Concentrations Of rGO Research Articles

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.

Enhancing Alginate Hydrogels as Possible Wound-Healing Patches: The Synergistic Impact of Reduced Graphene Oxide and Tannins on Mechanical and Adhesive Properties.

Hydrogels are three-dimensional crosslinked materials known for their ability to absorb water, exhibit high flexibility, their biodegradability and biocompatibility, and their ability to mimic properties of different tissues in the body. However, their application is limited by inherent deficiencies in their mechanical properties. To address this issue, reduced graphene oxide (rGO) and tannins (TA) were incorporated into alginate hydrogels (Alg) to evaluate the impact of the concentration of these nanomaterials on mechanical and adhesive, as well as cytotoxicity and wound-healing properties. Tensile mechanical tests demonstrated improvements in tensile strength, elastic modulus, and toughness upon the incorporation of rGO and TA. Additionally, the inclusion of these materials allowed for a greater energy dissipation during continuous charge-discharge cycles. However, the samples did not exhibit self-recovery under environmental conditions. Adhesion was evaluated on pig skin, revealing that higher concentrations of rGO led to enhanced adhesion, while the concentration of TA did not significantly affect this property. Moreover, adhesion remained consistent after 10 adhesion cycles, and the contact time before the separation between the material and the surface did not affect this property. The materials were not cytotoxic and promoted healing in human fibroblast-model cells. Thus, an Alg/rGO/TA hydrogel with enhanced mechanical, adhesive, and wound-healing properties was successfully developed.

Effects of Graphene Oxide (GO) and Reduced Graphene Oxide (rGO) on Green-Emitting Conjugated Copolymer's Optical and Laser Properties Using Simulation and Experimental Studies.

The properties of a conjugated copolymer (CP), poly[(9,9-Dioctyl-2,7-divinylenefluorenylene)-alt-co-(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene) (PDVF-co-MEH-PV), were investigated in the presence of graphene oxide (GO) and reduced graphene oxide (rGO) using absorption, fluorescence, laser, and time-resolved spectroscopy. CPs are usually dissolved in low-polar solvents. Although GO does not dissolve well, rGO and PDVF-co-MEH-PV dissolve in chloroform due to their oxygen acceptor sites. Hence, we studied rGO/PDVF-co-MEH-PV (CP/rGO), performing all experiments and simulations in chloroform. We performed simulations on PDVF-co-MEH-PV, approximate GO, and rGO using time-dependent density-functional theory calculations to comprehend the molecular dynamics and interactions at the molecular level. The simulation polymer used a tail-truncated oligomer model with up to three monomer units. The simulation and experimental results were in agreement. Further, the PDVF-co-MEH-PV exhibited fluorescence, laser quenching, rGO-mediated laser blinking, and spectral broadening effects when GO and rGO concentrations increased. The experimental and simulation results were compared to provide a plausible mechanism of interaction between PDVF-co-MEH-PV and rGO. We observed that for lower concentrations of rGO, the interaction did not considerably decrease the amplified spontaneous emissions of PDVF-co-MEH-PV. However, the fluorescence of PDVF-co-MEH-PV was considerably quenched at higher concentrations of rGO. These results could be helpful for future applications, such as in sensors, solar cells, and optoelectronic device design. To demonstrate the sensor capability of these composites, a paper-based sensor was designed to detect ethanol and nitrotoluene. An instrumentation setup was proposed that is cheap, reusable, and multifunctional.

Investigation on fatigue life of HAp and rGO hybrid coating on the PEEK artificial screws for dental implant

The mechanical behaviour of dental implants is crucial to their long-term endurance. Despite the demonstrated efficacy of dental implants, mechanical and biological concerns revealed in long-term follow-up studies continue to be a cause for concern. Screw loosening, which is usually caused by masticatory pressures when chewing, and peri-implantitis owing to microleakage are two of them, and if left untreated, they can lead to gradual loss of the supporting crestal bone. This study investigated the influence of hydroxyapatite (HAp) and reduced graphene oxide (rGO) hybrid coatings on the threads of a dental implant retention screw made of polyetheretherketone (PEEK). HAp with different concentrations of rGO (0.25, 0.5, 0.75, and 1%) coatings were investigated. The clamping force (CF) and coefficient of friction (COF) of the screw thread pair, as well as the single load fracture and dynamic fatigue life tests, were assessed to determine the integrity of the implant thread connection. The screw fracture mechanism and screw thread surface erosion morphology were also studied. The results revealed that C4 (HAp/rGO) coating might minimize COF, improve CF, and reduce fracture load. Furthermore, it demonstrated better anti-loosening properties under dynamic load. Most screw fractures happen on the screw's initial thread. The fracture end of a C3 combination coated screw was easily removed, but not that of a C4 combination coated screw.

