Corrosion Current Research Articles

Effect of Substrate Bias on the Microstructure and Properties of Non-Equimolar (AlCrSiTiZr)N Films with Different Cr/Zr Ratios Deposited Using Reactive Direct Current Magnetron Sputtering

To reduce the cost of tools operated in extreme environments, we developed films with excellent corrosion/oxidation resistance. Two high-entropy nitride films, (AlCrSi0.3TiZr)N and (AlCr1.5Si0.3TiZr0.5)N, were deposited using reactive DC magnetron sputtering under different substrate biases. The films exhibited a maximum hardness of 32.5 GPa ((AlCrSi0.3TiZr)N) and 35.3 GPa ((AlCr1.5Si0.3TiZr0.5)N) when deposited at −150 V, corresponding to 27 and 142% increases compared to those deposited at 0 V. This indicates that the bias strengthened (AlCr1.5Si0.3TiZr0.5)N (higher Cr/Zr ratio) more significantly. The enhancement of the mechanical properties was highly correlated with the interstitial point defects and densification of the film microstructures. The corrosion resistance of the films deposited on 6061 Al alloy substrate under different biases was tested in 0.1 M H2SO4. (AlCrSi0.3TiZr)N and (AlCr1.5Si0.3TiZr0.5)N displayed the lowest corrosion currents of 0.75 and 0.19 μA/cm2 when deposited at −100 and −150 V, respectively. These values are two orders of magnitude lower than that of the uncoated substrate. The (AlCr1.5Si0.3TiZr0.5)N film showed better oxidation resistance than the (AlCrSi0.3TiZr)N film and remained partially oxidized after heat treatment at 1000 °C. The (AlCr1.5Si0.3TiZr0.5)N film deposited at −150 V exhibits excellent mechanical properties and corrosion/oxidation resistances, making it suitable for protecting tools operating in harsh environments.

Current collectors corrosion behaviours and rechargeability of TiO2 in Aqueous Electrolyte Aluminium-ion batteries

Current collectors corrosion behaviours and rechargeability of TiO2 in Aqueous Electrolyte Aluminium-ion batteries

SYNTHESIS AND TESTING OF ACTIVE BASES FOR CORROSION INHIBITORS

The results of electrochemical testing of new active bases for the creation of commercial corrosion inhibitors under conditions simulating general and local corrosion are described. General corrosion using corrosion current, working electrode geometry, State Standard 9.506-87 methodology was calculated. The anodic polarization of the working steel electrode was a physical model and the basis for calculating local corrosion. The protective effect of reagents for the model environments of the Ural-Volga region and Western Siberia oilfields (Samotlor oilfield) were determined. Comparative measurements of the corrosion rate of substituted 1,3-dioxanes, ethanolamine benzoate with a commercial corrosion inhibitor were carried out. It was found that the best protective effect against general corrosion at the level of a commercial imidazoline-type corrosion inhibitor in the model environment of the Ural-Volga region (according to State Standard 9.506-87) and Western Siberia oilfields (Samotlor oilfield) has ethanolamine benzoate. Electrochemical modeling of local corrosion and measurement of the protective effect showed that ethanolamine benzoate has an inhibitory effect on the rate of local corrosion in the model environment of Ural-Volga oilfields and is promising for modifying commercial inhibitors and expanding the efficiency of these reagents.Reducing the risk of local corrosion requires special testing under conditions of simulation of this type of corrosion for commercial reagents.

Study of the coating effect of mildly oxidized graphene on aluminium current collectors by electrophoretic deposition and drop-casting methods for Li-ion battery application

Preventing current collector corrosion is critical in Li-ion batteries. This study investigates mildly oxidized graphene (MGO) coating on aluminium (Al) foil for corrosion resistance and battery performance for the first time. Electrophoretic deposition (EPD) and drop-casting are used to apply this coating. Polarization tests and SEM analysis are performed on coatings to determine the optimal EPD conditions. Optimal conditions for EPD of MGO on aluminium are 5 V and 40 s. Using LiNi0.8Co0.15Al0.05O2 (NCA) cathodes, the performance of cells on MGO-coated and uncoated aluminium (Bare-Al) is evaluated. EPD sample shows a capacity of 175 mAh/g at C/2, 35 mAh/g more than the Bare-Al sample despite a 67.3 Ω increase in charge transfer resistance (Rct). Due to inadequate adhesion, the drop-casted sample displays a 136 mAh/g capacity at C/2, poor rate capability, and higher Rct (335.48 Ω). MGO-coated aluminium batteries perform better under the EPD method because of improved corrosion resistance of current collectors, as demonstrated by reduced corrosion currents in the polarization curves and reduced conductivity losses in incremental capacity (ICA) results.

