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The respective roles of IOB and SRB in mixed microbial corrosion of carbon steel pipelines were investigated by surface analysis and electrochemical measurements. The results indicate that in initial corrosion stage the extracellular polymeric substances (EPS) of SRBs can hinder the adhesion of IOB and inhibit corrosion nodulation formation. As SRB:IOB increases from 0:22500 cells/mL to 22500:22500 cells/mL, the size and number of corrosion nodulations decrease by two orders of magnitude. In latter corrosion stage, the SRBs become the dominant microbes, accelerating the propagation of corrosion nodulations in mixed microbial system due to low dissolved oxygen (DO). [Display omitted] • Carbon steel presents uniform corrosion in single SRBs but nodulation corrosion in single IOBs. • In the initial corrosion stage corrosion is inhibited with mixed microbes compared with single IOBs or SRBs. • The EPS of SRBs can hinder IOB adhesion and further inhibit nodulation corrosion. • Corrosion nodulation dimensions are inversely proportional to the content ratio of SRBs: IOBs. • In the latter corrosion stage nodulation corrosion is accelerated by SRBs in mixed microbes. [ABSTRACT FROM AUTHOR]

Hydrazine used as oxygen scavenger in the secondary circuit of pressurized water reactors is hazardous to the environment and potentially carcinogenic, thus, suitable replacement chemicals for it are actively sought. In the present paper, decomposition products of two potential replacements – carbohydrazide and diethyl-hydroxylamine – are analyzed, and their effect on secondary water chemistry and corrosion of the main steam generator materials – carbon steel 22 K, stainless steel 0X18H10T and Alloy 690 – is studied by in-situ electrochemical techniques complemented by ex-situ analyses of the formed oxides by spectroscopic and microscopic methods. Quantitative interpretation of the electrochemical impedance data with the Mixed-Conduction Model allowed for the estimation of oxidation and corrosion release rates depending on scavenger formulation, alloy type and temperature. Conclusions on the extent of interaction of decomposition products with construction materials are drawn based on the experimental and calculational results. • The decomposition of carbohydrazide decreases pH and increases acidic conductivity in the first hours of testing due to the formation of CO 2. • Acetaldehyde, acetic acid, dimethylamine and ethylamine were the decomposition products that could be analyzed reliably from the DEHA decomposition. • The effect of scavenger type on the austenitic materials' oxide composition is rather small at the studied concentrations. • Electrochemical impedance spectroscopy was successfully applied to assess the structure of the forming oxides. • The differences between corrosion release rates on different materials in all studied scavenger formulations are not very large. [ABSTRACT FROM AUTHOR]

The role of electrode potential in CaCO 3 scaling behavior and kinetics on carbon steel and stainless steel surfaces is investigated through electrochemical tests, surface characterization, and numerical modeling. Under cathodic conditions, calcite is the dominant CaCO 3 polymorph, its lateral growth on steel surfaces follows exponential kinetics. However, under gradually promoted corrosion conditions of carbon steel, the presence of corrosion products induces more aragonite deposition and inhibits the lateral growth of CaCO 3 scale, gradually evolving from exponential to linear kinetics. This work provides further insight into how the cathodic and anodic reactions of steel corrosion respectively promote and inhibit CaCO 3 scaling. • CaCO 3 scaling behavior and kinetics are studied at cathodic and corrosion potentials. • Under cathodic condition, the lateral growth of calcite follows exponential kinetics. • Under corrosion, aragonite rises and the lateral growth evolves to linear kinetics. • The cathodic and anodic corrosion processes have opposite effects on CaCO 3 scaling. [ABSTRACT FROM AUTHOR]

The different inhibition behavior of imidazoline quaternary ammonium salt for high-pressure CO 2 flow accelerated corrosion of carbon steel gradual contraction and gradual expansion tubings was unveiled combing high pressure dynamic in situ electrochemical methods and microstructure characteristics analysis. It is manifested that there is no noticeable inhibition effect in high CO 2 partial pressure environments at extremely low inhibitor concentration. At low inhibitor concentration, the polarization resistance and inhibition efficiency increase firstly and then decrease along the flowing direction of gradual contraction tubing. However, the polarization resistance generally drops along the gradual expansion tubing. As the inhibitor concentration of the corrosion inhibitor is further increased, the polarization resistance and inhibition efficiency are reduced in a whole along the gradual contraction tubing. Nevertheless, the polarization resistance is raised, followed by a fall along the flowing direction of gradual expansion tubing. The inhibition effect at the top and the bottom of gradual contraction tubing exhibits symmetry while it is asymmetrical at the top and the bottom of inclination section in gradual expansion tubing. The distinct inhibition effect at different inhibitor concentration is relevant to flow characteristics of fluid at gradual contraction tubing and gradual expansion tubing. The findings could provide valuable guidance for the protection of flow accelerated corrosion at gradual contraction tubing and gradual expansion tubing under high CO 2 partial pressure conditions. • The inhibition behavior of IQAS for high-pressure CO 2 FAC of carbon steel GC and GE tubings was studied. • The R p and IE along GC tubing and GE tubing exhibits significantly distinction at different inhibitor concentration. • The R p values at the top and bottom of GC tubing are similar while they are quite different at GE tubing. • Hydrodynamics at GC/GE tubing play a vital role in inhibition behavior of IQAS at different inhibitor concentration. [ABSTRACT FROM AUTHOR]

The effects of flow velocity and silty sand on CO 2 corrosion of N80 carbon steel were studied using a small flow loop. Silty sand does not change the electrochemical characterization of corrosion but reduces the corrosion rate of steel. Under the low flow velocity, silty sand embeds in the sample surface, reducing active area for iron dissolution and delaying the formation of FeCO 3 in corrosion product layer. At medium and high flow velocity, silty sand erodes the sample surface, and wall shear stress damages the integrity of the corrosion product layer, but do not lead to greater corrosion rate. • Flow corrosion tests and in-situ electrochemical measurements were carried out using a small flow loop. • The corrosion rate of N80 steel increases with increasing flow velocity, and the critical flow velocity for N80 steel is between 1.5 m/s and 3.0 m/s. • Silty sand does not change the electrochemical characterization of steel corrosion but reduces the corrosion rate. • Silty sand embeds in the sample surface and reduces the active area for iron dissolution at low flow velocity. As the flow velocity increases, silty sand erodes the sample surface and damages the integrity of corrosion product layer. [ABSTRACT FROM AUTHOR]

