Sodium Chloride Environment Research Articles

Evaluation of Biosurfactants to Preflush for Offshore Wells.

With the improvement of environmental protection requirements in offshore oil and gas exploration, there is a great demand to find environmentally friendly surfactants for cementing preflush fluids. In the present paper, the application potential of three biosurfactants of rhamnolipid, lipopeptide, and sophorolipid in the preflush fluid was evaluated through a series of experiments. The experiments studied the interfacial tension (IFT) of the biosurfactants, resistance to temperature, salt resistance (sodium chloride and sea salt), and the influences of the studied biosurfactants on the rheological compatibility and capabilities to convert the wettability of the formation from oil-wet to water-wet, mud cake removal efficiency, and to improve the interfacial bonding properties of the preflush fluid. The results showed that rhamnolipid, lipopeptide, and sophorolipid exhibited excellent surface activities in high-temperature and sodium chloride (NaCl) environments. When exposed to sea salt, lipopeptides lost their function due to agglomeration, while rhamnolipids and sophorolipids maintained structural stabilities and high surface activities. When rhamnolipid was mixed with sophorolipid in a ratio of 2:1 at the same concentration, the combined biosurfactant had the best surface activity among the studied surfactants. The combined biosurfactant not only had good rheological compatibility with the drilling fluid and cement slurry but also showed excellent properties in the removal of mud cake. In addition, the effect of the removal of the mud cake was verified by the gas channeling experiment. The experimental results show that the presence of mud cake can reduce the bonding strength. When rhamnolipid was mixed with sophorolipid in a ratio of 2:1 at the same concentration, the removal efficiency of mud cake was the highest, and the interfacial bonding property of the cement sheath can be improved.

Enhancing thermal stability and corrosion resistance of carbon-carbon composites with iridium coatings deposited by electron beam physical vapor deposition

Abstract Carbon–carbon (C−C) composites are extensively used in high-temperature environments such as Combustor Liners and Turbine Blades in jet engines and Throat Inserts, Nozzle Extensions and Exit Cones in rocket engines due to their excellent thermal stability and mechanical properties. However, at temperatures exceeding 800 °C, these composites require additional protection to prevent degradation. This study aims to investigate the behavior of C−C composites when coated with high-purity metallic iridium using Electron Beam Physical Vapor Deposition (EBPVD). The research problem focuses on enhancing the high-temperature performance and corrosion resistance of C−C composites for aerospace applications. The methodology involves depositing a uniform 5.6 microns thick iridium coating on C−C substrates and characterizing the coating’s microstructure, hardness, and corrosion resistance. FESEM micrographs reveal that the iridium coating adheres uniformly to the substrate without any seepage, and XRD analysis confirms an FCC crystal structure with a densely packed grainy surface. Corrosion tests were conducted using a BIOLOGIC electrochemical workstation in a sodium chloride environment indicate a corrosion rate of 0.00307 mm year−1. The Nyquist, Bodo plots, and Taffel plots were constructed for the better understanding of the corrosion mechanism. While the OCP was constructed to understand the stability and the corrosion resistance of the C−C samples. Microhardness of the coating, measured under a normal applied load of 0.20 N, is 702 HV. The coated samples also could withstand thermal shocks between −40 °C and 1500 °C for 40 h without observable damage or color change. These findings demonstrate the potential of iridium-coated C−C composites to maintain structural integrity and performance in extreme aerospace environments, significantly impacting the field by providing a reliable protective solution for high-temperature applications.

تثبيط التآكل للصلب المقوى في كلوريد الصوديوم بنسبة 3.5 % باستخدام عقار بنتوكسيفيلين منتهي الصلاحية: دراسة فقدان الكتلة