Electrolyte Engineering Empowers Li||CFx Batteries to Achieve High Energy Density and Low Self‐Discharge at Harsh Conditions

AbstractGiven its exceptional theoretical energy density (over 2000 Wh kg−1), lithium||carbon fluoride (Li||CFx) battery has garnered global attention. N‐methylpyrrolidone (NMP)‐based electrolyte is regarded as one promising candidate for tremendously enhancing the energy density of Li||CFx battery, provided self‐discharge challenges can be resolved. This study successfully achieves a low self‐discharge (LSD) and desirable electrochemical performance in Li||CFx batteries at high temperatures by utilizing NMP as the solvent and incorporating additional ingredients, including vinylene carbonate additive, as well as the dual‐salt systems formed by LiBF4 with three different Li salts, namely lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, and LiNO3. The experimental results unfold that the proposed methods not only minimize aluminum current collector corrosion, but also effectively passivate the Li metal anode. Among them, LiNO3 exhibits the most pronounced effect that achieves an energy density of ≈2400 Wh kg−1 at a current density of 10 mA g−1 at 30 °C, nearly 0% capacity‐fade rate after 300 h of storage at 60 °C, and the capability to maintain a stable open‐circuit voltage over 4000 h. This work provides a distinctive perspective on how to realize both high energy density and LSD rates at high temperature of Li||CFx battery.

Strategies towards inhibition of aluminum current collector corrosion in lithium batteries

Aluminum (Al) foil, serving as the predominant current collector for cathode materials in lithium batteries, is still unsatisfactory in meeting the increasing energy density demand of rechargeable energy storage systems due to its severe corrosion under high voltages. Such Al corrosion may cause delamination of cathodes, increasement of internal resistance, and catalysis of electrolyte decomposition, thus leading to premature failure of batteries. Hence, a systematic understanding of the corrosion mechanisms and effective anticorrosion strategies are necessary to enhance overall performance of lithium batteries. In this review, the corrosive mechanisms related to Al current collectors are systematically summarized and clarified. In addition, an overview on recent progress and advancement of strategies toward inhibiting Al corrosion is presented. In the end, we also provide a perspective with motivation to stimulate new ideas and research directions to further inhibit Al corrosion to achieve high energy density, long cycle life, and high safety of lithium batteries.

Severe Plastic Deformation of Mg–Zn–Zr–Ce Alloys: Advancing Corrosion Resistance and Mechanical Strength for Medical Applications

Magnesium-based alloys hold potential for medical applications, but face challenges like rapid bioresorption and limited mechanical strength during early bone healing. In our study, we present a novel Mg–Zn–Zr–Ce alloy with low cerium content (up to 0.1 wt.% Ce) processed using two severe plastic deformation (SPD) techniques. Through an innovative combination of multiaxial forging and multipass rolling, we have achieved a fine-grained structure with an average grain size of the primary α-Mg phase of 1.0 μm. This refined microstructure exhibits improved mechanical properties, including a substantial increase in yield strength (σYS) from 130 to 240 MPa, while preserving ductility. The alloy’s composition includes α-Mg grains, cerium and zinc hydrides, and intermetallic phases with cerium and zinc elements. Tensile testing of the fine-grained alloy demonstrates an enhancement in yield strength (σYS) to 250 MPa, marking a 2.8-fold improvement over the conventional state (σYS = 90 MPa), with a modest 2-fold reduction in ductility. Crucially, electrochemical tests conducted in physiological solutions highlight substantial advancements in corrosion resistance. The corrosion current was reduced from 14 to 2 μA/cm2, while polarization resistance decreased from 3.1 to 8.1 kΩ∙cm2, underlining the alloy’s enhanced resistance to biodegradation. Our results show that the novel Mg–Zn–Zr–Ce alloy, after combined SPD, demonstrates mitigated bioresorption and enhanced mechanical properties. Our findings highlight the fact that the introduction of this innovative alloy and the application of SPD represent significant steps towards addressing the limitations of magnesium-based alloys for medical implants, offering potential improvements in safety and effectiveness.