Polyelectrolytes Enabled Reduced Graphite Oxide Water Dispersions: Effects of the Structure, Molecular Weight, and Charge Density.

The polyelectrolyte (PE)-based water dispersion of graphene-related materials (GRMs) represents an interesting intermediate for the development of advanced materials by sustainable processes. Although the proof of concept has been demonstrated, there is a lack of knowledge for what concerns the effects of parameters typical of PEs such as functionalization, molecular weight, and charge density. In this work, we evaluate the effects of such parameters on the quality and long-term stability of reduced graphite oxide (rGO) dispersion in aqueous media prepared by ultrasound sonication in the presence of different PEs. Four PEs were evaluated: polyacrylic acid (PAA), branched poly(ethylenimine) (BPEI), sodium carboxymethyl cellulose (CMC), and poly(sodium 4-styrenesulfonic acid) (PSS). The prepared dispersions were thoroughly characterized by means of UV-visible spectroscopy, thermogravimetric analysis, dynamic light scattering, and Raman spectroscopy. The highest concentrations of rGO were achieved by BPEI with a molecular weight of 25,000 and 270,000 Da (33 and 26 µg/mL, respectively). For other PEs, the rGO concentration was found to be independent of the molecular weight. The PAA-based dispersions displayed the best through-time stability while yielding homogeneous dispersion with a smaller average size and narrower size distribution.

Enhanced hydrogen evolution by rGO decorated copper nickel tin sulphide (CNTS-rGO) in acidic medium by water splitting

A simple hydrothermal synthesis approach for rGO decorated copper nickel tin sulfide (CNTS-rGO) micro flowers is devised in this research. Due to the depletion of fossil resources in the environment, the demand for energy has recently increased tremendously. Here we report the preparation of CNTS with various concentration of GO (Graphene Oxide) (10–50 mg). The prepared material is characterized for its structural and optical properties using XRD, FESEM, XPS, HRTEM, Raman studies and UV-DRS respectively. Surprisingly, graphene oxide incorporated CNTS material demonstrates an initial overpotential due to the abundance of active sites. Due to their unique properties, they prove to be intriguing and promising alternative catalysts. A minimal start overpotential of −235mV, a low Tafel slope of 57 mV dec−1 and outstanding long-term stability is found among one of the concentrations of rGO. This is the finest HER performance in acidic medium on electrochemical studies for CNTS-rGO.

Influence of Reduced Graphene Oxide on Crude Oil/Water Separation

Summary Despite the progress made in recent years in the involvement of graphene and its derivatives in oil/water emulsions as stabilizers or demulsifiers, materials’ interaction still needs to be understood. Reduced graphene oxide (rGO) is one of the graphene derivatives that has promising implications in oil/water separation. It has unique physical properties that include large surface area, structural defects, and several functional groups on its surface. This study presents and highlights the influence of rGO in oil/water separation. Crude oil was examined at different concentrations of rGO and in different phase ratios of oil/water). The results reveal that rGO has an excellent performance. However, this depends on the oil-in-water (O/W) phase ratio, rGO dosage, and interaction time. The interphase interactions were evident in electrical capacitance analysis, where the quasimetallic effect of rGO is dominant. We believe that this work will inspire researchers to further investigate the performance of rGO in oil/water separation, where in the future it can be easily tailored by controlling rGO properties.