Corrosion is a major issue affecting the durability and performance of various metallic materials, leading to substantial economic losses and safety hazards. The corrosion of reinforced steel in sodium chloride environment poses a significant concern for various industrial applications. This study aims to investigate the corrosion inhibition properties of expired pentoxifylline drug on reinforced steel in a 3.5% NaCl solution. The mass loss method was utilized to quantify the corrosion rate and assess the efficiency of the expired pentoxifylline drug as a potential corrosion inhibitor. The results indicate that the corrosion rate of steel in the 3.5% NaCl solution decreased significantly in the presence of expired drug. Higher concentrations of expired drugs have shown a greater impact on corrosion inhibition. Investigation of the effects of temperature on corrosion inhibition efficacy. The inhibition efficiency increased with increasing concentrations of the inhibitor and decreased with increasing immersion time. The experimental data were tested according to the Langmuir adsorption isotherm, through which the equilibrium adsorption constant (Kads) was calculated and found to be 4.38 litres mol-1 as the maximum value when immersed for one day. The standard free energy of adsorption (∆G_ads^o) ranged from 45 to 30.5 kJ mol-1. Keywords: Reinforced steel, sodium chloride medium, inhibition, expired drugs, pentoxifylline

Structural integrity and hybrid ANFIS-PSO modeling of the corrosion rate of ductile irons in different environments

Ductile iron (DI) samples were immersed in near-neutral, alkaline sodium hydroxide (NaOH), and sodium chloride (NaCl) environments for 180 days. The influence of microstructure on the corrosion resistance of three DI specimens was investigated. Microstructures, electrochemical measurements, and the characterization of the corroded surfaces were analyzed. The experimental results from this study were used to validate a model generated from hybrid adaptive neuro-fuzzy inferences system-particle swarm optimization (ANFIS-PSO) algorithms. The hybrid ANFIS-PSO modelling technique was improvised for a detailed evaluation of corrosion rate of ductile cast iron materials in different environments. The integrated hybrid ANFIS-PSO model revealed a sharp rise in localized corrosion caused by chloride-induced structural deterioration at the nanoscale for some of the grains. The performance results revealed that the fuzzy c-mean (FCM) clustering outperformed other clustering approach in the neuro-fuzzy model. Accuracy values of 92.9% and 93.7% were recorded for the training phase of ANFIS-FCM and ANFIS-PSO-FCM respectively for corrosion rates. The percentage error of the ANFIS-PSO predictions is significantly lower than the ANFIS-standalone prediction. This shows that the ANFIS-PSO with FCM approach is a better model for predicting corrosion rates. This will contribute to the body of knowledge for ductile iron, corrosion, and corrosion modelling using machine learning.

Electrochemical Deposition and Properties of Ni Coatings with Nitrogen-Modified Graphene Oxide

In this study, a method for producing nitrogen-modified graphene oxide (NMGO) using hydrothermal synthesis in the presence of triethanolamine is presented. The composition and structure of NMGO are characterized using X-ray phase analysis (XPA), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and Raman spectroscopy. Ni-based metal matrix coatings (MMCs) modified with NMGO were obtained from a sulfate-chloride electrolyte in the galvanostatic mode. The process of electrochemical deposition of these coatings was studied using chronovoltammetry. The microstructure of Ni–NMGO MMCs was studied using the XPA and SEM methods. It has been established that the addition of NMGO particles into the Ni matrix results in an increase in the microhardness of the resulting coatings by an average of 1.30 times. This effect is a consequence of the refinement of crystallites and high mechanical properties of NMGO phase. The corrosion-electrochemical behavior of studied electrochemical deposits in 0.5 M sulfuric acid was analyzed. It has been shown that the corrosion rate of Ni–NMGO MMCs in a 3.5% sodium chloride environment decreases by approximately 1.50–1.70 times as compared to unmodified Ni coatings. This is due to NMGO particles that act as a barrier preventing the propagation of the corrosion and form corrosive galvanic microelements with Ni, promoting anodic polarization.

Elucidating the effect of polyphenol-protein interactions on rheological properties of purple waxy rice