D-tyrosine enhances disoctyl dimethyl ammonium chloride on alleviating SRB corrosion

Microbiologically influenced corrosion (MIC) caused by sulfate reducing bacteria (SRB) is a serious challenge in many industries, but biofilm greatly decreases the toxicity of bactericides to cell inside. d-amino acids are potential enhancers for bactericides due to their excellent performance on biofilm inhibition. However, the mechanism of d-amino acid cooperating with bactericides for MIC inhibition is still unknown. In this study, d-tyrosine（D-Tyr）and disoctyl dimethyl ammonium chloride (DDAC) were selected as the typical d-amino acid and bactericide, respectively, to evaluate their synergetic inhibition on the corrosion caused by Desulfovibrio vulgaris. D-Tyr obviously enhanced the role of DDAC in inhibiting corrosion with high corrosion inhibition efficiency at 77.23 %. The attachment of EPS and live cells on the coupon surface decreased in the presence of D-Try, leading to more cells directly exposed to DDAC. Besides, D-Try decreased the amount of live cells on the surface and thus reduced the utilization of Fe by SRB and corrosion current. Moreover, dead cells settling to the coupon surface may form a protective lay to retard the contact between live SRB and Fe, leading to slow cathode reaction and less corrosion. Therefore, D-Tyr can reduce the coverage of biofilm, thereby reducing its protective effect on SRB and achieving better corrosion inhibition effect. This work provides a new strategy for improving bactericides and inhibiting MIC.

Study on Friction and Corrosion Performance of CrTiBN Coating in Artificial Seawater Environment

CrN, CrTiN, and CrTiBN coatings were deposited onto 316 stainless steel substrates using multi-arc ion plating techniques. Their morphology, microstructures, friction performance, and corrosion resistance in simulated seawater were systematically characterized. After being analyzed with X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy, the results revealed that CrN coatings had a primary face-centered cubic CrN structure. Following the addition of Ti and B elements, CrTiBN coatings exhibited a cross-sectional structure with hexagonal TiB2 and amorphous BN, displaying the most compact structure. Electrochemical impedance spectroscopy tests indicated that CrTiBN coatings had the highest polarization resistance, the highest phase angle, and the widest frequency range. During electrochemical polarization curve tests, CrTiBN coatings displayed a corrosion potential of 0.11 V, a polarization resistance of 2470 kΩ·cm2, and a minimal corrosion current of 1.94 × 10−8 A/cm2, demonstrating outstanding corrosion resistance. The results from the friction tests indicated that CrTiBN coatings exhibited the lowest friction coefficients of 0.16 and wear rates of 8.18 × 10−7 mm3/Nm. Insights gained from electrochemical friction–corrosion tests revealed that CrTiBN coatings maintained the highest Open Circuit Potential (OCP) throughout the corrosion and friction process. In summary, the introduction of Ti and B has clearly enhanced the friction and corrosion resistance properties of CrTiBN coatings in comparison to CrN coatings.

Microstructural features and corrosion behavior of Inconel 625 components fabricated using Wire and Arc Additively Manufacturing (WAAM)

Wire and arc additive manufacturing (WAAM) is the predominant technique to process Nickel-based superalloys due to its low cost and high flexibility. This article discusses the microstructural features and corrosion resistance of two Inconel 625 parts manufactured using the WAAM technique. Using the WAAM process, two single-walled Inconel 625(IN625) components were produced additively for inter-pass layer temperatures (IPT) of 200 °C and 300 °C. The grain size changed with a change in IPTs, according to an investigation using electron backscatter diffraction (EBSD). The preferred grain orientation changed from the texture {001} < 001> to {001} < 101> as the IPT increased. Potentiodynamic polarization was used to evaluate the corrosion behavior. The corrosion rate of the IPT 300 °C sample is 0.007255 mmpy, while the corrosion rate of the IPT 200 °C sample is 0.01315 mmpy. Tafel’s extrapolation technique calculated the corrosion current density and corrosion current potential. The scanning electron microscope (SEM) explored the corroded area, and the energy-dispersive X-ray spectroscope examined the elemental composition.