Electrospun composites of poly-3-hydroxybutyrate reinforced with conductive fillers for in vivo bone regeneration

The aim of this study was to investigate the biocompatibility and osteoinductive properties of fibrous scaffolds implanted in the bone tissue of white rats in vivo. The effect of various concentrations of conductive PANi (2 and 3 wt%) and rGO (0.2 and 1 wt%) in the PHB scaffolds on the reparative processes of bone callus formation in white rats was studied. On the 28th day after implantation, a histomorphological study of the preparations of the transverse section of the diaphysis of the femur of the implantation area was performed. The results of implantation tests in the femur revealed that all the studied scaffolds are biocompatible and the most pronounced stimulating effect on bone formation was observed for hybrid PHB scaffolds doped with 3 wt% PANi and 0.2 wt% rGO compared with pure PHB scaffolds, thus determining further prospects to study the osteoinductive features of hybrid PHB scaffolds.

Reduced graphene oxide nanofluidic electrolyte with improved electrochemical properties for vanadium flow batteries

Development of the Vanadium Redox Flow Battery (VRFB) has been widely reported but typically only focuses on one part of the cell (e.g. electrode, electrolyte, or membrane). Improvement to a single part of the cell may cause side effects on other parts during long-term cycling leading to an overall drop in the performance of the battery. To avoid this, the use of nanofluidic electrolyte seems to be a promising approach to enhance the performance of both electrode and electrolyte simultaneously. This paper aims to investigate the electrochemical performance of a newly prepared reduced graphene oxide (rGO) nanofluidic vanadium electrolyte, applicable for Vanadium Redox Flow Batteries (VRFB). Herein, we report for the first time a stable rGO/vanadium nanofluidic electrolyte with improved electrochemical performance. Benefiting from the low degree of oxidation as compared to GO, the rGO can provide high electrical conduction due to the presence of sufficient functional groups, which can facilitate the redox reactions. The effect of various concentrations of rGO on the electrochemical performance is investigated. The current collector (carbon cloth (CC) electrode) was further characterized using different physico-chemical techniques to underpin the stability of rGO nanofluids. The results suggested that the electrochemical performance of vanadium electrolyte increases with the concentration of rGO. Improvements of approx. 15% to 20% were achieved in peak potential separation and current density rates, respectively. In addition, the incorporation of rGO in nanofluidic electrolyte significantly decreases the electrolyte and charge transfer resistance by ∼10% and ∼99%, respectively, and improves the vanadium ion diffusion process by ∼50%.

Development of Waste Polystyrene-Based Copper Oxide/Reduced Graphene Oxide Composites and Their Mechanical, Electrical and Thermal Properties.

The current study reports the effect of different wt. ratios of copper oxide nanoparticle (CuO-NPs) and reduced graphene oxide (rGO) as fillers on mechanical, electrical, and thermal properties of waste polystyrene (WPS) matrix. Firstly, thin sheets of WPS-rGO-CuO composites were prepared through solution casting method with different ratios, i.e., 2, 8, 10, 15 and 20 wt.% of CuO-NPs and rGO in WPS matrix. The synthesized composite sheets were characterized by Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). The electrical conductance and mechanical strength of the prepared composites were determined by using LCR meter and universal testing machine (UTM). These properties were dependent on the concentrations of CuO-NPs and rGO. Results display that the addition of both fillers, i.e., rGO and CuO-NPs, collectively led to remarkable increase in the mechanical properties of the composite. The incorporation of rGO-CuO: 15% WPS sample, i.e., WPS-rGO-CuO: 15%, has shown high mechanical strength with tensile strength of 25.282 MPa and Young modulus of 1951.0 MPa, respectively. Similarly, the electrical conductance of the same composite is also enhanced from 6.7 × 10−14 to 4 × 10−7 S/m in contrast to WPS at 2.0 106 Hz. The fabricated composites exhibited high thermal stability through TGA analysis in terms of 3.52% and 6.055% wt. loss at 250 °C as compared to WPS.