Processing purple rice causes interactions between polyphenols and protein. The effect of covalent and non-covalent interactions on the viscosity of non-pigmented (Neches) and purple (HB-1) waxy rice cultivars was studied by using dithiothreitol (DTT), urea, sodium chloride (NaCl), and acidic (pH 2) and alkaline (pH 12) environments. Urea did not affect pasting properties of both cultivars. The pasting viscosity of whole grain Neches and HB-1 and milled Neches increased by NaCl, but not that of milled HB-1. DTT reduced the pasting viscosity of Neches, whereas that of HB-1 decreased moderately. Whole grain Neches and HB-1 and milled Neches exhibited greater pasting viscosity at pH 2, whereas milled HB-1 was unaffected. Pasting viscosity of Neches was slightly affected at pH 12, whereas that of whole grain HB-1 increased and milled HB-1 decreased. Protein fractions of both cultivars shared similar molecular weight and secondary structures, but polyphenols affected the tertiary structure. The polyphenol-protein cross-links played the predominant role in the viscosity development of purple rice and may enhance the stability of the protein network at pH 2 and in the presence of DTT, but were disrupted at pH 12. Polyphenol-protein interactions may improve starch pasting properties without the need for chemical modifications.

Chloride ion permeation and electrochemical impedance response of red mud-coal metakaolin geopolymer concrete

In geopolymer concrete, chloride ions largely contribute to the surface passivation of steel reinforcement and accelerate its corrosion. However, real-time nondestructive testing of chloride ion diffusion has not been widely conducted. Therefore, this study determined the distribution of chloride ions in red mud-coal metakaolin geopolymer concrete with different water-binding ratios under natural immersion conditions. The electrochemical properties of geopolymer concrete in a sodium chloride environment were examined by electrochemical impedance spectroscopy (EIS) and the relationship between these properties and the chloride ion diffusion coefficient was established. The experimental results showed that the contents of free chloride ions, total chloride ions, and bound chloride ions gradually decreased with increasing penetration depth; total chloride ions and free chloride ions increased at the same depth with increasing water-binder ratio; and bound chloride ions decreased with increasing ratio. In addition, the contents of free chloride ions, total chloride ions, and bound chloride ions gradually increased with the increase of the immersion age. The EIS results showed that there was a significant correlation between the diffusion coefficient and the electrochemical parameters. Therefore, EIS is suitable for detecting the diffusion of chloride ions in geopolymer concrete.

Corrosion resistance improvement of 430 stainless steel via plastic deformation induced uniform substructure

In this work, the influence of cold deformation rate on the microstructure evolution and corrosion behavior of 430 ferritic stainless steel in sodium chloride environment were studied by electron backscatter diffraction analysis, transmission electron microscopy analysis, scanning electron microscopy analysis, electrochemical analysis and X-ray photoelectron spectroscopy. Cold deformation changed the internal structure of the alloy, including grain boundary angle and special grain boundary. The corrosion resistance of the alloy was improved by low-speed deformation at a rate of 0.03 mm·s–1, which was mainly due to the increase of low angle grain boundaries and low coincidence site lattices, the uniform distribution of dislocations and the formation of a more stable passivation film. Deformation at a high rate of 3 mm·s–1 reduced the corrosion resistance of the alloy, which was attributed to the uneven distribution of dislocation density inside the alloy.

Experimental investigation on the durability of metakaolin-based geopolymer concrete in aggressive environments

The properties and performance of geopolymer concrete have been evaluated in numerous studies in recent decades. One of the fields of study is the evaluation of the durability of geopolymer concrete in aggressive environments. In this study, the influence of four experimental factors, including curing temperature (T), the weight ratio of sand to metakaolin (S/M), aggressive environment type (AE), and aggressive environment exposure time (Et) were investigated on the durability and mechanical properties of metakaolin-based geopolymer concrete (MGPC). Moreover, 5% sulfuric acid solution, 5% sodium chloride solution, and Persian Gulf seawater were used as aggressive environments. Response surface methodology (RSM) was implemented to statistically design and analyze the experiments. Mathematical models were derived for the prediction of residual compressive strength (RFc), weight changes (∆W), and compressive strength changes (∆Fc) of MGPC. The analysis of variance showed that all four factors had a significant effect on the responses, while only AE-S/M and AE-ET factors had an interaction. Design-Expert software (DX7) was employed for the optimization of design factors. Results revealed that the use of the optimum weight ratios of S/M (2.52, 2.07, and 1.29) at a curing temperature of 46 °C and an exposure time of 56 days led to RFc values of 34.12, 43.60, and 44.15 for sulfuric acid, sodium chloride, and Persian Gulf seawater aggressive environments, respectively. These results, which are higher than the minimum required compressive strength of concrete, along with the ∆Fc and ∆W values, confirm the acceptable durability of MGPC.

