Graphene Oxide Content Research Articles

Influence of Graphene Oxide Concentration and Ultrasonication Energy on Fracture Behavior of Nano-Reinforced Cement Pastes

The aim of this study is twofold. First, to assess the effect of the sonication process on the optimal dispersion of GO sheets for nanostructural reinforcement of cement pastes, as there is currently no clear criterion on this effect in the literature. For this purpose, in the first stage, the GO content in distilled water was fixed at 0.03% by weight, and the sheets were dispersed using different levels of ultrasonic energy, ranging from 0 J/mL to 2582 J/mL. In the second stage, to analyze the modification of pore structure due to the addition of GO sheets in different ratios (0–0.06% by weight) and its relationship with the mechanical and fracture properties of reinforced cement pastes. According to the results, it has been determined that the incorporation of GO sheets into the matrix alters the mechanical and fracture behavior, varying depending on matrix pore size and GO particle size. The addition of GO leads to a reduction in the average size of macropores (greater than 8 µm) of 13% for a dosage of 0.45% in weight and micropores (between 8 and 0.5 µm) in a 64% for the same composition with non-sonicated GO, although the total volume of pores in these ranges only decreased slightly. This reduction is more pronounced when the GO has not been sonicated and has larger particle size. Sonicated GO primarily modifies the range of capillary pores (<0.5 µm). The addition of GO with the highest degree of dispersion (465 nm) did not show significant improvements in compressive strength or Young’s modulus, as the cement used contains a significant volume of macropores that are not substantially reduced in any composition. Adding 0.030% ultrasonicated GO achieved a 7.8% increase in fracture energy, while an addition of 0.045% resulted in a 13.3% decrease in characteristic length, primarily due to the effect of capillary and micropores.

Structure Investigation of highly porous bioceramics based on biogenic hydroxyapatite with graphene oxide coating

Highly porous bioceramics (porosity equal to 93–94 %) based on biogenic hydroxyapatite and sodiumborosilicate glass (40wt% of glass) was prepared by foam replication method at 700 °C and coated by graphene oxide using CVD method. Obtained bioceramics samples were studied by SEM, XRD and Raman spectroscopy. Phase composition, morphology, skeleton density, porosity and compression strength were evaluated. It was shown that biogenic hydroxyapatite in highly-porous bioceramics composition is stable and keeps hydroxyapatite phase without secondary phase formation after sintering with sodiumborosilicate glass as well as after application of CVD method for graphene oxide coating. Formation of graphene oxide for coated bioceramics was confirmed by XRD, SEM and Raman spectroscopy. Significant effect of graphene oxide coating on the porosity and skeleton density was not detected due to thin layer and low content of graphene oxide, but it allows 30 % increasing the compression strength of highly porous bioceramics.

New graphene oxide doped polymer dispersed liquid crystal nanocomposites targeted to eco-friendly and energy-efficient smart windows

Graphene oxide-polymer dispersed liquid crystal (GO-PDLC) composites are proposed as a solution for energy-efficient switchable windows. These composites were prepared by incorporating varying concentrations of graphene oxide (GO) into a mixture of nematic liquid crystal (E7) and a UV–Vis curable resin using the polymerization-induced phase separation technique. The results indicate that the dispersion of GO at an optimum concentration of 0.005 wt% significantly affects the morphology, phase transition temperatures, and electro-optic properties of polymer dispersed liquid crystal (PDLC). In particular, the GO-PDLC composites exhibit a transition from an opaque to a transparent state at a remarkably low voltage (∼11.5 V) compared to pure PDLC cell. Dielectric analysis reveals that adding GO increases the permittivity, conductivity, and dielectric strength of PDLC composites. Moreover, the Cole-Cole plot indicates a non-Debye type relaxation in a higher frequency region. Furthermore, a blue shift in emission wavelength and enhanced photoluminescence intensity suggest alterations in electronic transitions within the composites. This comprehensive study provides valuable insights into optimizing the properties of PDLCs through the dispersion of GO, thereby offering promising prospects for their utilization in various optoelectronic applications.