The corrosion of carbon steel in alkaline anaerobic conditions and high temperature (80°C) was studied through mock-up tests representative of imperfect contact between steel and cementitious material. The evolution of the whole system, including cement mineralogy, reservoir solution chemistry, corrosion product and rate, was followed over one year. SEM-EDX and XRD analyses indicated that the corrosion product layer was mostly constituted of (Fe,Al)Si-Hydrogarnet ((Fe,Al)Si-HG) and that its densification progressively inhibited corrosion. Thermodynamic and reactive transport modelling helped to better constrain the chemical and temperature conditions of (Fe,Al)Si-HG formation. • The anoxic corrosion of carbon steel at 80°C leads to (Fe,Al)Si-Hydrogarnet formation. • The competing occurrence of magnetite or (Fe,Al)Si-HG as corrosion product is investigated. • The experimental observations are well supported by thermodynamic modelling. • Temperature, diffusion and calcium concentration are key controlling parameters. [ABSTRACT FROM AUTHOR]

In this work, the effects of Cl-, Ca2+, and Mg2+ on the corrosion inhibition performance of 2-mercaptopyrimidine (2-MP) were investigated. The analysis reveals a marked reduction in the inhibition efficiency of 2-MP, from 91.24 % to 76.29 %, as the NaCl content in the solution rises from 1 wt% to 20 wt%. UV–visible absorption spectroscopy and quartz crystal microbalance measurements indicate that the desorption of 2-MP worsens with an increasing content of corrosive ions. Molecular dynamics simulations reveal the inhibitor desorption mechanism. This work enhances understanding of ion effects on corrosion inhibition and film degradation in high salinity environments. • The corrosion inhibition performance of 2-mercaptopyrimidine in NaCl solutions with varying content is investigated. • The corrosion inhibition failure of 2-mercaptopyrimidine in solutions with high NaCl contents is thoroughly analyzed. • The formation of micelles by 2-mercaptopyrimidine in solutions with high NaCl contents is examined. • The investigation is performed regarding the effect of cation presence on the desorption of 2-mercaptopyrimidine. [ABSTRACT FROM AUTHOR]

Corrosion causes significant challenges in industrial settings, leading to economic losses and safety concerns. Previously, we developed a lignin-polydimethylsiloxane (lignin-PDMS) coating that exhibited high corrosion resistance. However, the adhesion of the developed lignin-PDMS coating to carbon steel was limited, affecting its overall performance. To address this, we incorporated dopamine (DOPA), known for its strong adhesive properties, as a pre-treatment before applying the coating. It was found that the adhesion and corrosion resistance of lignin-PDMS coated steel could be improved by adjusting the pH value of the DOPA solution. The steel treated with pH 4.5 DOPA solution showed two times higher adhesion strength to the coating than non-treated steel. After the DOPA treatment, the coating can maintain high barrier property for at least 3 months in 1 M NaCl solution, which is even better than commercial gelcoat, demonstrating super corrosion protection. Quartz Crystal Microbalance with Dissipation (QCM-D) and X-ray Photoelectron Spectroscopy (XPS) analyses confirmed the DOPA deposition on the steel surface. Our findings show that the DOPA-lignin-PDMS system is an environmentally friendly and efficient solution for enhancing the durability of steels in corrosive environments. • Dopamine improves lignin-polydimethylsiloxane coating's adhesion on steel. • pH 4.5 dopamine solution doubles coating's adhesion strength on steel. • Coating on dopamine-treated steel maintains barrier property for 3 months in 1 M NaCl. • Dopamine-lignin-polydimethylsiloxane system enhances the durability of steels in corrosive environments. [ABSTRACT FROM AUTHOR]

The corrosion rate of pipelines in the petroleum industry is heavily influenced by the weak acids present in the production stream. In a series of experiments at 65 °C, weak acids enhanced the cathodic reaction currents, significantly increasing the corrosion rate. The experiments were designed to investigate limiting electrochemical factors in solutions with low salt concentrations, focusing on predicting top-of-line corrosion corrosion rate. Carbonic acid, acetic acid, and formic acid, commonly found in produced fluids, were the subjects of this corrosion investigation. Under the investigated conditions, the corrosion rates were found to correlate with the undissociated weak acid concentration. • Effect of weak acid concentration on aqueous carbon steel corrosion in the presence of carbonic, acetic and formic acids. • pH and ferrous ions concentration measurements were linked with chemistry simulations and then corrosion rate. • Various independent methods were used for corrosion rate assessment. • Differences in corrosion mechanisms between acetic and formic acid were investigated. • Modelling work for assessment of potentiodynamic sweep data. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of the ε-Polylysine (E-PL) antimicrobial peptide on the corrosion behavior of P. aeruginosa attached to carbon steel surfaces. The results showed that E-PL exhibited good antibacterial and antibiofilm activity, further effectively inhibited the corrosion behavior of P. aeruginosa by biofilm thickness, surface morphology, corrosion product, EIS and molecular biology method. In addition, the transcriptome and qPCR data showed that E-PL significantly downregulated the expression of key genes in flagella, quorum sensing, biofilm formation, and phenazines for resisting microbiologically influenced corrosion. This study has theoretical significance for evaluating the corrosion of marine equipment. • The antibacterial, antibiofilm, and anticorrosive activity of E-PL against P. aeruginosa on the surface of Q235 carbon steel was evaluated. • The transcriptome data showed that E-PL significantly down-regulates the expression of key genes in motor flagella, quorum sensing, biofilm formation, and phenazines. • QPCR results showed that the E-PL decreased phenazine-related gene secretion of P. aeruginosa , further decreasing the extracellular electron transfer between bacteria and steel and resisting microbiologically influenced corrosion (MIC). [ABSTRACT FROM AUTHOR]

Iron carbonate (FeCO 3) layers influence the electrochemical properties of carbon steel during aqueous corrosion in carbon dioxide–saturated environments. In this study, electrochemical measurements conducted in an autoclave at 80°C and 5 barg are combined with cross-sectional imaging to elucidate interfacial properties of X65 carbon steel at key stages of FeCO 3 layer development. The effects of evolving system chemistry are also considered by variation of the X65 surface area to solution volume (A/V) ratio. FeCO 3 reduces general corrosion rates through a combination of active site blocking and restriction of mass transport, with resultant layer properties dependent on the A/V ratio. • Area to Volume Ratio significantly affects FeCO 3 corrosion product layer properties. • In-situ electrochemical techniques employed at 80°C, 5.5 pCO 2 and initial pH 3.7. • Four key stages in FeCO 3 corrosion product layer development on carbon steel. • Substrate protection provided by active site blocking and mass transport restriction through thick but porous FeCO 3 layer. [ABSTRACT FROM AUTHOR]

