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Nanocomposite grease was created to reduce wear and friction on surfaces and enhance thermal conductivity. The tribological and rheological properties of nano grease were studied. Calcium grease with varied doses of hybrid TiO2/CNTs/GNs (0.5, 1, 2, 3 wt.%) was prepared. Transmission electron microscope (TEM) was applied to look at the microstructure of nano grease. Tribological and rheological properties of the nano grease were examined by using a four-ball tester. Wear scar diameter (WSD) was reduced by 30% at the optimal TiO2/CNTs/GNs concentration of 2% before beginning to rise. As TiO2/CNTs/GNs are applied in concentrations ranging from 0 to 2 wt.%, the friction coefficient of nano additive containing calcium grease steadily declines. At 2% concentration, the reduction in coefficient of friction was 45% about base grease. The friction coefficient was increased after that to 3 wt.%. Shear rate was reduced when the dose of TiO2/CNTs/GNs was increased. As the concentration of nanomaterials and shear rate increased, so did the viscosity of nano grease. Shear stress and apparent viscosity of the calcium grease containing 3% by weight of TiO2/CNTs/GNs are 43% higher than pure calcium grease, although they are still much lower than pure grease. The inclusion of the nanomaterial causes a roughly 19.5% increase in the dropping point of base grease. The thermal conductivity of nano grease is significantly improved by nano additives, increasing by around 130%, and the additives have a dramatic linear growth on the thermal conductivity of nano grease. [ABSTRACT FROM AUTHOR]

This research investigates the biocompatibility, mechanical strength, and tribological properties of a hybrid composite material composed of high-density polyethylene (HDPE), hydroxyapatite (HAp), and titanium dioxide nanoparticles (Ti O 2 ). The study explores the microstructural characteristics of the composite material using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Samples of HDPE-30%HAp with varying concentrations of Ti O 2 (5, 10, 15, and 20%) were prepared and extruded using a twin-screw machine. The hybrid composite materials underwent mechanical tests (tensile, flexural, and hardness), tribological tests (friction and wear rate), and antibacterial tests (resistance to Escherichia coli and Staphylococcus aureus bacteria). The results indicate that the optimal hybrid composite sample was HDPE-30%HAP-10% Ti O 2 , which demonstrated excellent mechanical properties (maximum tensile strength of 25.93 MPa and young modulus of 480 MPa) and a low coefficient of friction (COF∼ 0.07) while achieving high wear resistance (wear rate in the order of 1 0 − 4 m m 3 N − 1 m − 1 ). The study shows that the improvement in mechanical properties results in a corresponding improvement in tribological properties. The antibacterial tests revealed that the hybrid composite material exhibited resistance to E. coli and S. aureus bacteria. The findings of this study suggest that the HDPE-30%HAP-10% Ti O 2 composite is a promising material for use in biomedical applications due to its excellent biocompatibility and desirable mechanical and tribological properties. The study demonstrates the potential of reinforced hybrid composite materials in overcoming the disadvantages of monolithic and hybrid micro-composites and highlights the importance of investigating the microstructural, tribological, and mechanical strength characteristics of composite materials for biomedical applications. [ABSTRACT FROM AUTHOR]

The tribological and rheological properties of hybridized nanocomposite of graphene nanosheets (GNs)/titanium dioxide (TiO2) nanoparticles (NPs) as grease additives were investigated under different concentrations (0.5, 1, 2, and 3 wt.%), different loads, and different temperature. Friction reduction and antiwear of grease having hybridized nanocomposite were measured by using a pin-on-disk tester. The rheological properties and the thermal conductivity of the modified grease were evaluated using a Brookfield rheometer and KD2 thermal analyzer. The morphology and composition of nano additives and nano grease were analyzed by HRTEM and XRD. The results show that the hybridized nano grease has better friction-reduction and anti-wear which are enhanced by about 46.7 and 43.9%, respectively, if compared to the base grease. The rheological behavior of the hybrid nano grease is generally enhanced with an increase in the concentration. On the other hand, thermal conductivity is directly proportional to an increase in the concentration of hybrid nanoparticles. [ABSTRACT FROM AUTHOR]

