Graphite Nano Research Articles

Investigating Properties of Hybrid Alumina/ Graphite Aluminium Matrix nano Composites

Huge demand of lightweight materials in aerospace, automotive and recreational goods enthuse the manufacturing sectors to further exploit the interesting characteristics i.e., high specific strength to weight ratio, wear resistance and stiffness1 with high thermal conductivity and lower co-efficient of thermal expansion. With this objective the effect of mixing alumina and/or graphite in aluminium 7075 hybrid nanocomposite was studied, w.r.t stirring time variation on mechanical properties (hardness, toughness and ultimate compressive strength) and validated by Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) to characterized AA7075/Al2O3/Gr hybrid composites. The impact of variation of mechanical stirring time followed by fixed ultrasonic time is investigated deploying Response surface methodology/ design of experiments. From the analysis it was observed that hardness, Ultimate compressive strength and toughness of developed nanocomposite generally improved with mechanical stirring combined with ultrasonic homogenisation, with some softness associated in case of graphite nano composited. Optimization results of weight percentage of alumina, graphite and stirring time are reported. How to cite this article: Singh S, Gupta A, Sharma VS. Investigating Properties of Hybrid Alumina/ Graphite Aluminium Matrix nano Composites. J Adv Res Mfg Mater Sci Met Engr 2019; 6(3&4): 8-20. DOI: https://doi.org/10.24321/2393.8315.201902

Enhanced Thermal Characteristics of NG Based Acetamide Composites

Fatty acids are a distinguished category of phase change materials (PCM). However, their inferior thermal conductivity value restricts their potential for thermal energy storage system. Carbonaceous nanomaterials have emerged as promising thermal conductivity enhancer materials for organic PCMs. The present study focuses on preparing a novel PCM nanocomposite comprising of small amount of nanographite (NG) in molten acetamide, an organic PCM, for elevation of the thermal characteristics and examining the trend of the nanocomposite through the course of charging / discharging process. These PCM-nanocomposites are prepared by dispersing NG in molten acetamide with weight fractions of 0.1, 0.2, 0.3, 0.4 and 0.5 %. The scanning electronic microscopic (SEM) analysis was conducted for the characterization of PCM nanocomposite. The energy storage behaviour of the prepared nanocomposites were analyzed with the help of differential scanning calorimeter instruments, which showed that there is no observable variation in the melting point of the nanocomposite, and a decline in the latent heat values. Furthermore, thermal conductivity trend of the nanocomposites caused by NG addition was investigated, which indicated enhancement of thermal conductivity with increasing NG concentration. Further, nanocomposites with a 0.4 wt. % of NG, displayed appreciable increase in rate of heat transfer, reducing melting time and solidification time by 48 and 47 %, respectively. The prepared PCM nanocomposites displayed superior heat transfer trend, permitting substantial thermal energy storage.

Preparation, thermal characterization and examination of phase change materials (PCMs) enhanced by carbon-based nanoparticles for solar thermal energy storage

• An experimental framework for NePCMs development was proposed and utilised. • GNPs outperformed MWCNTs and NG on thermal conductivity enhancement of NePCMs. • Adding 3 wt% of GNPs into myristic acid enhanced the thermal conductivity by 176.26%. • Nano-additives reduced phase change temperature range and super-cooling of the PCM. • The NePCMs developed showed good stability and bulk phase change performance. This paper presents the preparation and thermal characterization of phase change materials (PCMs) enhanced by carbon-based nanoparticles, including graphene nanoplatelets (GNPs), multi-walled carbon nanotubes (MWCNTs) and nano-graphite (NG). A systematic experimental framework, consisting of material selection and preparation, material property characterization and thermal performance examination, was proposed and used in this study to facilitate the development of nano-enhanced PCMs (NePCMs) for solar thermal energy storage applications. By applying this framework, the characteristics and potential performance of PCM composites can be comprehensively understood, and better assessed before practical applications. It was found that the thermal conductivity of the myristic acid (MA) can be significantly enhanced by adding the nanoparticles in particular GNPs as additives into the PCM. The thermal conductivity of the PCM composites can be improved by 176.26%, 47.30% and 44.01% respectively under the solid phase, by adding GNPs, MWCNTs and NG with a concentration of 3 wt%. However, the concentration of the nanoparticles needs to be carefully determined to maximise the benefit in thermal conductivity enhancement. Different from that under the solid phase, the thermal conductivity enhancement of the NePCMs developed under the liquid phase followed linear increasing trends with relatively low increasing rates, when increasing the concentration of the nanoparticles. Besides the thermal conductivity enhancement, the adding of nanoparticles also modified the phase change process with a smaller phase change temperature range and eliminated supercooling while maintaining the high latent heat capacity. A further thermal performance examination demonstrated that the prepared NePCMs showed high thermal and chemical stability, which can be used to substantially reduce the phase transition time, and therefore are good potential candidates for solar thermal energy storage applications.