Transport Properties of Lightweight Concrete Incorporated with Expanded Clay Aggregate in Marine Environment

Employing porous material such as expanded clay lightweight aggregate (EC LWA) as an internal curing agent in the production of mass concrete proof to mitigate early age cracks in resulting concrete. However, introducing EC LWA could increase the porosity of concrete, leading to concrete degradation due to water penetration. Thus, this research aims to investigate the suitable natural aggregate replacement rate with EC LWA in the production of concrete with acceptable mechanical and transport properties. Three replacement rates of 0, 50, and 100% were applied. The water-per-cement ratio of 0.6 was used to produce concrete. The workability of fresh concrete and the compressive strength were tested. The transport properties of concrete were assessed by monitoring the capillary water uptake of concrete. To mimic the marine environment, the concrete sample was immersed in sodium chloride and sodium sulphate for seven days. The result shows that the workability, bulk density, and compressive strength of concrete with 50% EC LWA have a similar value to the reference sample. Moreover, samples with 50% EC LWA also have a slower capillary rate in a sodium chloride environment than in fresh water.

Mineral Katkılı Çimento Bulamacı Kaplanmış Betonarme Donatıların Korozyon Performansının İncelenmesi

Reinforcement corrosion is considered as one of the most important parameters determining the service life of reinforced concrete structures. In this study, an alternative method that protects reinforced concrete reinforcements against the effects of corrosion has been examined. Within the scope of the study, in addition to the traditionally produced reference reinforced concrete samples, reinforced concrete samples produced with mineral additive cement slurry coated reinforcements were prepared. In addition to silica fume at 30% of the cement amount by mass, blast furnace slag at 25% and 50% of the cement amount was used in mineral added cement slurries. According to the test results, it was determined that the slurry coating application decreased the corrosion potential values and the corrosion current density values of the reinforcements in the samples exposed to the wetting and drying cycles in the sodium chloride environment.

Construction of magnetic Fe3O4@NH2-MIL-100(Fe)-C18 with excellent hydrophobicity for effective protein separation and purification

Due to the appearance of amino and carboxyl groups on the surface of NH2-MIL-100(Fe), a stable Metal-Organic Frameworks (MOFs), it is ready to be modified with other functional ligands to provide versatile applications. In this study, we have successfully employed aliphatic C18 carbon chain to functionalize the magnetite-doped Fe3O4@NH2-MIL-100(Fe). The remarkable hydrophobic surface of Fe3O4@NH2-MIL-100(Fe)-C18 with a water contact angle of 98.93° allowed it to selectively form hydrophobic interaction with a protein in a high concentration of sodium chloride environment. The complex was easily harvested with a magnet, and the bound protein was able to be eluted by reducing sodium chloride concentration. The maximum protein binding capacity reached approximately 28.74 μg of BSA/mg with Fe3O4@NH2-MIL-100(Fe)-C18. Our results have demonstrated that the Dulbecco’s phosphate buffer could provide a better “salt-out” effect and afford a higher resolution to separate proteins in a mixture. In addition, we have successfully employed the magnetic Fe3O4@NH2-MIL-100(Fe)-C18 in the purification of recombinant green fluoresce protein by replacing the stage of using a commercial hydrophobic interaction resin, and achieved almost the same purification efficiency. Fe3O4@NH2-MIL-100(Fe)-C18 also provides us with the higher protein binding capacity than other commercial products, reliable performance for fifteen repeat uses, and more convenient and affordable method for protein purification in laboratory.

Electrochemical corrosion performance of friction stir processed cold spray metal matrix composite coatings on AZ31B magnesium alloy under sodium chloride environment

The main objective of this investigation is to study the effect of friction stir processing (FSP) on the surface integrity and corrosion resistance of low-pressure cold sprayed (LPCS) aluminium alloy/aluminium oxide metal matrix composite (Al-Al2O3 MMC) coating deposited on AZ31B magnesium alloy for aerospace and automobile applications. The Al-Al2O3 MMC coating was developed on AZ31B magnesium alloy using a LPCS system. FSP was performed on the MMC coating using a stirring tool made of H13 tool steel. The structural integrity of the coating was analyzed using scanning electron microscopy (SEM). The phase analysis of coating was studied using x-ray diffraction (XRD). The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were performed to study the corrosion resistance of cold sprayed and FSPed samples. Results showed that FSP improved the structural integrity of MMC coating. Both the EIS and potentiodynamic polarisation test results reveal that FSP treated samples provide superior corrosion resistance than cold sprayed samples. This is due to the increase in interfacial bonding between matrix and reinforcement phase. The degree of separation and dispersal of alumina in the Al alloy matrix is increased through the shear force generated by the FSP tool on the coating surface.

