ISSN 2305-6894

2019, Vol. 8, Issue 1 (pp. 1-149)

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The influence of Co-Amoxiclav on the corrosion inhibition of mild steel in 1 N hydrochloric acid solution

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1 School of Mechanical Engineering, Vellore Institute of Technology [VIT], Vellore, 632014 India
2 Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology [VIT], Vellore, 632014 India

Abstract: The influence of an antibiotic Co-Amoxiclav is studied for use as a low cost and ecofriendly corrosion inhibitor for mild steel in acidic environment in particular to 1 N hydrochloric acid medium. The corrosion inhibition effect and the performance of the inhibitor has been extensively studied by weight loss studies, Tafel polarization experiments, electrochemical impedance spectroscopy and hydrogen permeation measurements. The dosage of the antibiotic was varied from 5×10–4 M to 15×10–4 M. It has been established that the inhibitor performed well and showed 88% inhibition efficiency at 15×10–4 M concentration of Co-Amoxiclav molecules. The electrochemical studies such as Potentiodynamic polarization proposes that the antibiotic viz., Co-Amoxiclav acted as a mixed type of inhibitor. The increased charge transfer resistance and decreased double layer capacitance obtained from electrochemical impedance spectroscopy confirmed that said antibiotic has performed as good inhibitor in 1 N hydrochloric acid medium. Hydrogen permeation measurements showed that the compound acts as cathodic inhibitor, but predominantly under mixed control. It has been noticed that a definite correlation exists between chemical and electrochemical studies for the inhibition action of Co-Amoxiclav molecules on the corrosion of mild steel in 1 N HCl medium. Diffused reflectance spectroscopy (DRS) studies established that only the mere adsorption of antibiotic on mild steel surface took place and not influence on the surface morphology. The adsorption of this compound on mild steel surface obeys Temkin’s adsorption isotherm.

Int. J. Corros. Scale Inhib., , 1, 1-12 PDF (1 206 K)
doi: 10.17675/2305-6894-2019-8-1-1

Mass transfer analysis considering gas phase diffusion and experimental verification for surface painting a waterborne MCI in concrete

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1 School of Civil Engineering, Yantai University, Yantai 264005, China
2 School of Materials Science and Technology, Southeast University, Nanjing 211189, China
3 Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands

Abstract: The mass transfer numerical model including the long-term gas phase diffusion of a waterborne migrating corrosion inhibitor (MCI, named PCI-2016) in concrete was investigated in this study. The PCI-2016 was prepared by using multi-compound and chelate-induced techniques. The concentrations of nitrogen in different thickness of cover concrete after surface-painted different amounts of PCI-2016 were calculated by this mass transfer model. The calculated data were basically consistent with the nitrogen contents tested by Kjeldahl method at interface between steel bar and mortar matrix. To verify the anticorrosion performance of painting PCI-2016 steel bars bedded in mortar specimens containing different content of NaCl painted with relevant amounts of PCI-2016 were also investigated by the linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). The results revealed that the Icorr of steel bar in the specimen containing 1.25% NaCl (wt. to cement) after painting with 5 g PCI-2016 for 3 days and 28 days decreased from 0.67 μA·cm–2 (before painting) to 0.25 μA·cm–2 and 0.06 μA·cm–2, respectively. The numerical analysis and test results supported that the gas phase transfer model is suitable to calculate the weight of PCI-2016 at the interface zone between steel bar and concrete, and the painted the certain amounts of PCI-2016 on the surface of mortar could show an identified repairing effect on the corrosive steel bar.