Additively manufactured graphitic electrochemical sensing platforms

Additive manufacturing (AM)/3D printing technology provides a novel platform for the rapid prototyping of low cost 3D platforms. Herein, we report for the first time, the fabrication, characterisation (physicochemical and electrochemical) and application (electrochemical sensing) of bespoke nanographite (NG)-loaded (25 wt%) AM printable (via fused deposition modelling) NG/PLA filaments. We have optimised and tailored a variety of NG-loaded filaments and their AM counterparts in order to achieve optimal printability and electrochemical behaviour. Two AM platforms, namely AM macroelectrodes (AMEs) and AM 3D honeycomb (macroporous) structures are benchmarked against a range of redox probes and the simultaneous detection of lead (II) and cadmium (II). This proof-of-concept demonstrates the impact that AM can have within the area of electroanalytical sensors.

Enriched mechanical, UV shielding and flame retarding properties of cotton fabric coated with graphite nano platelets filled polyaniline–gum arabic nanocomposites

Graphite nanoplatelets (GnP) were prepared by ultrasonication of thermally expanded graphite intercalated compound. In-situ oxidative polymerization was done to prepare GnP (1 wt%, 3 wt% and 5 wt%) filled polyaniline–gum arabic (GnP/PANI–GA) nanocomposites. These nanocomposites were further coated on the surface of the cotton fabric through the pad-dry-cure process. The characterization of the prepared nanocomposites and their coating was done by Fourier transform infrared spectroscopy and field emission scanning electron microscopy along with energy dispersive spectroscopy. Also, the mechanical, ultraviolet shielding and flame retarding properties of these coated fabrics were analysed as per ASTM D 5035, AATCC TM 183 and FMV SS 302 standards. 3 wt% GnP/PANI–GA nanocomposite coated fabric showed enriched tensile strength of (145 N) in weft direction, ultraviolet protection factor of 58, burn time of 173 s and limiting oxygen index of 26.10% as compared to 116 N, 5, 88 s and 18.3% respectively for the pure cotton fabric. Overall, the 3 wt% GnP/PANI–GA nanocomposite was evaluated as the optimum concentration because of the uniform dispersion of GnP in PANI/GA nanocomposite.

Experimental investigations on nano powder mixed Micro-Wire EDM process of inconel-718 alloy

This research investigates the effect of graphite nano powder suspended in dielectric medium of Micro-Wire EDM process of inconel alloy. The main influencing parameters such as voltage, capacitance, and powder concentrations were considered. The machining characteristics of material removal rate (MRR), kerf width (KW) and surface roughness (SR) were investigated. Twenty seven experiments were carried out based on full factorial design by varying voltage, capacitance and powder concentration each at three levels. Data were analyzed using Design Expert software. It is from the experimental investigations show that the presence of graphite nano powder in the dielectric can improve the topography and roughness of the machined surface significantly especially Ra values reduced from 0.830 µm to 0.418 µm in addition to higher material removal rate of 0.0055 mm3/min. The higher material removal rate as well as good surface quality was achieved at graphite nano powder concentration of 0.5 g/l, capacitance of 0.01 µF and Voltage of 100 V.

