Multi-walled Carbon Nanotube Composites Research Articles

Hollow Zinc Oxide Microsphere–Multiwalled Carbon Nanotube Composites for Selective Detection of Sulfur Dioxide

This work reports the first utilization of anthocyanin extracted from black rice (Oryza sativa L.) grains as a structure-directing agent for the synthesis of hollow zinc oxide (ZnO) spheres via a simple solvothermal reaction and their subsequent modifications with various amounts of multiwalled carbon nanotubes (MWCNTs). Following hybridization with MWCNTs, some MWCNTs are observed to penetrate into the inner cavities of the spheres, while ZnO nanoparticles are formed on the surface of some MWCNTs. When employed as a sulfur dioxide (SO2) sensor, the ZnO-MWCNT (15:1) composite displays a high response of 156 to 70 ppm of SO2 at an optimum temperature of 300 °C as well as good selectivity to SO2 with the response to 50 ppm of SO2 gas being 3 times higher than those to other gases, such as CO, CO2, methanol, toluene, hexane, and xylene. Interestingly, the sensing behavior of this composite is strongly influenced by the proportion of MWCNTs. Specifically, n-type sensing behavior is observed for both ZnO-MWCNT (10:1) and (15:1) composites, while p-type behavior is observed for the ZnO-MWCNT (5:1) composite. The switch in sensing behavior suggests the major contribution of p-type MWCNTs to the electronic and sensing properties of the ZnO/MWCNT composites. The density functional theory (DFT) simulations on the adsorption of SO2 on the ZnO/CNT system reveal that the SO2 molecule only chemically interacts with the O adatom of ZnO (i.e., oxygen atom adsorbed on the surface of ZnO) to form sulfur trioxide (SO3), and charge transfer is observed from ZnO to CNT, which enhances the change in resistance of the composite sensor upon exposure to SO2 gas.

Fiber organic electrochemical transistors based on multi-walled carbon nanotube and polypyrrole composites for noninvasive lactate sensing.

Multi-walled carbon nanotubes (MWCNT) play a synergistic role with conducting polymer in practical applications such as biological sensing. In this paper, multi-walled carbon nanotube and polypyrrole (PPy) composites were prepared on a fiber surface for the first time, and their morphology and electrical properties were characterized. Compared with PPy-coated fiber, the presence of carbon nanotubes induced the growth of large areas of PPy nanowires. In addition, fiber organic electrochemical transistors (FECTs) based on PPy and MWCNT were assembled, showing a higher on/off ratio, better stability, and greater flexibility. The lactate biosensor based on FECTs exhibits high sensitivity, with a correlation coefficient of R = 0.9889, quick response time of 0.6-0.8s, a wide linear response range of 1nM-1mM, and excellent selectivity for lactate. Furthermore, the lactate concentration in human sweat was successfully detected by a FECT-based sensor. The hybrid fibers can be easily woven and placed on fabric simply by stitching. This favorable performance of the FECT-based sensor makes it suitable for noninvasive sensing of lactate. Therefore, it provides a promising platform for future use in healthcare and detection applications. Graphical abstract.

The enhanced power factor of multi-walled carbon nanotube/stabilized polyacrylonitrile composites due to the partially conjugated structure

The studies of organic thermoelectric (TE) materials mainly focus on conductive polymers due to their conjugated molecular structures and high intrinsic electrical conductivity. When the conductive polymer is mixed with certain insulating polymers, the power factor was found enhanced. It is doubtful that the partially conjugated molecular structure is beneficial to the TE performance. Polyacrylonitrile (PAN) is an insulating polymer with a non-conjugated structure in its backbone, however, it has a partially conjugated structure after thermal treatment. In this work, a composite of PAN and multi-walled carbon nanotubes (MWCNT) was made and thermally treated in order to study the partially conjugated structure on the improvement of the power factor. By controlling the PAN content and the temperature of thermal treatments, a maximum power factor of 22 μW/mK2 was obtained from the MWCNT/PAN composite with 45% PAN content after thermally treated at 300 °C in air, which is 300% and 80% higher than that without PAN and before thermal treatment, respectively. It is demonstrated that the partially conjugated polymers play an important role in TE performance and they are promising candidates for high-efficient organic TE materials.

