinery, coatings, robotics, and especially, biomedical applications. Depending on whether the self‐healing component is added to the polymer or is inherent to the polymeric matrix, the self‐healing properties of the polymeric materials can be classified into extrinsic and intrinsic self‐healing. Hydrogels are one of the most used polymers in self‐healing applications for various purposes, including tissue engineering, drug delivery, etc. Nanoparticles can endow some essential features to hydrogels, such as improving mechanical properties, more efficient healing ability, conductivity, and antibacterial and magnetic features. In the current study, various biomedical applications of self‐healing polymers using nanoparticles are discussed in detail, showing the impact of addition of nanoparticles. Perfect antibacterial properties with the addition of copper sulfide or silver nanoparticles were achieved. In addition, enhancing compression modulus up to three times and endowing conductivity to the hydrogel as the effect of carbon nanotube addition and better mechanical properties caused by graphene oxide and iron oxide nanoparticles were reported. These are just a few examples of the results achieved by adding nanoparticles to the self‐healing polymers described in this study.

On the evolution of protective oxide chemistry and corrosion resistance of electrodeposited FeCrMnNiCo-carbon nanotube composite coatings

ABSTRACT Reinforcement of carbon nanotube (CNT) into FeCrMnNiCo High Entropy Alloys (HEA) was carried out using electrodeposition method. Different volume fractions of functionalised CNTs (0.5, 1.0, 5.0, 10.0, 20.0, 30.0 mg/L) were dispersed in the aqueous electrolyte bath to synthesise HEA-CNT composite coatings. Effect of CNT addition on the phase constitution, morphology, composition, roughness, contact angle and ultimately on corrosion resistance of the pristine coating was investigated. The study revealed that the corrosion behaviour of the composite coatings was highly sensitive to the volume fraction of CNTs in the coatings. The change in the corrosion rate was, however, not monotonic and it was observed that the corrosion rate decreased progressively with CNT addition reaching a minimum followed by a sharp increase in corrosion rate thereafter. The protection efficiency of pristine coating was enhanced remarkably by 74.27% with the addition of an optimum amount (10 mg/L) of CNTs. The enhanced corrosion resistance was due to fine-grained morphology, reduced surface roughness from 1194. 9 ± 3.6 nm for pristine coating to 721.3 ± 1.8 nm for the highest corrosionresistant coating, enhanced hydrophobicity with a tremendous increase in water contact angle from 85.2° to 152.8°. Additionally, the dominance of more stable oxides of chromium (Cr2O3) and nickel (NiO) on the passive oxide layer made the coating less susceptible to corrosive media. Beyond the optimum CNT volume fraction, the drastic deterioration in corrosion-resistance observed beyond the optimum was attributed to increased surface defects in the forms of cracks due to the incorporation of agglomerated CNTs into the coating matrix.

Effect of Carbon Nanotubes Addition on the Formability of Al-CNT Composite

Being very strong fibers, carbon nanotubes (CNTs) are excellent choice for various metal matrix composites (MMCs). Many researchers have reported amelioration in mechanical and thermal characteristics of the MMCs driven by CNTs addition. However, the effect of multi-walled carbon nanotubes (MWCNTs) addition on the formability of the MMC is relatively less addressed area. In present study, 0.2 wt. % MWCNTs were added in aluminum matrix using induction melting technique and their effect on the various aspect of metal forming characteristics were studied. Two different type of MMC were prepared i.e., re-melting flux (RM) MMC using re-melting flux and multi-functional flux (MF) MMC using multifunctional flux.The experimental results showed that the MF Flux MMC had ultimate tensile strength 65% more than pure aluminum. An analogous behavior was seen in true stress-true strain characteristics along with necking stress and tensile toughness. Contrarily, the hardening factor, strength coefficient, necking strain and strain rate sensitivity values decreased in case of RM Flux MMC and increased for MF Flux MMC as compare to the pure aluminum. This behavior of the materials could be attributed to the process variation used for the incorporation of nanotubes in aluminum matrix.

Effects of carbon nanotubes addition on the superconducting properties and critical current density of NdBa2Cu3O7−δ

Polycrystalline NdBa2Cu3O7−δ samples with 0 to 1.5 wt% carbon nanotubes (CNTs) addition have been synthesized via the solid-state reaction method. The samples were examined by the four-point probe temperature-dependent electrical resistance, critical current density and AC susceptibility measurements. X-ray diffraction (XRD) patterns showed that the addition of CNTs did not change the orthorhombic structure of the samples and there was no systematic variation in the lattice parameters. CNTs addition increased the transition temperature with the highest onset transition temperature, Tc onset = 96 K for the 1 wt% added sample. The critical current density increased from 2600 mA/cm2 for the pure NdBa2Cu3O7−δ to 4960 mA/cm2 for the 1.0 wt% CNTs added sample. It is suggested that the grain boundaries improved with CNTs addition, and this plays an important role in the electrical transport properties. Addition of CNTs enhanced the flux pinning and improved the grain boundaries of high-temperature superconductors. The effect of CNTs on other cuprate high-temperature superconductors has also been compared with these NdBa2Cu3O7−δ samples.