Effect of saline environment on the fatigue crack growth resistance of WE43 Mg alloy

New magnesium alloys have been developed to reduce the weight of engineering components without compromising the mechanical properties and corrosion resistance; however, there is a lack in the literature regarding such properties. Hence, this work focuses on studying the fatigue crack propagation of the WE43 magnesium alloy, considering the effects of air and sodium chloride environments. Fatigue results showed similar behavior for both, main and transverse, directions regarding the rolling mill process. Yet, fatigue crack rates (FCR) were higher in the sodium chloride environment than in laboratory air, which could be attributed to hydrogen embrittlement and anodic dissolution at the crack tip. Laboratory air FCR results presented a lower m value (3.63 and 1.72) than the one found for the sodium chloride environment (9.15 and 4.83), indicating a lower FCR rate variation with ΔK. Comparing FCR for saline and air conditions, at the end of Paris' region II, FCR in the saline environment was enhanced by almost two orders of magnitude (ΔK= 11 MPa.m1/2). Furthermore, fractography showed mixed intergranular and transgranular cracking in the saline environment.

Tribocorrosion Behavior of 2205 Duplex Stainless Steel in Sodium Chloride and Sodium Sulfate Environments

Tribocorrosion Behavior of 2205 Duplex Stainless Steel in Sodium Chloride and Sodium Sulfate Environments

Investigation on Mechanical and Microstructure Properties of Steel Fiber Reinforced Concrete

This paper studied the microscopic and mechanical property degradation of axially compressed concrete with different steel fiber content under chemical erosion and freeze-thaw environment. Concrete cylinders with three types of steel fiber contents (0%, 1%, 2%) were selected to study the durability behavior concerning different environmental effects up to 28 days, which included tap water, 3.5% sodium chloride solution, 10% sodium sulfate solution, 5% sulfuric acid solution, 2 mol/L sodium hydroxide solution, and 100 freeze-thaw cycles. The variation of specimens’ microstructure and axial bearing capacity with different fiber content was studied with the chemical erosion cycle increase, and the mass and pH variations of the specimen were measured. According to the law of micro-cracks, the deterioration degree was judged, and a numerical analysis model was established to quantify the reliability of the structure with different fiber content. The results show that the addition of steel fiber can effectively improve the axial bearing capacity of concrete, and a freeze-thaw environment and chemical erosion can accelerate fiber-reinforced concrete’s failure. The optimal content of steel fiber was determined, which is 1% for sodium chloride and sodium sulfate environments, and 2% for the freeze-thaw cycle, dilute sulfuric acid, and sodium hydroxide environments. The finite element software Abaqus was used to simulate and analyze the freeze-thaw cycle and mechanical test of concrete, which verified the rationality of the test results. Research results will provide a theoretical basis for predicting the performance deterioration of steel fiber reinforced concrete under different erosion conditions and periods.

Permeability of High-Performance Fiber Reinforced Concrete Immersed in High Concentration Sodium Chloride Solution