2-Benzylsulfanyl-1H-benzimidazole(2B1BI) was synthesized and used to inhibit the corrosion of carbon steel in supercritical CO 2 brine at various rotation speeds. Thiourea (TU) can improve the inhibition of 2B1BI. The corrosion inhibition mechanism and adsorption process were investigated by electrochemical techniques and theoretical calculations. The results show that 2B1BI-TU mixed corrosion inhibitors exhibit increased adsorption with strong bonds on steel, forming a denser and more persistent protective film. This film can effectively inhibit corrosive particles, slowing down both general and localized corrosion. This study explores the potential of the new inhibitor as an efficient corrosion inhibitor in challenging environmental conditions. [Display omitted] • 2-Benzylsulfanyl-1H-benzoimidazole(2B1BI) was synthesized. • 2B1BI was used as a corrosion inhibitor under dynamic supercritical CO 2 conditions. • The synergistic corrosion inhibition parameter of 2B1BI and thiourea (TU) is 16.63. • The 2B1BI-TU mixed corrosion inhibitor film is stable under dynamic fluid flow. • 2B1BI-TU mixed corrosion inhibitor inhibits the general and localized corrosion. [ABSTRACT FROM AUTHOR]

Organic acids can severely corrode metals, despite rarely reaching particularly low pH values. The mechanisms underlying the corrosion process in the presence of organic acids can be different and more complex with respect to the ones in the presence of strong acids. Since organic acids are commonly found in several industrial environments, they pose a serious threat that needs to be carefully addressed and investigated. Throughout the years, many research efforts have been put towards predictive modeling of corrosion. The Tafel-Piontelli model aims at becoming a universal and versatile model for acidic corrosion, able to adapt to different situations and predict corrosion rates of active metals exposed to all kinds of acidic environments. The model foundations are grounded in the principles of the corrosion process, regulated by the Tafel law. The efficacy of the model was tested on carbon steel samples immersed in solutions of weak acids with increasing proticity — formic, azelaic, and citric acid — at temperatures ranging from 20°C to 60°C and pH values from 3 to 4. The validation analysis was conducted using two primary tests: mass loss tests to assess corrosion rates and potentiodynamic polarization tests to determine the kinetic parameters of the cathodic and anodic reactions involved in the corrosion process. The results from the experiments are promising, confirming and extending the predictive capabilities of the model to the case of organic acids. These findings have broad implications for improving safety and durability in industrial applications where organic acids are prevalent, highlighting the model's potential to significantly enhance preventive strategies and material selection. • Mechanistic model for the prediction of the corrosion rate of metals in weak acids • Tests performed on carbon steel in monoprotic, diprotic and triprotic organic acids • Mass loss tests used to evaluate the corrosion rate at different pH and temperature • Potentiodynamic polarization tests used to validate the kinetic parameters of the model • Promising fit in the entire temperature (20°C-60°C) and pH (3−4) range considered [ABSTRACT FROM AUTHOR]

Surface boronizing treatment, which forms lattice defects between the boronized layer and the metal substrate, is an effective anti-corrosion strategy. We explored the bonding mode between boron-oxygen ligands and Fe substrate. [BO3] is bonded to Fe with Fe-B bonds, while [BO4] tends to form Fe-O bonds. The larger coordination number of B and O is beneficial to resist Cl- attack. Furthermore, carbon steels were amino-functionalized through a silanol condensation reaction. The electronic localization shifted toward Fe, which was conducive to the formation of hydrogen bonds between amidogen and boron-oxygen complex anions, which increased the boronizing efficiency by tenfold. [Display omitted] • The boronizing mechanism of different configurations of borates was determined. • Chemical adsorption was enhanced by amino modification to intensify boronizing. • The boronizing layer of carbon steel exhibited an exogenous self-healing effect. • After 3 days of self-diffusion boronizing, the anti-corrosion rate reached 93.9 %. [ABSTRACT FROM AUTHOR]

The corrosion behavior of three austenitic stainless steels with basial composition of 20Cr25Ni (R1, SR1 and R1Al) was investigated in supercritical CO 2 at 650℃. R1 was cold-rolled, SR1 was solution-annealed and R1Al was R1 with aluminum addition. The results indicate that solution annealing enhanced the corrosion resistance, reducing weight gain by 37.9% and mitigating preferential corrosion. Adding aluminum to R1 further improved its corrosion resistance, decreasing weight gain by 75.5% and eliminating preferential corrosion. The oxide film structure of R1 is SiO 2 , Mn 2 O 3 , Cr 2 O 3 from the inside out, while that of R1Al is Al 2 O 3 , Cr 2 O 3 , and spinel oxides. • Three high-Cr stainless steels were prepared, showing great corrosion resistance in SC-CO 2. • Solution annealing improved the corrosion resistance of cold rolled stainless steel. • Al addition modifies the structure of oxide film, significantly improving corrosion resistance. [ABSTRACT FROM AUTHOR]

In this work, CTAB-MMT/epoxy coatings (CMC) are prepared by modifying epoxy resin with CTAB-MMT composite through a hydrothermal method. Meanwhile, external electric field generated by the cathode polarization is further stressed on the coatings to enhance their self-healing properties. When the coatings are scratched by external force, the electric field tends to induce the corrosion inhibition group CTA+ to overcome the electrostatic interaction with MMT and detach from MMT, and then the released CTA+ migrates to the carbon steel surface targetedly and quickly to form an adsorption film to inhibit corrosion under the action of electric field. • A new strategy for self healing of coatings induced by electric field was designed. • Electric field was used to enhance the release, migration and action of inhibitor. • Electric field induces CTA+ to be detached from MMT quickly and migrate targetedly. • Electric field enhances orientational action of CTA+ on the area to be corroded. [ABSTRACT FROM AUTHOR]

In this study, the corrosion behavior and corrosion mechanism of titanium-steel composite plate was studied through immersion tests in simulated marine solution. The result shows that the corrosion behavior of titanium-steel composite plate is coordinated by various corrosion behaviors in the near interface area and the far interface area. The corrosion behavior of carbon steel matrix in the far interface area of titanium-steel composite plate in simulated solution is the same as that of carbon steel, because it is far from the interface and is not accelerated by galvanic effect. The corrosion reactions started with localized corrosion induced by inclusions and the diffusion of aggressive ions, and then changed from localized to uniform corrosion. The carbon steel at the interface is accelerated by galvanic effect in the early stage, and the tiny defects at the interface can also be used as the basic point of corrosion initiation. In the later stage, the corrosion at the interface reached a certain level, and the corrosion at the interface turned into the joint action of galvanic corrosion and crevice corrosion. In the whole corrosion process, corrosion is more likely to occur due to stress concentration at the interface. Under the combined action of different corrosion behaviors, the corrosion rate at the interface of titanium-steel composite plate is faster than that at the far interface area. • Elucidate the regional variations in TA2/Q345B composite panel corrosion. • Localized corrosion in distant interface areas results from inclusion dissolution. • Near-interface corrosion is hastened by galvanic corrosion and crevice corrosion. • Interface stress leads to swifter corrosion than distance carbon steel areas. [ABSTRACT FROM AUTHOR]