The Rheological and Structural Properties of Aqueous Graphene Oxide Dispersions: Concentration and pH Dependence.

A modified Hummer's method was used to synthesize aqueous dispersions of graphene oxide (GO). The morphology, chemical structure, and exfoliation state of GO were analyzed by combining scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The structural and rheological properties of the GO dispersions were studied as a function of GO concentration and pH. Increasing the concentration of GO revealed shorter interparticle distances between GO sheets. This induced a transition from fluid to nematic gel-like structures, as observed by polarized optical microscopy (POM). The Herschel-Bulkley model was used to fit the shear thinning curves and to demonstrate the viscoelastic behavior. Both the yield stress and viscoelastic moduli in the linear viscoelastic regime increased. As pH increases, the color of the aqueous GO dispersions becomes darker, the negative values of the zeta potential increase, the distances between the GO sheets decrease as observed by a slight shift of the correlation peak toward higher values of the scattering vector modulus in small-angle X-ray scattering (SAXS), and the rheological properties (yield stress and viscoelastic moduli in the linear viscoelastic region) decrease. These results can be explained by a change in the morphology of GO related to their hydrophilicity. This work presents relationships between rheological and structural properties of GO sheet dispersions, with particular emphasis on the effects of concentration and pH.

Dispersion frequency technique to explain the charge transfer process involved in cadmium detection using aniline, N-phenylglycine and graphene oxide based electrochemical sensor

A new technique, termed as dispersion frequency (DF) technique, based on Maxwell Wagner dispersion frequency, was proposed for the first time in an electrochemical sensor to explain the charge transfer mechanism involved, behind the sensing process. Dispersion frequency can be characterized by the maximum dispersion in capacitance, which is an interfacial relaxation effect, and occurs in systems where electric current passes through the electrode electrolyte interface across the double layer. In this work, this technique was used to explain the reason behind the improvement in the selectivity by varying the film thickness and amount of graphene oxide (GO), in composite (from aniline, N-phenylglycine and GO) films. For that purpose, electrochemical impedance spectroscopy (EIS) experiments were conducted, and the DF values were evaluated. It was found that the DF values decrease with film thickness and increase with the GO content when detecting Cd2+ in buffer. Also, the DF value changed (decreased) in presence of interfering species. Thus, it was demonstrated that the DF values could be used to predict and explain the interference effect. The behavior of the DF values was opposite to that of the barrier width (BW) values as studied in a previous work which too were a function of the film thickness and the GO content. Both explain independent physical phenomena which are related to the same charge transfer process. In this work, a correlation coefficient relating the barrier width and dispersion frequency values with respect to film thicknesses at any specific amount of GO content was evaluated. This correlation coefficient can be used to evaluate one parameter if the other is known for a series of film thicknesses by doing lesser number of EIS experiments.

Experimental investigation on physical properties and early-stage strength of ultrafine fly ash-based geopolymer grouting material

The conventional cement grouting materials possess certain drawbacks that hinder their environmental compatibility. The utilization of geopolymer grouting materials with the raw material of fly ash is anticipated to serve as a proficient approach in mitigating the environmental problem caused by solid wastes. Consequently, this study employed ultrafine fly ash (UFA) and granulated blast furnace slag (GBFS) as composite base materials to fabricate a kind of novel geopolymer grouting material. The addition of 0.05 % − 0.2 wt% graphene oxide (GO) facilitated the preparation of this material, and the physical properties and early-stage strength were experimentally investigated. The micro-analysis was conducted using micro-analysis techniques, including Fourier transform infrared and energy dispersive X-ray spectroscopy, etc. The findings indicated that as the contents of GO and GBFS increased, the flowability slightly decreased; the addition of GBFS and GO can contribute to the elevation of viscosity; the initial and final setting times were decreased. The bleeding rate decreased and increased with increasing GO and GBFS contents. It was also found that the GO and GBFS were beneficial to increase the water retention rate. Furthermore, the inclusion of GO and GBFS significantly enhanced the early-stage compressive strength of the grouting material. The GO and GBFS contents of 0.1 % and 60 % resulted in the attainment of maximum compressive strength of samples, with the value of 15.89 MPa at the first day. The simultaneous utilization of GO and GBFS facilitates the generation of a greater quantity of calcium-alumina-silicate-hydrate gel, thereby substantially enhancing the initial compressive strength of grouting materials. The results of this study could provide valuable perceptions into the production of sustainable grouting materials with low carbon emissions and the recycling utilization of solid wastes.

