The depreciation of assets and safety threats because of corrosion has forced to develop eco-friendly and smarter corrosion protection strategies. In this study, natural Gum Arabic (GA) was used as a ...corrosion inhibitor and loaded into cerium oxide nanoparticles (CONPs) to develop an environment-friendly additive for corrosion protection of coated steel in the marine environment. This additive was uniformly dispersed into an epoxy formulation that was used to protect steel plates. Epoxy coatings containing CONPs, without GA, were also prepared as reference. High-Resolution Transmission Electron Microscopy (HR-TEM) and Fourier Transform infrared spectroscopy (FTIR) revealed the successful loading of GA into the CONPs. Thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) techniques confirmed approximately ⁓30.0 wt% loading of GA into the CONPs. Electrochemical impedance spectroscopy (EIS) demonstrated the anticorrosion properties of the epoxy coatings modified with the GA loaded CONPs when compared to reference coatings. The corrosion protection mechanism postulates that GA loaded CONPs act as a filler material for epoxy coating and it can also aid the recovery of the protective properties of the epoxy coating leading to the formation of a stable protective layer.
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•Environmentally friendly Anticorrosive pigments (CeO2 loaded with Gum Arabic) were added in coating for corrosion protection of steel.•The anti-corrosive pigments were characterized by different techniques and confirmed the loading of Gum Arabic into CeO2.•Improved anti-corrosion properties of coated samples were evidenced by Electrochemical Impedance Spectroscopy (EIS) techniques.•The Corrosion inhibition mechanism suggests that Gum Arabic delays coating degradation and adsorbs on steel substrate to form a protective layer.
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•Self-healing performance of epoxy-based double-layer coatings are reported.•The epoxy matrix is reinforced with modified zirconia (ZrO2) nanoparticles.•ZrO2 nanoparticles are ...modified with Imidazole and PEI as the self-healing agent.•Epoxy-based nanocomposite coatings are deposited as pre and topcoat on substrate.•EIS results demonstrated good corrosion resistance of double-layer coatings.
This work reports the self-healing behavior of epoxy-based double-layer nanocomposite coatings designed to mitigate corrosion in various industrial applications. Zirconia (ZrO2) nanoparticles were used as a carrier to load separately self-healing agent, polyethyleneimine (PEI), and corrosion inhibitor, imidazole (IM). The loaded ZrO2 nanoparticles with IM and PEI were doped into the epoxy matrix and applied on polished steel substrate to form pre and top layers of nanocomposite coatings, respectively. TEM analysis confirms the almost globular morphology of the zirconia nanoparticles with a particle size of 15–25 nm. The chemical bonding interactions among various species were confirmed through FTIR. The synergistic effect of self-healing agent and corrosion inhibitor in epoxy-based double-layer nanocomposite coatings demonstrated the pH and time dependence release of inhibitor and self-healing agent. A comparative EIS analysis conducted in 3.5 wt% NaCl solution reveals that epoxy-based double-layer nanocomposite coatings demonstrate improved corrosion resistance performance as compared to the blank epoxy and single layer epoxy reinforced coatings. This enhanced corrosion resistance of epoxy-based double-layer nanocomposite coatings can be ascribed to the efficient release of loaded IM and PEI in response to the external stimuli and can be potentially considered to circumvent corrosion in oil & gas and marine applications.
Utilizing the unparalleled theoretical capacity of sulfur reaching 1675 mAh/g, lithium–sulfur (Li–S) batteries have been counted as promising enablers of future lithium ion battery (LIB) applications ...requiring high energy densities. Nevertheless, most sulfur electrodes suffer from insufficient cycle lives originating from dissolution of lithium polysulfides. As a fundamental solution to this chronic shortcoming, herein, we introduce a hierarchical porous carbon structure in which meso- and macropores are surrounded by outer micropores. Sulfur was infiltrated mainly into the inner meso- and macropores, while the outer micropores remained empty, thus serving as a “barricade” against outward dissolution of long-chain lithium polysulfides. On the basis of this systematic design, the sulfur electrode delivered 1412 mAh/gsulfur with excellent capacity retention of 77% after 500 cycles. Also, a control study suggests that even when sulfur is loaded into the outer micropores, the robust cycling performance is preserved by engaging small sulfur crystal structures (S2–4). Furthermore, the hierarchical porous carbon was produced in ultrahigh speed by scalable spray pyrolysis. Each porous carbon particle was synthesized through 5 s of carrier gas flow in a reaction tube.