The current study aims to explore the tensile fracture mechanism and thermo-mechanical efficiency of polyamide-6 (PA6) reinforced with titanium dioxide (TiO2) and multiwalled carbon nanotubes (MWCNTs). The uniform dispersion of the MWCNTs and appreciable interfacing between PA6, TiO2, and MWCNTs were revealed in the fractography figures. The crystallization temperature and degree of crystallinity have been enhanced by the addition of nanoparticles to the PA6 matrix. Young's modulus, tensile strength, and Charpy impact strength improved proportionally concerning reinforcement content. The essential work of fracture (EWF) method was applied to evaluate the toughening and fracture behavior of PA6 hybrid systems. Considerable improvement (+60.6%) in the EWF of PA6–TiO2–MWCNT nanocomposites was observed at 4 wt.% CNT and 2 wt.% TiO2. Limiting oxygen index (LOI) findings demonstrate that a polymer with a combination containing titanium dioxide and multiwalled carbon nanotubes has a highly substantial retardant influence. As a result, the TiO2–CNT combination acts as a synergist filler, offering versatile PA6 composite products. [ABSTRACT FROM AUTHOR]

Abstract The tribological and rheological properties of hybridized nanocomposite of graphene nanosheets (GNs)/titanium dioxide (TiO2) nanoparticles (NPs) as grease additives were investigated under different concentrations (0.5, 1, 2, and 3 wt.%), different loads, and different temperature. Friction reduction and anti-wear of grease having hybridized nanocomposite were measured by using a pin-on-disk tester. The rheological properties and the thermal conductivity of the modified grease were evaluated using a Brookfield rheometer and KD2 thermal analyzer. The morphology and composition of nano additives and nano grease were analyzed by HRTEM and XRD. The results show that the hybridized nano grease has better friction-reduction and anti-wear which are enhanced by about 46.7 and 43.9%, respectively, if compared to the base grease. The rheological behavior of the hybrid nano grease is generally enhanced with an increase in the concentration. On the other hand, thermal conductivity is directly proportional to an increase in the concentration of hybrid nanoparticles. [ABSTRACT FROM AUTHOR]

Oils and grease have beneficial effects on moving parts such as connecting rod, gears, shafts, and engine to reduce wear and friction. The properties of lubricants such as tribological and rheological properties are an important role in oils and grease characterization. Nano additives on lubricant oils play an important role in anti-wear; reduce the coefficient of friction and enhance the rheological properties. The Tribological and rheological behavior of base oil 15W50 which have different concentrations of multi-wall Carbon Nanotubes (MWCNTs) (0.5, 1, 1.5, and 2 wt%), and constant amount of graphene nanosheets (GNSs) (0.5 wt%) were investigated. This research is the first one in studying the effect of hybrid nano additives of (MWCNTs) and (GNs) on the tribological and rheological properties of lubricant oils. Tribological characterization was carried out on four ball testing model under different loads (200, 400, 600, and 800 N). The kinematic viscosity, flash point, pour point, and thermal conductivity of nanofluid added 15W50 lubricant are estimated and compared with base oil. The results showed that nano additives improve the wear scar and coefficient of friction by 78% and 48%, respectively. The flash point, thermal conductivity, kinematic viscosity, and pour point, were improved by 15%, 77%, 76.8%, and 20%, respectively compared with the base oil. The hybrid addition of CNTs/GNs nanoparticles enhanced the properties of 15W50 engine oil. [ABSTRACT FROM AUTHOR]