Innovative Nanostructuring of Li–Zn ferrite/graphene composites with tunable properties

The Li-ferrite and graphene oxide (GO) nanocomposites, denoted as (Li0.5-x/2ZnₓFe2.5-x/2O4: x = 0.25), were produced through ultrasonication. The wet method generated Li-ferrite, while the Hummers' method synthesized the GO. X-ray diffraction (XRD) was used to validate the development of Li-ferrite and GO in the nanocomposites. The dimensions of the crystal were determined between 41 and 52 nm, and the porosity of the composites increased with the higher quantity of GO. The scanning electron micrographs (SEM) of ferrites illustrated the formation of uniform and well-defined grains with consistent shapes, exhibiting properties well-suited for effective microwave absorption. The electrical resistance of spinel ferrite was measured at approximately 3.34 × 1011 Ω-cm and significantly lowered as the fraction of GO increased at ambient temperature. As per Maxwell Wagner's model, the electrical permittivity exhibited interfacial polarization with distinct real and imaginary components. The AC conductivity exhibited a positive correlation with the GO content due to the conductive properties of GO and the improved charge hopping mechanism. The frequency exponent parameter's value falls from 0.36 to 0.95 b y the Jonscher's Power law. The magnetic susceptibility of all the samples exhibited a progressive decrease as the temperature increased. The choice of using lithium-based ferrite as filler is made to strengthen the ferrite/GO composites and improve their magnetic and electrical properties. This is undertaken to harness these composites for high-frequency applications, such as their use as microwave absorbers in microwave devices.

Enhancing fresh strawberry preservation: Fabrication and characterization of electrospun fibers decorated with functionalized graphene oxide

AbstractThis study focuses on developing an innovative packaging material for fresh strawberries composed of electrospun poly(ε‐caprolactone) (PCL)/poly(vinylpyrrolidone) (PVP) fibers decorated by pure graphene oxide (GO) and functionalized GOs with silane agents using the electrospinning technique. Initially, synthesized GO was first functionalized by silane agents, and followed by the fabrication of electrospun PCL/PVP fibers incorporating both pure GO and functionalized GOs. The surface morphological analyses revealed the uniformity, smoothness, and beadless in the fabricated fibers. The average fiber diameter of the PCL/PVP/0.5A‐GO fibers was found as 3244 ± 56 nm. Electrospun PCL/PVP/0.5A‐GO and PCL/PVP/0.5G‐GO fibers exhibited increased water absorption ratios over 20 days. The incorporation of GO into the polymer matrix, along with an increase in GO concentration, enhanced the tensile strength of the fibers, found as 5.149 ± 0.032 kPa. In preservation tests on fresh strawberries, PCL/PVP/0.5A‐GO fibers demonstrated superior freshness compared with unpacked strawberries and other variants. The study also highlighted the inhibitory effects of fibers decorated with 0.5% APTES‐GO, showing the highest inhibition zone. In summary, fibers incorporating 0.5% A‐GO effectively extended the shelf‐life of fresh strawberries, making them a promising packaging material for perishable goods.