Polypyrrole-S-coated MWCNT composites as cathode materials for lithium-sulfur batteries

A composite of MWCNTs@S-PPy with excellent electrical conductivity and good restriction on polysulfide has been prepared for lithium-sulfur batteries. In this composite, sulfur particles confined to polypyrrole (PPy) are uniformly distributed on the surface of carbon nanotubes. The MWCNTs@S-PPy composite with a sulfur content of 48.8 wt% delivers a high initial discharge capacity of 1304.9 mAh g−1 at 0.2 C and remains a stable capacity of 986.3 mAh g−1 after 300 cycles. The significant improvement in the electrochemical performance can be attributed to the core-shell structure supported by the multiwalled carbon nanotubes (MWCNTs) and S-PPy composite, which own excellent electronic conductivity and alleviate the “shuttle effect” of lithium polysulfide. These results suggest that the MWCNTs@S-PPy composite is a promising cathode material for high-performance lithium-sulfur batteries.

Mechanical Properties and Electrical Conductivity of Poly(methyl methacrylate)/Multi-walled Carbon Nanotubes Composites

Carbon nanotubes (CNTs) remain one of the most efficient reinforcing material for enhanced mechanical and electrical properties. In this study, the effects of multi-walled CNTs (MWCNTs) fillers on mechanical, structural, and electrical properties of polymethyl methacrylate (PMMA)/MWCNTs composites were studied. The PMMA/MWCNTs composites, containing varying MWCNTs concentration of 0.1, 0.3, and 0.5 wt%, were prepared by a solution casting method. The mechanical properties of the composites such as tensile strength, elongation, Young modulus, tear resistance, fracture energy, impact strength, and hardness were investigated. Results showed that the mechanical properties of the composites were enhanced significantly. At 0.5 wt% MWCNTs, the tensile strength, elongation, tear strength, hardness, fracture energy and impact strength increased by 397%, 567%, 89%, 27%, 12%, and 36%, respectively, while the Young modulus decreased by 26% compared to pure PMMA polymer sample. Both the dc electrical conductivity and the activation energy increased with increased concentration of MWCNTs. From the electrical conductivity measurements, the percolation threshold was found to equal ~ 0.55 wt% MWCNTs. Based on the Fourier-transform infrared spectroscopy analysis, enhancement of mechanical and electrical properties is attributed to the formation of covalent bonds between polymer strands and MWCNTs. Moreover, a mechanism was proposed to describe the influence of MWCNTs on electrical and mechanical properties of PMMA/MWCNTs composites.

Structure, functional composition and electrochemical properties of nitrogen-doped multi-walled carbon nanotubes synthesized using Co–Mo, Ni–Mo and Fe–Mo catalysts

We studied the effect of Co–Mo/MgO, Ni–Mo/MgO, and Fe–Mo/MgO catalysts on the structure and functional composition of nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) synthesized by chemical vapor deposition method. Polyoxomolybdates containing Co–Mo, Ni–Mo, Fe–Mo сores were used as the catalyst precursors and acetonitrile was the source of carbon and nitrogen for the growth of N-MWCNTs in argon atmosphere at 900 °C. The Ni–Mo/MgO catalyst promoted the formation of N-MWCNTs with the smallest outer diameter of 8 nm and the highest content of embedded nitrogen of 2.7 at.% with a predominance of pyridinic nitrogen form. Co–Mo/MgO and Fe–Mo/MgO catalysts yielded thicker N-MWCNTs with an average outer dimeters of 12 and 15 nm and lower nitrogen content of 2 and 1.5 at.%, respectively. N-MWCNTs were tested as electrodes in electrochemical capacitors and Li-ion batteries. A higher efficiency of the N-MWCNTs synthesized using Ni–Mo/MgO catalyst confirmed the advantage provided by a high content of nitrogen in the nanotube walls.