In recent years, since the discovery of Nano-additives especially carbon nanotubes (CNTs) and graphene, many interesting articles on composites with CNTs have been studied. CNTs have attracted considerable interest in all fields of science because of its unique characteristics. In this study, aluminum (Al) matrix reinforcement by the different volume fraction of Al2O3 and CNTs composites have been manufactured by using a powder metallurgy technique. The effects of tribological behaviors, density, hardness, and compression strength behavior of aluminum matrix Nano-composite were investigated before and after Hot Isostatic pressing (HIP). Transmission Electron Microscopy (TEM) and Scanning Electron Microscope (SEM) were employed to check the CNTs and hybrid composites. Results show that the density of nanocomposites decreased by 38% but after HIP, the density decreased by 45%. In addition, the hardness enhanced by 40% but, after HIP the hardness became 67%. On the other side, the compressive strength enhanced by 38% and 60% before and after HIP respectively. The coefficient of friction of nanocomposites are improved by 39%, 48% with HIP and without HIP while the wear rates improved by the addition of Al2O3 and CNTs at all volume fraction by 20%, but after HIP the enhancement became 45% at all volume concentration. [ABSTRACT FROM AUTHOR]

Molded plastic gears have long provided an alternative to metal gears in lightly loaded drives. They transmit power quietly and often without lubrication in numerous applications, furthermore decrease the quantity of parts and oppose chemicals in numerous applications. Previously, plastic gears were restricted to to 0.25 hp because of varieties in their properties and uncertainties about how they react to natural conditions such as moisture, temperature and chemical. Today, better molding controls combined with design practices that more accurately encompass environmental factors have boosted plastic gear drive capacity to 1.5 hp. Using reinforcement this is standout amongst the most practices to enhance the gear performance. This study estimated the effects of multilayer graphene nanoplatelets (MLNGPs) as an additive on polyamide 6 (PA6) spur gear performance. These include strength, elastic modulus, thermal stability, dynamic mechanical analysis, moisture absorption, and wear characteristics.The nanocomposite gear was made by melt mixing method and injection moulded into thick flanges. The flanges were machined using CNC milling machine to produce spur gear. The wear experiments were performed at a running speed of 1400 rpm and at torques of 13 and 16 Nm with different concentration 0, 0.1, 0.3 and 0.5 wt% MLNGPs using test rig. The result showed that 0.3% of MLGNPs is the optimum concentration. Young's modulus increased up to 40%, Vickers microhardness value increased up to 25%, storage modulus E’ is increased up to 37% and glass transition temperature is increased up to 14%. On the other hand TGA result shows that the Tonest increased up to 7.5% and Td increased up to 2%, and wear decreased by 35% at 16 Nm and 54% at 13 Nm. [ABSTRACT FROM AUTHOR]

The objective of this paper is to investigate the effect of Multi-Walled Carbon Nanotubes (MWCNTs) content on microstructure and dry sliding wear behavior of hypo-eutectic A356Al-Si alloy Metal Matrix Nano-Composites (MMNCs). Composites containing 0.5, 1.5, and 2.5 wt.% MWCNTs were prepared by rheocasting technique followed by squeeze casting. Characterization of nanocomposites was done by scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis (EDX), dry sliding wear tests were performed in a pin-on-disk wear tester against a steel disk at various speeds and normal loads. Results revealed that a decrease in both wear rate and friction coefficient of the nanocomposites considerably with the increase of MWCNT's content. The formation of the hard compact transfer layer on the pin surface nanocomposites assisted in increasing the wear resistance of these materials. It is that the transfer layer which was formed under an applied load of 20 N can act as a protective layer and help in reducing the wear rate. The results indicate the nano composites could be used in light-weight applications where moderate strength and wear properties are needed. [ABSTRACT FROM AUTHOR]

The addition of graphene nanosheets (GNSs) in lubricating grease could significantly reduce the interfacial friction and improve the load-bearing capacity of the parts. Therefore, it has been considered as having great potential as lubricant additives. In this study, we synthesized GNSs that are prepared by a modified Hummer method, and investigated the effect of GNS with different concentration (0.5%, 1%, 2%, 3%, and 4 wt%) on the tribological properties of the calcium grease. The friction and wear experiments were performed using a four-ball tribometer. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were employed to examine the GNS and the friction mechanisms. Results indicate that the friction reduction ability and anti-wear property of the base grease can be improved with the addition of GNS. It was also found that the friction reduction decreases by 61%, and the wear scar diameter (WSD) decreases by 45%, and the extreme-pressure (EP) properties increased 60% at 3 wt% GNS. It is clear that the GNS in grease easily forms protective deposited films to prevent the rubbing surfaces from coming into direct contact, thereby improving the entire tribological behavior of the grease. [ABSTRACT FROM PUBLISHER]