3D printed polymer-matrix loaded with graphene oxide

This research deals with adding graphene oxide, resulting in a novel resin suitable for additive manufacturing technologies based on layer-by-layer photopolymerization. The mechanical and thermal properties demonstrate that the specimens manufactured with graphene oxide with low concentration achieve an excellent combination of strength and ductility. Graphene oxide highly influences the molecular dynamics of the polymeric matrix, modulating the glass transition and thermal stability so that it obtains a more elastic behavior or enhanced stiffness, depending on the concentration. The structural properties show that the structural disorders in the polymer matrix are due to variations in graphene oxide content, so graphene oxide embedded in the photopolymer resin did not produce relevant structural changes, form any covalent bond, or add new functional groups.

Effect of microcapsules’ mechanical stability on the encapsulated cells’ behavior

Stem cell microencapsulation offers immunoprotection, utilizing natural polymers such as sodium alginate (SA), chitosan, and derivatives such as trimethyl chitosan (TMC). Additive minerals improve microcapsule properties and cell differentiation. Layering increases mechanical strength and shields cells from the host’s immune system. This study explores the impact of incorporating nano-hydroxyapatite (nHA) and graphene oxide (GO) into the three-layer alginate–TMC–alginate microcapsules housing human adipose mesenchymal stem cells (haMSCs). The experimental design focused on optimizing the mechanical stability, with the ideal GO and nHA contents identified as 0.81% and 34% w/w, respectively. Rheological analysis revealed enhanced mechanical consistency, evidenced by higher storage modulus and lower loss factor in the optimized sample. Viability of the microencapsulated haMSCs, assessed through acridine orange/propidium iodide staining and MTT assays, affirmed the nontoxic nature of the microcapsules. Osteogenic potential was evaluated via alkaline phosphatase (ALP) activity measurement and immunocytochemistry staining. Microcapsules containing nHA and GO exhibited significantly elevated ALP activity, underscoring the pivotal role of these additives in enhancing mesenchymal stem cell differentiation. The highest osteocalcin deposition occurred in the optimized and SA/nHA 40% w/w groups in the differentiation medium. This comprehensive investigation highlights the potential of three-layer microcapsules with nHA and GO for bone tissue engineering applications.

Preparation of cellulose derived carbon/reduced graphene oxide composite aerogels for broadband and efficient microwave dissipation

The development of cellulose derived carbon-based composite aerogels with light weight, broad bandwidth and strong absorption remains a challenging task. In this work, the cellulose derived carbon/reduced graphene oxide composite aerogels were prepared by a two-stage process of chemical crosslinking and high-temperature carbonization. The results revealed that the as-fabricated binary composite aerogels had a unique lightweight characteristic and three-dimensional porous network structure, which was chemically crosslinked by epichlorohydrin. Furthermore, the weight concentration of graphene oxide (GO) had a notable influence on the electromagnetic parameters and microwave absorption properties of the composite aerogels. The obtained binary composite aerogel possessed the optimal microwave dissipation capability when the concentration of GO was 1.5 mg/mL. Remarkably, the minimum reflection loss reached −50.42 dB at a thickness of 2.47 mm and a filling ratio of 17.5 wt%. Concurrently, the composite aerogel with a comparable thickness of 2.73 mm showed a wide effective absorption bandwidth of 7.28 GHz, spanning the total Ku-band and extending into a portion of the X-band. The radar cross section contribution of binary composite aerogels in the far-field was also simulated by computer simulation technique. In addition, the potential microwave attenuation mechanism was proposed. It was believed that the results of this paper would offer a reference for the preparation of cellulose derived carbon-based composite aerogels as efficient and broadband microwave absorbers.

