Electrolytic Corrosion Research Articles

Sulfonated poly(vinyl alcohol) as an artificial solid electrolyte interfacial layer for Li metal anode

The cycle performance of Li metal batteries with high energy-density is hindered by the stability of Li metal anode. In this manuscript, sulfonated poly(vinyl alcohol) (SPVA) was synthesized and used as an artificial solid electrolyte interfacial (SEI) layer to construct stable Li metal anode interface. The ionic conductivity of SPVA coating layer in liquid electrolyte was calculated according to the theories of interfacial polarization in heterogeneous systems by dielectric method. In the Li|PE|SPVA/Cu or Li/SPVA|PE|SPVA/Li cells, Li deposits beneath the SPVA layer, surviving from the corrosion of liquid electrolyte and excessive volume expansion. Benefited from the constructed stable artificial SEI layer, the interfacial polarization and internal resistance in the symmetric cells are reduced. The cycle performance of LiFePO4|PE|SPVA/Li cell has been greatly improved, which could be stably cycled for more than 500 cycles.

Machine learning‐based analysis and prediction of the interfacial corrosion processes of copper cathode plates during the electrolytic production of copper powders

AbstractPresent efforts to support the essential industrial‐scale electrolytic production of copper‐based metal powders urgently require approaches to the real‐time predicting of corrosion of copper cathodes employed in electrolytic production processes. However, current approaches are extremely limited owing to the difficulty of accurately modeling the complex cathode corrosion process. In this study, the corrosion process under different parameters was analyzed by a self‐designed continuous electrolytic corrosion experimental device, clarify the influence mechanism of current density on the corrosion of the solid–liquid–gas interface area, and addresses this issue by applying a random forest machine learning approach based on three process parameters, including the electrolyte temperature, liquid‐level fluctuation cycle period, and current density. The dataset employed in the model is obtained using a novel experimental corrosion test method based on electrode arrays. The experimental results include the corrosion rates of copper cathode plates at different positions relative to the liquid electrolyte level during the electrolysis process. The resulting stochastic model is demonstrated to obtain a high prediction accuracy of 97% for the various regions of copper cathode plates defined according to liquid electrolyte level.

Anticorrosion activity of 2-thiоhуdantoin-Shiff base derivatives for mild steel in 0.5 M HCl

Several 2-thiohyd?nt?in?Shiff base derivatives were prepared as ecofriendly corrosion inhibitors for mild steel in acid environment. Their anticorrosion properties were studied on mild steel in 0.5 M HCl solution as corrosion electrolyte by using usu?l gr?vim?tri? and different el??tr??hemic?l techniques (w?ight l?ss m??sur?m?nt, p?t?nti?dyn?mi? p?l?riz?ti?n and p?t?nti?st?ti? ?l??tr??h?mic?l imp?d?n?? s???tr?sc???). Mild steel surface was characterized using two analytical techniques, scanning electron microscopy for surface morphology and elemental composition and atomic force microscopy. The study has shown that the inhibiting action of these environmentally benign inhibitors synthesized from inexpensive commercially available starting materials could be attributed to adsorption on the metal surface.

Experimental Study on the Degradation of Bonding Behavior between Reinforcing Bars and Concrete after Corrosion and Fatigue Damage

In marine environments, the durability of reinforced concrete structures such as bridges, which suffer from the coupled effects of corrosion and fatigue damage, is significantly reduced. Fatigue loading can result in severe deterioration of the bonds between reinforcing steel bars and the surrounding concrete, particularly when reinforcing bars are corroded. Uniaxial tension testing was conducted under static loading and fatigue loading conditions to investigate the bonding characteristics between corroded reinforcing bars and concrete. An electrolyte corrosion technique was used to accelerate steel corrosion. The results show that the bond strength was reduced under fatigue loading, although the concrete did not crack. Therefore, fatigue loading has negative effects on the bond strength between corroded steel bars and concrete. The effects of corrosion cracking on bond strength become more pronounced after corrosion cracking appears along the main reinforcing bars. When the average width of cracking along main reinforcing bars exceeds 3 mm, the bonding properties deteriorate rapidly based on the effects of corrosion cracking, whereas fatigue loading exhibits no additional effects on bond strength.