Assessing the Performance of Nano Lubricant on Zinc Aluminium Alloy

In the field of tribology, Zinc Aluminium (ZA) alloys have been widely investigated for their superior wear characteristics. They were found to be suitable alternatives for bearing bronzes for the operating conditions of high mechanical load and moderate sliding speeds. Addition of nano-particles in the lubricating oil (base oil) to enhance the characteristics of the base oil is known as nano lubrication. In this study, sliding wear behaviour of ZA27 was investigated under dry, base oil and nano oil lubrication conditions, by varying load, sliding distance and sliding speed. With the base oil as SAE 40, nano graphite was added in two step method which was further used to identify the lubrication regime under different lubrication conditions. From the limited study of single melt samples, the results appear that the wear behaviour of ZA27 alloy improved under nano lubrication conditions with reduction in operating temperature. It could be observed from SEM images that the presence of nano-particles reduced scarring and wear, leading to enhancement in the tribological performance of ZA27 alloy.

Improved Wear Resistance of UHMWPE Fibers by Modified Nano-Graphite

Single ultra-high molecular weight polyethylene (UHMWPE) fiber was modified by modified nano-graphite (NG) in wear resistance. Wear resistance, tensile strength, thermogravimetric analysis (TGA) were used to characterize the effect of modified NG on the properties of UHMWPE fiber. The results showed that with the increasing content of modified NG, the wear resistance of UHMWPE fiber was enhanced and its tensile strength was decreased. Considering the tensile strength and wear resistance of fiber, the optimum content of modified NG in UHMWPE fiber was around 0.58%. At this content, the wear resistance and thermal decomposition temperature of UHMWPE fiber were increased 1.88 times and 50°C respectively than pure UHMWPE fiber.

Some Features of Doping of Nano–Graphite in Natural Coir Fibre Epoxy Composites

Nanokompozit polimerlerin, biyomedikal muhendislik, elektronik yapi muhendisligi ve daha bircok cesitli sektor de; bilim ve teknolojideki yeni gelismeler nedeniyle dogrudan/dolayli kullanimlari girisimde bulunulmustur. Biz bu arastirmada, dogal hindistan cevizi lifi takviyeli polimer kompozitlerinde nano-grafitin katkisini kullandik. Kullanilan kompozit numuneleri, agirlik fraksiyonu ile bir epoksi recine matrisinde% 45 dogal hindistan cevizi lifi ve% 3.2 nano-grafit (N-G) idi. Dogal hindistan cevizi lifi icindeki % nano-grafit agirliginin uzerinde doping yaptigimiz da gerilme mukavemetinin kabaca % 45-50 ve geri kalaninin mekanik ozelliklerin ise ortalama 2-3 kat arttigini bulduk. Son olarak, SEM analizi ile mevcut lif elyafi kompozit numunelerinde nano grafitin iyi bir dagilimini ortaya koyduk.

The effect of graphite particle size on the corrosion and wear behaviour of the PEO-EPD coating fabricated on commercially pure zirconium

The practical importance and intricacy in the application of zirconium and its alloys have triggered widespread attention towards the enhancement of its mechanical and corrosion resistance properties. Composite coatings were fabricated on zirconium metal by integrating Plasma electrolytic oxidation (PEO) and Electrophoretic deposition process (EPD). The effect of particle size on the PEO-EPD coating characteristics were studied by comparing the properties of the coatings produced in micro and nano sized graphite particle containing electrolytes. The surface morphology, topography was studied using scanning electron microscope (SEM) and optical profilometer, and the phase analysis was done using X-Ray diffraction (XRD). The diffraction peaks corresponding to graphite indicate the successful incorporation of graphite particles in the coating fabricated in the particles containing electrolyte. The electrochemical corrosion studies by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) reveals the superior corrosion resistance of nano graphite incorporated zirconia coating. The increase in wear resistance and scratch resistance was also observed for the nano graphite incorporated coating. Thus, incorporation of the nano graphite particle into the zirconia layer proved to be beneficial for improving wear, friction resistance, scratch resistance and electrochemical corrosion resistance.