A quantitative phase-field model has been developed to simulate aqueous corrosion on low carbon steel under chloride-based electrolytes at different pHs. All relevant transport phenomena are included through physically interpretable variables. In particular, both diffusion and migration charge transport are modelled. Separated electrical potentials for the electrolyte and the metal are considered, and physically meaningful boundary conditions are provided. Using this model, different polarization conditions can be predicted and many parameters not observable/challenging during experiments, can be obtained. Finally, since the proposed model includes different time scales, a segregated numerical integration algorithm is proposed to speed up simulations. • Development of a quantitative phase-field model for aqueous corrosion. • Different experimental dynamic processes are captured by the model. • Different details not observable during experiments can be obtained. • Physically meaningful definitions of variables and boundary conditions are implemented. • Reduction of computational cost using fractional step time integration. [ABSTRACT FROM AUTHOR]

Cathodic protection (CP) is a consolidated technique involving the circulation of a cathodic current (i prot) from an anode to a structure. This causes the electrode alkalisation depending on i prot and on the kinetics of the diffusive motion of ions, influencing the surface state of the metal. In this paper, the surface condition of carbon steel under CP has been studied through in-situ Raman spectroscopy and atomic force microscopy (AFM), combined with electrochemical impedance spectroscopy (EIS), for a protection potential (E prot) of − 1.1 V/CSE (Cu/CuSO 4). Results show that depending on alkalisation, Fe 3 O 4 converts to other ferric species like γ-Fe 2 O 3 and α-FeOOH. • Cathodic current modifies thickness and structure of pre-formed Fe passive film. • Excessive alkalisation converts magnetite to maghemite and goethite. • Dissolution-precipitation reactions form a deposit thick ∼ 32 nm. • Cell impedance diminish after the flow of a cathodic current in present conditions. [ABSTRACT FROM AUTHOR]

The microbiologically influenced corrosion (MIC) of X80 carbon steel in sea mud by sulfate reducing bacteria (SRB) was investigated and two unique MIC promotion mechanisms in sea mud were identified. For carbon steel at the seawater-mud interface, difference in the concentrations of sessile cells enhanced galvanic effect between the regions in seawater and sea mud, with the carbon steel in sea mud serving as the anode. SRB in sea mud established significant biofilms on sand grains, enabling the SRB attached on sand grains to participate in the biocatalytic cathodic process of MIC by the contact between sand grains and metal. • Carbon steel suffered more severe SRB-induced microbiologically influenced corrosion in sea mud than in seawater. • The difference in the population of sessile SRB cells on carbon steel give rise to a galvanic effect. • SRB establish biofilms on sand grains and enhance the electrical conductivity of the sandy sea mud. • SRB cells in sand grains biofilms participate in the biocatalytic cathodic process of carbon steel MIC in sea mud. [ABSTRACT FROM AUTHOR]

The in-depth influence mechanism of the functional groups and conjugated structure of aromatic inhibitor on the corrosion protection ability of CaAl layered double hydroxide (CaAl-LDH) in epoxy coatings was investigated by performing the inhibitor modification using three typical aromatic inhibitors. The electrochemistry impedance spectroscopy (EIS) measurement demonstrated that CaAl-LDH-MBT showed superior protection for carbon steel in epoxy coatings. Density functional theory (DFT) calculation and molecular dynamic (MD) simulation indicated that the aromatic conjugated structure with larger π electron clouds and heteroatoms with lone pair electrons would contribute to the enhanced corrosion protection. • Three common aromatic inhibitors were used to modify CaAl-LDH and protection effect was compared. • DFT calculation and molecular dynamics simulation were performed to support experimental result. • The enhanced π electron cloud with conjugation effect and lone pair electrons led to the protection. • LEIS and Raman characterization were performed to investigate the corrosion protection mechanism. • The LDH modified with aromatic inhibitors presented effective corrosion protection in coatings. [ABSTRACT FROM AUTHOR]

An innovative and sustainable sodium alginate-sodium silicate (SASS) inhibitor blend is investigated for carbon steel in a dynamic 3 wt% NaCl environment. Potentiodynamic scans and electrochemical impedance spectroscopy are performed to estimate inhibition efficiency (IE) and inhibition mechanism. Synergistic, highly efficient (up to 99%) blends are obtained due to formation of a structured film and integration of SA throughout the film thickness. Furthermore, the electrochemical behaviour of multiple SA:SS blend ratios is analysed, pointing to the necessity of sufficient SA and SS to form the most protective blend. Based on these findings, a mechanism for the film formation is also proposed. [Display omitted] • Green corrosion inhibitors are a must in future industrial applications. • Alginates and Silicates provide mediocre and good corrosion inhibition, respectively. • Combination of both creates a clear synergy in corrosion inhibition efficiency. • Optimization of the silicate-to-alginate ratio was performed. • A film formation mechanism was proposed for separate inhibitors and blends. [ABSTRACT FROM AUTHOR]

The effect of sulfate reducing bacteria (SRB) and nitrate reducing bacteria (NRB) on under-deposit corrosion (UDC) of carbon steel is studied by weight loss tests, electrochemical measurements and surface analysis. The results show that SRB-induced UDC is significantly inhibited by NRB. This inhibition is attributed to the accumulation of NRB in deposits suppressing the growth of SRB, as revealed by the analysis of total accumulation number of bacteria and the characterization of bacteria-formed micro-holes indicating localized accumulation of bacteria in deposits. The suppressed SRB growth in deposits is discussed based on the NRB-induced biologically competitive exclusion and metabolite inhibition mechanisms. • Effect of coexistence of SRB and NRB on under-deposit corrosion (UDC) is studied. • The inhibition of NRB on SRB-induced UDC is experimentally verified. • The inhibition results from the accumulation of NRB in deposits. • Evidence (micro-hole) of localized bacterial accumulation in deposits is observed. [ABSTRACT FROM AUTHOR]

The synergistic corrosion effect of microorganisms and deposits on carbon steel corrosion was assessed with magnetite and sand. In the presence of the microbial consortium with magnetite, uniform corrosion rates were 3.5 times higher (0.611 mm/year) than the sum of the corrosion rates promoted by the consortium and deposit separately (0.056 and 0.110 mm/year, respectively). Conversely, with sand, uniform corrosion rates were only 1.5 times higher (0.093 mm/year) than the sum of the corrosion rates promoted by the consortium and deposit separately (0.056 and 0.006 mm/year, respectively). The heightened synergistic effect is attributed to magnetite's semi-conductive nature. • Deposits and microorganisms have a synergistic corrosion effect on carbon steel. • Sand and magnetite exacerbate MIC by 1.5 and 3-fold, respectively. • Magnetite leads to a heightened synergistic corrosion effect than sand. • Bacteria enhance 15 times sand-UDC and 5.5 times magnetite-UDC. [ABSTRACT FROM AUTHOR]

