Rotating Cylinder Electrode Research Articles

Corrosion of Copper, Cupronickel, Nickel Aluminium Bronze and Super-Duplex Stainless Steel Rotating Cylinder Electrodes in Seawater under Turbulent Flow Conditions

The corrosion of uncoated metals in a marine environment restricts the choice of suitable engineering metals and alloys. Anodic dissolution of metal and cathodic reduction of oxygen are important processes and formation of a surface oxide film can affect both electrode reactions. Charge transfer and mass transfer data can provide information on corrosion rate and mechanism. Several metals and alloys having a history of use in marine engineering are considered, including copper, two copper alloys (cupronickel and nickel aluminium bronze) plus a more recent addition to strong, corrosion resistant alloys (a super duplex stainless steel). The rotating cylinder electrode offers the benefits of a controlled, turbulent flow of electrolyte, facilitating controlled mass transfer in a compact cell geometry which is well-suited to bench-top operation. These features are illustrated using a variety of electrochemical techniques, including open-circuit potential vs time monitoring, linear sweep voltammetry, rotation speed step- or potential step current transients and linear polarisation resistance measurements. Seawater taken from Langstone Harbour, Hampshire, UK, was filtered, air-saturated, pH 8.0 and maintained at 25 °C. Dimensionless group correlations and graphical plots (using an analogous approach to the Koutecky-Levich equation for an RDE) enabled contributions of charge transfer-, mixed- and mass transfer- controlled data to be appreciated, allowing the Tafel slopes of electrode reactions, the diffusion coefficient of dissolved oxygen, the mass transfer coefficient for oxygen reduction and the mean corrosion rate to be estimated.

Methodology for Corrosion Inhibitor Persistency Studies in Batch Inhibition

A novel methodology and experimental apparatus were developed to address the limitations of previous studies and investigate corrosion inhibitor persistency under batch treatment conditions. This approach effectively removed all residues after inhibitor application and prevented O2 ingress during film formation and subsequent steps. A model compound corrosion inhibitor (CI) was utilized to validate the methodology and investigate the effects of solvent on CI persistency. In all experiments, CI was applied in situ on the prepared API 5L X65 steel rotating cylinder electrode inside the empty deoxygenated glass cell using a holder and vial. The setup used a reservoir of CO2-sparged uninhibited brine to continuously dilute the test electrolyte at a constant flow rate. Electrochemical measurements were performed at 20-min intervals to characterize the inhibition behavior over time.

(Invited) Graphene Oxide As an Additive for Ni-Fe Electrodeposition

In contrast to graphene, graphene oxide (GO) is readily disperse in aqueous electrolytes and can be reduced along with nickel and iron metal ions. While others had incorporated graphene in Ni-Fe deposits, no previous studies have addressed the role of GO particles on metal deposition. Ni-Fe is characterized by the anomalous codeposition behavior where there is a tendency of more Fe to be deposited than Ni even though there is an excess of Ni ions in the electrolyte. This behavior has been modeled assuming adsorbed intermediates. Here, the influence of GO on the deposit composition, structure and anomalous codeposition effect is investigated. The deposits were galvanostatically electrodeposited from a boric acid-sulfamate electrolyte at pH 2 containing commercial graphene oxide platelets. Two different cell configurations were examined:1) a rotating cylinder electrode (RCE) and 2) a copper mesh. The rotating cylinder as a working electrode was used in order to investigate mass transport. The copper mesh working electrode was placed in close contact to a flat bottom pH probe in order to examine the local pH change. The addition of GO to the electrolyte had an effect on the deposit composition and the local pH change (Fig 1). The deposit composition had either more Ni or remained the same compared to an electrolyte without GO on the RCE electrode at electrode rotation rates of 372 and 1000 rpm (Fig 1 (a) and (b)). The larger Ni content in the deposit was due to an enhanced Ni partial current density in the presence of GO. The local pH during the deposition on the mesh electrode with vigorous electrolyte stirring increased the local pH (Fig 1(c)). The composition behavior is similar to the results from the RCEs, with higher Ni content in the presence of GO. The local pH increase when GO was present is considered a factor that drives the enhanced Ni content, that may be a consequence of changes in adsorbed hydrogen. GO was not incorporated into the deposit; however, it had a dramatic effect on the morphology. There was less micro-cracks when GO was present in the electrolyte suggesting less adsorbed hydrogen. Thus, GO influenced the adsorbed intermediates making the electrodeposition less anomalous and having less cracks. Acknowledgement: This work was supported in part by the AESF Foundation. Figure 1. The influence of GO in the electrolyte during Ni-Fe electrodeposition (a) composition on a RCE, rotating rate (a) 372, (b)1000 rpm and (c) local pH measurements on a mesh electrode under vigorous stirring, 30 mA/cm2. Figure 1