Construction of spherical ZnTiO3/MWCNTs composites as anode material for high-performance Li-ion batteries

Spherical ZnTiO3 / multi-walled carbon nanotube (ZnTiO3 / MWCNTs) composite was synthesized via a simple one-step solvothermal strategy with subsequent sintering process. The obtained ZnTiO3 nanospheres in pure ZnTiO3 and ZnTiO3 / MWCNTs materials have a diameter of about 200–300 nm. The MWCNTs are well dispersed ZnTiO3 electrode materials and form a three-dimensional conductive network structure. The ZnTiO3 / MWCNTs composite shows higher reversibility of intercalation and deintercalation for Li ions, better electrochemical activity and smaller electrochemical polarization than those of ZnTiO3 negative electrode during cycling. The lithiation (delithiation) capacities for pure ZnTiO3 are only 270.9 (516.5), 256.3 (262.9), 201.8 (199.3), 162.3 (161.6), 131.4 (129.9) and 89.9 (90.4) mAh g−1 at the current densities of 50, 100, 300, 500, 800 and 1600 mA g−1, respectively. However, the ZnTiO3 / MWCNTs composite delivers lithiation (delithiation) capacities of 349.3 (633.0), 321.6 (329.1), 264.9 (262.5), 230.6 (229.2), 188.6 (188.5) and 136.4 (135.9) mA h g−1 at the same rates. The remarkable high rate capability of ZnTiO3 / MWCNTs electrode can be owed to the uniform distribution of ZnTiO3 nanopheres within the carbon matrix conductive network and the improvement of electronic conductivity. The results further indicate that MWCNTs modification is an effective mean to improve electrochemical properties of ZnTiO3 electrode material.

Stretchable chipless RFID multi-strain sensors using direct printing of aerosolised nanocomposite

Wireless communicated sensors currently play a major role in due to the importance of data for internet-of-things (IoT) devices. Specifically, chipless radio frequency identification (RFID) technology is a widely used technique for communication of data due to its printability, simplicity, and low cost. Here, stretchable and chipless RFID strain sensors were fabricated by direct printing of aerosolized nanocomposites using an aerodynamically focused nanomaterial printing system, which is a direct printing process for conductive and stretchable pattern printing onto flexible substrate. In particular, microscale porous conductive patterns composed of silver nanoparticle and multi-walled carbon nanotube composites were printed onto polydimethylsiloxane. The fabricated sensor exhibited motion with a high degree of freedom, including the ability to be stretched, twisted, or folded. Moreover, it demonstrate a gauge factor >0.5 and maximum strain limit >20 %, with resonance frequency controllability due to regulation of the geometrical properties of LC resonance circuits. Because the original sensor characteristics allowed independent sensing in a single direction, we fabricated an RFID strain sensor that could measure normal strain, as well as shear strain in all directions. Finally, we directly printed the sensor onto air tubes and verified its performance.

Factors that Affect Network Formation in Carbon Nanotube Composites and their Resultant Electrical Properties

This review paper explores the formation of carbon nanotube (CNT) polymer composites as a function of material and processing parameters. The effect of different polymer systems, increasing multiwall CNT content, modification of CNTs, processing conditions, and aspect ratio are discussed in detail for multi-walled carbon nanotubes (MWCNT) composites along with some examples for SWCNT composites. All of these factors influence the microstructure and how the network of CNTs forms within it. Often, researchers choose to modify the CNTs to aid in their distribution; however, this may result in a reduction or increase in conductivity depending on many factors. The electrical properties are directly affected by changes in the CNT network and how the material has been processed. As soon as the network forms, percolation occurs and the conductivity increases. In order to understand how to control the properties of CNT composites, all material characteristics and processing conditions must be taken into account.

Investigation on Tribological and Machining Characteristics of Al 7075/MWCNTs Nanocomposites

In the present research work, an attempt has been made to fabricate the aluminum metal matrix composite by stir casting method. Aluminum 7075 alloy is used as a matrix which is reinforced with multi-walled carbon nanotubes (MWCNTs) with varying 4 wt% fabricated through liquid-state method (stir casting). The machining was performed using EDM. Experiments were carried out to analyze microstructure, mechanical, tribological, and machining characteristics such as microhardness, tensile strength, wear rate, coefficient of friction, material removal rate, and surface roughness. Also, the samples were studied under a scanning electron microscope, energy dispersive X-ray analysis, and X-ray diffraction analysis to investigate the dispersion, chemical composition, and elemental analysis of multi-walled carbon nanotubes in Al7075. The microscopic study of metal matrix composite samples shows a good dispersion of MWCNT into Al7075. Results show that the microhardness and tensile strength increase by 6% and 25%, respectively. The wear rate and coefficient of friction of composites are decreased by 39% and 48% at a sliding speed of 3 m/s.

