Corrosion Problems Research Articles

Photoelectrocatalytic Reduction of CO2 to CO via Cu2O/C/PTFE Nanowires Photocathodes

AbstractThe consumption of fossil fuels releases large amounts of carbon dioxide (CO2) in the atmosphere, causing a serious greenhouse effect. Photoelectrochemical (PEC) reduction of CO2 to chemical fuels is an effective way to alleviate the current energy and environmental crisis. However, it is still difficult to rationally design efficient PEC CO2 reduction photocathodes. Cuprous oxide (Cu2O) is a promising photocathode material, but its surface is susceptible to the accumulation of photogenerated electrons leading to corrosion and activity reduction, and is accompanied by hydrogen evolution reaction (HER), both of which lead to the overall low conversion efficiency of CO2 reduction by Cu2O. In this study, the PEC CO2 conversion efficiency was improved by the synergistic effect of the C electron transport layer to accelerate the electron transfer to alleviate the Cu2O corrosion problem and the polytetrafluoroethylene (PTFE) hydrophobic layer to inhibit the HER. The test showed that the CO yield of Cu2O/C/PTFE at the optimum potential (−0.7 V vs. RHE) was 54.6 μmol cm−2 h−1, which was 3.2 times higher than that of pure Cu2O. This study provides a facile strategy for constructing an efficient photocathode with great potential for CO2 reduction.

Exploring molecular composition of upgraded pyrolysis bio-oil using GC×GC-(EI/PI)-TOF MS with different column set-ups

Bio-oils produced from the pyrolysis of lignocellulosic biomass are rich in oxygen, which causes instability and corrosion problems. Therefore, dedicated post-pyrolysis treatments such as hydrotreatment are required to increase the H/C ratio of the products to be used as fuel or chemicals. Here, a characterization method based on two-dimensional gas chromatography (GC×GC) was developed to highlight the evolution of the volatile fraction during hydrotreatment. Six samples obtained at different times of the hydrotreatment were analyzed. In this way, information on catalyst deactivation was obtained. The combination of information from normal and reversed phase GC×GC analysis provides a detailed characterization of the hydrotreated bio-oils. Furthermore, the use of soft photoionization (PI), in addition to conventional electron impact ionization (EI), yields a better understanding of the compound structures present in the sample. Identification and semi-quantification of the sample components indicate that the concentration of paraffins, cycloalkanes, and monoaromatics have largely decreased during hydrotreatment, while the concentration of oxygenated species and polycyclic aromatic hydrocarbons have increased. Using complementary GC methods highlights changes in the molecular composition of volatile species that correlate with catalyst performance. This approach can be used to follow the decrease in hydrodeoxygenation activity as a function of time on stream to estimate the catalyst aging during the hydrotreating process.

Historical defects in buildings – No. 6: Regent Street disease

In this note, Hugh Docherty highlights the problem of corrosion of structural steelwork behind masonry elevations in buildings dating from the first half of the 1900s.

ЗАХИСТ ВІД КОРОЗІЇ НАФТОПЕРЕРОБНОГО ОБЛАДНАННЯ ЗА ДОПОМОГОЮ ІНГІБІТОРІВ З ВІДНОВЛЮВАЛЬНОЇ СИРОВИНИ.ОГЛЯД

The article provides information about corrosion problems in the oil refining industry and the scale of losses associated with it. The causes of corrosion associated with the presence of sulfur compounds, hydrochloric acid and chlorides, naphthenic acids, etc. in oil are described. A set of methods aimed at reducing the corrosion effect of these components is given. The use of inhibitors is one of the most effective and widespread such methods. The use of corrosion inhibitors from renewable raw materials is becoming more and more popular. The article provides an overview of literary sources related to the study of “green” corrosion inhibitors.