Int. J. Corros. Scale Inhib., , 1, 13-24 PDF (787 K)
doi: 10.17675/2305-6894-2019-8-1-2

Influence of Lavandula Dentata essential oil on the corrosion inhibition of carbon steel in 1 M HCl solution

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1 Materials Nanotechnology and Environment, Mohamed V University, Faculty of Science, 4 Av. Ibn Battouta, B.P. 1014 RP, M-10000 Rabat, Morocco
2 Chemistry of Natural Products, Faculty of Science and Technology, University of Corsica, UMR CNRS6134, Corsica, France

Abstract: Within this study we are concerned by the corrosion inhibition of the essential oil of Lavandula Dentata (EOLD) in carbon steel in 1 M hydrochloric acid solution, the investigation was performed using gravimetric method, Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic polarization measurements. The results of electrochemical techniques and gravimetric measurements revealed that the EOLD tested as inhibitor leads to a systematic reduction in the kinetics of steel corrosion processes. Potentiodynamic polarization study has shown that EOLD is inhibitor of a cathodic type. The effect of temperature on the corrosion behavior of carbon steel in the presence and absence of EOLD was studied in the temperature range from 303 K to 333 K. The findings about Electrochemical Impedance Spectroscopy revealed a frequency distribution of the capacitance, simulated as constant phase element. Inhibition efficiencies, determined by potentiodynamic polarization, electrochemical impedance spectroscopy and weight loss methods, are in good agreement. The extracted of EOLD, by hydrodistillation, is analyzed by gas chromatography (GC), indeed, this technique of analysis has shown that its major component is: camphor (50.3%). The EOLD inhibitor adsorbed physically on the carbon steel surface obeys the Langmuir adsorption isotherm. The parameters of activation energy was fairly evaluated and discussed in this work.

Int. J. Corros. Scale Inhib., , 1, 25-41 PDF (893 K)
doi: 10.17675/2305-6894-2019-8-1-3

Suppression of local corrosion of steel, brass and copper with IFKhAN-114 volatile inhibitor

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1 All-Russian Scientific Research Institute of Use of Machinery and Oil Products, Novo-Rubezhnyi per., 28, Tambov, 392022, Russian Federation
2 Tambov State Technical University, Sovetskaya str., 106, Tambov, 392000, Russian Federation
3 Derzhavin State University, Internatsyonalnaya str., 33, Tambov, 392000, Russian Federation
4 Angara GmbH, In der Steele 2, D-40599, Düsseldorf, Germany

Abstract: The possibility of preventing local corrosion of carbon steel St3, copper M2 and two-phase (α + β) brass L62 in an atmosphere with 100% relative humidity of air containing up to 0.6 vol.% CO2, 60 mg/m3 NH3, 30 mg/m3 H2S and IFKhAN-114 volatile corrosion inhibitor (VCI) was studied. The suppression of the local corrosion of carbon steel St3 and copper, which are constituents of the steel/copper, steel/brass and copper/ brass macro galvanic pairs, was evaluated in the presence of IFKhAN-114 in the second series of the experiments. The combined metal samples consisting of an outer metal ring 2.8 cm in diameter, into which a washer of metal of a different nature with a diameter of 2.0 cm was inserted through a tight fit, were used for corrosion tests of contact galvanic pairs. When assessing the effect of VCI on the overall corrosion rate of the above-mentioned steel/copper, steel/brass, and copper/brass galvanic pairs, their integral corrosion losses for 240 h per unit time were taken into account. Photography of the nature of the damage to the surface of the components of galvanic pairs was carried out after completion of corrosion tests and removal of corrosion products. It was shown that local corrosion of the macro-pair components in the form of ulcers and numerous pits observed in the presence of 0.60% CO2 or 0.2% CO2 + 20 mg/m3 NH3 + 10 mg/m3 H2S in uninhibited air, was hindered almost completely in the presence of the IFKhAN-114 inhibitor. The corrosion of these metals under these conditions is uniform, and the protective effect of the inhibitor is, %: 74 (steel), 99 (brass) and 60 (copper).