The effect of graphene nanosheets (GNS) on the rheological characteristics and thermal conductivity of calcium grease used in marine applications, and water pumps for lower demanding applications, has been experimentally evaluated in this paper. Various volume fractions of GNS (0.5, 1, 2, 3, and 4% wt.) have been immersed in the grease aiming at finding the better percentages that improve the properties of nanogrease. The rheological characteristics and thermal conductivity were evaluated w ith a Brookfield Rheometer DV-III ULTRA and KD2 thermal analyzer, respectively. The results of the modified calcium grease indicated that the best concentration of GNS is 3% wt. The rheological characteristics of the grease with a different volume fraction of GNS indicated a non-Newtonian behavior. Thermal conductivity of nanogreas also increases with an increase of GNS volume fraction. Moreover, the apparent viscosity, shear stress and dropping point increase by 59%, 52%, and 65%, respectively, with increasing GNS volume fraction. [ABSTRACT FROM AUTHOR]

Recently, nanofluids attract considerable interest for enhanced rheological behavior and thermal performance. The aim of this research is to study the influence of additives Multi-Walled Carbon Nanotubes (MWCNTs) on the rheological behavior and its structure, thermal conductivity, and the influence of shear thinning rate on oil separation at different temperatures for calcium grease. Various concentrations of MWCNTs (0.5, 1, 2, 3, and 4%) have been added to the grease to obtain the best percentages that improve the properties of nanofluid. The microstructure of MWCNTs and nanofluid were examined by X-ray diffraction (XRD), Transmission Electron Microscope (TEM), and Scanning Electron Microscope (SEM). These experimental investigations were evaluated with a Brookfield programmable Rheometer DV-III ULTRA. The results indicated that the optimum concentration of MWCNTs was 3%, and the dropping point increasing about 11%. The rheological behaviors of the nanofluids show that the grease with various concentrations of MWCNTs demonstrates non Newtonian behaviors and the results indicated that the shear stress, apparent viscosity and thermal conductivity increase with the increase of volume concentration of MWCNTs to 65%, 52%, and% 56, respectively. [ABSTRACT FROM AUTHOR]

The augmentation of lubricant oil properties is key to protecting engines, bearings, and machine parts from damage due to friction and wear and minimizing energy lost in countering friction. The tribological and rheological properties of the lubricants are of utmost importance to prevent wear under unembellished conditions. The marginal addition of particulate and filamentous nanofillers enhances these properties, making the lubricant oil stable under severe operating conditions. This research explores the improvement in SAE 5w-30 base oil performance after the addition of multiwalled carbon nanotubes (MWCNTs) in six marginal compositions, namely, Base, 0.02, 0.04, 0.06, 0.08, and 0.10 weight percentage. The effect of the addition of MWCNTs on flash and pour points, thermal conductivity, kinematic viscosity, friction coefficients, and wear are investigated and reported. X-ray diffraction and transmission electron microscopy are used to characterize the MWCNTs. The purity, crystallinity, size, shape, and orientation of the MWCNTs are confirmed by XRD and TEM characterization. Pour points and flash points increase by adding MWCNTs but inconsistency is observed after the 0.06 wt.% composition. The thermal conductivity and kinematic viscosity increase significantly and consistently. The friction coefficient and wear scar diameter reduce to 0.06 wt.% MWCNTs and then the trend is reversed due to agglomeration and inhomogeneity. A composition of 0.06 wt.% is identified as the optimum considering all the investigated properties. This composition ensures the stability of the tribo-film and hydrodynamic lubrication. [ABSTRACT FROM AUTHOR]