Preparation of efficient hydrochloric acid corrosion inhibitor from natural grease

Abstract To alleviate the metal corrosion problem caused by incomplete acid discharge during pickling or acidification, a corrosion inhibitor, long chain fatty hydrazides (LCFH), with a significant corrosion inhibition effect was synthesized from natural grease. The corrosion inhibition and adsorption properties of LCFH on carbon steel in 1 M HCl solution were studied by static sample weight loss test, electrochemical impedance spectroscopy, and potentiodynamic polarization curve. The results showed that LCFH exhibits excellent corrosion inhibition performance in HCl solution. The inhibition efficiency increases with the increase of inhibitor concentration. When the concentration of LCFH is 40 mg/L, the inhibition efficiency can reach 97.9%. The potentiodynamic polarization curve shows that LCFH is a corrosion inhibitor that mainly inhibits the cathodic reaction. The corrosion inhibitor is spontaneously adsorbed on the surface of low-carbon steel in physical form, which conforms to the Langmuir isothermal adsorption model.

Bond performance between ribbed BFRP bar and seawater sea-sand concrete: Influences of rib geometry

To solve the corrosion problems of steel bars in reinforced seawater sea-sand concrete (SSC) structures, fibre reinforced polymer (FRP) bars are promising alternatives. The bond between FRP bars and SSC determines the capacity and serviceability limit states of structures composed by them. The rib geometry of FRP bars is one of the most important factors influencing their bond performances with concrete. However, it has not received sufficient attentions on existing studies and standards. Therefore, this study investigated the bond performance between SSC and ribbed basalt FRP bars with different rib geometry through pull-out tests on 36 specimens. It is found that the bond strength declined with the increase of rib width and dent width, while the increase of rib height improved the bond strength. The ultimate and residual slip were strongly correlated with the rib spacing. Finally, a bond strength model that can well predict the experimental results was proposed.

Corrosion maps: Stability and composition diagrams for corrosion problems in CO2 transport

We present a Pourbaix-like graphical approach to assess the corrosive nature of impure CO2 streams for carbon capture and storage purposes. The effects of critical N- and S-containing impurities is evaluated. The model behind the approach assumes that chemical equilibrium is established, with some kinetic effects accommodated. The input is the composition of the stream (total quantity of S, N, H and O) and the output is the equilibrium composition (speciation). Comparison with experimental data shows that the content of acids in the CO2 stream upon reaching chemical equilibrium is a strong indicator of the corrosiveness of a given mixture.

Perancangan Proteksi Katodik pada Tangki Olein Kapasitas 450 KL dengan Metode SACP

Cathodic protection is needed as corrosion mitigation in oil tanks on land to minimize internal and external corrosion. Corrosion problems that often arise in tanks are corrosion on the shell, roof and bottom. In this research, a corrosion protection system was designed for an olein storage tank with a capacity of 450 kL for one of the palm oil ship industries located in Kalimantan. The corrosion protection used is SACP (Sacrificial Anode Cathodic Protection) where active anodes are used to protect metal surfaces which are more passive against corrosion attacks. To provide good corrosion protection, sufficient current, number of anodes and correct placement are required. From the calculation results it was found that for the shell, the current required is 0.0102446 A with a total of 46 anodes and the placement of each anode is 5.36 m. For the same bottom and roof, each requires a current of 0.0103869 A with 7 anodes and a distance within a radius of 6.74 m.

Synergistic mixture of Camellia Oleifera shell extract and KI as an eco-friendly and highly efficient composite inhibitor for steel corrosion in H2SO4 media

To address the severe corrosion problems faced by steel, a natural corrosion inhibitor derived from Camellia Oleifera shell extract (COSE) was developed. The effectiveness of COSE as well as its synergistic mixture of COSE/KI in inhibiting the corrosion of steel in H2SO4 was investigated using weightlessness and electrochemical techniques. The results show that the maximum inhibition efficiency of individual COSE is 77.28 % at 20 °C, and is increased to 93.08 % for the mixture of COSE/KI. The adsorption of COSE, KI and COSE/KI on steel surface conform to Langmuir adsorption isotherm. COSE/KI has a stronger adsorption than either COSE or KI. Electrochemical analysis indicates that COSE/KI is a hybrid inhibitor primarily focusing on the cathodic inhibition. Mixing COSE with KI shows considerably larger charge transfer resistance and smaller double-layer capacitance than individual COSE and KI. Characterization tests such as metallurgical microscopy, SEM, AFM and contact angle confirm that the addition of COSE/KI could reduce the roughness of steel surface, while increase the hydrophobicity, then effectively alleviate the corrosion on the steel surface. XPS analyses demonstrated that the corrosion inhibition layer on the steel surface was induced by the adsorption of the polar groups in COSE. The components responsible for COSE’s effectiveness were thoroughly examined using FTIR and liquid chromatography-mass spectrometry (LC-MS), which identified the presence of compounds such as flavonoids and phenylpropanoids. The synergistic effect of the active ingredients (rutin, quercetin, tea saponin, tea polyphenols, et al.) with KI was also confirmed. Finally, theoretical calculations were conducted to analyze properties of rutin, quercetin and tea polyphenols on the iron layer. The results show all these molecules exhibit efficient inhibition, with quercetin showing better inhibitive ability by parallel adsorption.