Effect of norcholine fluid derivative on the resilience of mild steel to electrochemical degradation in weak HCl media

The resilience of mild steel to electrochemical degeneration in weak electrolyte corrosion (0.5 M HCl) was assessed at discrete concentrations of Norcholine derivatives by potentiodynamic polarization and open circuit potential analysis. Degradation rate of the steel substantially declined with augmentation of Norcholine concentration from 9.49 mm/y in control HCl (no Norcholine) to 0.27 mm/y at highest Norcholine value of 15%. The degradation rate at this inhibitor concentration correlates of 97.1% protection performance. Norcholine demonstrated cathodic inhibition effect from observation of the negative deviation in corrosion potential. Norcholine was also observed to indicate substantial passive reaction mechanism on the anodic polarization regions of the polarization graphs. This translates to evolution of non-porous layer on the steel exterior. Open circuit potential graphs indicate substantial variation between the inhibited and acid degraded graphs of the steel. Mathematical computations through analysis of variance demonstrates Norcholine concentration and potential tracking time are statistically important variation sources influencing the protection performance of Norcholine at values of 68.03% and 26.4%.

Study of an Ionic Fluid on the Electrochemical Test of A36 Carbon Steel Ingot

An ionic fluid based on aromatic heterocyclic family constituted by 1,3-diazole groups was investigated. The purpose is to describe their electrochemical characteristics in order to identify the strategy to avoid the A36 carbon steel surface degradation by using electrochemical measurements. We found that the linear polarization resistance reveals an increasing value when the organic unsaturated cyclic ionic fluid was added to the corrosive electrolyte. The polarization curves and Tafel Extrapolation obtained to know the slopes tafel and the inhibitor efficiency from current density (icorr) shows a high efficiency inhibition value.

An odyssey of lithium metal anode in liquid lithium–sulfur batteries

Lithium–sulfur (Li–S) batteries exhibit outstanding energy density and material sustainability. Enormous effects have been devoted to the sulfur cathode to address redox kinetics and polysulfide intermediates shuttle. Recent attentions are gradually turning to the protection of the lithium metal anodes, since electrochemical performances of Li–S batteries are closely linked to the working efficiency of the anode side, especially in pouch cells that adopt stringent test protocols. This Perspective article summarizes critical issues encountered in the lithium metal anode, and outlines possible solutions to achieve efficient working lithium anode in Li–S batteries. The lithium metal anode in Li–S batteries shares the common failure mechanisms of volume fluctuation, nonuniform lithium flux, electrolyte corrosion and lithium pulverization occurring in lithium metal batteries with oxide cathodes, and also experiences unique polysulfide corrosion and massive lithium accumulation. These issues can be partially addressed by developing three-dimensional scaffold, exerting quasi-solid reaction, tailoring native solid electrolyte interphase (SEI) and designing artificial SEI. The practical evaluation of Li–S batteries highlights the importance of pouch cell platform, which is distinguished from coin-type cells in terms of lean electrolyte-to-sulfur ratio, thin lithium foil, as well as sizable total capacity and current that are loaded on pouch cells. This Perspective underlines the development of practically efficient working lithium metal anode in Li–S batteries.

Bilayer coatings for temporary and long–term corrosion protection of magnesium–AZ31 alloy

Phosphate and silane containing organic self–assembled (SA) layers serve as pre–treatments on magnesium alloy sheet materials. A reliable protection was achieved in this work via application of alkyd–based coatings on the pretreated surface. The idea of adopting SA pre–treatments as functional layers at metal–polymer interface is to influence the adhesive properties between solid metal substrate and alkyd–based coating. Hexadecyltrimethoxysilane (HDTMS) deposited metal surfaces exhibit stronger adhesive strength, while a near homogeneous distribution of the octadecylphosphonic acid (ODPA) and perfluorodecylphosphonic acid (PFDPA) exhibit low adhesive phenomenon, when placed as pre–layers in bilayer coatings. Electrochemical impedance results after 168 h of immersion reveal that the organophosphate and organosilane deposited bilayer films demonstrate protective properties with almost no interface defects. Moreover, organophosphate treated bilayer coatings enhance easy peeling of alkyd coat after protecting the surface from corrosive electrolytes. Bilayer coatings developed on AZ31 sheets can confer temporary or long–term corrosion protection depending on further processing strategy and offer efficient alloy protection for both purposes.