This paper aims to study the permeability of High-Performance Concrete containing natural pozzolan and reinforced with fibers in high concentration sodium chloride solution. Optimized finely ground natural pozzolan was employed as 6% of partial substitution of the cement. Polypropylene fibers with 6 mm and 12 mm lengths were introduced individually for a volume fraction of 0.1% and 0.15% respectively. Then, in combination with a total fiber content of 0.25%. The effect of sodium chloride attack on the performance of concretes was assessed through the measurement of the compressive strength, splitting tensile strength, sorptivity, rapid chloride permeability test, apparent and intrinsic gas permeability, and visual inspection at various testing ages (28, 90, 180, and 365 days). A total of four (04) types of concretes were cast: one (01) High-Performance Concrete (HPC), and three (03) High-Performance Fiber Reinforced Concrete (HPFRC) stored in tap water and sodium chloride environment. From the experiments performed, it can be concluded that the polypropylene fibers introduction into HPC favorably affect its chemical resistance to chloride attack and long-term durability. The difference in the permeability of HPC and HPFRC stored in tap water and chloride environment is not significant. Furthermore, the visual investigation of HPFRC after 365 days of immersion in sodium chloride environment showed no sign of degradation. Based on the results obtained in this study, we recommend the use of hybrid fiber-reinforced concrete (F0-0.25%) as a low permeable material in a severe chloride environment.

Influence of Heat Input on Cold Metal Transfer Welded Joints

ABSTRACT During welding, the heat input is a critical parameter in determining the quality of the joints welded by any welding process. In the case of dissimilar welding, as dissimilar metals have significant differences in melting point, it is challenging to achieve an adequate joint. The emerging cold metal transfer welding process can resolve it effectively by controlling the heat while joining dissimilar metals. Therefore, in this research work, Aluminum-galvanized steel dissimilar joints were fabricated using varying heat inputs and their mechanical, metallurgical, and corrosion properties were evaluated. Furthermore, the second-phase formation at the weld interface has been investigated, and corrosion behavior is analyzed using electrochemical techniques in a 0.1% sodium chloride environment. The Tafel polarization and electrochemical impedance spectroscopy studies reveal it improved corrosion resistance due to an increase in heat input. The reduced solidification defects and the establishment of an appropriate intermetallic layer thickness with a suitable microstructure at the interface are the reasons for the improved corrosion resistance and strength of the dissimilar joints.

Performances of plant based corrosion inhibitors in controlling corrosion of mild steel in sodium chloride environment

Addition of corrosion inhibitors is one of the most commonly used corrosion control method in current industries. However, most of corrosion inhibitors available on the market are inorganic and toxic which pose threat to the environment when they are discharged. Thus, green corrosion inhibitors that are non-toxic, renewable, cheaper and environmentally friendly are required to mitigate this issue. One of the viable sources of green corrosion inhibitors is by using plant extracts. The present study focused on the application of green corrosion inhibitors using Jatropha curcas and Hibiscus sabdariffa (Roselle) extracts in controlling corrosion of mild steel in 3.5% NaCl environment. Results of immersion test showed that Jatropha extract recorded highest inhibition efficiency at 90.84% while Roselle extract attained highest inhibition efficiency at 77.35% in NaCl environment. Potentiodynamic polarization test performed signify that both extracts were mixed-type inhibitors. The presence of adsorptive protective films formed on the surface of mild steel sample were proven through electrochemical impedance spectroscopy (EIS) analysis. Results of potentiodynamic polarization test and EIS analysis were in agreement with results of immersion test. Tests performed indicate that both Jatropha and Roselle have high inhibitive performances in 3.5% NaCl environment with Jatropha extract performing slightly better than Roselle extract. Further studies on type of adsorption as well as determination and quantification of phytochemical compounds affecting inhibition performances should be done to further understand and improve the inhibition performances of the extracts.

The Effectivity of Oil Palm Inhibitor Processed by Aminolysis to Control Corrosion on Steel in Sodium Chloride Environment

A green inhibitor based on Palm kernel oil (PKO) was prepared to investigate its corrosion inhibition behaviour against steel ASTM A36 in sodium chloride solution. The aminolysis method was used to synthesize the green inhibitor and produced fatty acid diethanolamine. Afterwards, the mixture of PKO and diethanolamine of 1:6 and 1:20 were prepared. These mixtures were added into sodium chloride solution with concentration 50, 100, 500, and 1,000 ppm and they were used as working solution in corrosion testing. Corrosion testing was conducted using anodic polarization. The confirmation of microstructure of steels surfaces were done by optical microscope. The results obtained from corrosion testing showed that inhibitors of palm oil, especially palm kernel oil (PKO), provided a good corrosion protection effect. The present work provided very promising results in the preparation of green corrosion inhibitors.