Electrodeposited Ni-Fe-TiO2 Alloy Composites for the Hydrogen Evolution Reaction

Hydrogen is a carbon-free alternative energy source that is environmentally friendly, has high energy density, and is a promising fuel for future generations. Water splitting is an efficient way to produce hydrogen, requiring a catalyst with a small overpotential and Tafel slope, and good stability. However, only 4 % of global hydrogen is produced by water electrolysis due to high cost and lack of inexpensive replacements of the active platinum electrocatalyst.1 However, replacing these noble metal electrocatalysts with those comprised of lower, earth-abundant elements remains challenging as these materials impart a higher overpotential and thus require higher energy. Guided by the recognised enhancements of TiO2 particles in Co-Mo alloys for HER, earth-abundant, low-cost Ni and Fe metals are examined as composite electrocatalysts Ni-Fe-TiO2 towards HER.2 Nano-scale TiO2 particles were embedded into Ni-Fe alloys by using galvanic and pulse-reverse electrodeposition, onto rotating cylinder electrodes. Pulse-reverse electrodeposition considerably increased the concentration of the particles incorporated into the alloy. The composition and morphology were characterized by X-ray fluorescence (XRF) spectroscopy and scanning electron microscopy (SEM), respectively. The addition of particles to the electrolyte affected both the deposit composition and morphology. The alloy composites were then used as electrocatalysts in 1 M KOH to characterize HER via linear sweep voltammetry on the resulting hydroxide surface. The surface area was examined in a ferri/ferrocyanide electrolyte. The polarization data in 1 M KOH shows a significant reduction in the HER overpotential when TiO2 particles are present in the Ni-Fe deposit. The surface analysis of Ni-Fe and Ni-Fe-TiO2 confirmed that the improvement in HER activity is not due to surface roughness but an intrinsic one. The stability of the electrocatalysts under an electrolysis for HER was examined at -10 mA/cm2 for 24 hr and the working electrode potential remained stable over time; Tafel polarization curves after electrolysis were similar to those prior to electrolysis. References Le, P. A., Trung, V. D., Nguyen, P. L., Phung, T. V. B., Natsuki, J., & Natsuki, T. RSC advances, 13(40), 28262-28287 (2023).C. Wang, H. K. Bilan, and E. J. Podlaha. J. Electrochem. Soc. 166 F661 (2019). C. Wang and E. J. Podlaha, J. Electrochem. Soc. 167, 132502 (1~4) (2020).

Rotating cylinder electrode in reactive CO2 capture: Identifying active C species via transport, VLE models and kinetics

AbstractThis article explores technical challenges and potential methodologies for understanding electrochemical Reactive CO Capture (RCC) mechanisms. RCC offers potential energy cost advantages by directly converting captured CO into fuels and chemicals, unlike traditional carbon capture and utilization (CCU) processes that require sequential capture, concentration, and compression. However, direct conversion of captured CO introduces complexity due to additional equilibrium buffer reactions, making it challenging to identify active species for reduction in electrochemical studies. This article discusses methods to integrate transport, thermodynamics, and kinetics concepts to identify active carbon sources in RCC. Vapor‐Liquid Equilibrium (VLE) and transport models are validated against experimental results obtained in a gastight rotating cylinder electrode reactor and are shown as useful tools for studying RCC in heterogeneous electrocatalysts across different capture agents, solvents, and temperatures. This article establishes an experimental framework for advancing research in electrochemical RCC.

Electroreduction of Captured CO2 on Silver Catalysts: Influence of the Capture Agent and Proton Source.