A polymeric cathode-electrolyte interface enhances the performance of MoS2-graphite potassium dual-ion intercalation battery

Anion intercalation in the graphite cathode of a dual-ion battery (DIB) occurs at unusually high voltage (>4.5 V K + /K). This exacerbates electrolyte degradation and corrosion of Al current collectors, leading to poor coulombic efficiency (CE), typically <90%, and short cell life as a result. These limitations can be mitigated if a stable cathode-electrolyte interface layer (CEI) can form on the graphite electrode. In this study, we demonstrate that the performance of a potassium-based DIB can be improved with a triallyl phosphate (TAP) monomer added in 6 m KN(SO 2 CF 3 ) 2 (KTFSI)-dimethyl carbonate (DMC) electrolyte. The TAP additive forms a stable polymeric CEI on the graphite particles and thus increases the CE of the cell to 97%–99%. Together with MoS 2 -negative electrodes with a pre-formed solid electrolyte interphase (SEI) layer, the DIB concept has been shown to offer specific capacities from ∼40 to 80 mAh g −1 with an average discharge voltage of 3.7 V. • Design principle for high-performance MoS 2 -graphite dual-ion battery is proposed • Impact of electrolyte additives on the negative and positive electrodes is investigated • Triallyl phosphate is used to generate a polymeric CEI on graphite cathode • MoS 2 with pre-formed SEI layer ensures stable cycling and high coulombic efficiency A dual-ion battery operates at unusually high voltage, which is needed to intercalate anions in a graphite cathode. Asfaw et al. explore strategies to create more stable electrode-electrolyte interfaces in an effort to design potassium-based MoS 2 -natural-graphite dual-ion battery with high coulombic efficiency and long cycle life.

Interfacial microstructure and strengthening mechanism of W/steel diffusion bonding joint using a porous NiFeWss interlayer prepared by in-situ reduction

90WNiFe alloy (W) and 30CrMnSiA steel (steel) were diffusion bonded using the porous NiFeWss interlayer, which was prepared on the surface of W substrate using electrolytic corrosion technology and showed high structural adaptability. The typical microstructure of joint is W/diffusion layer (NiFeWSS matrix + tiny W particle)/steel. Benefiting from the absence of brittle intermetallic compounds, the appropriate thermal expansion coefficient of (NiFeWSS matrix + W particle) diffusion layer and the incomplete coherent interface between NiFeWSS matrix and W particle in diffusion layer, the high property W/steel joint with tensile strength of 289 MPa and elongation of 8.14% was obtained.

Integrated and Unassisted Solar Water‐Splitting System by Monolithic Perovskite/Silicon Tandem Solar Cell

Photoelectrochemical (PEC) water splitting to hydrogen is a clean process that can achieve green hydrogen. However, the integrated PEC devices have some problems, such as serious incident light loss, poor stability, and high cost. Here, the low‐cost perovskite/silicon tandem cell instead of the costly III−V tandem cell as the light absorber is used, combined with high‐transmittance quartz glass as a protective layer forming an unassisted solar water‐splitting device. Quartz glass can minimize incident light loss and prevent electrolyte corrosion of solar cells. A solar‐to‐hydrogen efficiency of 19.68% is achieved, and the performance can be maintained for 20 h without noticeable change. This structure design provides a novel integrated solar water‐splitting system.

Hydrogen at Scale Using Low-Temperature Anion Exchange Membrane Electrolyzers

Among the two commercial low-temperature electrolyzers, alkaline liquid electrolyzers (AELs) and proton exchange membrane electrolyzers (PEMELs), AELs have the largest market share. They are durable, with a system lifetime of 30–40 years. The principal issues are high ohmic resistance and thicker diaphragms lowering voltage efficiency and limiting current density performance. In addition, the use of corrosive liquid electrolytes increases system-level costs. Typically, the pressure ranges available are low and hence the need for additional compression technologies for hydrogen storage and transportation. In comparison with AELs, PEMELs have higher current density and voltage efficiency, fast dynamic response, compact cell design, and the ability to be pressurized. However, the principal disadvantage of PEMELs is their costly platinum-group metals and titanium-based stack components. Anion exchange membrane electrolyzers (AEMELs) combine the features and advantages of AELs and PEMELs. In AEMELs, denser hydroxide ion exchange membranes replace the microporous diaphragm separators of AELs, thus enabling hydrogen pressurization and operation at high current density. In addition, they replace precious metals in PEMELs with earth-abundant, inexpensive materials, making them more affordable and scalable.