Outstanding interlaminar strength of carbon fiber reinforced epoxy resin via graphene oxide chemical bridge bonding

Carbon fiber reinforced polymers (CFRPs) are susceptible to interlaminar failure under high shear stress, which reduces their service life. Herein, we report a strategy to address the interlaminar damage problem of CFRPs by utilizing graphene oxide (GO) as a bridge to chemically bond carbon fibers and epoxy resin. Amino groups were grafted on the surface of carbon fibers to react with GO, then active amino functional groups were introduced onto GO, enabling crosslink with the epoxy resin. The chemical bonding force and mechanical interlocking effect of GO tightly integrated the carbon fibers with the epoxy resin, greatly reducing relative slip under high shear stress. This flexible and robust connection resulted in a significant improvement in the interfacial adhesion strength of CFRPs. The GO content and type of amino reactants were optimized to fabricate CFRPs, and the interlaminar shear strength and transverse fiber bundle tensile strength were increased to 76.36 MPa and 34.2 MPa, which were 46.2 % and 77.2 % higher than those of pre-modification materials, respectively. This research demonstrates that the chemical bonding provided by grafting graphene oxide significantly enhances interlaminar bond strength, thereby extending the service life of CFRPs and offering a promising path for manufacturing high-strength composites.

An Experimental Study on Mechanical Properties of Concrete by Partial Replacement of Cement with Graphene Oxide

Abstract: An essential building material, concrete is always changing for increased sustainability and performance. This study looks into the effects of replacing some of the cement in M60 grade concrete with graphene oxide. One amazing nanomaterial that is available in powder, sheets, flakes, and oxide form is graphene oxide. It has lately been used in the building industry and is robust, elastic, and lightweight. It has excellent qualities that are advantageous in the building industry. Adding graphene oxide to concrete composites improves binding strength to concrete structures, lowers permeability, and speeds up the pace of hydration. The concrete samples are tested for slump, split tensile strength, compressive strength, flexural strength, and durability after seven, twenty-eight, and fifty-six days. Graphene oxide concentrations in concrete compositions ranging from 0.5% to 2% by cement weight. The findings demonstrate that adding graphene oxide to concrete enhances its strength, with some mix compositions exceeding regular concrete. The mechanisms producing the strength increase are illuminated by the analysis of the experimental data, underscoring the potential of these additional components to enhance the durability as well as sustainability of concrete structures. These discoveries advance the field of construction material engineering by contributing to ongoing attempts to create high-performance and sustainable concrete compositions.

Collaborative polarization in a solution of coupled hydroxychloroquine-graphene oxide: Optoelectrical measurements

Optical UV–vis and electrical impedance measurements were conducted at room temperature on aqueous solutions with hydroxychloroquine (HCQ) and graphene oxide (GO) molecules. Remarkably, at sufficiently high GO concentration, the HCQ-GO solution exhibited the least loss factor and the Debye relaxation process, suggesting that the polarization of coupled HCQ-GO molecules is cooperative and, hence, correlated within the Debye relaxation time. Indeed, our systematic molecular dynamic calculations of the equilibrium Dipole Auto-Correlation Function (DACF) showed that adding GO enhances the decay relaxation time of DACF for HCQ samples. Moreover, the depression of the characteristic UV absorption peak (at ∼ 342 nm) with increasing GO concentration validated the presence of the HCQ-GO interaction in our samples, agreeing with our calculation based on the simplified time-dependent density functional theory. Our work is, thus, timely regarding the current high demand for a method to remove HCQ from the aqueous environment. It is also relevant to drug delivery applications considering the anticancer efficacy of HCQ and the biocompatible GO as a potential drug carrier.