Corrosion, surface, and tribological behavior of electrophoretically deposited polyether ether ketone coatings on 316L stainless steel for orthopedic applications

Electrophoretic deposition (EPD) of polyether ether ketone (PEEK) coatings on metallic implants has recently attracted a great deal of interest; however, further investigation into their corrosion, surface, and tribological properties is required for their clinical application. Using Potentiodynamic polarization and Mott-Schottky analysis of PEEK coatings, we analyzed the electrochemical corrosion behavior of electrophoretically deposited PEEK coatings on 316L stainless steel (SS) substrates. In addition, the tribological behavior of the coatings was determined through pin-on-disc and scratch testing. Initially, the EPD parameters were optimized using a Taguchi Design of Experiment (DoE) approach. The coatings exhibited irregular shaped grains along with ∼66 μm of thickness. Fourier transform infrared spectroscopy confirmed the presence of functional groups ascribed with PEEK. The coatings were moderately hydrophobic and had an average roughness of ∼2 μm. The corrosion studies demonstrated promising features of current density and corrosion potential, indicating that corrosion resistance significantly improves with PEEK coating. Electrochemical impedance spectroscopy also confirmed the corrosion resistance of PEEK coating. The coatings exhibited a slightly lower wear resistance than SS samples, but still possessed adequate wear and scratch resistance for biomedical applications. The current study confirmed that the PEEK coatings on metallic implants is effective for orthopedic applications where corrosion and tribology are major concerns.

On biodegradability of 3D printed polyvinylidene fluoride composites

Polyvinylidene fluoride (PVDF) is one of the established biocompatible thermoplastics for scaffolding applications. But due to its partial biodegradability, its use as a bio-absorbable implant is limited. Some studies have outlined that reinforcement of hydroxyapatite (HAp), and chitosan (CS) helps in improving the biodegradability of the PVDF composite matrix. But hitherto little has been reported on the biodegradability comparison for virgin PVDF, and PVDF composite matrix (with different proportions of HAp and CS as reinforcement). This study reports the biodegradability of virgin PVDF, 90% PVDF–10% HAp, 90% PVDF–8% HAp–2% CS, and 90% PVDF–9% HAp–1% CS based on a corrosion testing (open circuit potential, polarization resistance, corrosion current, corrosion rate [CR], surface roughness (Ra), and porosity %) in simulated bodily fluid (SBF) for possible bio-absorbable implant applications. The study suggests that the biodegradability of 90% PVDF–9% HAp–1% CS is maximum having CR 26.389mm2/year, mainly due to the presence of more hydroxyl group (-OH). The corresponding porosity % and Ra (after corrosion testing) were noticed as 12.45% and 19.12 µm. The results are supported by scanning electron microscopy (SEM) images.

Numerical modeling for predicting service life of reinforced concrete structures exposed to chloride

In recent decades, there has been a growing interest in predicting the service life of reinforced concrete structures vulnerable to chloride-induced corrosion. The service life is divided into initiation and propagation phases, considering the de-passivation of the reinforcement's protective film as a threshold for active corrosion. However, it is observed that the corrosion process is gradual, requiring considerable time before significant damage occurs. This research presents a comprehensive numerical model that incorporates both passive and active corrosion contributions to predict the service life. The model utilizes a finite difference approach to simulate transportation processes, corrosion current, and rust growth. Time-varying boundary conditions, including relative humidity, temperature, and surface chloride concentration, are considered in solving the partial differential equation governing the transportation processes. The incorporation of both passive and active corrosion contributions, as well as the consideration of time-varying boundary conditions, enhances the accuracy of the predictions. Sensitivity analysis is conducted to evaluate the effects of corrosion rate, cross-section loss rate, and service life, considering variations in relative humidity, temperature, water-to-cement ratio, and cover depth. The results highlight the significant impact of relative humidity and water-to-cement ratio on corrosion rate and cross-section loss. Changing the water-to-cement ratio from 0.5 to 0.4 was observed to double the overall service life of an identical structure. Additionally, cover depth was identified as a crucial factor affecting the service life of the structure. Changing the cover depth from 40 mm to 80 mm enhanced service life by three and a half times in the present case study. Temperature fluctuations had a relatively minor effect within acceptable limits, allowing the use of average temperatures for service life estimation, particularly in coastal regions. The comprehensive model presented can provide aid in informed decision-making for corrosion prevention and mitigation strategies in practice.