In the context of carbon reutilization, the direct electroreduction of captured CO2 (c-CO2RR) appears as an appealing approach since it avoids the energetically costly separation of CO2 from the capture agent. In this process, CO2 is directly reduced from its captured form. Here, we investigate the influence of the capture agent and proton source on that reaction from a combination of theory and experiment. Specifically, we consider methoxide-captured CO2, NH3-captured CO2, and bicarbonate on silver electrocatalysts. We show that the proton source plays a key role in the interplay of the chemistries for the electroreduction of protons, free CO2, and captured CO2. Our density functional theory calculations, including the influence of the potential, demonstrate that a proton source with smaller pKa improves the reactivity for c-CO2RR, but also increases the selectivity toward the hydrogen evolution reaction (HER) on silver surfaces. Since c-CO2RR requires an additional chemical protonation step, the influence of the proton source is stronger than that of the HER. However, c-CO2RR cannot compete with the HER on Ag, Experimentally, the dominant product observed is H2 with low amounts of CO being produced. Through a rotating cylinder electrode cell of well-defined mass-transport properties, we conclude that although methanol solvent exhibits a lower HER activity, HER remains dominant over c-CO2RR. Our work suggests that methoxide is a potential alternative capture agent to NH3 for direct reduction of captured CO2, though challenges in catalyst design, particularly in reducing the onset potential of c-CO2RR to surpass the HER, remain to be addressed.

The effects of flow rate on impedance measurements of marine coatings using a rotating cylinder electrode

The effects of flow rate on impedance measurements of marine coatings using a rotating cylinder electrode

Augmentation of Polymer-FeCO3 Microlayers on Carbon Steel for Enhanced Corrosion Protection in Hydrodynamic CO2 Corrosion Environments.

Carbon dioxide (CO2) internal corrosion of carbon steel pipelines is a significant challenge and is typically managed by adding corrosion inhibitors. In certain operational conditions, a natural protective layer of iron carbonate (FeCO3) can form on the internal walls of the pipeline, offering inhibition efficiency comparable to that of standard surfactant inhibitors. However, incomplete coverage of the FeCO3 layer on carbon steel can sometimes trigger localized corrosion. Our previous research demonstrated that poly(allylamine hydrochloride) (PAH) can work synergistically with FeCO3 when the corrosion product partially covers X65 carbon steel surfaces in an aqueous CO2 corrosion environment. In this study, we utilize rotating cylinder electrode (RCE) tests along with electrochemical measurements to investigate the FeCO3-PAH hybrid structure in a dynamic environment. We characterize the general and localized corrosion behavior as well as the surface properties of both naturally formed FeCO3 and FeCO3-PAH hybrid layers using interferometry and focused ion beam scanning electron microscopy.

Empirical Study of the Effect of Nanocoolant Particles on Corrosion Rate of 316 Stainless Steel

The advancement of nanotechnology has had an impact on the use of heat exchangers. Nanocoolants, which offer higher thermal efficiency than traditional coolants, have paid significant attention. These innovative fluids, which contain nanomaterials, not only have better heat efficiency but also improve energy efficiency compared to regular coolants. However, the presence of solid nanoparticles in the coolant may cause corrosion and erosion of tubes, leading to massive degradation of those parts. To evaluate the effectiveness of nanocoolant particles, this research was conducted by studying the impact of using nanocoolant on erosion-corrosion occurring on metal surfaces. The study focused on the erosion-corrosion of stainless steel (AISI 316) in coolant solutions containing nanoparticles. The experiments utilized a rotating cylinder electrode (RCE) with rotational speeds ranging from 0 to 1800 rpm and a temperature range of 30°C-70°C. The corrosion rate was determined using the linear polarization resistance (LPR) method, while the erosion was measured by calculating the average surface roughness of the samples. The design of the experiment (DOE) was utilized to find the mathematical expressions of the effects of the nanocoolant on erosion and corrosion. The findings revealed that the corrosion rate and surface roughness of the samples increased with an increase in temperature and rotation speed. Furthermore, the erosion-corrosion effects of the nanocoolant were less significant in stagnant conditions than in flow conditions, and significant differences were observed when compared with conventional coolant. Additionally, synergistic erosion and corrosion processes were detected at higher temperatures and higher rotation speeds for both types of coolants.