The Effect of Agglomeration on the Electrical and Mechanical Properties of Polymer Matrix Nanocomposites Reinforced with Carbon Nanotubes.

In this work, we investigated the effect of carbon nanotubes addition and agglomeration formation on the mechanical and electrical properties of CNT–polymer-based nanocomposites. Six specimens with carbon nanotubes (CNTs) fractions of 0%, 0.5%, 1%, 2%, 4% and 5% were manufactured and characterized by dynamic mechanical analysis (DMA) and four-probe method. The stress–strain curves and electrical conductivity properties were obtained. Scanning electron microscopy (SEM) was used to characterize both agglomeration and porosity formation. By employing micromechanics, through representative volume element (RVE), finite element analysis (FEA) and resistor network model (RNM), the Young’s modulus and electrical conductivity values were calculated. The samples’ elastic moduli showed an increment, reaching the maximum value at a CNTs fraction of 2%, thereafter an adverse effect was caused in the high CNT percentage samples. The final electrical conductivity seemed greatly altered with the addition of CNTs, reaching the percolation threshold at 2%. The unavoidable formation of CNT agglomerates appeared to influence the final physical properties. The CNT agglomerates adversely affect the mechanical performance of high-CNT-percentage samples. Conversely, an exponential increment in the electrical conductivity was presented as the agglomerates formed networks allowing the transport of electrons through the tunnelling effect. These phenomena were experimentally and numerically confirmed, showing a good correlation.

Effect of carbon nanotubes addition on thermoelectric properties of Ca3Co4O9 ceramics

Increasing the phonon scattering center by adding nanoparticles to thermoelectric materials is an effective method of regulating the thermal conductivity. In this study, a series of Ca3Co4O9/x wt.% CNTs (x = 0, 3, 5, 7, 10) polycrystalline ceramic thermoelectric materials by adding carbon nanotubes (CNTs) were prepared with sol-gel method and cold-pressing sintering technology. The results of x-ray diffraction and field emission scanning electron microscopy show that the materials have a single-phase structure with high orientation and sheet like microstructure. The effect of adding carbon nanotubes to the thermoelectric properties of Ca3Co4O9 was systematically measured. The test results of thermoelectric properties show that the addition of carbon nanotubes reduces the electrical conductivity and Seebeck coefficient of the material. Nevertheless, the thermal conductivity of the samples with carbon nanotubes addition is lower than that of the samples without carbon nanotubes. At 625 K, the thermal conductivity of Ca3Co4O9/10 wt.% CNTs sample is reduced to 0.408 W⋅m−1⋅K−1, which is about 73% lower than that of the original sample. When the three parameters are coupled, the figure of merit of Ca3Co4O9/3 wt.% CNTs sample reaches 0.052, which is 29% higher than that of the original sample. This shows that an appropriate amount of carbon nanotubes addition can reduce the thermal conductivity of Ca3Co4O9 ceramic samples and improve their thermoelectric properties.

Experimental studies on the effect of Carbon nanotube additives with Calophyllum Inophyllum biodiesel in CI engine

The rapid depletion of Non-renewable fuel sources coupled with environmental degradation, has led us further into the exploration of alternate energy resources. Biodiesels originating from non-edible feedstocks have garnered much attention in a span of few years. The current study focuses on the addition of Carbon Nanotubes in Tamanu oil biodiesel in a Diesel engine. In this study, parameters such as brake thermal efficiency, unburned hydrocarbon, carbon monoxide, and NOx emissions have been studied. The performance of these biodiesel-diesel blends were charted and results are compared with diesel. It is noted that the inclusion of nano-additives in dosages of 30 and 60 ppm enhances brake thermal efficiency, the drawback being increased specific fuel consumption. The emissions of HC, NOx and emissions show a favorable trend with addition of CNT but CO2 emissions were observed to be on the higher side. Also graphs were plotted revealing the relevant combustion characteristics of the test fuels. They are further discussed in detail and a comprehensive conclusion was made.