Mechanical, corrosion and cavitation erosion properties of LM 9 grade aluminium – multi-walled carbon nanotubes composites

ABSTRACT This paper is intended to study mechanical, corrosion and cavitation erosion properties of aluminium metal matrix composites with Multiwalled carbon nanotubes (MWCNTs) as reinforcement. Multi-walled carbon nanotubes in different weight percentages (1, 2 and 3%) are reinforced in Light metal 9 (LM 9) aluminium alloy using the ultrasonic stir casting method. Hardness, pitting corrosion potential and erosion resistance are evaluated to assess the influence of different weight percentages of MWCNTs as reinforcements in LM 9 alloy. The results indicate that Aluminium – MWCNTs composites possess an improved hardness of up to 150 % compared to base LM 9 alloy. The pitting corrosion resistance of composites was found to be excellent with minimum corrosion damage to the composite specimen. Cavitation erosion test performed as per ASTM G32 indicates a decrease in erosion wear for composites reinforced with MWCNTs compared to base material LM 9. The property improvement of the LM 9 – MWCNT composite under dynamic conditions is verified using SEM micrographs. The effect of weight percentage of MWCNTs found to be significant in the enhancement of properties. There are 16 % and 30 % reductions respectively in pitting corrosion potential and erosive wear respectively for composite with 3 % MWCNTs.

Dual Function Metallo–Organic Assemblies for Electrochromic–Hybrid Supercapacitors

AbstractAn integrated electrochromic–hybrid supercapacitor (EHSC) is demonstrated; the device’s operation (charging–discharging) is indicated by optical changes (from colored to transparent). The heart of the device is an electrochromic metallo–organic layer that functions as both the battery‐type electrode and the charge indicator. The capacitive electrode is a layered composite of multiwalled carbon nanotubes (MWCNTs) and a conductive polymer (poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate, PEDOT:PSS). The device operates under low potentials (−0.6 to 2 V), displays high energy and power densities (≈2.2 Wh kg−1 and ≈2529 W kg−1), a high coulomb efficiency (99%), a short charging time (≈2 s), and a charge retention (V½) of ≈60 min. Stability, both in color and energy, for more than 1000 consecutive charging–discharging cycles is demonstrated. No significant changes in device temperature are indicated under the operating conditions. The EHSC is wired with a conventional circuit board to be charged and subsequently to operate a diode. The results demonstrate the potential of metallo–organic assemblies for usage in these types of supercapacitors.

Corrosion, mechanical and thermal properties of aluminium alloy metal matrix nano composites (AA-MMNCs) with multi-walled carbon nanotubes

This paper is intended to study mechanical, corrosion and thermal properties of aluminium metal matrix composites with Multiwalled carbon nanotubes as reinforcements. In the present study, aluminium base alloy (LM 9) is reinforced with multi-walled carbon nanotubes (MWCNTs) in 1%, 2 and 3% using stir casting. Tests are conducted to evaluate for hardness, thermal behavior under varying temperature, and thermal conductivity to assess the influence of MWCNTs as reinforcements. The results indicate that Aluminium—MWCNTs composites possess improved mechanical properties. DSC thermographs indicate that there is no change in the thermal behavior of the composites under varying temperature conditions. Thermal conductivity measured using hot disc thermal analyzer showed a marginal reduction in the thermal conductivity due to increase in density of microstructure and resulting improved hardness.

Investigation on mechanical properties of Al6061 alloy – Multiwall carbon nanotubes reinforced composites by powder metallurgy route

Al6061 alloy reinforced multiwall carbon nanotubes composites is manufactured by powder metallurgy process. Microstructure of samples is investigated using scanning electron microscope to check the distribution of carbon nanotubes in aluminium alloy. Micro hardness, impact strength and ultimate tensile strength of Al6061 alloy and Al6061 alloy - multiwall carbon nano tubes composites are examined. Micrograph of composites shows better dispersion of multiwall carbon nanotubes in Al6061 alloy. Addition of multiwall carbon nanotubes improved the hardness, impact strength and ultimate tensile strength of matrix. Hardness of Al6061 increased up to 18.6% by reinforcing 1.5 wt% of multiwall carbon nanotubes in Al6061 alloy. Impact strength and ultimate tensile strength increased up to 66.6and 11.93% respectively by adding 1.5 wt% of reinforcements in Al6061 alloy. 1.5 wt% of multiwall carbon nanotubes in aluminium 6061 alloy offered better mechanical properties compared to Al6061 alloy and 1.5 wt% reinforced Al6061 composites.