Impact of Graphene oxide (GO) and reduced Graphene Oxide (rGO) on the TiO2 thin film composite (TiO2: GO/ rGO) photoanodes

Graphene and its derivatives have several advantages such as large surface area, great chemical stability, high transmittance, and good electrical conductivity, which are the fundamental qualities required by photovoltaic industries. GO and rGO are mixed in various proportions ranging 0 wt.% - 15 wt.% to spin coat TiO2: GO/rGO composite thin films. The effect of graphene oxide and reduced graphene oxide on the performance the TiO2 based composite photoanodes are obtained. A tetragonal anatase phase of TiO2 was confirmed by the XRD analysis. The calculated crystallite size decreases with lower concentrations of GO and rGO but starts to increase for higher concentrations. The spectrophotometer studies have confirmed that the optical bandgap of pure TiO2 films is decreased on doping with GO and rGO. The SEM analysis have confirmed that the surface is tightly packed with the uniformly distributed grains, and they are very compact.

Pb(II) Adsorption Properties of a Three-Dimensional Porous Bacterial Cellulose/Graphene Oxide Composite Hydrogel Subjected to Ultrasonic Treatment.

A three-dimensional porous bacterial cellulose/graphene oxide (BC/GO) composite hydrogel (BC/GO) was synthesized with multi-layer graphene oxide (GO) as the modifier and bacterial cellulose as the skeleton via an ultrasonic shaking process to absorb lead ions effectively. The characteristics of BC/GO were investigated through TEM, SEM, FT-IR, NMR and Zeta potential experiments. Compared to bacterial cellulose, the ultrasonic method and the carboxyl groups stemming from GO helped to enhance the availability of O(3)H of BC, in addition to the looser three-dimensional structure and enriched oxygen-containing groups, leading to a significantly higher adsorption capacity for Pb(II). In this paper, the adsorption behavior of BC/GO is influenced by the GO concentration, adsorption time, and initial concentration. The highest adsorption capacity for Pb(II) on BC/GO found in this study was 224.5 mg/g. The findings implied that the pseudo-second-order model explained the BC/GO adsorption dynamics and that the data of its adsorption isotherm fit the Freundlich model. Because of the looser three-dimensional structure, the complexation of carboxyl groups, and the enhanced availability of O(3)H, bacterial cellulose exhibited a much better adsorption capacity.

Raman spectroscopic quantification of graphene oxide in soil: Transport, surficial enrichment and environmental effects

The transport and retention data in environmental media are indispensable for the hazard evaluations of graphene materials. Due to the complexity of soil, the transport of graphene is hard to quantify without isotope labeling. Herein, we developed 2D Raman mapping as a label-free technique to quantify graphene oxide (GO) in soil. After pre-treatment by hydrazine hydrate to quench its fluorescence, the quantification of GO in soil was achieved in the range of 0.1–1000 mg/L by measuring the average G-band intensity. In column transport experiment, the transport and retention of GO in soil depended on the solution chemistry. Lower pH and higher ionic strength hindered the transport of GO. In particular, Ca2+ showed the most obvious retardation on the transport of GO. GO enriched in the surficial soil layer by several folds of the initial concentrations, and higher GO concentration led to more surficial enrichment. The sowing manner of seeds affected the soil enrichment of GO, too. The surficial enrichment of GO reduced its direct contact with seedling roots, resulting in the alleviation of GO toxicity. Our results provided a facile method to study the environmental behaviors of graphene and highlighted the crucial impacts of environmental media on the graphene toxicity.

Cellulose acetate scaffold coated with a hydroxyapatite/graphene oxide nanocomposite for application in tissue engineering.