Equivalent conversion investigation of environmental corrosion of suspenders in long-span suspension bridge

Purpose This paper aims to investigate the equivalent relationship between accelerated corrosion tests and real environmental spectrum of suspenders in long-span suspension bridge considering multiple factors action. Design/methodology/approach Based on Faraday's law, corrosion current was used as a measure of metal corrosion, and the equivalent conversion relationship between laboratory environment and real service environment was established. The equivalent conversion method for bridge structural steel had been determined under different temperature, humidity, pH value and NaCl concentration conditions. The compilation of environmental spectra for large span bridges considering multiple factors and the principle of equivalent conversion have been proposed. Findings Environmental factors, including temperature, humidity, pH value and NaCl concentration, have significant impact on the corrosion degree of suspension steel wires, and only considering these two factors for equivalent conversion cannot accurately reflect the true service environment of the bridge. The 33.8-h salt spray accelerated corrosion test using the standard conditions can be equivalent to one year of suspenders corrosion in a real service environment. Originality/value The equivalent accelerated corrosion method for steel wires proposed in this study can effectively predict the corrosion degree of the suspenders, which has been verified to be correct and can provide theoretical guidance for the development of corrosion test plans for steel wires and engineering technical basis for anti-corrosion control and calendar life research of suspension bridge suspenders.

A rapid one-step preparation method of the repairable three-dimensional antifouling superhydrophobic 2.5EPZF coating on magnesium alloys

Although three-dimensional (3D) superhydrophobic coating has been gradually prepared on the surface of metal substrate for anticorrosion and antifouling, their complex preparation steps and equipment requirements limit their practical application. Herein, by a rapid one-step spray preparation method the fabricating 3D superhydrophobic 2.5EPZF (2.5 g epoxy resin/polycaprolactone (PCL)/zinc oxide/perfluorodecyltriethoxysilane) coating is prepared. This method utilizes a certain degree of directional arrangement of macromolecular long chain polymers (PCL) as solvent evaporation during the spraying process to form a filamentous structure to construct the 3D coating. This preparation mechanism provides us a novel theoretical guidance method for preparing 3D coating. Further, the silk thickness and mesh density of the 3D mesh structure is controlled by adding epoxy resin. When the amount of epoxy resin is 2.5 g, the surface of 2.5EPZF coating is with about 1–3 μm thick branch frame and 0.1–0.4 μm thin treetop. And the water-contact angle (CA) of 2.5EPZF is 156.6 ± 1.5° and the sliding angle (SA) is < 10° . The 2.5EPZF coating exhibits durable antifouling, strong mechanical&chemical durability, and corrosion resistance. The corrosion current of the 2.5EPZF coating for 0 day's immersion and 35 days’ immersion in NaCl solution is 1.043 × 10−12 A•cm−2 and 1.1703 × 10−11 A•cm−2, respectively. Under solar irradiation and at 50 °C for 30 min, the 2.5EPZF coating is with scratching recovering. Additionally, the composite coating can be prepared by a large area. It is expected that this method is readily used and shows great application potentials.

Study of fretting-initiated crevice corrosion and crevice corrosion affected fretting of stainless steel

Fretting crevice corrosion of total hip joints have been associated with joint replacement failure. However, researchers have not considered the interaction between fretting corrosion and crevice corrosion. In this study, an artificial crevice system that could perform fretting in the center of the crevice was designed, and fretting-initiated crevice corrosion (FICC) under different crevice widths, along with the effect of crevice corrosion on fretting corrosion, were studied. The results showed that FICC was more obvious under a smaller crevice, and pitting corrosion initiated at the shear band, resulting in crevice corrosion. Furthermore, corrosion pre-treatment significantly increased the fretting corrosion current.