Int. J. Corros. Scale Inhib., , 1, 42-49 PDF (479 K)
doi: 10.17675/2305-6894-2019-8-1-4

Corrosion studies of mild steel in sulphuric acid medium by acidimetric method

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1 Department of Chemistry, Benue State University, Makurdi, Nigeria
2 Centre for Food Technology and Research, Benue State University Makurdi, Nigeria

Abstract: Many corrosion monitoring techniques are available to study the behaviour of inhibitors in various media. Common among these techniques are weight loss, gasometric, thermometric, acidimetric, electrochemical impedance spectroscopy and a host of others. Each of these techniques has its strengths and weaknesses. While some of them are quite prone to errors, others require, extremely, expensive instrumentation. The acidimetric technique is, however, the least applied of among these techniques, in spite of its obvious advantages of simplicity, less prone to error and inexpensiveness. In this research work, we applied the acidimetric technique to the study of corrosion inhibition of mild steel in H2SO4 medium using urea, an organic molecule, as an inhibitor. The efficacy of the technique was then compared with an established and commonly applied corrosion monitoring technique; the weight loss technique. The two techniques were found out to give quite comparable results. However, the acidimetric technique was found to be faster, simpler, and yielded comparatively better results. The inhibition efficiency, %IE, which has the same trend for the two methods, decreased with increase in temperature, suggestive of physisorption. This was collaborated by values of activation energy, Ea, which are all below 80 kJ/mol. The adsorption mechanism of urea adsorption onto the metal surface was, therefore, resolved with the use of Adejo-Ekwenchi isotherm adsorption model to be physisorption, with the best fit adsorption isotherms being the Langmuir and El-Awady isotherm models.

Int. J. Corros. Scale Inhib., , 1, 50-61 PDF (703 K)
doi: 10.17675/2305-6894-2019-8-1-5

The protective effect of Schiff and Mannich bases on steel corrosion in neutral media

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1 OOO NPO NEPhTEKhIM, ul. Pulkovskaya 10, St. Petersburg, 196158, Russian Federation
2 Kalashnikov Izhevsk State Technical University, 7, Studencheskaya St., Izhevsk, 426069, Russian Federation
3 Udmurt State University, 1, Universitetskaya St., Izhevsk, 426034, Russian Federation

Abstract: The protective effect of Schiff and Mannich bases – morpholine and benzotriazole derivatives – on steel corrosion in neutral media has been studied. These substances were previously investigated as inhibitors of atmospheric corrosion. Protective properties were calculated by the effect of the inhibitors on the anodic dissolution rate. The electrochemical measurement was carried out in a mixed electrolyte of 70 mg/dm3 NaCl + 80 mg/dm3 Na2SO4, containing 10% isopropyl alcohol to ensure the solubility of the inhibitors. It has been found that all studied inhibitors – derivatives of morpholine and benzotriazole are more effective than unsubstituted starting compounds. The paper analyzes the dependencies of corrosion inhibitors of this class on a complex of physicochemical properties, such as saturated vapor pressure, electron density on heteroatoms, ionization potentials (PI) of inhibitors, and Hansch hydrophobic constants. Based on literature and experimental data, the protective effect of the morpholine and benzotriazole derivatives investigated in the present work is due to the hydrophobicity effect of the molecules. The decrease in the rate of anodic dissolution in the presence of inhibitors is due to a decrease in the dielectric constant of the electrode layer during the adsorption of inhibitors.

Int. J. Corros. Scale Inhib., , 1, 62-68 PDF (860 K)
doi: 10.17675/2305-6894-2019-8-1-6

Improvement and stabilization of the electrochemical properties of zinc alloys during casting

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1 Vladimir State University, ul. Gor’kogo, 87, Vladimir, 600000, Russian Federation
2 COR/SCI, LLC, 6421 Dorset Lane, Solon, OH 44139, USA