Electrochemical performance of a three-layer electrode based on Bi nanoparticles, multi-walled carbon nanotube composites for simultaneous Hg(II) and Cu(II) detection

Electrochemical analysis is a promising technique for detecting biotoxic and non-biodegradable heavy metals. This article proposes a novel composite electrode based on a polyaniline (PANi) framework doped with bismuth nanoparticle@graphene oxide multi-walled carbon nanotubes (Bi NPs@GO-MWCNTs) for the simultaneous detection of multiple heavy metal ions. Composite electrodes are prepared on screen-printed electrodes (SPCEs) using an efficient dispensing technique. We used a SM200SX-3A dispenser to load a laboratory-specific ink with optimized viscosity and adhesion to draw a pattern on the work area. The SPCE was used as substrate to facilitate cost-effective and more convenient real-time detection technology. Electrochemical techniques, such as cyclic voltammetry and differential pulse voltammetry, were used to demonstrate the sensing capabilities of the proposed sensor. The sensitivity, limit of detection, and linear range of the PANi-Bi NPs@GO-MWCNT electrode are 2.57×102 μA L μmol−1 cm−2, 0.01 nmol/L, and 0.01 nmol/L–5 mmol/L and 0.15×10−1 μA L μmol−1 cm−2, 0.5 nmol/L, and 0.5 nmol/L–5 mmol/L for mercury ion (Hg(II)) and copper ion (Cu(II)) detection, respectively. In addition, the electrode exhibits a good selectivity and repeatability for Hg(II) and Cu(II) sensing when tested in a complex heavy metal ion solution. The constructed electrode system exhibits a detection performance superior to similar methods and also increases the types of heavy metal ions that can be detected. Therefore, the proposed device can be used as an efficient sensor for the detection of multiple heavy metal ions in complex environments.

Reinforcing MWCNTs to enhance viscoelastic properties of polyurethane nanocomposites by using nano DMA techniques

Multi-walled carbon nanotubes (MWCNTs)-reinforced polyurethane (PU) composites were fabricated by using solution mixing technique followed by compression molding. Nano dynamic mechanical analysis was carried out to investigate the viscoelastic properties of PU/MWCNTs composites within a frequency range of 5–250 Hz. At higher frequencies (250 Hz), the storage modulus of PU/MWCNTs composites with 10 wt% loading of MWCNTs was enhanced by 148% in equivalence to pristine PU. An improvement of 13.3% in storage modulus was observed at a loading frequency of 250 Hz in comparison to that of a loading frequency of 75 Hz, which indicates that the effect of MWCNTs on storage modulus was more pronounced at higher frequencies. At 75 Hz, a minor composition of MWCNTs (3 wt%) was sufficient to reduce the value of tan δ from 0.20 to 0.15, indicating that the material becomes more elastic after reinforcing MWCNTs. This significant improvement in the mechanical behavior of composite material has been attributed to the uniform dispersion of MWCNTs, and their adhesion with PU molecules. Reported enhancement in the elastic behavior of PU composite will boost the applicability of PU-based composite material for the fabrication of high-strength boots, gloves, and jackets required to absorb high vibration frequencies experienced during conditions such as rock drilling.

Effect of Filler Alignment on Piezo-Resistive and Mechanical Properties of Carbon Nanotube Composites.

Highly aligned multi-walled carbon nanotube (MWCNT) polymer composites were fabricated via a roll-to-roll milling process; the alignment of the MWCNTs could be controlled by varying the speed of the rotating rolls. The effect of MWCNT alignment on the polymer matrix was morphologically observed and quantitatively characterized using polarized Raman spectroscopy. To provide a more detailed comparison, MWCNT composites with alignment in the transverse direction and random alignment were fabricated and tested. Enhanced mechanical and electrical properties were obtained for the aligned MWCNT composite, which can be attributed to the efficient electrical network and load transfer, respectively. In addition, a cyclic stretching test was conducted to evaluate the piezo-resistive characteristics of the aligned MWCNT composites. The composites with an aligned filler configuration showed an exceptionally high degree of strain sensitivity compared to the other composites.