Effect of carbon nanotube addition in two sizing agents on interfacial properties of carbon fiber / polycarbonate composites

In order to improve the interfacial bonding between carbon fiber (CF) and polycarbonate (PC), sizing agents of water-borne polycarbonate (WPC) and water-borne polyurethane (WPU) containing carbon nanotubes (CNTs) were used to treat CFs. CNTs were dispersed in the two sizing agents after treated with concentrated nitric acid. The effects of the type of sizing agents and the CNT content on the interfacial properties of composites were investigated by two methods, single fiber fragmentation test (SFFT) for monofilament reinforced composite and transvers tensile for directional bundle composite. Results show that WPU is more conducive to improving the interfacial bonding properties of CF/PC composites because of its better film-forming property than WPC, and the addition of CNTs has a beneficial effect on the interfacial properties of composites when the content of CNTs is 0.1 wt%. Over dose of CNTs causes agglomeration, which is unfavorable for the improvement in interfacial properties. CNTs can effectively prevent interfacial slip, thus significantly improve the interfacial properties in SFFT, while the improvement is not obvious in transvers tensile because the adhesion of the sizing agents plays a leading role.

Effects of CNTs addition on the microstructure and microhardness of stainless steel alloy/carbon-manganese non-alloyed steel welding

In recent years some progress has been made about the addition of Carbon Nanotubes (CNTs) in the stainless steel metal matrix by pulsed Gas Tungsten Arc Welding (P-GTAW). Despite that, there is lack of information regarding to microstructural modifications induced by CNTs in dissimilar welding. In this sense, we present the welding of nanocomposite based on Nickel/Carbon Nanotubes-stainless steel 316L alloy (Ni/CNTs-SS 316L), as the welding metal, on carbon-manganese (C-Mn) non-alloyed structural steel, as the base metal. The microstructure of manufactured specimens with/without nanocomposite was characterized by: optical microscopy; Raman spectroscopy; scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and electron backscattering diffraction (EBSD). Moreover, Vickers tests were performed from the welding metal (WM) to the base metal (BM) before/after temper treatment in order to investigate the microhardness changes. The results show that dilution rate and grain size for specimen with nanocomposite was higher than without nanocomposite; the CNTs affected the misorientation angle and texture of the WM; the topside microhardness from WM with Ni-CNTs was on average 30.40% higher than BM; and, in transverse cross-section microhardness was 31% higher than control sample on average at fusion line zone. These results indicate that addition of CNTs in the metallic matrix by dissimilar welding is a fertile ground for new studies applicable to manufacturing industry.

The effect of carbon nanotube addition on the mechanical properties and biological functionality of poly‐ether‐ether‐ketone–hydroxyapatite composites

AbstractThis study examines the effect of functionalized multi‐walled carbon nanotube (CNTs) dispersion on mechanical properties of poly‐ether‐ether‐ketone–hydroxyapatite–carbon nanotubes (PEEK‐HAP‐CNTs) nanocomposite. The nanocomposites have been fabricated for biomedical applications using a melt processing at 400°C. The results showed that CNTs increase the effective contact area between PEEK and HAP in the nanocomposite. The addition of 0.1 wt% CNTs to the composite led to an elastic modulus and compressive strength improvement for 13% and 31% compared to PEEK‐HAP. The scanning electron microscopy images showed the microstructure of the composites. The results of cell attachment, alkaline phosphatase, spreading, proliferation, and alizarin red tests showed that adding CNT into the composite improved the function of MG‐63 cells. In conclusion, PEEK‐HA‐CNT is more suitable to be used as an implant material than PEEK and PEEK‐HA composites.

Composite structural batteries with Co3O4/CNT modified carbon fibers as anode: Computational insights on the interfacial behavior

Interface is vital for high-performance composites. We report energy-storage structural composites with Co3O4/CNT modified carbon fiber as anodes, aiming at enhancing their electrochemical and interfacial stability simultaneously. The interfacial failure is readily to occur at fiber/matrix interface as volume of Co3O4 active particles expands during charging, and thus carbon nanotubes (CNTs) are incorporated surrounding active particles. The interfacial failure mechanism is investigated using a cohesive zone model (CZM). Effects of CNT addition, CNT density, particle geometry and patterns, and failure criterion parameters of polymer electrolyte on the interfacial behavior are all discussed. After CNT addition, failure will initiate at CNT/matrix interface instead of CF/matrix interface for anode without CNT. Also, particle patterns with nonuniform density that can decrease stress near CF interface and enable deformation outward (or absorb deformation) will ensure excellent interfacial performance. Polygonal particles infinitely close to a circular sphere shape possessing small gap/voids between CNTs will be ideal. The findings in this work will provide novel pathways for the design and fabrication of composite structural batteries with high interfacial stability.