In current study, the flow accelerated corrosion behaviors of X65 steel gradual contraction and gradual expansion pipes under high-pressure conditions were comparatively investigated by establishing dynamic in situ electrochemical tests under high CO 2 partial pressure conditions in a loop apparatus. The findings indicate that the corrosion rate is reduced along the flowing direction of gradual contraction pipe. Nevertheless, the corrosion rate firstly descends and subsequently ascends along the flowing direction of gradual expansion pipe, and the lowest corrosion rate is presented in inclination segment close to the straight pipe with large diameter. The corrosion rate at the top wall of gradual contraction pipe is symmetrical to that at the bottom wall, while it is asymmetrically distributed at the top wall and the bottom wall of inclination segment in gradual expansion pipe. The distribution of corrosion rate is correlated with the flow fields at gradual contraction and gradual expansion pipes. Furthermore, the special corrosion rate distribution at inclination segment of gradual expansion pipe is ascribed to the formation of secondary flow and vortexes. • Corrosion rate descends with an enhanced flow velocity along the flowing direction of the gradual contraction pipe. • Corrosion rate at the inclination segment is lower than that at straight pipe of the gradual expansion pipe. • Corrosion rate at top/bottom is symmetrical at gradual contraction pipe and it is asymmetrical at gradual expansion pipe. • The corrosion rate distribution is associated with the hydrodynamics at gradual contraction/expansion pipes. [ABSTRACT FROM AUTHOR]

The microstructure of the hot-rolled and annealed ODS-FeCrAl steels and related oxide scales formed in the oxygen-containing liquid lead at 600 °C was investigated by SEM-EDS, EBSD and TEM. The post-annealing caused partial recrystallization of hot-rolled ODS steel, which significantly reduced the intense θ-fiber (<001>||ND) and local dislocation density. After corrosion, the hot-rolled ODS steels exhibited complex and locally uneven oxide scales while the annealed ODS steels formed a uniform triple-layered oxide scale. A new insight into the relationship between oxidation depth and grain orientation was proposed, highlighting the significance of orientation-dependent dislocations on the transition of external/internal oxidation mechanisms. • The 1100 °C annealing reduces the intense (<001 >||ND) by partial recrystallization. • Fine and randomly oriented grains are formed due to high-density Y 4 Zr 3 O 12 particles. • Orientation-dependent dislocations lead to diversity of oxide scales in local areas. • High-density dislocations promote the formation of the Cr/Al-enriched oxide layer. [ABSTRACT FROM AUTHOR]

Two-type specimens with different microstructure e.g. A70 contains finer-grained ferrite and austenite, while abundant coarse ferrite is obtained in A30. The different response on hydrogen embrittlement behavior results from the fundamental differences of microstructure. The dominant role of hydrogen in A30 lies in its local plastic enhancement influence on coarse ferrite, which is the efficient diffusion path for hydrogen, and that in A70 consists in its decohesion effect on ferrite/austenite interfaces, due to the inherited hydrogen of the fresh martensite at interfaces. This work provides a vital insight for microstructural design to improve hydrogen embrittlement resistance for medium Mn steels. • The initial GBs characteristics play a decisive role in the annealed microstructure. • The 3-dimensional channels regulate the structure-induced hydrogen redistribution. • Hydrogen redistribution controls HE behaviours and types of HE mechanisms. • HE mechanisms, i.e. HELP and HEDE, are clarified at multiscale. [ABSTRACT FROM AUTHOR]

The mutual promotion behavior of pipeline oil sludge and wild SRB on pipeline steel corrosion was investigated. The resistance probe technique was used for long-term monitoring of MIC underneath SRB oil sludge. Corrosion of pipeline steel under oil sludge was the result of multifactorial coupling. SRB biofilm enhanced the conductivity of the oil sludge that serves as an electron transfer "bridge" between the SRB and carbon steel, accelerating the extracellular electron transfer process of MIC, and hence the dissolution of the carbon steel. Delivery of dazomet (DMTT) was a long-term strategy for mitigating pipeline corrosion under SRB oil sludge. • Oil sludge samples were collected in the field and SRB was isolated. • The oil sludge enhanced the SRB-MIC of the X60 steel. • SRB biofilms increased the conductivity of the oil sludge and triggered large localized corrosion pits. • Resistance probe technology was used to monitor the long-term corrosion rate of the X60 steel. • Dazomet (DMTT) was able to inhibit pipeline corrosion underneath SRB oil sludge for a long period of time. [ABSTRACT FROM AUTHOR]

The corrosion behaviour of deep pit-like features on carbon steel under silica sand deposits has been evaluated using a bespoke localised corrosion cell. Local pH and electrochemical measurements were performed, including impedance spectroscopy and galvanic coupling. The corrosion rate of X65 carbon steel at four different recession depths up to 9 mm was evaluated in the presence and absence of a ∼8 mm-thick silica dioxide deposit layer, in a carbon dioxide-saturated environment. The deposit reduced corrosion rates to approximately 1 mm·yr−1 and iron carbonate formed on the steel surface under the deposit due to an increase in local pH. • Bespoke test cell enabled evaluation of under deposit localised corrosion behaviour. • Carbon steel positioned at various recession depths under thick SiO 2 deposit layers. • The deposit reduced corrosion rates significantly and increased near surface pH. • This pH increased facilitated the precipitation of FeCO 3 on the steel surface. • Galvanic measurements confirmed under deposit specimens acted as the net cathodes. [ABSTRACT FROM AUTHOR]

Thermal calcareous scaling has been studied on a simulated heat-exchange carbon steel cylinder set-up in a CaCO 3 -rich CO 2 -saturated solution (SI calcite =2) using in situ electrochemical methods and ex situ surface characterization. Open circuit potentiometry (OCP) and electrochemical impedance spectroscopy (EIS) indicate dramatic increases to the impedance of the electrode over the first two days. The response quickly changes from a single capacitive loop in the early hours to an impedance characterized by a 45° slope at low frequency in Nyquist format, suggesting fast precipitation kinetics towards a protective state. At the end of 14-day tests, SEM and µ-Raman spectroscopy detected a distinctly layered aragonite-calcite scale. The bi-layered precipitate film is proposed to limit the diffusion of cathodic reactants across the porous, permeable scale, resulting in the 45° slope linear tail characteristic of the so-called transmission line response. EIS responses are experimentally re-evaluated away from open circuit, prior to proposing a bespoke equivalent circuit based on De Levie's porous electrode model to link the electrochemical data to surface observations. • Unique heat exchanger electrode set-up employed for electrochemical study in a CaCO 3 scaling solution. • Surface characterization reveals a dual layer calcite-aragonite structure grown at the metal interface. • Detailed EIS assessment indicates significant changes of the electrochemical response as thick and porous scale form. [ABSTRACT FROM AUTHOR]