Preparation and corrosion resistance properties of duplex stainless steel (00Cr22Ni6MnMoCu)

In the present paper, a new kind of duplex stainless steel (DSS, 00Cr22Ni6MnMoCu) was prepared. Cr30 was chosen as a comparison of microstructures and mechanical properties with 00Cr22Ni6MnMoCu. Corrosion tests with 3.5% NaCl solution and electrolytic solution for 00Cr22Ni6MnMoCu were carried out to analyze the corrosion pattern of test materials. It can be concluded that: (1) Austenitic and ferrite duplex stainless steel has an optimized phase distribution, high toughness and strength when the ratio of two-phase content is 1:1. (2) Corrosion tests show that the corrosion resistance of 00Cr22Ni6MnMoCu is 12 times compared to ferrite stainless steel Cr30. (3) Electrolytic corrosion tests show that for 00Cr22Ni6MnMoCu, the corrosion is caused by intergranular corrosion. For Cr30, it is mainly caused by pinholes. However, Cr30 has a poor corrosion resistance because of the presence of a large amount of carbides and their phase boundaries caused by the electric potential difference between the carbide and the matrix.

Horizontally arranged zinc platelet electrodeposits modulated by fluorinated covalent organic framework film for high-rate and durable aqueous zinc ion batteries

Rechargeable aqueous zinc-ion batteries (RZIBs) provide a promising complementarity to the existing lithium-ion batteries due to their low cost, non-toxicity and intrinsic safety. However, Zn anodes suffer from zinc dendrite growth and electrolyte corrosion, resulting in poor reversibility. Here, we develop an ultrathin, fluorinated two-dimensional porous covalent organic framework (FCOF) film as a protective layer on the Zn surface. The strong interaction between fluorine (F) in FCOF and Zn reduces the surface energy of the Zn (002) crystal plane, enabling the preferred growth of (002) planes during the electrodeposition process. As a result, Zn deposits show horizontally arranged platelet morphology with (002) orientations preferred. Furthermore, F-containing nanochannels facilitate ion transport and prevent electrolyte penetration for improving corrosion resistance. The FCOF@Zn symmetric cells achieve stability for over 750 h at an ultrahigh current density of 40 mA cm−2. The high-areal-capacity full cells demonstrate hundreds of cycles under high Zn utilization conditions.

Enhanced Long-Term Reliability of Seal DeltaSpot Welded Dissimilar Joint between 6061 Aluminum Alloy and Galvannealed Steel via Excimer Laser Irradiation.

Structural-adhesive-assisted DeltaSpot welding was used to improve the weldability and mechanical properties of dissimilar joints between 6061 aluminum alloy and galvannealed HSLA steel. Evaluation of the spot-weld-bonded surfaces from lap shear tests after long-term exposure to chloride and a humid atmosphere (5% NaCl, 35 °C) indicated that the long-term mechanical reliability of the dissimilar weld in a corrosive environment depends strongly on the adhesive–Al6061 alloy bond strength. Corrosive electrolyte infiltrated the epoxy-based adhesive/Al alloy interface, disrupting the chemical interactions and decreasing the adhesion via anodic undercutting of the Al alloy. Due to localized electrochemical galvanic reactions, the surrounding nugget matrix suffered accelerated anodic dissolution, resulting in an Al6061-T6 alloy plate with degraded adhesive strength and mechanical properties. KrF excimer laser irradiation of the Al alloy before adhesive bonding removed the weakly bonded native oxidic overlayers and altered the substrate topography. This afforded a low electrolyte permeability and prevented adhesive delamination, thereby enhancing the long-term stability of the chemical interactions between the adhesive and Al alloy substrate. The results demonstrate the application of excimer laser irradiation as a simple and environmentally friendly processing technology for robust adhesion and reliable bonding between 6061 aluminum alloy and galvannealed steel.