Thermal and optical properties of aromatic polyamide–hydrazides modified with multiwalled carbon nanotubes

Three wholly aromatic polyamide–hydrazides I–III containing various amounts of meta-/para-phenylene rings and their multiwalled carbon nanotube (MWCNT) composites have successfully been synthesized. These polymers were synthesized via a low-temperature solution polycondensation reaction of either meta-aminobenzhydrazide or para-aminobenzhydrazide (PABH) with an equimolar amount of isophthaloyl chloride (ICl) producing polymer I (100% meta-phenylene rings) and II (50% para-phenylene rings/50% meta-phenylene rings), respectively. The polymer III (75% para-phenylene rings/25% meta-phenylene rings) was synthesized by reacting PABH with mixture of equimolar ratios of terephthaloyl chloride and ICl. MWCNTs (0.1 wt%) have been incorporated into these three polymer matrices via a solution sonication technique. The structures of the polymers were confirmed by elemental analyses, Fourier-transform infrared, and proton nuclear magnetic resonance spectroscopy. The homogeneous distribution of the MWCNTs within the polymer matrices was proved by field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy observations. Thermal and optical properties of the as-prepared polymers were being enhanced to some extent upon inclusion of MWCNTs as illustrated from the results of thermogravimetric analysis and ultraviolet–visible spectroscopy.

Effect of Surface Modification on Multi-Walled Carbon Nanotubes and their Reinforced Nylon Composites

In this study, a series of nanocomposites were prepared by melt-blending method using Nylon (Nylon12, PA12) and multi-walled carbon nanotubes (MWCNTs) with various contents such as 0.0 wt.%, 0.5 wt.%, 1.0 wt.%, 3.0 wt.%. In order to improve the dispersion of MWCNTs in composites, the MWCNTs were first acid treated by the HNO3 solution to functionalize the carboxylic groups on the surface. Subsequently, this acid treated MWCNTs were reacted with Polyetheramine (Jeffamine® M2070) and Polyethylenimine under mild conditions, respectively, to obtain the chemically modified MWCNTs (M-M2070 and M-PEI). The amide groups formed on these chemically modified MWCNTs will enhance the compatibility of MWCNTs and Nylon. The effects of different modification methods on the thermal properties, mechanical properties and electrical resistance of these Nylon12/MWCNTs composites were investigated. The results showed that M-M2070 and M-PEI dispersed in Nylon12 homogeneously, and can improve the mechanical and thermal properties of the composite materials effectively. The DMA analysis revealed that the storage moduli of nanocomposites were increased with increasing MWCNTs content. Among all, the nanocomposites containing 3wt% of M-M2070 and M-PEI were shown increased storage moduli 48.2% and 29.8%, respectively. TGA analysis showed that pyrolysis temperature of neat Nylon12 was 412.7 °C, and was increased about 43 °C by addition of M-M2070 and 36.7 °C by addition of M-PEI. Moreover, the surface resistance of neat Nylon12 was 1.68×1014 ohm/sq, and was decreased to 1.33×105 and 4.34×106 ohm/sq by addition of 3wt% M-M2070 and M-PEI, respectively. The resistance values of these nanocomposites have achieved the level of static dissipation, and can prevent the harm of static electricity.

Investigation on mechanical, wear, and machining characteristics of Al 7075/MWCNTs using the liquid state method

In the present research work, an attempt has been made to fabricate the aluminum metal matrix composite by the stir casting method. Aluminum 7075 alloy is used as a matrix which is reinforced with multi-walled carbon nanotubes (MWCNTs) with varying percentage (0 wt.%, 1.0 wt.%, 2.0wt.%, and 3.0 wt.%). Experiments were carried out to analyze microstructure, mechanical, tribological, and machining characteristics such as microhardness, tensile strength, wear rate, coefficient of friction, material removal rate (MRR), and surface roughness (Ra). Also, the samples were studied under a scanning electron microscope (SEM), energy dispersive X-ray analysis (EDAX), and X-ray diffraction analysis (XRD) to investigate the dispersion, chemical composition, and elemental analysis of multi-walled carbon nanotubes in Al 7075. The microscopic study of metal matrix composite samples shows a good dispersion of MWCNT into Al 7075. Results show that the microhardness and tensile strength increase by 6% and 25%. The wear rate and coefficient of friction of composites are decreased by 39% and 48% at a sliding speed of 3 m/s. In addition, the metal removal rate decreases by 40% and the surface roughness enhanced by 38% respectively.