Carbon steel (CS) was pre-treated in CO 2 -saturated methyldiethanolamine (aq) to form FeCO 3 surface films, the protectiveness of which against corrosion in monoethanolamine was studied using electrochemical impedance spectroscopy, open circuit potential measurements and ex situ surface characterisation. Only pure, dense FeCO 3 films were found to provide protection in lab-scale tests. Dissolved O 2 in pre-treatment solutions resulted in traces of iron (hydr)oxide within the films, exacerbating non-uniform corrosion. Impure films were compromised in pilot-scale experiments in the CO 2 capture plant at Imperial College London. Therefore, pre-treating CS with methyldiethanolamine is not a robust corrosion control strategy for industrial CO 2 capture plants. • Pilot-scale stability tests of protective films formed through pre-treatment were conducted. • Pure FeCO 3 formed by pre-treating carbon steel was protective against corrosion in ethanolamine. • Dissolved O 2 in methyldiethanolamine resulted in iron oxide within the film. • Iron (hydr)oxide in surface films enhanced non-uniform corrosion in ethanolamine. • Pre-treatment with methyldiethanolamine should not be used for corrosion control. [ABSTRACT FROM AUTHOR]

The effects of pre-erosion initial structures on X65 carbon steels exposed to CO 2 corrosion were studied by various surface analysis techniques and electrochemical measurement methods. The results show that at a CO 2 partial pressure of 2.5 MPa, a FeCO 3 layer was formed, while at 0.1 MPa, only the Fe 3 C layer was present. Higher CO 2 partial pressure intensified the corrosion process despite the denser FeCO 3 layer. Among the different impact angles (5°, 30°, and 90°), 30° had the greatest impact on the samples, followed by 90°. The synergistic effect of CO 2 partial pressure and initial structure significantly promoted CO 2 corrosion. • Analysis of pre-erosion initial structures under three impact angles. • Highest CO 2 corrosion rate observed at 30° impact angle. • Formation of Fe 3 C at CO 2 pressure of 0.1 MPa and both Fe 3 C and FeCO 3 at 2.5 MPa. • Inadequate protection from dense corrosion product film at 2.5 MPa. • Synergistic effect of pre-erosion and CO 2 pressure on corrosion. [ABSTRACT FROM AUTHOR]

The corrosion interaction mechanism of carbon steel was studied to address the mutual interference of carbon steels under coating defects in the atmospheric environment. The findings revealed that the electrochemical interactions between the carbon steels were primarily influenced by the solution resistance, cathode area, and cathode-to-anode area ratio. In addition, the upper limit of the accelerating effect of the macrocell current on the anodic corrosion rate was determined by theoretical deduction. Finally, the corrosion-accelerating effect of the macrocell current was determined to assess the corrosion rate of carbon steels with electrochemical interactions under defects. • The variation of macrocell current with electrolyte film thickness was monitored. • i corr of carbon steel was obtained by fitting the potentiodynamic polarization curve. • Solution resistance and area ratio on macrocell current were theoretically analysed. • The mechanism of macrocell current on carbon steel corrosion in the atmosphere was studied. [ABSTRACT FROM AUTHOR]

Methacryloyloxyethyl trimethyl ammonium chloric modified nano-lignin corrosion inhibitor (DMC-NL) is prepared and firstly applied as a novel biomass-derived corrosion inhibitor for carbon steel in HCl solution. Nanosizing and modification processes can enhance its anticorrosion ability, the corrosion inhibition efficiency increases with additive amount and can reach 95.3 ± 0.9% for 15 mg/L. DMC-NL is belonging to the mixed-type corrosion inhibitor and its anti-corrosion ability gradually increases with immersion time. The dense film with two-tier structure forms on metal surface by interactions between N and Fe atoms. This work provides the new insight and opportunity of development of biomass-derived eco-friendly corrosion inhibitor. [Display omitted] • Modified Nano-Lignin effectively inhibited acid-driven corrosion. • A dense protective film formed on metal surface through the interactions between N and Fe atoms. • Providing new insight and broadening application of biomass to prepared eco-friendly corrosion inhibitor. [ABSTRACT FROM AUTHOR]

The stress corrosion cracking mechanism of X80 carbon steel under the combined actions of chloride and bicarbonate ions in alternating wet-dry environment was investigated by performing slow strain rate tensile test and in-situ electrochemical detection during the SCC process under constant load. The results showed that the oxidation and reduction reaction cycle of iron oxide during wet-dry cycle would accelerate the corrosion process. The pitting under the corrosion product layer at high concentrations of chloride and bicarbonate was the origin of SCC under the action of stress concentration, which made steel display high SCC susceptibility. • The interaction of chloride and bicarbonate on corrosion was explored. • In-situ electrochemical testing was used in the SCC process. • SCC mechanism of X80 steel in alternating wet-dry was clarified. [ABSTRACT FROM AUTHOR]

This study utilizes transfer learning (TL) to enhance long-term atmospheric corrosion predictions. Using a Fe/Cu galvanic-type sensor, we gathered data in a controlled SAE J2334 salt spray setting and transferred this to an uncontrolled outdoor environment. Among TL methods tested, freezing the initial layer and fine-tuning others at a lower rate was most effective. The approach excelled at forecasting outdoor corrosion behaviour using a limited dataset. This approach could provide a solution to extrapolate results from controlled corrosion tests to unpredictable outdoor conditions and addressing data scarcity in machine learning modelling in the context of atmospheric corrosion. • TL to extrapolate SAE J2334 data to outdoor settings using Fe/Cu ACM corrosion sensor. • Performance assessed by accuracy in predicting split I ACM intervals. • Optimal TL: freeze initial layer; fine-tune at 1 × 10−5 learning rate. • TL superior to benchmark models in cases of scarce outdoor training data. • TL model excels in detecting I ACM peaks vs. base model for a 1-week outdoor training data case study. [ABSTRACT FROM AUTHOR]

In situ Synchrotron Radiation X-ray Diffraction (SR-XRD) is employed to follow the evolution of corrosion products on X65 carbon steel in a CO 2 -containing aqueous environment (80 °C, pH 6.3–7.3). A custom-designed flow cell is used to follow the real-time concomitant changes in electrochemical behaviour and corrosion product growth during stages of both natural and potentiodynamically driven 'pseudo-passivation'. We show that no detectable crystalline magnetite (Fe 3 O 4) phase forms during 'pseudo-passivation' across all conditions studied. Furthermore, the results suggest the significant ennoblement observed during 'pseudo-passivation' in these experiments can be strongly related to the accumulation of iron carbonate (FeCO 3) on the steel surface. • Surface layers play a key role in pseudo-passivation of carbon steel. • Synchrotron radiation XRD employed in-situ with electrochemical techniques. • Investigation at 80 °C, in pH range from 6.3 to 7.3 in CO 2 environments. • Pseudo-passivation strongly linked to wide coverage of X65 steel by iron carbonate. • Magnetite (Fe 3 O 4) was not detected by SR-XRD under these conditions. [ABSTRACT FROM AUTHOR]