Effect of brine salinity on the partitioning, distribution and corrosion inhibition performance of a quaternary amine corrosion inhibitor

Surfactant corrosion inhibition performance in water–oil environments is influenced by complex relationships between their physical properties, solution chemistry and interfacial characteristics. The existence of polar heads/nonpolar tails influences both the preferential distribution of the surfactant between the two media as well as the phase in which micellisation occurs. Both phenomena affect the efficiency of the surfactant inhibitor and its adsorption at the metal-solution interface. To demonstrate the complexity of such interactions, the effect of brine salinity on the critical micelle concentration (CMC) and partitioning/distribution behaviour of a quaternary amine corrosion inhibitor (alkyldimethylbenzylhexadecylammonium chloride, or BAC-C16) in a brine and toluene system (at 1:1 ratio) was explored. All experiments were conducted at 50 °C and pH4 over varying salinities (0.1, 1 and 10 wt%) of NaCl brine. Both CMC and partitioning characteristics of BAC-C16 are significantly affected by aqueous phase salinity, with an inversion of the partitioning response observed between concentrations of 0.1 and 1 wt% NaCl. The effect of BAC-C16 partitioning/distribution behaviour on corrosion inhibitor performance was examined using rotating cylinder electrode experiments. The results illustrate that in order to establish the true corrosion inhibition behaviour, consideration of the chemical distribution characteristics is crucial.

ASSESSMENT OF INHIBITORS' PERFORMANCE ON CORROSION DEGRADATION OF CARBON STEEL IN FLOW ENVIRONMENTS USING ROTATING CYLINDER ELECTRODE (RCE)

This study investigates sweet corrosion mitigation methods focusing on the efficacy of inhibitors. Specifically, it examines the performance of two types of inhibitors: water-soluble and oil-soluble. Utilising a Rotating Cylinder Electrode (RCE) setup, turbulence is induced in saline solutions to assess the impact of inhibitors on the corrosion of carbon steel. Scanning Electron Microscopy (SEM) is employed to analyse corrosion degradation patterns and material damage mechanisms. Given the prevalent use of inhibitor injection in the oil sector, it is crucial to evaluate and compare the effectiveness of various inhibitors to recommend optimal options and further studies. The findings contribute to advancing corrosion mitigation strategies, providing insights into the performance of inhibitors in flow environments and aiding in the development of more effective corrosion control measures for carbon steel structures. The inhibitors under study are sourced from local oil company vendors. With a projected duration of six months and a total budget of KD 9850, this investigation aims to provide valuable insights into corrosion mitigation strategies

Paired electrochemical recovery of metal ions from emulated e-waste leached solutions in an RCE electrochemical reactor

This work proposes the paired electrochemical recovery of metal ions, cathodically and anodically, from emulated e-waste leached solutions. Under this methodology, the recovery of a bimetallic deposit of copper-silver at the cathode, and lead dioxide at the anode, was successfully achieved in an undivided rotating cylinder electrode (RCE) electrochemical reactor. The RCE electrochemical reactor was implemented at 300 rpm and different current densities, 50, 40, 30, 20, and 10 mA/ cm2. Different compositions of the bimetallic copper-silver deposits were obtained depending on the current density applied, while in the anodes, only the deposition of lead dioxide was performed at any current density. The concentration depletion of metal ions was determined at different intervals of time. The cell voltage, cathode, and anode potential vs. SCE, were continuously monitored, and the values were useful to evaluate the energetic performance of the RCE electrochemical reactor. Figures of merit are presented to describe the performance of the RCE electrochemical reactor in the paired recovery of metal ions from emulated e-waste leached solution.

CATHODIC PROTECTION OF CARBON STEEL IN 0.1N NaCl SOLUTION UNDER FLOW CONDITIONS USING ROTATING CYLINDER ELECTRODE

The effect of applied current on protection of carbon steel in 0.1N NaCl solution (pH=7) was investigated under flow conditions (0-0.262 m/s) for a range of temperatures (35-55°C) using rotating cylinder electrode. Various values of currents were applied to protect steel from corrosion, these were Iapp.=Icorr., Iapp.=2Icorr. and Iapp.=2.4Icorr. under stationary and flow conditions. Corrosion current was measured by weight loss method. The variation of protection potential with time and rotation velocity at various applied currents was assessed. It is found that the corrosion rate of carbon steel increases with rotation velocity andhas unstable trend with temperature. The protection current required varies with temperature and it increases considerably when the rotation velocity was increased. The protection potential decreases appreciably (shifts to more negative) with time and with increasing rotation velocity. Also it shifts to more positive with increasing temperature.