•High-chromium steel showed 1.5 times higher Rp values than mild steel.•EIS is the most suitable technique to evaluate the corrosion performance of ECR.•High-chromium steel showed 48% less macrocell ...current than mild steel.
An experimental study is carried out in this paper to evaluate the corrosion performance of mild steel reinforcing bars (MS), high strength steel reinforcing bars (HS), epoxy-coated steel reinforcing bars (EC), and high-chromium steel reinforcing bars (HC) under harsh environmental conditions. Reinforcing bars (rebar) of 16 mm diameter and 310 mm length were embedded in cylindrical concrete samples of 60 mm diameter and 350 mm length, and subjected to a Southern Exposure test for sixteen months. The open circuit potential (OCP) was monitored during the exposure period until corrosion initiation. The linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), and Tafel plot techniques were employed to assess the corrosion rates on the rebar surfaces. The macrocell corrosion current was monitored by connecting the corroding rebar with an external stainless steel bar of the same size. The polarization resistance of the HC was found to be 1.5 times higher than that of the MS. The EIS technique showed that EC, even with damaged epoxy coating, has the highest resistance to chloride attack. The macrocell current of HC rebar was 48% less than that of MS during the active corrosion state. The LPR, EIS and Tafel plots analysis provided the current densities, which were close to each other; indicating the validity of these techniques to study the problem at hand. The corrosion rates from electrochemical methods were compared against the ones calculated by gravimetric methods. The quantitative results from this research may be used in service life prediction of concrete structures with different types of rebar. Extensive analysis of the results indicates that the corrosion resistance of the evaluated steels was in the following decreasing order: EC, HC, MS, and HS.
Considering the promising electrochemical performance of the recently reported pyrophosphate family in lithium ion batteries as well as the increasing importance of sodium ion batteries (SIBs) for ...emerging large‐scale applications, here, the crystal structure, electrochemical properties, and thermal stability of Na2FeP2O7, the first example ever reported in the pyrophosphate family for SIBs, are investigated. Na2FeP2O7 maintains well‐defined channel structures (triclinic framework under the P1 space group) and exhibits a reversible capacity of ≈90 mAh g−1 with good cycling performance. Both quasi‐equilibrium measurements and first‐principles calculations consistently indicate that Na2FeP2O7 undergoes two kinds of reactions over the entire voltage range of 2.0–4.5 V (vs Na/Na+): a single‐phase reaction around 2.5 V and a series of two‐phase reactions in the voltage range of 3.0–3.25 V. Na2FeP2O7 shows excellent thermal stability up to 500 °C, even in the partially desodiated state (NaFeP2O7), which suggests its safe character, a property that is very critical for large‐scale battery applications.
Na2FeP2O7 is reported as the first member in the pyrophosphate family for sodium battery cathodes. Utilizing the well‐defined channel structure, Na2FeP2O7 exhibits a reversible capacity of ≈90 mAh g−1 with several different plateaus corresponding to distinctive Na sites. The thermodynamic and kinetic behaviors of this compound during battery operations are explained well using first principles calculations.
The application of Lithium-ion batteries (LIBs) in portable electronics and electric vehicles (EVs) has increased in the past decade. Extended commercialization of LIBs for advanced applications ...requires the development of high-performance electrode materials. LiNi0.5Mn1.5O4 (Lithium Nickel Manganese Oxide referred to as LNMO) has attracted much attention as a cathode material due to its high voltage and energy density, lower cost, and environmental friendliness. However, LNMO cathodes are currently suffering from poor cyclability and capacity degradation at elevated temperatures. Many strategies have been suggested in the literature to address the challenges associated with numerous families of cathode materials. Among those, surface modification techniques like surface coatings have proven to be promising. Surface coatings have a good effect on the electrochemical performance of LNMO, as these result in increasing electronic and ionic conductivity, fast ions mobility and high diffusivity. Towards this direction, a systematic review of research progress carried out in the area of coated LNMO has been summarized. More precisely, the impact of numerous coating materials in improving cyclability and capacity retention at elevated temperatures of LNMO has been discussed along with a variety of coating synthesis technologies.