• Corrosion of type 310S under cathodic polarization in chloride/bromide melt is studied. • Cathodic protection is effective to decrease the corrosion rate of type 310S. • The thickness of chromium depletion layer decreased by lowering the protection potential. Corrosion behaviour of type 310S stainless steel (310S) was investigated under cathodic polarisation in a chloride–bromide melt at 923 K to confirm the feasibility of cathodic protection. Potentiostatic cathodic polarisation was carried out at different potentials for 48–144 h. Mass loss after 48 h of corrosion was 1.32 mg·cm−2 without cathodic protection. This mass loss can be reduced by one order of magnitude on cathodic polarisation of 0.86 V. On this extent of cathodic polarisation, Cr-dissolution was largely suppressed. For carbon steel, a similar reduction in mass loss was observed just by 0.35 V of cathodic polarisation. [ABSTRACT FROM AUTHOR]

• The general corrosion rate decreased from 3.19 to 0.38 mm/year as temperature increased from 90 °C to 250 °C. • At 200 °C, both general and localised corrosion rates increased as increasing in CO 2 partial pressure. • Increasing temperature can promote Fe 3 O 4 formation, same for reducing CO 2 partial pressure. • The low corrosion rate at high temperature was attributed to the thin Fe 3 O 4 layer. • The thickness of the thin Fe 3 O 4 layer is 200 nm and covered the entire surface. This study investigates the corrosion performance of X65 carbon steel at elevated temperatures (up to 250 °C) and CO 2 partial pressures (up to 28.5 bar pCO 2). A detailed appraisal of how the corrosion products can protect against general and localised corrosion is presented. The morphology and chemical composition of corrosion products were determined using various microscopic and spectroscopic techniques, with localised corrosion rates being determined by surface profilometry. An increase in temperature or reduction in CO 2 partial pressure favours the formation of a protective magnetite layer. It is thermodynamically more stable and more protective than iron carbonate in these conditions. [ABSTRACT FROM AUTHOR]

• Localized corrosion was initiated at the pearlite colony boundaries and prior austenite grain boundaries in AISI 1045 steels. • Phosphorus segregation was detected at these boundaries. • The localized corrosion resistance at these boundaries was improved by an intercritical heat-treatment. The localized corrosion resistance at the microstructural boundaries of AISI 1045 carbon steels was accessed. Under KFM measurements, regions with low corrosion potentials were found at the pearlite colony boundary in the ferrite-pearlite structure and the prior austenite grain boundary in the martensite structure, and phosphorus was segregated in these regions. The localized corrosion resistance at these boundaries was improved via intercritical heat-treatment at 1023 K (the two-phase region of austenite and ferrite) after austenitizing, which may be attributable to the apparently homogenous dissolution of ferrite forming elements, such as phosphorus, in the ferrite phase during the treatment. [ABSTRACT FROM AUTHOR]

• More Fe2+ leads to better planktonic and sessile Desulfovibrio vulgaris growth. • More Fe2+ increases dissolved H 2 S concentration despite increased FeS precipitation. • More Fe2+ in the culture medium increases carbon steel weight loss and pit depth. • With more Fe2+, increased corrosion is primarily attributed to more sessile cells. • Electrochemical measurements corroborate weight loss and pit depth data. Ferrous ion (Fe2+) in a sulfate reducing bacteria (SRB) culture medium is known to enhance microbiologically influenced corrosion (MIC) of carbon steel, but the underlining mechanism is controversial. This work showed that it was due to better sessile cell growth that was likely attributed to Fe2+ detoxification of H 2 S. Two hundred ppm (w/w) initial Fe2+ in the ATCC 1249 medium achieved a 4.7 times higher Desulfovibrio vulgaris sessile cell count and 5.0 times higher C1018 carbon steel weight loss, compared to 20 ppm. Linear polarization resistance, electrochemical impedance spectroscopy and potentiodynamic polarization measurements corroborated weight loss and pitting data trends. [ABSTRACT FROM AUTHOR]

• Increasing exposure in air produced more hydroxylated native oxide films on steel. • The passive film became increasingly more protective with age of native oxide film. • The passive films consist of a inner Fe(II)-rich layer and an outer FeOOH layer. • A kinetic model was reasonably optimized on the experimental impedance spectra. Electrochemical impedance spectroscopy (EIS), open circuit potential (E oc) measurements and angle-resolved X-ray photoelectron spectroscopy (AR-XPS) were used to investigate the effect of exposure in air on the passivation of carbon steel electrodes in a neutral aerated glutarate solution. The electrochemical measurements showed that for native oxide films aged between 4 h and 120 h the passive films became increasingly more protective. Analysis of the XPS revealed a bilayer structure of the passive film (inner Fe(II)-rich, outer Fe oxyhydroxide), with increasing values of the Fe(III)/Fe(II) intensity ratio, and gave evidence that passivation was favored by progressively hydroxylated native oxide films. [ABSTRACT FROM AUTHOR]

• Zn2+ was effective as both a scale and a corrosion inhibitor in artificial seawater. • Zn2+ inhibits the CaCO 3 precipitation via a coprecipitation mechanism. • Zn2+ inhibits the corrosion of carbon steel via the adsorption at cathodic sites. • The CaCO 3 scaling decreased the corrosion inhibition performance of Zn2+. In this paper, the inhibition mechanism of Zn2+ in trace concentration on both the CaCO 3 precipitation and corrosion of carbon steel in artificial seawater was investigated using various electrochemical and surface analysis methods. The results showed that zinc ions affect both the nucleation and growth stages of CaCO 3 crystallization and the best scale inhibition was achieved at 4 ppm concentration. The corrosion inhibition mechanism of Zn2+ was developed by blocking the cathodic sites on the carbon steel surface. Moreover, addition of 6 ppm zinc ions both before and after the scale deposition significantly diminishes carbon steel corrosion. [ABSTRACT FROM AUTHOR]

Brønsted acid ionic liquids (BAILs) can act as effective corrosion inhibitors, and their inhibition efficiency increases with alkyl tail length. According to the molecular orbital theory, the frontier molecular orbitals of ionic liquids will interact with the Fe surface via cycling electron donation/back-donation mode. i.e., -SO 3 H group, donates electrons to vacant d-orbitals of Fe atoms; Imidazolium ring with π-electrons accepts electrons from the Fe orbital during back-donation. The longer alkyl tail with decreased hydrophilicity can displace water molecules more effectively from the steel surface to narrow the distance between ionic liquids and the steel surface, which makes better coverage for ionic liquids adsorbing on the steel surface, finally leads to higher corrosion inhibition. • Both of the BAILs act as mixed-type inhibitors, i.e., suppress both the anodic and cathodic processes. • The weak hydrophilicity of the BAIL with longer alkyl tail leads to higher inhibition efficiency. • Frontier orbitals of BAILs interacted with the Fe surface via cycling adsorption by electron donation/back-donation. • The BAIL cations oriented with the steel surface in a relative parallel mode for good inhibition with high coverage. This study investigated corrosion inhibition of task-specific ionic liquids, 1-(4-sulfonic acid) butyl-3-ethyl imidazolium hydrogen sulfate and 1-(4-sulfonic acid) butyl-3-decyl imidazolium hydrogen sulfate, for carbon steel in 0.5 M HCl by electrochemical tests, SEM, UV–vis, XPS, contact angle measurements, molecular orbital theory, and MD simulations. The inhibition efficiency of both ionic liquids increased with concentration, and the latter one shows higher inhibition efficiency of 97.9% due to the weaker hydrophilicity caused by increased alkyl tail. The mechanism of inhibition was found to be through adsorption onto the steel surface with cycling donation and back-donation of electrons. [ABSTRACT FROM AUTHOR]