SELECTION OF AN EFFICIENT TRANSPORTATION PROCESS OF VERY HIGH VISCOSITY AND HEAVY OILS AND INVESTIGATION OF RESULTING COMPLICATIONS

The article discusses the investigation of the difficulties that arise during the transportation of very high viscosity crude oils and the features of the transportation process. Among high-viscosity oils in Azerbaijan, "Muradkhanli" oil can be mentioned. Special attention is paid to the rheologically complex behavior processes of such crude oils. In general, the storage and transportation of very high viscosity oils has been and remains a complex process for oil producing countries around the world. Heavy and highly viscous crudes are thick and sludgy, so they resist flow through pipelines during transport and are often transported by truck or rail, adding significant costs and potential hazards. Pipeline transportation of oils is also hampered by asphaltene and paraffin precipitation, formation water and salt content, and corrosion problems. Of course, each of these cases should be taken into account. There are various ways to improve this process (by heating, by adding depressants with different reagent composition, etc.). Keywords: high viscosity, heavy crude oil, depressant, railway-transportation, oil crystallization.

Corrosion Behavior of Nacre-Inspired (TiBw-TiB2)/Al Composites Fabricated by Freeze Casting.

Nacre-inspired metal matrix composites have received much attention due to their excellent deformation coordination ability, which can achieve the synergy of strength and ductility. The preparation of nacre-like Al matrix composites by freeze casting has been a promising application, but the continuous ceramic-rich layer affects the corrosion resistance of the composites, facing complex corrosion problems during service. In this work, the microstructure and corrosion behavior of the nacre-inspired (TiBw-TiB2)/Al composites fabricated by freeze casting and squeeze casting were systematically studied. The results indicated that the Al layers and ceramic-rich layers had little change, about 35 μm and 31 μm, respectively, with an increasing ratio of the Ti/TiB2. Meanwhile, a high Ti/TiB2 ratio resulted in an increase in the Fe-Ti intermetallic phases, which was detrimental to the corrosion performance of the composites and was prone to pitting. The electrochemical test results showed that the 3Ti7TiB2 composite had the lowest corrosion current density (15.9 μA) and intergranular corrosion depth (231 μm), indicating that it had the best corrosion resistance, which can be attributable to its stable and dense passivation film. Two different corrosion phenomena during the intergranular corrosion test existed in the present nacre-inspired (TiBw-TiB2)/Al composites: intergranular corrosion in the Al matrix layer and pitting corrosion in the ceramic-rich layer. Among all the composites, the corrosion depth of the 3Ti7TiB2 composite was the smallest and significantly less than that of the 2024Al alloy. In addition, the continuous ceramic-rich layer acted as a corrosion channel during corrosion, significantly degrading the corrosion resistance of the nacre-like Al composites.