The development of highly efficient photocatalysis has been prepared by two different methods for the photodegradation of Cr(VI) from an aqueous solution under visible light. The electrospun polyethersulfone (PES)/iron oxide (Fe3O4) and multi-wall carbon nanotubes (MWCNTs) composite nanofibers have been prepared using the electrospinning technique. The prepared materials were characterized by SEM and XRD analysis. The result reveals the successful fabrication of the composite nanofiber with uniformly and smooth nanofibers. The effect of numerous parameters were explored to investigate the effects of pH value, contact time, concentration of Cr(VI), and reusability. The MWCNTs-Fe3O4@PES composite nanofibers exhibited excellent photodegradation of Cr(VI) at pH 2 in 80 min. The photocatalysis materials are highly stable without significant reduction of the photocatalytic efficiency of Cr(VI) after five cycles. Therefore, due to its easy separation and reuse without loss of photocatalytic efficiency, the photocatalysis membrane has tremendous potential for the removal of heavy metals from aqueous solutions. [ABSTRACT FROM AUTHOR]

This research investigates the biocompatibility, mechanical strength, and tribological properties of a hybrid composite material composed of high-density polyethylene (HDPE), hydroxyapatite (HAp), and titanium dioxide nanoparticles (Ti O 2 ). The study explores the microstructural characteristics of the composite material using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Samples of HDPE-30%HAp with varying concentrations of Ti O 2 (5, 10, 15, and 20%) were prepared and extruded using a twin-screw machine. The hybrid composite materials underwent mechanical tests (tensile, flexural, and hardness), tribological tests (friction and wear rate), and antibacterial tests (resistance to Escherichia coli and Staphylococcus aureus bacteria). The results indicate that the optimal hybrid composite sample was HDPE-30%HAP-10% Ti O 2 , which demonstrated excellent mechanical properties (maximum tensile strength of 25.93 MPa and young modulus of 480 MPa) and a low coefficient of friction (COF∼ 0.07) while achieving high wear resistance (wear rate in the order of 1 0 - 4   m m 3 N - 1  m - 1 ). The study shows that the improvement in mechanical properties results in a corresponding improvement in tribological properties. The antibacterial tests revealed that the hybrid composite material exhibited resistance to E. coli and S. aureus bacteria. The findings of this study suggest that the HDPE-30%HAP-10% Ti O 2 composite is a promising material for use in biomedical applications due to its excellent biocompatibility and desirable mechanical and tribological properties. The study demonstrates the potential of reinforced hybrid composite materials in overcoming the disadvantages of monolithic and hybrid micro-composites and highlights the importance of investigating the microstructural, tribological, and mechanical strength characteristics of composite materials for biomedical applications.

Fracture in the hip joint is a major and quite common health issue, particularly for the elderly. The loads exploited by the lower limbs are very acute and severe; in the femur, they can be several folds higher than the whole weight of the body. Nanotechnology and nanocomposites offer great potential in biomedical applications. The organic materials are more biocompatible. Mechanical properties like strength and hardness are challenging parameters which control the selection of a joint. HDPE in its pure form has been successfully used as a prosthetic foot (external) but failed as an implant material due to limited mechanical properties. High-density polyethylene thermoplastic polymer (HDPE) and multi-walled carbon nanotubes (MWCNT)/Nano-Alumina is selected as a potential material for a biomedical implant and its mechanical properties and biocompatibility have been discussed. HDPE/MWCNT/Alumina (Al 2 O 3 ) nanocomposites have not been explored yet for prosthetic implants. These nanocomposites were prepared in this investigation in different compositions. Prepared material has been physiochemically characterized to check the morphology and the structure. MWCNTs enhanced hardness and elastic modulus of the HDPE. Optimization of the material composition revealed that hybrid composite with structure (2.4% Al 2 O 3 and 0.6% MWCNT) exhibits better mechanical properties compared to other ratios with 3% MWCNTs and 5% MWCNTs. Thermal gravimetric analysis (TGA) dedicates that the percentage of crystallization has been increased to 6% after adding MWCNT to HDPE. The moisture absorption decreased to 90% with 5% MWCNT. Experimental results of Colorimetric assay (MTT) of a normal human epithelial cell line (1- BJ1) over Al 2 O 3 /MWCNT@HDPE showed <20% cytotoxic activity, proving its acceptance for medical use. HDPE/MWCNT/Al 2 O 3 nanocomposites emerged as a candidate material for artificial joints.