A pre-feasibility experimental study of using surface-enhanced flake graphite to build up PEFC bipolar plates

Abstract The aim of this study is to determine the feasibility of using Surface-enhanced flake graphite (SFG) as a primary filler in an epoxy matrix. The mixture is expected to be used to build polymer electrolyte fuel cell (PEFC) bipolar plates by means of hot pressing manufacturer process. Mechanical properties, i.e., flexural and tensile strength, of the samples were measured for different SFG and Nano Graphite (NG) proportions as a secondary filler. It was found that the samples with 40 and 50wt% of SFG in epoxy (EP) show flexural stress values falling between 30 and 19 MPa, and the average tensile stress was 13 MPa. The highest electrical conductivity value found in this study is 1.95 S/cm (with 50 and 10wt% of SFG and NG in EP) which is in the same range of commercial bipolar plates.

Wear Behavior of Graphite Nano Plates/Al Composites

An a luminum matrix composite reinforced with 1–5 wt % graphite nano platelets ( CNPLs ) has been fabricated by cold pressing followed by hot extrusion techniques. The wear test conditions used were implemented at different wear loads, (10 N, 20 N, 30 N, 40 N, and 50N) with three different sliding speed of 0.2, 0.4, and 0.8 m/sec. The effects of nano graphite content on the structure characteristics and properties of composites were investigated. Scanning electron microscopy (SEM) has been used to examine the dispersion of CNPLs and aluminum. The results showed that CNPLs were distributed homogeneously in the (CNPLs/Al) composites. The CNPLs content significantly affects the mechanical properties of (CNPLs/Al) composites. Meanwhile, the 2.0 wt % CNPLs /Al composite is found to exhibit the highest hardness. Experimental results showed that at all the loads studied the wear resistance of the composites was better when compared with the monolithic aluminum matrix.

Experimental investigation of cutting parameters using nano lubrication on turning AISI 1040 steel

Abstract An accurate machining process is done when the heat generated due to the large friction between the tool and workpiece is controlled. Turing has utmost importance in metal removal process. Elevated temperatures are recorded in turning process which intern effects the tool life and surface finishing of the part, proper lubrication may improves the tool life and surface finishing. Much advancement has been made in the machining aspects with regards to the lubricants used. Vegetable oils are showing better results when compared to petroleum based oils in controlling the heat generated in machining process. Nano crystalline powders can improve the properties of the base coolant. Minimum quantity lubrication (MQL) is an effective tool for avoiding flood supply. The present investigation deals with the use of a mixture of nano crystalline Graphite and Sunflower oil as a lubricant and as an alternative to the cutting fluids to reduce friction and thereby improve the surface finish of the final product. The experimental study is carried out on influence of different particle sizes of graphite nano powder on machining parameter.

A 2D and 3D study of the texture of wear scars for soybean oil additivated with nano graphite

Based on studies on characterization of surface topography, the following conclusions can be drawn: surface texture analyses are statistical. There is no agreed methodology for characterizing both the texture of worn surfaces and those of new ones (unworn). The methodology depends on many factors: the shape and size of triboelements, the available equipment and software, the set of selected parameters, the user experience and ingenuity. Worn scars were obtained after tests on four ball machine (European conditions [30], at LubriTest laboratory of “Dunarea de Jos” University). The test parameters for each tested lubricant were: force at main shaft of the four ball machine -100 N, 200 N and 300 N (± 5%). sliding speeds of 0.383 m/s, 0.537 m/s and 0.691 m/s, test time - 60 minutes (± 1%), the concentration of the additive is 0.25%, 0.50% and 1% (wt), respectively. Analysing the data from this study, it can be seen that for all measurements, St is higher than Rt, which means that the maximum values were not found on the axis of the ellipse perpendicular to the sliding direction. This is logical because in a circular or almost circular contact, the maximum contact pressure is towards the front of the contact. Thus, a 3D study will also include the area of maximum contact pressure that will most likely affect the surface texture quality to a greater extent. For some test regimes, i.e. (F=100 N, v=0.38 m/s), lower values were obtained than those obtained on the initial surfaces of the balls, which implies that the test regime acts as a running-in process, improving the surface quality Amplitude parameters and three functional parameters will be analysed in this paper.