Production and tribological evaluation of polypropylene nanocomposites with reduced graphene oxide (rGO) for using in water-lubricated bearings

In this work, polypropylene (PP) nanocomposites with microwaves reduced graphene oxide (rGO) were prepared and tribologically evaluated with a focus on their use in water-lubricated sliding bearings. The PP+rGO nanocomposites were produced at low concentrations of rGO (0.05–1 wt.%) and large-scale by twin-screw extrusion, and their mechanical and water wettability properties were evaluated by uniaxial tension, Shore D hardness and contact angle measurements, respectively. Tribological performance of the nanocomposites was assessed under dry, water lubricated and micro-abrasion conditions by accelerated wear and friction tests using a micro-abrasion tester. The elastic modulus, tensile strength and hardness of the nanocomposites were enhanced, while toughness and wettability decreased with increasing the rGO content. Separately, their friction coefficient and specific wear rates remained almost unchanged for dry testing, but were reduced with water lubrication. Reduction of friction coefficient and specific wear rates are attributed to decreased adhesion and slip of the water lubricating layer at the nanocomposites surfaces. In contrast, friction and wear of the nanocomposites increased with rGO content under micro-abrasion, which is ascribed to reduction of toughness by the addition of rGO. The results in this work suggest PP+rGO nanocomposites as potential alternative materials to produce water-lubricated bearings.

Functionalized Reduced Graphene Oxide Thin Films for Ultrahigh CO2 Gas Sensing Performance at Room Temperature.

The demand for carbon dioxide (CO2) gas detection is increasing nowadays. However, its fast detection at room temperature (RT) is a major challenge. Graphene is found to be the most promising sensing material for RT detection, owing to its high surface area and electrical conductivity. In this work, we report a highly edge functionalized chemically synthesized reduced graphene oxide (rGO) thin films to achieve fast sensing response for CO2 gas at room temperature. The high amount of edge functional groups is prominent for the sorption of CO2 molecules. Initially, rGO is synthesized by reduction of GO using ascorbic acid (AA) as a reducing agent. Three different concentrations of rGO are prepared using three AA concentrations (25, 50, and 100 mg) to optimize the material properties such as functional groups and conductivity. Thin films of three different AA reduced rGO suspensions (AArGO25, AArGO50, AArGO100) are developed and later analyzed using standard FTIR, XRD, Raman, XPS, TEM, SEM, and four-point probe measurement techniques. We find that the highest edge functionality is achieved by the AArGO25 sample with a conductivity of ~1389 S/cm. The functionalized AArGO25 gas sensor shows recordable high sensing properties (response and recovery time) with good repeatability for CO2 at room temperature at 500 ppm and 50 ppm. Short response and recovery time of ~26 s and ~10 s, respectively, are achieved for 500 ppm CO2 gas with the sensitivity of ~50 Hz/µg. We believe that a highly functionalized AArGO CO2 gas sensor could be applicable for enhanced oil recovery, industrial and domestic safety applications.

Performance of chemically synthesized Mn3O4/rGO nanocomposite for electrochemical supercapacitor: a cost-effective high-performance electrode

The manganese oxide graphene oxide (Mn3O4/rGO) composite heterojunction with copper oxide is useful for the production of an electrochemical supercapacitor. The graphene oxide and manganese oxide composite have been synthesized by adopting a method of co-precipitation. The composite of Mn3O4/rGO was synthesized with different concentrations of Mn3O4 and rGO. The structural, morphological, electrochemical and supercapacitive properties of Mn3O4/rGO composite have been examined. The electrochemical and supercapacitive properties have been studied with regard to different substrates. The Mn3O4/rGO composite was deposited on different substrates such as steel, copper and brass. The CuO/Mn3O4/rGO shows relatively better specific capacitance (856 F g−1) and better stability (82% retention after 2000 cycles) than other substrates used. The present work describes the development of cost-effective and high-performance CuO/Mn3O4/rGO-based nanomaterials for supercapacitors. The CuO/Mn3O4/rGO composite can be used as a flexible supercapacitor device.

Supermolecular Structure of Poly(butylene terephthalate) Fibers Formed with the Addition of Reduced Graphene Oxide.

Nanocomposite fibers based on poly(butylene terephthalate) (PBT) and reduced graphene oxide (rGO) were prepared using a method able to disperse graphene in one step into a polymer matrix. The studies were performed for fibers containing four different concentrations of rGO at different take-up velocities. The supermolecular structures of the fibers at the crystallographic and lamellar levels were examined by means of calorimetric and X-ray scattering methods (DSC, WAXS, and SAXS). It was found that the fiber structure is mainly influenced by the take-up velocity. Fibers spun at low and medium take-up velocities contained a crystalline α-form, whereas the fibers spun at a high take-up velocity contained a smectic mesophase. During annealing, the smectic phase transformed into its α-form. The degree of transformation depended on the rGO content. Reduced graphene mainly hindered the crystallization of PBT by introducing steric obstacles confining the ordering of the macromolecules of PBT.