Синтез производных класса 2-алкил-5-фенил-4,5,6,7- тетрагидро-[1,2,4]триазоло[1,5-a]пиримидин-7-ола

The problem of acid corrosion of steel is of significant importance, particularly in the context of the oil extraction industry, where acid treatment of wells and surrounding spaces is widely employed. This research article focuses on the synthesis and investigation of previously unstudied derivatives of the class of 2-alkyl-5-phenyl-4,5,6,7-tetrahydro-[1,2,4]triazolo[1,5-a]pyrimidin-7-ols – organic compounds potentially highly effective as inhibitors of acid corrosion of steel. The method for synthesizing the proposed compounds involves the condensation of 3-alkyl-5-amino-1H-1,2,4-triazoles with cinnamaldehyde. The structure of the synthesized compounds has been confirmed using 1H NMR and LCMS methods. The study has revealed that the developed synthesis conditions yield the target tetrahydrotriazolopyrimidinols with alkyl substituents containing up to three carbon atoms. However, an increase in the length of alkyl substituents intensifies side reactions, making the isolation of the target compounds challenging. The obtained research results are significant for the development of effective organic inhibitors of acid corrosion of steel of a new class. These findings can serve as a basis for further research in this area, contributing to the development of new methods for corrosion prevention and improving the resistance of materials used in the oil industry. Thus, this study not only describes a new synthetic approach to obtaining inhibitors of corrosion in the tetrahydrotriazolopyrimidinol class but also holds prospective practical value in the field of industrial technologies and materials science.

Long-term properties evolution and life prediction of glass fiber reinforced thermoplastic bending bars exposed in concrete alkaline environment

Glass fiber reinforced polypropylene (GFRPP) bending bars have many advantages, such as high toughness, high durability, repeated molding and recycling, which can be used in concrete structures to replace steel stirrup for solving the problems of corrosion and service life. However, the changes in the properties of GFRPP bending bars during long-term use in alkaline concrete environments require further investigation. In the present study, GFRPP bending bars were immersed in alkaline solution at 20 °C, 40 °C, and 60 °C for as long as 180 d. The water absorption, hydrolysis, mechanical properties, and microscopic properties of the bending bars were evaluated to understand the long-term performance and mechanism of degradation. The bending bars had a higher saturated water absorption percentage and time along with a lower diffusion rate than the straight bars due to the presence of pores and micro-cracks formed during the bending process. The dissolution of the glass fibers in alkaline solution led to the partial mass loss of the GFRPP bars. Compared to the control, the tensile strength retention of the bending bars was 20.6%–56.0 %. The tensile failure mode changed from fiber bursting before immersion to shear fracture after immersion due to the decreased interfacial bonding strength and increased glass fiber brittleness. The primary degradation mechanisms were the etching of glass fibers, interface debonding, and increased void volume (∼23.7 %). The bending bars were more seriously eroded than the straight bars due to the twisting of the fibers and imperfect interfaces. The predicted degradation times of the GFRPP bending bars ranged from 1.7 years (Haikou) to 3.9 years (Harbin), corresponding to a stable tensile strength retention of 22.13 %. The results provide a basis for evaluating the durability and service life of GFRPP bending bars and promote the application of GFRPP composite stirrups in concrete structures.

Small Molecule Oxidation Facilitated Seawater Splitting for Hydrogen Production: Opportunities and Challenges

Direct seawater splitting is an environment‐friendly and promising technology to replace freshwater electrolysis for hydrogen production. The challenge of seawater electrolysis lies in the competition between chloride oxidation reaction (CER) and oxygen evolution reaction (OER), as well as electrode corrosion and poisoning caused by chloride. Some small molecules have lower anodic electrocatalytic oxidation potentials compared to OER and CER, making them possible to substitute OER and/or CER in coupled electrolyzers not only to eliminate the electrode corrosion problem but also to significantly enhance the energy efficiency of seawater electrolysis. This article reviews the progress of such small molecule oxidation facilitated seawater electrolyzer. Starting with an overview of the key challenges in seawater electrolysis, this review introduces the fundamentals and advantages of the coupled seawater electrolyzers and discusses the strategies for anodic small molecule oxidation and cathodic hydrogen evolution reaction, including utilizing Cl‐ as a reactive medium, value‐added chemical synthesis, pollutants electrooxidation, and optimizing electrolyzers. Finally, the challenges and prospects of small molecule oxidation facilitated seawater splitting are summarized, aiming to provide impetus for research and development on coupled seawater electrolysis technologies.