The objective of this study was to synthesize and characterize porous Cellulose Acetate (CA) scaffolds using the electrospinning technique and functionalize the surface of the scaffolds obtained through the dip-coating method with a Hydroxyapatite (HA) nanocomposite and varying concentrations of graphene oxide (GO) for application in tissue engineering regeneration techniques. The scaffolds were divided into four distinct groups based on their composition: 1) CA scaffolds; 2) CAHAC scaffolds; 3) CAHAGOC 1.0% scaffolds; 4) CAHAGOC 1.5% scaffolds. Scaffold analyses were conducted using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS), and in vitro cell viability assays (WST). For the biological test analysis, Variance (two-way) was used, followed by Tukey's post-test (α = 0.05). The XRD results revealed the predominant presence of CaP phases in the CAHAC, CAHAGOC 1.0%, and CAHAGOC 1.5% groups, emphasizing the presence of HA in the scaffolds. FTIR demonstrated characteristics of cellulose and PO4 bands in the groups containing HA, confirming the presence of CaP in the synthesized materials, as also indicated by XRD. Raman spectroscopy showed the presence of D and G bands, consistent with GO, confirming the successful incorporation of the HAGO nanocomposite into the scaffolds. The micrographs displayed overlapping electrospun fibers, forming the three-dimensional structure in the produced scaffolds. It was possible to observe hydroxyapatite crystals filling some of these pores, creating a suitable structure for cell adhesion, proliferation, and nutrition, as corroborated by the results of in vitro tests. All scaffolds exhibited high cell viability, with significant cell proliferation. Even after 48 h, there was a slight reduction in the number of cells, but a noteworthy increase in cell proliferation was evident in the CAHAGOC 1.5% group after 48 h (p < 0.05). In conclusion, it can be affirmed that the produced scaffolds demonstrated physical and biological characteristics and properties capable of promoting cell adhesion and proliferation. Therefore, they represent significant potential for application in tissue engineering, offering a new perspective regarding techniques and biomaterials applied in regenerative therapies.

Study on the Effects of GO on the Microstructure and Wear Resistance of CuCrZr Plasma Cladding Coatings

This study investigates the enhancement of wear resistance in CuCrZr rails through the plasma cladding of CuCrZr-GO coatings with a varying graphene oxide (GO) content. The microstructure, phase composition, and mechanical properties of CuCrZr coatings containing 0%, 0.2%, 0.4%, 0.6%, and 0.8% GO were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), ESD surface scanning, friction and wear tests, and hardness analysis. The findings indicated that increasing the GO content from 0% to 0.6% results in a transition in the coating microstructure from columnar to equiaxed crystals, leading to an improved density. However, at 0.8% GO, numerous porosity defects were observed. The coating containing 0.6% graphene oxide (GO) exhibited a superior performance, with a hardness of 75, a friction coefficient of approximately 0.7, and a wear mass of 2.84 mg under a 10 N load. In comparison to the CuCrZr coating lacking GO, the hardness showed an increase of around 4.8%, the friction coefficient decreased by approximately 5.1%, and the wear mass diminished by 59.4%. These findings hold significant implications for extending the operational lifespan of electromagnetic railguns.

Synergistic effects of Li-based ferrite and graphene oxide in microwave absorption applications

The successful fabrication of composites consisting of ferrites with a composition of Li0.4Mg0.25Zn0.25Fe2.2O4 and Graphene oxide was carried out using the ultra-sonication technique. The current study examined the impact of graphene oxide in spinel ferrite employing X-ray diffraction, dielectric, and magnetic susceptibility studies. The X-ray diffraction investigation confirmed the spinel phase formation in ferrite and graphene oxide synthesis. The measured range for the size of crystallites was found to be between 48.43 and 30.07 nm. The DC resistivity of cubic ferrite at room temperature was determined to be 1.715 ×1010 ohm-cm by a two-probe approach. Furthermore, it was observed that the resistivity fell significantly as the content of graphene oxide increased. The dielectric constant exhibited behavior consistency with the Maxwell-Wagner phenomenon of interfacial polarization. The rise in graphene oxide content in ferrite results in high AC conductivity of composites due to the relatively large value of conductivity of graphene oxide and the improved charge hopping mechanism. The magnetic susceptibility of all the samples demonstrated a progressive decline as the temperature increased, which can be attributed to the disruption of spin alignment at the Curie temperature. The observed Curie temperature of all samples was 413–473 K. Integrating spinel ferrite with Graphene oxide has significantly improved the magneto-electrical characteristics, indicating potential applications in supercapacitors, high-frequency electromagnetic devices, and microwave absorption.