Carbon nanotube-reinforced intermetallic matrix composites: processing challenges, consolidation, and mechanical properties

Intermetallic compounds (NiAl) are potential high-temperature structure materials due to their exceptional physical and thermo-mechanical properties. NiAl offer a wide range of applications which stem from aerospace to automobile industry but their utilization is restricted owing to low ductility and fracture toughness. However, carbon nanotubes (CNTs) have been recognized to impact strength and improve mechanical properties in metal matrices because of their superior tensile strength, high aspect ratio, low density, and elastic modulus. This has contributed to advance developments of novel materials. In recent times, CNTs have been a focus of immense research due to presence of sp2 C–C bonds in their outer shells, with continuous cylindrical shape which significantly contributed to their superior characteristics. The processing methods of integrating CNTs in metal matrices as well as maintaining their structural integrity through the powder metallurgy routes are reviewed. The mechanical properties, microstructure evolutions, effect of CNT addition, and sintering mechanism are also articulated in this review.

Effect of carbon nanotube addition on structure and properties for extrudates of high‐density polyethylene

ABSTRACTWe investigated the structure and properties of strands of high‐density polyethylene (HDPE), containing multi‐walled carbon nanotubes (MWCNTs) extruded from a capillary rheometer. Surprisingly, we found that the MWCNTs enhanced the chain orientation of HDPE, and that in the absence of MWCNTs, orientation relaxation occurred in the HDPE immediately after passing through the die. Conventional differential scanning calorimetry measurements indicated that MWCNT acts as a nucleating agent and raises the crystallization temperature 2–4 °C under quiescent condition. In the flow field, oriented MWCNTs behave like polymeric chain extended crystals “shish” and greatly accelerate the flow‐induced crystallization of the HDPE “kebab.” Consequently, the modulus was significantly increased in the flow direction. These findings demonstrate that the addition of MWCNTs is an effective method of enhancing the rigidity of HDPE. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48010.

On the Tensile Tests of Polyurethane and Its Composites with Carbon Nanotubes

Neat polyurethane (PU) specimens and composites of polyurethane with variable amounts of multiwalled carbon nanotubes (MWCNTs) were subjected to tensile tests, stress relaxation tests, and strain rate jumps. Since the already published data about the effect of carbon nanotubes addition to polymer matrix are somewhat contradictory, great care was taken to understand the mechanical properties of neat PU specimens. The studies revealed that the tensile curves of neat PU are substantially influenced by several factors, such as strain rate, age, and thickness of the specimens. The addition of MWCNTs into the PU matrix had a negligible effect on the mechanical properties of composites at low strains (ε < 0.2). With increasing strain, the MWCNTs addition augmented the strength of the composites, and at high local deformations, as in the previously reported indentation experiments, the adhesion strength between functionalized carbon nanotubes and PU matrix substantially influences the mechanical behavior. The material response to the transient mechanical test showed an Arrhenius-type behavior and was analyzed accordingly. The magnitude of the activation volume scaled with the average length of the free segment of the polymer molecules.

Effect of Carbon Nanotube Addition on the Superconducting Properties of BSCCO Samples Textured via Laser Floating Zone Technique

In this research, the effect of carbon nanotube (CNT) addition on the structural and superconducting properties of Bi2Sr2CaCu2Oy + x wt% CNT materials with x = 0, 0.5, 1, and 3 prepared by solid state method, followed by directional grown using the laser floating zone (LFZ) technique has been investigated. XRD measurements showed that all samples are composed of almost single Bi-2212 phase. SEM images proved that Bi-2212 phase is the major one, with minor amounts of (Sr,Ca)3BiOx, and Bi-2201 secondary phases. According to the magnetic results, carbon nanotubes decrease Tc values and significantly reduce the magnetic hysteresis loops area and the magnetic critical current density.

Spark plasma sintering of Ni3Al-xB-1wt% CNT (0.0 < x < 1.5 at%) nanocomposite

This paper investigates the effects of carbon nanotubes (CNT) addition on the structure and mechanical properties of Ni3Al-xB (0.0 < x < 1.5 at%) intermetallic compound. Ni3Al-xB-1wt%CNT nanocomposite powders were first synthesized by mechanical alloying. Effects of CNT addition on the lattice strain and crystallite size of synthesized powders were investigated by means of X-ray diffraction (XRD) analysis. Scanning electron microscope (SEM) was used to study powder morphologies. Powders, synthesized by mechanical alloying, were then consolidated using spark plasma sintering (SPS), conducted at 950 °C under pressure 50 MPa. Microhardness and shear punch tests were employed to study the mechanical properties of sintered samples. Results show that CNT addition is accompanied by a decrease in crystallite size and a significant improvement of mechanical properties of Ni3Al-xB (0.0 < x < 1.5 at%) intermetallic compounds.