In-situ constructed interface buffer layer enabled highly reversible Zn Deposition/Stripping for long-lifespan aqueous zinc metal anodes

Despite the advantages of high capacity, high safety and low cost, zinc anodes also face the inherent problems of dendritic growth, corrosion and passivation, vastly limiting the development and application of aqueous zinc ion batteries (AZIBs). Here, the epigallocatechin gallate (EGCG) was used as a hydroxyl-rich natural electrolyte additive for AZIBs. During charge–discharge process, the EGCG can be preferentially adsorbed on the zinc anode, and act as an interface buffer layer to weaken the direct contact between active water molecule and zinc anode. Based on this effect, the interface buffer layer is helped to inhibit the water-induced side reactions of hydrogen evolution, zinc corrosion and passivation, and lower the polarization overpotential, contributing to highly reversible Zn deposition/stripping behavior. As a result, the Zn||Zn symmetric batteries can maintain a stable cycling for more than 1500 h at 1.0 mA cm−2 and 1.0 mAh cm−2. Furthermore, the assembled Zn||MnO2 full batteries still delivered high capacity retention of 98.02 % after 400 cycles at 1.0 A/g. This finding enriches the design thoughts for the development of high-efficiency and practical AZIBs.

Mn-doped nickel-copper phosphides as oxygen evolution reaction electrocatalyst in alkaline seawater solution

Compared with traditional water electrolysis, electrolysis of seawater has larger resources and a brighter future. However, seawater contains more elements that have greater corrosive effects on electrodes; especially chloride ions (seawater contains more chloride ions) have the greatest impact. The existence of the corrosion problem creates greater difficulties in electrolyzing seawater, further limiting the efficiency of the electrocatalyst for electrolysis of seawater. In this paper, we report a Mn-doped Ni2P/Cu3P as an environmentally friendly monofunctional electrode for seawater electrolysis, which was made by a simple hydrothermal phosphatization operation method. The experimental results show that Mn-doped Ni2P/Cu3P presents overpotential of only 161 mV for oxygen evolution reaction (OER) at iR compensation of 90 and a current density of 10 mA cm−2. It has a small Tafel slope (25.15 mV dec−1) and a large capacitance (9.58 mF cm−2 on 1 × 1 nickel foam), which exceeds most reported oxygen evolution activities of non-precious metal-based electrocatalysts for electrolysis of alkaline seawater. The performance of Ni2P/Cu3P was probably significantly enhanced due to Mn doping by some characterization means. Through Density functional theory (DFT) analysis, it is known that the doping of Mn gives a large enhancement in the adsorption energy of water when Ni2P/Cu3P is electrolyzed with seawater. This paper provides train of thought for the exploration of excellent electrocatalysts for electrolysis of alkaline seawater.

Applications of graphene in organic anticorrosive coatings

The problem of corrosion of materials has lasted for a long time, corrosion causes damage to the structure of buildings and bringing loss of economy. The coating method, which is an easy and economical way to solve the problem, is still unable to satisfy the needs limited by the paints properties. However, this can be solved by introducing graphene, by its special 2-D material properties, to the paint. And a lot of researchers are working on this now. This paper mainly focuses on the overview of how graphene be applied to anti-corrosive coatings, the problems that are faced, what are solutions for those, and what are the advantages that graphene has in the area. Resulting that graphene is mainly used with organic anti-corrosion materials, by filling the holes in those materials to stop the corrosion molecules from infiltrating through. Graphene can also be used as containers, carrying corrosion inhibitors that would be released and fill the crack when the coating is damaged. By modifying graphene, problems like agglomeration and accelerating corrosion can be solved. The result will be used for researchers who are looking for a conclusion in the graphene anti-corrosive coatings research area and provide the main focuses and details.

Air Corrosion of Layered Cathode Materials for Sodium-Ion Batteries: Cation Mixing and a Practical Suppression Strategy.