Abstract: The main reasons for the appearance of electrochemical heterogeneity of cast sacrificial galvanic anodic alloys in the “metal–electrolyte” system are internal factors related to the nature of the metal, its composition, structure, etc. Obviously, when developing the technology for manufacturing of cast anodes, special attention should be paid to ensuring the structural homogeneity of the alloys. The main role in the formation of the structure and basic properties of cast anodes is played by thermal processes that affect the conditions for solidification of the melt in the mould. The results of studies of the structure and basic electrochemical properties of cast zinc sacrificial alloys (ZSA) depending on the cooling conditions are presented in this paper. The analysis of the temperature fields of the solidifying metal (when the metal is cooled) and the shape (when the mould is heated) at different cooling intensities has made it possible to optimize the duration of the casting cycle. This takes into account the cooling conditions determined by the initial temperature of the mould, which ensures a homogeneous structure and stable electrochemical properties of the material over the entire thickness of the tread. For example, it is established that for the casting of zinc alloys treads weighing 18 kg, the temperature of the mould before casting should be 120–160°C. In these conditions, the necessary quality of cast sacrificial anodic alloys is achieved: Current Capacity–Efficiency 93–96%; Corrosion Potential –Ec = 815–820 mV vs. SHE. The required duration of the casting cycle is 10–14 min. Similar data was obtained for sacrificial anodes of various shapes and sizes. Based on the results of studies of the thermal interaction of zinc anodes with a casting mould (sandy-argillaceous, cast iron and steel water-cooled) using numerical simulation methods, the expediency of casting anodes into water-cooled moulds is provided, providing the most favorable conditions for heat removal and obtaining a homogeneous structure of cast treads. Based on the results obtained, a technology has been developed for casting zinc anodes of various sizes, which provides high and stable electrochemical properties.

Int. J. Corros. Scale Inhib., , 1, 69-83 PDF (2 159 K)
doi: 10.17675/2305-6894-2019-8-1-7

Application of low field nuclear magnetic resonance technique to characterize the mass transfer of corrosion inhibitors in concrete

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School of Civil Engineering, Yantai University, Yantai, 264005, China

Abstract: A green aqueous product named PCI-2016 has been developed by using multicompound and chelate-induced techniques recently. The mass transfer process of the product in concrete by using low field nuclear magnetic resonance technique was carried out. The one-dimensional saturated capillary absorption experiment of specimens immersed in PCI-2016 were carried out. The variation of the absorbed mass and penetrating height of the PCI-2016 with time was observed. The results indicated that the absorbed mass and penetrating height of PCI-2016 increased with the increase of time, and the initial growth rate in 24h is the larger and then tends to gentle. The saturation of PCI-2016 in test block at different ages and positions was calculated by frequency coding which is collected by using low field nuclear magnetic resonance experiment. The variation of PCI-2016 saturation at different depths from the surface with time can also be calculated by the modified MCI transport model. Compared with the results, the numerical results are in good agreement with the experimental results. So the low field nuclear magnetic resonance can be used to measure the transport process of PCI-2016 in cement-based materials. It provided a reference for characterizing the mass transfer process of corrosion inhibitor in concrete.

Int. J. Corros. Scale Inhib., , 1, 84-92 PDF (648 K)
doi: 10.17675/2305-6894-2019-8-1-8

3,6-Di(pyridin-2-yl) pyridazine derivatives as original and new corrosion inhibitors in support of mild steel: Experimental studies and DFT investigational

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1 Laboratoire de Chimie Organique Appliquée, Université Sidi Mohamed Ben Abdellah, Faculté des Sciences et Techniques, Route d'Immouzer, BP 2202 Fès, Morocco
2 Department of Chemistry, College of Sciences, University of Sharjah, PO Box: 27272, UAE
3 Laboratoire de Chimie de la matière condensée, Université Sidi Mohamed Ben Abdellah, Faculté des Sciences et Techniques, Route d'Immouzer, BP 2202 Fès, Morocco
4 Laboratoire de chimie analytique appliquée, matériaux et environnement (LC2AME), Faculté des Sciences, B.P. 717, 60000 Oujda, Morocco
5 University of Echahid Hamma Lakhdar, PO Box 789, El-Oued, Algeria
6 Instituto de Ciencia Molecular (ICMol), Université de Valencia