Development of rGO encapsulated polymeric beads as drug delivery system for improved loading and controlled release of doxycycline drug

Objective: The aim of this study was to design a biodegradable core–shell structure where in reduced graphene-oxide (rGO) and doxycycline (DXC) drug comprise the core while polymer such as chitosan (CS) and alginate (ALG) acts as shell for attaining high loading efficiency and sustained release of drug.Significance: Cytotoxic drug used in conventional chemotherapeutic methods usually suffer from poor site selectivity and this has been resolved by using targeted delivery of anticancer drug with controlled drug release property.Methods: The structural and morphological properties of as synthesized drug delivery carrier were characterized by a range of techniques. Drug encapsulation efficiency and the studies on, in vitro release of the drug from these nanocarriers at different concentrations of rGO were carried out.Results: Across all batches of rGO-polymeric beads, the highest loading capacity of 85% was noted for rGO of wt 5 mg/ml. Further, for the formulations of only rGO, highest LE of 90% was noticed in 1 h and 100% loading was noticed in 3 h. The interaction of DXC and its release from the nanocarriers were controlled by the pH changes. At pH 1.2 for rGO-polymeric beads + DXC, the DXC release was reached 27.4% after 2 h; and at pH 5.4, the same beads liberated 57% of the drug after 4 h; and at pH 7.4 after 8 h, 90% of DXC was released into the medium.Conclusions: rGO-polymeric beads supported long-lasting and continuous DXC release which is slower at acidic pH (endosomal pH) than at physiological.

Reduced Graphene Oxide Incorporated GelMA Hydrogel Promotes Angiogenesis For Wound Healing Applications.

PurposeNon-healing or slow healing chronic wounds are among serious complications of diabetes that eventually result in amputation of limbs and increased morbidities and mortalities. Chronic diabetic wounds show reduced blood vessel formation (lack of angiogenesis), inadequate cell proliferation and poor cell migration near wounds. In this paper, we report the development of a hydrogel-based novel wound dressing material loaded with reduced graphene oxide (rGO) to promote cell proliferation, cell migration and angiogenesis for wound healing applications.MethodsGelatin-methacryloyl (GelMA) based hydrogels loaded with different concentrations of rGO were fabricated by UV crosslinking. Morphological and physical characterizations (porosity, degradation, and swelling) of rGO incorporated GelMA hydrogel was performed. In vitro cell proliferation, cell viability and cell migration potential of the hydrogels were analyzed by MTT assay, live/dead staining, and wound healing scratch assay respectively. Finally, in vivo chicken embryo angiogenesis (CEO) testing was performed to evaluate the angiogenic potential of the prepared hydrogel.ResultsThe experimental results showed that the developed hydrogel possessed enough porosity and exudate-absorbing capacity. The biocompatibility of prepared hydrogel on three different cell lines (3T3 fibroblasts, EA.hy926 endothelial cells, and HaCaT keratinocytes) was confirmed by in vitro cell culture studies (live/dead assay). The GelMA hydrogel containing 0.002% w/w rGO considerably increased the proliferation and migration of cells as evident from MTT assay and wound healing scratch assay. Furthermore, rGO impregnated GelMA hydrogel significantly enhanced the angiogenesis in the chick embryo model.ConclusionThe positive effect of 0.002% w/w rGO impregnated GelMA hydrogels on angiogenesis, cell migration and cell proliferation suggests that these formulations could be used as a functional wound healing material for the healing of chronic wounds.