Mechanical and Electrical Characterization of Two Carbon/Ultra High Molecular Weight Polyethylene Composites Created Via Equal Channel Angular Processing

Ultra-high-molecular-weight-polyethylene (UHMWPE) has the greatest impact strength of any thermoplastic and has a variety of both industrial and biomedical applications. Equal channel angular processing (ECAP) is a fabrication method for UHMWPE that introduces shear into the polymer matrix by deforming the polymer through an angular channel, with the goal of enhancing mechanical properties. Both nanographite (NG) and carbon black (CB) attract interest as potential carbon additives for use in creating UHMWPE conductive polymer composites (CPC), but they have not yet been extensively tested in conjunction with ECAP. This study presents a systematic evaluation of the mechanical and electrical properties of 1.0 wt % CB/UHMWPE and NG/UHMWPE composites created using ECAP. These samples are compared against pure UHMWPE ECAP controls as well as compression molded (CM) composite samples. Results indicate that both NG and CB carbon additives successfully create CPCs with a corresponding decrease in mechanical properties. ECAP results in comparatively high mechanical and conductive properties when compared with compression molding. Electrical conductivity is shown to be inversely correlated with tensile strain in a repeatable manner, and microstructural theory is discussed. This work suggests a method to produce flexible, conductive UHMWPE composites that vary consistently and predictably with applied strain, which could have a variety of biomedical and industrial applications.

Synthesis and Characterization Electro Catalytic Al-Ni and Nano Graphite Electrodes for Rechargeable Al Ion Battery

Synthesis and Characterization Electro Catalytic Al-Ni and Nano Graphite Electrodes for Rechargeable Al Ion Battery

Tribological behaviour on aluminium –nano Titanium Di Oxide with addition of solid lubricant nano Gr powder metallurgy composite

The aluminium-nano titanium di oxide hybrid composite with self lubricant nano graphite is processed by powder metallurgy. The wear behaviour was experimentally investigated on the aluminium combined with titanium di oxide 5wt% and graphite 5wt% at nano scale in reinforcement with different density com at different sliding velocity of 1.5m/s, 2m/s, 2.5m/s along with the different loads of 5N, 7N, 10N. The wear test was conducted on the pin on disc apparatus. The equal weight percentage of TiO2 and Gr in Al MMCs changing the hardness and density of the hybrid composites due to the occupancy of volume fraction in the Al-TiO2-Gr hybrid composites. The TiO2 provide strength of the hybrid composites and the graphite exhibited both excellent wear resistance and friction coefficients.

Nano indentation and morphology study of the polypropylene and high density polyethylene nanocomposites based on exfoliated graphite Nano platelets/Nano- magnesium oxide

Polypropylene (PP) and high density polyethylene (HDPE) were successfully fabricated using injection molding machine, by the addition of exfoliated graphite nanoplatelets composites reinforced with 2wt.t% of nano-magnesia. The nanoindentation properties and microstructure of the composites were investigated, in the current study. The XRD patterns of both composites showed the peaks of xGnP and n-MgO, where their intensity became stronger with increasing the concentration of xGnP added into both polymers. In addition, the SEM micrographs revealed a good dispersion of fillers within the matrix. The nanoindentation properties of both nanocomposites revealed better properties with compared to the virgin polymers. The PP nanocomposites showed an improvement of hardness up to 22 % and 118% with the compositions of 1xGnP/2n-MgO and 5xGnP/2n-MgO respectively. In addition, HDPE/1xGnP/2n-MgO and HDPE/5xGnP/2n-MgO represented a dramatic improvement of hardness up to 146% and 341% respectively with compared to virgin polymer. In addition, the enhancements in reduced modulus of PP and HDPE were proportional to the xGNP loading.