Abstract: Corrosion inhibition performance of three new synthesized novel compounds namely, 1-((3,6-di(pyridin-2-yl)pyrdazin-4-yl)methyl)-indoline-2,3-dione (FM1), 4-(morpholinomethyl)-3,6-di(pyridin-2-yl)pyridazine (FM2) and 3,6-di(pyridin-2-yl)-4-(p-tolyl)-pyridazine (FM3) on mild steel (MS) was investigated by HCl with 1 M concentration. The corrosion inhibition performance of the synthesized compounds was studied by weight lοss, impedance spectroscopy(EIS) and potentiodynamic polarization (PDP) methods. The results showed that tһe corrosion inhibition efficiency increases with the increase in the concentration of the compounds (FMs). The PDP measurements reveal that the type of these compounds is a mixed-type behavior. The results of impedance studies (EIS) showed that in the presence of FMs, the Rct values increase while the Cdl values decrease due to the adsorption of inhibitors (FMs) on the mild steel surface. EIS study showed that there is one capacitance loop related to charge transfer mechanism. The adsorption of (FMs) on the mild steel surface obeys the Langmuir-adsorption isοtherm. The 1-((3,6-di(pyridin-2-yl)pyrdazin-4-yl)methyl)-indoline-2,3-dione (FM1) showed a better inhibition performance in comparison with the FM2 and FM3. The theoretical results which shows also a good correlation with the electrochemical experiments and weight loss measurements.

Int. J. Corros. Scale Inhib., , 1, 93-109 PDF (1 223 K)
doi: 10.17675/2305-6894-2019-8-1-9

Effect of organic corrosion inhibitors on the crack growth rate in pipe steel X70 in a weakly acidic solution

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1 A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr. 31, 119071 Moscow, Russian Federation
2 Gubkin Russian State University of Oil and Gas, Leninsky pr. 65, Moscow, 119991 Russian Federation
3 Institute of Natural Gases and Gas Technologies – Gazprom VNIIGAZ LLC, Moscow Oblast, Razvilka settlement, 142717 Russia Russian Federation

Abstract: The effect of a number of organic corrosion inhibitors (CIs) on the growth rate of a corrosion crack in pipe steel X70 in a weakly acidic (pH 5.5) citrate buffer solution in the absence and in the presence of 1 mM Na2S has been studied. A static straining load was applied to the specimens, with the stress intensity factor in the crack tip corresponding to the plateau of the kinetic curve of steel X70 destruction. The crack growth rate was determined from the change in the electric resistance of a specimen. The hydrogen penetration rate into metal was determined using the hydrogen electrochemical desorption method. It has been shown that CIs can considerably slow down the corrosion crack growth. In the solution containing no sulfide ions, the best protective properties are shown by IFKhAN-P-3 inhibitor (based on a salt of polyoxometalates with amines) and by a mixture of this inhibitor with phosphate (IFKhAN-P-8). In the presence of sulfide ions, the best inhibitors of stress corrosion cracking (SCC) of pipe steel include the IFKhAN-P-3 and IFKhAN-P-8 formulations, as well as modifications of the IFKhAN-29 inhibitor and a quaternary ammonium compound, Catamin AB. Good correlation is observed between the corrosion crack growth rate and the anodic dissolution rate of mild steel in electrolytes containing corrosion inhibitors. Only a poor correlation is observed between the crack growth rate and the rate of hydrogen penetration into the metal; the existence of this relationship is apparently due to the fact that all the CIs studied slow down not only the anodic dissolution of steel but also the penetration of hydrogen into the metal. The conclusion has been made that local anodic dissolution of the metal is the predominant mechanism of the growth of corrosion cracks in pipe steel in weakly acidic electrolytes. The ability of organic compounds to inhibit SCC can be estimated by the anodic current density at constant potential selected in the region of active dissolution of mild steel.