Immobilized rGO/TiO2 Photocatalyst for Decontamination of Water

The preparation of immobilized graphene-based photocatalyst layers is highly desired for environmental applications. In this study, the preparation of an immobilized reduced graphene oxide (rGO)/TiO2 composite by electrophoretic deposition (EPD) was optimized. It enabled quantitative deposition without sintering and without the use of any dispersive additive. The presence of rGO had beneficial effects on the photocatalytic degradation of 4-chlorophenol in an aqueous solution. A marked increase in the photocatalytic degradation rate was observed, even at very low concentrations of rGO. Compared with the TiO2 and GO/TiO2 reference layers, use of the rGO/TiO2 composite (0.5 wt% of rGO) increased the first-order reaction rate constant by about 70%. This enhanced performance was due to the increased formation of hydroxyl radicals that attacked the 4-chlorophenol molecules. The direct charge transfer mechanism had only limited effect on the degradation. Thus, EPD-prepared rGO/TiO2 layers appear to be suitable for environmental application.

Fabrication, characterization and micromechanics modeling of the electrical conductivity of reduced graphene oxide/aramid nanofiber nanocomposites

Graphene-based materials with high graphene concentration are of great interest for multifunctional, structural electrode materials that simultaneously store electrical energy and carry structural loads. Graphene-based materials can have a high electrochemically active surface area, high electrical conductivity, and good stiffness and strength. Published analytical studies of electrical conductivity are mostly focused on graphene-based polymer nanocomposites with very low concentrations of conductive fillers, for percolation purposes. In the research reported herein, reduced graphene oxide (rGO) and aramid nanofiber (ANF) nanocomposite films with higher concentrations of rGO, up to 100 wt% rGO, were fabricated and characterized for their electrical conductivity. In addition, a hybrid micromechanical and phenomenological model of electrical conductivity was developed to include the effects of rGO waviness and conductivity, volume fraction of ANF, random orientation of rGO and ANFs, interphase thickness and interphase conductivity. The experimentally measured in-plane conductivity of rGO/ANF nanocomposite films decreases exponentially with the addition of ANFs. For example, the experimental in-plane conductivity of rGO/ANF nanocomposite films was increased 30-fold by decreasing the ANF loading from 25 wt% to 0 wt%. This exponential relationship can be explained by the model proposed. The model showed that the influence of the interphase thickness and interphase conductivity was more significant than that of waviness. The effective in-plane conductivity changed by 20% when the waviness was decreased from maximum observed value to minimum. The effective in-plane conductivity decreased by two orders of magnitude when the interphase thickness was changed from 0 to 0.5 nm and the interphase conductivity was 0.09 S m−1. The model results agreed with the experimental data when the interphase thickness and conductivity vary with the volume fraction of rGO. The addition of ANFs is significant due to the influence it has on the microstructure of the composite and the interphase structure and conductivity. This model can be used for composites with coated fibers or continuous polymeric matrix by adjusting the interphase morphology.

Electrochemical detection of reduced graphene oxide nanoparticles in aqueous solution

We have demonstrated electrochemical detection of reduced graphene oxide (rGO) nanoparticles on an ultramicroelectrode (UME) in aqueous solution using rGO collision events. The collision phenomena are detected by monitoring a current–time transient. To attract the rGO to the UME surface, a positive electric field was developed near the UME using a redox reaction. As model systems, ferrocenemethanol and ferrocyanide oxidation reactions were adopted. Amperometric current measurements showed a staircase current response after attachment of rGO on the UME surface. The magnitude of the staircase current is given by the stepwise increase in current, which can provide insight into the size distribution of the rGO colliding with the UME. In the presence of higher concentrations of rGO, multiple collision events happened sequentially on the UME. In this case, an increasing current trend, rather than a single staircase current, was observed. The overall current increment for a given time is a measure of the concentration of rGO in solution. By using this method, charged conductive materials in an aqueous solution can be sensitively detected and/or accumulated.

Effect of Reduced Graphene Oxide Reinforcement on the Wear Characteristics of Electroless Ni-P Coatings

Electroless composite coatings with various concentrations of reduced graphene oxide (rGO) particles were deposited onto mild steel substrate. The effects of adding rGO particles by varying their concentration from 0 to 100 mg/L on morphology, composition, microhardness, adhesion, wear and friction of the electroless composite coatings were investigated. Among the various parameters that influence the tribological behavior, sliding velocity was varied within a specific range for definite concentrations of rGO to obtain enhanced wear resistance in this study. The micrographs of the worn surfaces and indented spots were examined for the nature of wear mechanism and interfacial adhesion. The wear rate increased with increasing sliding velocity but was relatively stable for coatings with lower concentrations of rGO.