First electrochemical Couette-Taylor reactor for studying the influence of transport phenomena on electrochemical kinetics

This study presents the first electrochemical Couette-Taylor reactor (eCTR). It was implemented with 20 large electrodes exposed to the same hydrodynamics from Taylor numbers (Ta) of 144 to 28,800. The limiting currents (IL) recorded with hexacyanoferrate (III/II) at different concentrations and at different Ta were used to calculate the Nernst diffusive layer thickness (δN, ranged from 14.6 to 423 µm). Two hydrodynamic regimes were identified: the wavy (Ta from 144 to 1,440) and the turbulent (Ta > 2,200) vortex flows which corresponded to the correlations δN∝Ta-0.44 and δN∝Ta-0.70, respectively. The second correlation confirmed the theoretical equation established by Gabe & Robinson for turbulent flow. In contrast, the wavy vortex flow cannot be approached by the laminar or turbulent hypothesis. Dimensionless correlations gave comparable results between the eCTR and rotating cylinder electrodes under turbulent vortex flow and confirmed the specific behavior of the Couette-Taylor wavy vortex flow.

Analysis of crude oil effect for CO2 corrosion of carbon steel - A rotating cylinder electrode approach

Crude oils, especially heavy crude oils, are rarely used in multiphase-flow loop experiments because of the experimental difficulties. Variations in the tested fluid viscosity, emulsification processes, water cut (WC), flow velocity and flow patterns, interactions between the crude oil and brine, the difficulty in obtaining metal/environment electrical continuity by covering the metal surface with crude oil, and the difficulty of selecting appropriate instrumentation to monitor the experiment are some of these problems. Studies indicate that crude oil can change the brine chemistry and influence the preferential oil/water metal-surface wettability, which impacts the corrosion process. Based on the assumption that corrosion would only occur when free water is separated from an emulsion, the risks could be reduced by transporting emulsified crude oils. However, as the solubility of water in crude oil is low, free water can be formed at the bottom of horizontal pipelines when the emulsion destabilizes, causing an increase in corrosion processes. In previous author’s studies, carbon-steel flow-induced corrosion (FIC) tests were carried out in a multiphase-flow corrosion loop containing a liquid phase of brine plus light or heavy crude oils (WC 80) with a gaseous phase of CO2. Higher corrosion rates for heavy crude oil were observed, which were not expected. No experimental studies in multiphase-flow corrosion loops using heavy crude oils in CO2-brine solution were found in the literature. In attempting to understand the reason for the higher aggressiveness of the heavy crude oil, rotating cylinder electrode (RCE) tests were performed under the same conditions used in the multiphase-flow loop.

Electrochemical evaluation of Trasar trac 102 as a corrosion inhibitor on API 5L X65 steel and theoretical study

Electrochemical evaluations of the commercially available inhibitor Trasar Trac102 were carried out under static and hydrodynamic conditions on API 5L X65 steel immersed in NaCl 3% wt. By Electrochemical Impedance Spectroscopy (EIS) techniques, obtaining the best efficiency of 95.4% under static conditions at 20 ppm. It was detected by rotating cylinder electrode that as the revolutions per minute of 100, 500 and 1000 rpm were increased, the inhibition efficiency tended to decrease as a result of the adsorption–desorption process of the organic molecules by the rotation rate. The results showed that the adsorption type of Trasar Trac102 on API 5L X65 steel in NaCl 3% wt was to form a monolayer on the metal surface according to the model fit with Langmuir isotherm. Scanning Electron Microscopy (SEM) was used for surface characterization, which shows a great difference in the target systems with corrosion products as a result of the deterioration caused by the corrosive medium and in the presence of the inhibitor. The results of the chemical analysis (EDX) show a significant decrease of oxygen in the presence of the inhibitor, suggesting that Trasar Trac102 is adsorbed directly on the steel. Dispersion-Corrected Density Functional Theory (DFT) calculations were used to characterize the interactions between the inhibitor components and the steel surface by a cluster approach. Mostly, chemisorption was explained by bonds established between oxygen atoms of inhibitor components and iron ones of the steel surface. Due to their free binding energies computed, metasilicate and mercaptobenzothiazol are expected to interact strongly and to adsorb spontaneously on the steel surface. Also, metasilicate is the component that obtained the largest charge transference to iron cluster.