Ultrathin HfO2 passivated silicon photocathodes for efficient alkaline water splitting

HfO2 has many favorable characteristics for use in energy conversion devices including high thermodynamic stability, good chemical stability in corrosive electrolytes, high refractive index, and wide bandgap. Here, we report surface passivation of a c-Si photocathode by ultrathin HfO2 prepared using atomic layer deposition as an effective approach for enhancing its photoelectrochemical (PEC) performance. The effect of the thickness of HfO2, deposition temperature, and annealing in forming gas on the passivation performance are systematically investigated. We demonstrate that the Si photocathode with a p+/n/n+ structure decorated with a Ni3N/Ni cocatalyst and an HfO2 interlayer follows a metal–insulator–semiconductor mechanism with thicker HfO2 films proving detrimental to the PEC performance. The Si photocathode passivated with a 1 nm HfO2 layer exhibits an enhancement in the onset potential by 100 mV, an applied-bias photon-to-current efficiency of 9%, and improved operational stability. This work provides insights into the application of HfO2 as a passivating layer for Si photoelectrodes for solar hydrogen production.

Quantum and dynamic investigations of Complex iron- alkaloid-extract Cytisine derivatives of Retama monosperma (L.) Boiss. Seeds as eco-friendly inhibitors for Mild steel corrosion in 1M HCl

• The adsorption of Cytisine derivatives on the iron surface was modeled using DFT calculations as well as the dynamic Monte Carlo simulations. • DFT calculations were used to study the interaction of these inhibitors with iron Fe n (n=1-5). • MC and MD simulations were adopted to simulate the adsorption of Cytisine derivatives on the iron Fe (111) surface in vacuum as well as in acidic solution. • The radial distribution function (RDF), mean square displacement (MSD) and fractional free volume (FFV) were also studied using MD simulation. In this study, the adsorption of Cytisine derivatives as an eco-friendly inhibitor for mild steel corrosion [ 1 , 2 ] on the iron surface was modeled using density functional theory (DFT) calculations and the Monte Carlo (MC) as well as Molecular dynamics (MD) simulations to elucidate the interactions involved. Firstly, the interaction of these inhibitors with iron clusters Fe n (n=1-5) was studied by DFT as a representative example of a corrosion inhibition process. Moreover, structures, binding energies, partial atomic charge NBO and natural bond orbital analysis of the resulting complexes support the existence of considerable binding between these inhibitors and Fe n (n=1-5) clusters. Then, the dynamic Monte Carlo (MC) simulation was also adopted to simulate the adsorption of Cytisine derivatives on the iron Fe (111) surface in vacuum as well as in acidic solution containing 491 H 2 O, 4 hydronium ion H 3 O + and 5 chlorine ion Cl − . Besides, to advance the understanding of interactions between these molecules and iron surface, the radial distribution function (RDF), mean square displacement (MSD) and fractional free volume (FFV) were also studied in this paper. Our results of both the Fe n (n=1-4) clusters and the Fe (111) surface made it possible to show noticeable competitiveness between the three protonated inhibitors with a slight superiority for the n-CytN9H+ molecule. Furthermore, based on the diffusion coefficient we found that the three protonated inhibitors have a good capacity to slow down the movement of corrosive particles and consequently to inhibit the metallic substrate against corrosive electrolyte.

Developing multi-wall carbon nanotubes/Fusion-bonded epoxy powder nanocomposite coatings with superior anti-corrosion and mechanical properties