• Identification of the self-catalytic characteristics in the pitting cavity. • Discovery of high chloride and no oxygen in the pitting cavity. • Exploration of core-shell chemical and structural distribution in pitting corrosion. • Revelation of the porous core being rich in chloride and the shell being rich in oxygen in pitting corrosion. • Insight into the pitting microstructures with a ferric chloride core and an iron oxide shell. Carbon steel experiences serious pitting corrosion in the atmospheres containing chloride ions. The present research is focused on revealing a three-dimensional chemical and microstructural insight into pitting corrosion with high spatial resolution nano-tomography by addressing 1018 carbon steel after exposed in the marine atmosphere. A well-defined core-shell structure for pitting corrosion products was revealed by using a combination of dual-beam focused ion beam system with scanning electron microscope (FIB/SEM) and high-resolution transmission electron microscope (HRTEM). The core is made of ferric chloride and the shell is constituted with iron oxides. Pitting corrosion is a self-catalytic process and the corrosion products grow to be porous flower-type structures. The porosity in the core provides a diffusion path for the ions. Inclusions promote pitting corrosion growth. [ABSTRACT FROM AUTHOR]

• Carbon steel was corroded in contact with anoxic clay at 90 °C. • Corrosion damage equaled 8.5 and 29.5 μm at 7 and 76 months, respectively. • Heterogeneous corrosion with Fe silicate, ankerite or akaganeite at 7 months. • Comparable interfaces contain Fe silicate, chukanovite, sulfide for 15–76 months. • Long-term generalized corrosion approximated by a linear law. Rods of low alloy carbon steel were corroded under anoxic conditions in compact clay at 90 °C. Gravimetrically-assessed corrosion damage equalled 8.5 μm at 7 months, then slowly increased to 29.5 μm at 76 months. The corrosion damage was heterogeneous at 7 months, and two distinct aspects coexisted: steel was replaced by (Fe,Si,O) corrosion products in some areas, and by Si-poor hydroxide and covered by akaganeite (FeO(OH,Cl)) in others, indicating corrosion in suboxic conditions. A magnetite fringe contacted the steel surface. For greater reaction times, akaganeite disappeared, and only (Fe,Si,O) corrosion products containing Fe sulfide and chukanovite were detected. [ABSTRACT FROM AUTHOR]

Highlights • Phytic acid doped polyaniline nanofibers were prepared in water solution. • The specific area of phytic acid doped polyaniline nanofibersis 69.4 m2 g−1. • The inhibitor load rate of phytic acid doped polyaniline nanofibers is 10.3%. • Phytic acid doped polyaniline and benzotriazole has a synergistic effect. Abstract Corrosion protection of epoxy coatings containing phytic acid doped polyaniline nanofibers(PANI–PA–NFs) loaded with benzotriazole (PANI-PA-NFs/BTA) for Q235 carbon steel was studied in this work. Synthesized PANI–PA–NFs and the coating performances were characterized in detail. The specific area and inhibitor load rate of the prepared PANI-PA-NFs are 69.4 m2 g−1 and 10.3%, respectively. Epoxy coating containing 2 wt. % PANI-PA-NFs/BTA shows the best protection ability and self-healing function. The self-healing function of epoxy coating containing PANI-PA-NFs/BTA is attributed to the synergistic effect between PANI-PA and BTA. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Interlinked chitosan-ZnO (CZNC-10) nanocomposite inhibited the biocorrosion of SRB on carbon steel. • CZNC-10 co-formed protective film on carbon steel to prevent bacterial attack during initial days of incubation. • CZNC-10 inhibitor caused damage to SRB cells and significant reduction of corrosion products. • Charge transfer resistance (R ct) increased 3.2 times than the control after 21 days of incubation in presence of CZNC-10. Abstract In this report, interlinked chitosan-ZnO nanocomposite at 10% ZnO (CZNC-10) is successfully used as green biocide for biofilm control and reduction of biocorrosion on carbon steel material. It was found that 250 μg/mL CZNC-10 can be used efficiently for the inhibition of sulfate reducing bacteria (SRB) biofilm on carbon steel. The R ct values after 21 and 28 days of incubation in presence of CZNC-10 are almost 3.2 and 2.8 times higher than the control respectively, indicating a strong corrosion inhibition with 74% as maximum inhibition efficiency. [ABSTRACT FROM AUTHOR]

Highlights • Thalassospira sp. is isolated and identified as one of facultative iron-reducing bacteria. • The effects of Thalassospira sp. on corrosion behavior of Q235 carbon steel in air-saturated seawater is investigated. • The presence of Thalassospira sp. promotes corrosion of Q235 carbon steel. • The heterogeneous adhesion of Thalassospira sp. biofilm provides an advantage for pitting corrosion of Q235 carbon steel. Abstract Thalassospira sp. is an iron-reducing bacterium isolated from the marine environment. Effects of T. sp. on corrosion behaviors of Q235 carbon steel in air-saturated seawater were studied. Results of electrochemical measurements and weight loss indicated that the presence of T. sp. promotes Q235 carbon steel corrosion. Surface analyses results showed that heterogeneous adhesion is a typical character for T. sp. biofilm on surface of Q235 carbon steel, and pitting corrosion is induced. The corrosion mechanism model of Q235 carbon steel in air-saturated seawater containing T. sp. is proposed through surface micromorphology analyses, composition determination and current distribution. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Electrolyte obtained from cement paste submitted to leaching. • Corrosion current density values below 0.1 μA/cm² in less than 24 h. • Similar steel passivation in Portland and Belite-Ye'elimite-Ferrite pore solutions. Abstract The quest for low-CO 2 emission alternatives to Portland cement is pushing the cement industry to develop new types of binders. Besides the need of equivalent mechanical properties, a major issue concerns the passivating ability of these new materials. Belite-Ye'elimite-Ferrite binders (BYF) are attracting increasing interest of cement developers, but there are still doubts about their intrinsic protectiveness. Carbon steel passivation in BYF leachates was studied and compared to OPC leachates through electrochemical techniques and X-ray photoelectron spectroscopy. In both media, steel was highly passivated in less than 24 h, protected by a ca 5 nm thickness film. [ABSTRACT FROM AUTHOR]