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The present work studied the effect of temperature on the corrosion behavior of API X120 steel in a saline solution saturated with CO
in absence and presence of polyethyleneimine (PEI) as an ...environmentally safe green inhibitor. The effect of PEI on the corrosion behavior of API X120 steel was investigated using destructive and non-destructive electrochemical techniques. The overall results revealed that PEI significantly decreases the corrosion rate of API X120 steel with inhibition efficiency of 94% at a concentration of 100 μmol L
. The adsorption isotherm, activation energy and the thermodynamic parameters were deduced from the electrochemical results. It is revealed that the adsorption of PEI on API X120 steel surface follows Langmuir adsorption isotherm adopting a Physi-chemisorption mechanism. Finally, the samples were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques to elucidate the effect of aggressiveness of corrosive media on the surface morphology and the corrosion performance of API X120 steel. The surface topography result indicates that the API X120 steel interface in PEI presence is smoother than CO
with Cl
ions or Cl
ions only. This is attributed to the compact protective film limits the aggressive ions transfer towards the metallic surface and reduces the corrosion rate. Moreover, PEI inhibition mechanism is based on its CO
capturing ability and the PEI adsorption on the steel surface beside the siderite layer which give the PEI molecules the ability to reduce the scale formation and increase the corrosion protection due to capturing the CO
from the brine solution.
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Self-healing polymeric coating is a class of self-healing materials applied on the surface of a metal to provide a dense barrier, to protect the metal from the corrosive environment. ...Currently, Self-healing polymer materials are an emerging area of research due to their high attributes, including intrinsic and extrinsic mechanisms with autonomous/non-autonomous healing approaches, longer lifespan, eco-friendly, high durability, and sustainability. The polymer coating matrix provides the efficient release of incorporated self-healing agents after triggering due to the crack formation in the polymer matrix, which aids the self-healing performance of the polymeric matrices. A variety of studies have been reported in the literature on self-healing coating matrices; however, none of them have been reported as such. This comprehensive review covers; (1) the generations of self-healing, (2) types of mechanisms, (3) classification based on self-healing polymer matrices, (4) typical fabrication techniques, (5) potential applications, and some critical thoughts on the choice and design of the self-healing system.
Sodium ion batteries (SIBs) have many advantages such as the low price and abundance of sodium raw materials that are suitable for large-scale energy storage applications. Herein, we report an ...Mn-based pyrophosphate, Na2MnP2O7, as a new SIB cathode material. Unlike most Mn-based cathode materials, which suffer severely from sluggish kinetics, Na2MnP2O7 exhibits good electrochemical activity at ∼3.8 V vs Na/Na+ with a reversible capacity of 90 mAh g–1 at room temperature. It also shows an excellent cycling and rate performance: 96% capacity retention after 30 cycles and 70% capacity retention at a c-rate increase from 0.05C to 1C. These electrochemical activities of the Mn-containing cathode material even at room temperature with relatively large particle sizes are remarkable considering an almost complete inactivity of the Li counterpart, Li2MnP2O7. Using first-principles calculations, we find that the significantly enhanced kinetics of Na2MnP2O7 is mainly due to the locally flexible accommodation of Jahn–Teller distortions aided by the corner-sharing crystal structure in triclinic Na2MnP2O7. By contrast, in monoclinic Li2MnP2O7, the edge-sharing geometry causes multiple bonds to be broken and formed during charging reaction with a large degree of atomic rearrangements. We expect that the similar computational strategy to analyze the atomic rearrangements can be used to predict the kinetics behavior when exploring new cathode candidates.
AbstractThis paper reviews the methods adopted to produce high-performance concrete (HPC) and ultrahigh-performance concrete (UHPC). The chronological development of these concretes in terms of their ...constituents, mixture proportions, mixing protocols, and particle packing models from selected literature are presented. The paper highlights the earliest techniques that were used to obtain cementitious materials with high strength and durability, including pressure mixing and heat curing. The paper also covers the work done on HPC and UHPC since the late 1990s and summarizes the current state of the art. Numerous mixture proportions to attain target compressive strengths between 100 and 200 MPa are presented. Higher compressive strengths are achieved with denser mixtures (with practically achievable maximum particle packing densities, i.e., interparticle pores are minimized). In other words, particle packing density is a major attribute in the achievement of low porosity, flowability, durability, and reduced defects in concrete. Therefore, models, theories, and trial methods to achieve a higher packing density in concrete are presented.
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