The aim of the study is to achieve homogeneous dispersion quality of multi-wall carbon nanotubes (MWCNTs) within fusion-bonded epoxy (abbreviate FBE) powder coatings by co-processing methods of the ball milling and hot melt extrusion. The surface of the MWCNTs is modified with polyvinylpyrrolidone (m-MWCNTs) before utilization as nanofiller in the FBE powder coatings. The structure and morphology of the MWCNTs and m-MWCNTs are investigated by X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and transmission electron microscopy. The dispersion quality of the m-MWCNTs in the epoxy coatings is evaluated by scanning electron microscopy. The corrosion resistance and mechanical properties of the FBE powder coatings containing various amounts of m-MWCNTs are studied by salt spray, electrochemical impedance spectroscopy, and pull-off adhesion tests. The results indicate that the corrosion resistance and the adhesion strength of the nanocomposite coating have improved by adding 0.2 wt% m-MWCNTs. The uniform dispersion of the nanofiller as well as increasing the pathway of the corrosive electrolytes into the coating matrix are the main reasons of improving the coating resistance. The tensile strength of the nanocomposite coating has improved by almost 53.7% through loading 0.2 wt% m-MWCNTs into the coating. The enhanced tensile strength indicates that the load-transfer has enhanced due to the better interfacial bonding. The results of this paper reveal that the combination of ball milling with hot melt extrusion is a promising approach for preparing nanocomposite powder coatings with enhanced corrosion resistance, mechanical performance, and thermal properties.

Aminomethylpyridazine isomers as corrosion inhibitors for mild steel in 1 M HCl: Electrochemical, DFT and Monte Carlo simulation studies

Three isomers of aminomethylpyridazine, namely 4-pyridazinemethanamine (Pz1), 3-aminomethylpyridazine (Pz2) and 3-amino-6-methylpyridazine (Pz3) were studied for their corrosion prevention abilities on mild steel in 1 M HCl with the aid of potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) and computational methods. Other procedures such as Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–vis) spectrometer and scanning electron microscopy (SEM) were employed to support the results obtained from the PDP, EIS and computational techniques. The effect of different mode of substitution of aminomethyl group on the pyridazine molecule on corrosion inhibition potentials was investigated. The compounds showed increasing corrosion inhibition efficiency with increase in concentration, with Pz2 showing up to 91% inhibition efficiency at 500 ppm. The order of inhibition efficiency of the compounds is Pz2 > Pz1 > Pz3. The shift in corrosion potential ranged from 17 mV to 44 mV with respect to the blank result, suggesting that the compounds exhibited mixed-type inhibitive effects, though with Pz1 and Pz2 being predominantly anodic and Pz3 being mainly cathodic in character. The dissolution of steel in the corrosive electrolytes followed a single-charge-transfer mechanism and the inhibitors formed pseudo-capacitive protective film over the steel surface in 1 M HCl. FTIR and UV–vis spectra revealed the interactions between mild steel and the inhibitor molecules, while the SEM plates revealed the morphology of steel surface in the corrosive electrolytes at varying degree of inhibitor concentration, confirming the protection efficiency of the pyridazines on mild steel. DFT calculations showed that Pz2 has the lowest lying unoccupied frontier molecular orbital. Monte Carlo simulations also confirmed highest magnitude of adsorption energy for Pz2 adsorbed on Fe(110) compared to Pz1 and Pz3.

Corrosion inhibition performance of azelaic acid dihydrazide: a molecular dynamics and Monte Carlo simulation study.

The adsorption of azelaic acid dihydrazide as an environmentally friendly mild steel corrosion inhibitor on the iron surface was modeled in this study. We used density functional theory (DFT) calculations and Monte Carlo (MC) and molecular dynamics (MD) simulations to illustrate the interactions engaged. The interaction of the azelaic acid derivatives with iron metal (Fe) was examined by DFT as a typical example of a corrosion prevention mechanism after the optimized molecular structures of these molecules were investigated. Structures, binding energies, Fikui's charge indicator, electron transfer, and chemical potential are all discussed. The presence of significant binding between the inhibitor and Fe metal is supported by analysis of the resultant complex. Then, in an acidic solution comprising 491 H2O, nine chlorine ion Cl-, and nine hydronium ion H3O+, molecular dynamics and Monte Carlo (MC) simulation were used to model the adsorption of azelaic acid dihydrazide on the iron Fe (110) surface. In addition, radial distribution function (RDF) and interaction energy (Ei) were evaluated in this work to further our understanding of interactions between azelaic acid dihydrazide and iron surfaces. Furthermore, we discovered that our inhibitors have an excellent ability to slow down the movement of corrosive particles in law temperature and thus to inhibit the metallic substrate against corrosive electrolyte, based on the temperature impact investigation. The result of density functional theory and Monte Carlo and molecular dynamics descriptors obtained were in good agreement with the experimental result.