(Invited) Graphitic Intercalation Compounds: A Versatile Nano-Template for the Synthesis of Multi-Functional Electrocatalysts

Bifunctional catalysts, which can perform both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) at low overpotentials with high turnover efficiency (TON) and frequency (TOF), are highly sought after. Platinum group metals are among the best catalysts for both OER and ORR but their scarcity and high cost calls for alternatives. In this context non-precious transition metal and metal oxide are promising options despite their lower intrinsic catalytic activity and chemical stability.1 Carbon nano materials are promising materials for electro catalytic application thanks to their high surface areas, electrical conductivity and stability in acidic or basic aqueous solutions.2 Graphite can be intercalated by potassium forming a graphite intercalation compound (GIC) of defined stages. GICs can be readily exfoliated to monolayer graphene in organic solvents solely by stirring. These graphenide solutions are composed of charged graphene layers and are thermodynamically stable.3,4 In analogy to large flake size graphite, graphitic nano carbons with lateral sizes bellow 50 nm can also be intercalated successfully and can be dissolved in absolute organic solvents. Graphenide solutions have been used in a variety of different applications e.g. to generate transparent conductive films, quantum dots, and surfactant-free graphene in water.5 Additionally, their reducing character has been used to graft functional moieties covalently to the carbon framework.6 In this talk, the exploitation of the reduction potential of graphenide solutions for earth abundant metal nanoparticle generation will be discussed. The advantages of using graphenides as reduction reagent in nanoparticle synthesis are : i) graphenide solutions are strong reducing agents and no additional reducing agent is needed, ii) the redox reaction takes place in close proximity of the carbon lattice and the decoration of the carbon framework thus proceeds efficiently, iii) the amount of reduction agent can be controlled by the concentration of the respective graphenide solution used, iv) the by-product of the reaction is only the respective potassium salt, which can be removed easily. The resulting composite materials are interesting and promising earth abundant electrocatalysts, due to their structure, small size, morphology and conductive framework. These nanocarbon / metal nanoparticle composite materials exhibit high bifunctional electro catalytic activity towards ORR and OER as well as long term stability.7 Xia, W., et al., (2016) Angew. Chem. Int. Ed. 55, (8) 2650-2676.Mazzaro, R., et al., (2015) ChemistryOpen 4, (3), 268-273.Pénicaud, A., et al.,. (2013). Acc. Chem. Res. 46, (1), 129–137.Vallés, C., et al.. (2008) J. Am. Chem. Soc. 130, 15802–15804.Bepete, G., et al., (2016) Nat. Chem. 9, 347–352.Hof, F., et al., (2014) Chem. - A Eur. J. 20, 16644–16651.Hof, F., et al., (2017) Chem. - A Eur. J. 23, 15283–15288.

Development of graphite carbon nitride based fluorescent immune sensor for detection of alpha fetoprotein

A novel fluorescent immunosensor for determination of alpha fetoprotein (AFP) in serum samples has been developed based on the nano graphite carbon nitride (g-C3N4) as fluorophore and immunomagnetic beads (MBs) as separation material. The bulk g-C3N4 was obtained by thermal polymerization of melamine, and then carboxylated and exfoliated to acquire the carboxylated nano g-C3N4 (c-n-g-C3N4), which has been characterized and the results showed that it had excellent fluorescent properties. The antibodies of AFP (Ab1, Ab2) were conjugated to the MBs and the c-n-g-C3N4, respectively. In assay of AFP detection, the magnetic part of the immunosensor, MBs-Ab1, would form the sandwich type complex with the signal part of the sensor, c-n-g-C3N4-Ab2. The developed immunosensor could simplify the process of separation due to the MBs. The results illustrated that proposed approach held a good linearity between the fluorescence intensity of the sensor and the AFP concentration ranging from 5–600ng/mL with the limit of detection as low as 0.43ng/mL, and its spiking recoveries ranged from 98.2% to 105.9% with RSD from 2.1% to 3.5%. The fabricated fluorescent immunosensor possesses the merits of good sensitivity, excellent selectivity, high biocompatibility and low cost, and the results provide a novel clue to develop immunosensor for determination of the biomarkers in complex matrices.