Int. J. Corros. Scale Inhib., , 1, 110-122 PDF (717 K)
doi: 10.17675/2305-6894-2019-8-1-10

Use of fatty amide and anionic surfactant as corrosion inhibitors for carbon steel in different atmospheres

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1 Instituto de Ciencias Físicas de la UNAM, Av. Universidad s/n, Chamilpa, 62210 Cuernavaca, Morelos, México
2 Universidad Autónoma del Estado de Morelos, CIICAP, Av. Universidad 1001, 62209, Cuernavaca, Morelos, México

Abstract: Sulfonated corrosion inhibitors have been used to protect materials in in-door or out-door storage temporarily. However, the use of environmentally friendly inhibitors becomes a necessity to reduce the environmental impact. In this work, fatty amides and anionic fatty surfactants were synthesized from inedible coconut and palm oil. These active compounds were formulated in natural wax and synthetic oil as vehicles of the anticorrosive formulation. The fatty amides were characterized by FTIR and NMR Spectroscopies. The corrosion behavior of carbon steel covered with these inhibitors was compared with the action of two marked products sulfonate base. Quantification of accelerated corrosion testing of preventive inhibitor coated evaluation was made by weight loss measurements after exposure in a fog chamber, simulating four types of atmospheres, namely marine, industrial-marine, rural and rural polluted. It was found fatty amide inhibitor from palm oil reduces corrosion rate efficiently for carbon steel protecting in rural environment 336 h with a 98.4% of efficiency and for a polluted rural environment 168 h (98.8%) in fog chamber. For Prohesion cyclic conditions, the temporary protective layer regularly used to protect until 244 h with 99.8% of efficiency. XRD patterns of rust samples revealed the presence of Fe3O4 as the main phase in the film. The SEM micrographs showed that the fatty amide base coating presented an excellent efficiency in the four proposed atmospheres. Finally, this work is the first evaluation study of fatty amides in conditions of accelerated corrosion in the fog chamber.

Int. J. Corros. Scale Inhib., , 1, 1223-138 PDF (1 641 K)
doi: 10.17675/2305-6894-2019-8-1-11

Effect of anionic composition of solutions of mineral acids containing Fe(III) on their oxidizing properties

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A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow, 119071 Russian Federation

Abstract: Solutions of HClO4, HBr, H2SO4, HCl, H3PO4, HF and some of their mixtures containing Fe(III) and Fe(II) cations were studied at 20–95°C by potentiometry. The oxidizing ability of such solutions of individual acids decreases in the series: HClO4 > HBr > H2SO4 > HCl > H3PO4 > HF. This effect is the result of the enhancement in this series of the ability of anions of acids to bind Fe(III) cations into complex compounds that are less prone to reduction in comparison with its aqua complexes. To decrease the oxidative ability of acid solutions (HCl and H2SO4) with a weak ability of anions to bind Fe(III) cations to complex compounds, it is possible to add acids (H3PO4 or HF) that generate anions binding Fe(III) into stable and hardly reducible complexes. In the H2SO4–H3PO4–H2O, H2SO4–HF–H2O, HCl–H3PO4–H2O, and HCl–HF–H2O systems containing Fe(III) and Fe(II), the dependence of the redox potential of the Fe(III)/Fe(II) couple on the anionic composition of the medium showed that H3PO4 is the most promising additive that reduces the oxidizing properties of HCl and H2SO4 in solutions. In the HCl–H3PO4–H2O system taken as an example, the main regularities of changes in the oxidizing properties of two-component acid mixtures containing Fe(III) and Fe(II) are revealed. Variation in the total content of an equimolar Fe(III)+Fe(II) mixture (C = 0.01–0.10 M) in 1 M HCl + 1 M H3PO4 nearly does not affect its oxidative ability. Conversely, an increase in the relative content of Fe(III) in the system considerably increases its oxidative potential. At a fixed concentration of the Fe(III) + Fe(II) mixture (0.04 M) in the HCl + H3PO4 system, an increase in the concentration of these acids from 1 to 4 M slightly reduces the oxidative properties of the system. Improving the corrosion protection of steel in HCl or H2SO4 solutions containing Fe(III) salts with a composite inhibitor (IFKhAN-92 + KNCS + hexamine) can be effective when H3PO4 is added. This effect is largely determined by the binding of Fe(III) cations to phosphate complexes, which have a lower oxidizing capacity compared to its aqueous, sulfate and chloride complexes.

Int. J. Corros. Scale Inhib., , 1, 139-149 PDF (492 K)
doi: 10.17675/2305-6894-2019-8-1-12

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