New benzisoxazole derivative: A potential corrosion inhibitor for mild steel in 0.5 M hydrochloric acid medium -insights from electrochemical and density functional theory studies

6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole. HCl (FPBH), a substituted benzisoxazole derivative, was prepared from isonipecotic acid and characterized using various spectroscopic techniques. Using electrochemical examinations such as potentiodynamic polarisation (PDP) and electrochemical impedance spectroscopic (EIS) technique, the corrosion mitigation capabilities of this compound for mild steel (MS) in 0.5 M HCl medium were investigated. Theoretical studies were performed using quantum chemical calculations and density functional theory (DFT). PDP results exhibited the mixed-type behavior of FPBH and showed a maximum efficiency of 94.5 % at 1 × 10−3 M. The development of a protective adsorbed layer of FPBH decreases the corrosion current density (icorr) and corrosion rate (CR). The EIS technique revealed that the rise in the charge transfer resistance (Rct) values and reduction in the thickness of the double-layer capacitance (Cdl) reflected the drop in corrosion rate. The adsorption of FPBH took place through physisorption by conforming Langmuir's isotherm. The DFT method was performed on the optimized structure of FPBH to get additional evidence on the action mode of FPBH with the metal surface.

Understanding the Effect of Electrochemical Properties and Microstructure on the Microgalvanic Corrosion of Mg Alloys via Phase-Field Simulations

In this work, we apply a phase-field model to gain insights into the corrosion behavior of Mg alloys. Specifically, we study the effect of electrochemical properties of the materials and their environment and the spatial distribution of second phases in a magnesium alloy. To this end, we perform sensitivity analyses in which we separately vary the exchange current density and corrosion potential of the second phase, as well as the electrolyte conductivity. We describe the effects of these parameters on the corrosion current and the resulting corrosion-front morphology. We also confirm that the ratio between the Wagner length, calculated for the anodic phase, and the initial width of the anodic domain is a good predictor of the morphological characteristic of the corroding surface. In addition, we examine the effect of the microstructure on the corrosion behavior in both 2D and 3D systems by varying the shape, size, and distribution of the second-phase regions. Our findings provide insights into the influence of the two-phase microstructure on the corrosion behavior in a magnesium alloy.

Frequency characteristics analysis of pipe-to-soil potential under metro stray current interference using continuous wavelet transform method

This study aims to investigate the impact of stray current interference from metro systems on the pipe-to-soil potentials of metallic pipelines, which is closely associated with stray current corrosion. The pipe-to-soil potentials were assessed using coupon testing, while in-situ measurement was conducted to measure the metro leakage currents. The collected field data from the pipe-to-soil potentials and metro leakage current measurements were subjected to a statistical analysis using Continuous Wavelet Transform (CWT) and linear correlation methods. The analysis revealed consistent dominant frequencies of interference at the same test point for both on-potentials and off-potentials conditions, as well as within different time periods. However, variations in dominant frequencies of interference were observed among test points along different sections of the pipeline. Notably, three primary test points exhibited frequencies of 8.3, 8.9, and 7.8 mHz, corresponding to the main interstation travel intervals of neighboring metro lines. Furthermore, the dominant period ranges of interference of metro stray current interference were found to align with the interstation travel interval ranges of the metro lines. When the OVPD acts, the leakage current of the metro station grounding system near the test point has a significant contribution to the amplitude of pipe-to-soil potential fluctuation. These findings highlight the significant role of interstation travel intervals in the periodicity of metro stray current interference. The identified dominant interference frequency ranges can be utilized to determine interference sources and evaluate the extent of metro stray current corrosion.

Research on Nano-Titanium Modified Phenolic Resin Coating and Corrosion Resistance

Nano-titanium can be used in the field of anticorrosive coatings due to its excellent corrosion resistance. In this paper, phenolic resin was modified by nano-titanium using a physicochemical method. The nano-titanium-modified phenolic resin was used as a matrix to prepare the anticorrosive coating. The microstructures of the coatings were analyzed by Scanning Electron Microscope (SEM), X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR). Raman and UV spectrum adhesion of the coating was tested by a scratching method. The corrosion behavior was studied by electrochemical workstation and salt spray test. The results showed that the corrosion resistance of pure phenolic resin coating was significantly improved by the nano-titanium-modified phenolic resin. The coating containing 4% titanium nanoparticles exhibited the best corrosion resistance, with the highest impedance and the smallest corrosion current. The coating remained intact after 480 h of salt spray, showing the best salt spray resistance performance.