Layered oxide cathodes of sodium-ion batteries (SIBs) are considered promising candidates due to their fascinating high capacity, good cyclability, and environmental friendliness. However, the air sensitivity of layered SIB cathodes causes high electrode manufacturing costs and performance deterioration, hampering their practical application. Herein, a commercial O3-type layered Na(Ni1/3Fe1/3Mn1/3)O2 (NNFM) material is adopted to investigate the air corrosive problem and the suppression strategy. We reveal that once the layered material comes in contact with ambient air, cations migrate from transition metal (TM) layers to sodium layers at the near surface, although Na+ and TM ions show quite different ion radii. Experimental results and theoretical calculations show that more Ni/Na disorder occurs in the air-exposed O3-NNFM materials, owing to a lower Ni migration energy barrier. The cation mixing results in detrimental structural distortion, along with the formation of residual alkali species on the surface, leading to high impedance for Na+ diffusion during charge/discharge. To tackle this problem, an ultrathin and uniform hydrophobic molecular layer of perfluorodecyl trimethoxysilane is assembled on the O3-NNFM surface, which significantly suppresses unfavorable chemistry and structure degradation during air storage. The in-depth understanding of the structural degradation mechanism and suppression strategy presented in this work can facilitate high-energy cathode manufacturing from the perspective of future practical implementation and commercialization.

Selection of Crosslinking Agents for Acrylic Resin Used in External Coatings for Aluminum Packaging in the Beverage Industry

Paints and coatings are widely used in various applications such as walls, cars, packaging, and food products. The quality of food packaging is essential due to its direct or indirect contact with food. The demand for high-quality food packaging is increasing due to the higher production and consumption rates. However, containers used in the beverage industry often face problems like scratches and abrasions during transportation. This study aimed to investigate different formulations of external coatings for beverage cans to improve their physical resistance properties and prevent corrosion and surface damage problems. The study involved reacting an acrylic resin with six different amino resins, including methylated melamine, butylated melamine, glycoluril, methylated urea, butylated urea, and benzoguanamine, in various proportions. The results of 25 formulated samples were compared based on properties such as adhesion, durability, and chemical resistance. The outcomes of the study showed significant differences among the crosslinking agents. Among all the crosslinking agents, methylated melamine showed the most favorable results in the analyses, proving to be effective in almost all tests.

Preparation and Application of CO2-Resistant Latex in Shale Reservoir Cementing

With the application of CO2 fracturing, CO2 huff and puff, CO2 flooding, and other stimulation technologies in shale reservoirs, a large amount of CO2 remained in the formation, which also lead to the serious corrosion problem of CO2 in shale reservoirs. In order to solve the harm caused by CO2 corrosion, it is necessary to curb CO2 corrosion from the cementing cement ring to ensure the long-term stable exploitation of shale oil. Therefore, a new latex was created using liquid polybutadiene, styrene, 2-acrylamide-2-methylpropanesulfonic acid, and maleic anhydride to increase the cement ring’s resistance to CO2 corrosion. The latex’s structure and characteristics were then confirmed using infrared, particle size analyzer, thermogravimetric analysis, and transmission electron microscopy. The major size distribution of latex is between 160 and 220 nm, with a solid content of 32.2% and an apparent viscosity of 36.8 mPa·s. And it had good physical properties and stability. Latex can effectively improve the properties of cement slurry and cement composite. When the amount of latex was 8%, the fluidity index of cement slurry was 0.76, the consistency index was 0.5363, the free liquid content was only 0.1%, and the water loss was reduced to 108 mL. At the same time, latex has a certain retarding ability. With 8% latex, the cement slurry has a specific retarding ability, is 0.76 and 0.5363, has a free liquid content of just 0.1%, and reduces water loss to 108 mL. Moreover, latex had certain retarding properties. The compressive strength and flexural strength of the latex cement composite were increased by 13.47% and 33.64% compared with the blank cement composite. A long-term CO2 corrosion experiment also showed that latex significantly increased the cement composite’s resilience to corrosion, lowering the blank cement composite’s growth rate of permeability from 46.88% to 19.41% and its compressive strength drop rate from 27.39% to 11.74%. Through the use of XRD and SEM, the latex’s anti-corrosion mechanism, hydration products, and microstructure were examined. In addition to forming a continuous network structure with the hydrated calcium silicate and other gels, the latex can form a latex film to attach and fill the hydration products. This slows down the rate of CO2 corrosion of the hydration products, enhancing the cement composite’s resistance to corrosion. CO2-resistant toughened latex can effectively solve the CO2 corrosion problem of the cementing cement ring in shale reservoirs.