Effect of Velocity on Dissolved Oxygen Cathodic Polarization using a Rotating Cylinder Electrode

The aim of the present work to study the effect of changing velocity (Reynold's number) on oxygen cathodic polarization using brass rotating cylinder electrode in 0.1, 0.3 and 0.5N NaCl solutions (PH = 7) at temperatures 40, 50 and 600 C. Cathodic polarization experiments were conducted as a function of electrode rotational speed and concentration.

Effects of Hydrodynamic Environment on the Interaction of Shewanella oneidensis with Low Carbon Steel and the Impacts on Corrosion

Microbiologically influenced corrosion (MIC) impacts various industries such as oil/gas production and transmission, wastewater treatment, power generation, and chemical processing. In such settings, the combined impacts of microbiological activities and fluid flow dynamics could be primary controllers of metal corrosion. We examined the relative influences of fluid flow and the activities of the facultative Fe(III) reducing bacterium, Shewanella oneidensis MR-1, on the corrosion of carbon steel. Rotating cylinder electrode experiments were used to determine the shear stress and velocity at the surface of the metal coupon in a newly constructed flow system. The system was then used to study the impact of increasing fluid velocity and shear stress on the corrosion rate of coupons in O2-limited and O2-nonlimited incubations. Confocal scanning laser microscopy was used to monitor biofilm development on the metal surface at increasing shear stress. We found that the activities of S. oneidensis inhibited corrosion, even under conditions of high shear stress and limited attachment, indicating that the respiratory consumption of O2 by planktonic S. oneidensis protects the metal surface from enhanced corrosion.

Coupling covariance matrix adaptation with continuum modeling for determination of kinetic parameters associated with electrochemical CO2 reduction

Coupling covariance matrix adaptation with continuum modeling for determination of kinetic parameters associated with electrochemical CO2 reduction

A Combination of Laboratory Testing, RCE, and Corrosion Loop for Inhibitor Selection

Corrosion inhibitors are evaluated in the oil industry with electrochemical tests of resistance to linear polarization with rotating cylinders following ASTM G170 and NACE 3T199 standards. With these tests, we can determine the corrosion rate (CR) and efficiency of corrosion inhibitors. In this work, a corrosion test protocol used by hydrocarbon-producing companies for the testing of corrosion inhibitors was used. This protocol consists of a 1045 carbon steel working electrode in a NACE solution composed of 9.62% NaCl, 0.45% CaCl2, 0.19% MgCl2, and 89.74% H2O, at a temperature of 65 °C and saturated with CO2. Each inhibitor tested was subjected to a series of 6000-4000-2000-4000-6000 rpm tests using rotating cylinder electrodes (RCEs). These electrochemical studies were carried out with the rotating cylinder to evaluate the ability of the inhibitor to prevent the corrosion of carbon steel in the presence of a centrifugal force. In our opinion, this test does not provide corrosion engineers with enough information to be used as a predictive tool, since what is obtained is the CR in a very short testing time. This document proposes the use of two more appropriate test methodologies, the rotating cylinder electrode (RCE) and the flow loop (FL), to evaluate the performance of the corrosion inhibitor. For the FL, the selected flow rate was 1.2 m/s, the same rate that fluids have in oil company pipelines installed in Neuquén, Argentina. Firstly, according to the company’s protocol, inhibitors are required to have an efficiency greater than or equal to 90% in RCE tests; therefore, inhibitors that meet these requirements were tested in the FL test. Unlike the RCE test, the FL test represents the experimental conditions of the laboratory that are closest to reality, for the evaluation of the performance of the inhibitors used in the pipelines of the oil and gas industry. FL tests have several problems involving corrosion, erosion, abrasion, biphasic fluids, the time it takes for the inhibitor to become effective, and the duration of its effectiveness.