ISSN 2305-6894

2016, Vol. 5, Issue 4 (pp. 282–375)

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N-Substituted unusual amino acids as corrosion inhibitors. Part IV: N-Acyl derivatives of unnatural amino acids with double bond

1 Óbuda University, Faculty of Light Industry and Environmental Engineering, Doberdó u. 6., 1034 Budapest, Hungary
2 Department of Interfaces and Surface Modification, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117 Budapest, Hungary

Abstract: Corrosion inhibition efficiency of unusual phenyl alanine derivatives (substituted in the phenyl ring and double bond in the side chain) were investigated in neutral aqueous solution by weight loss test and by atomic force microscopy. The influence of the substituents in the phenyl ring as well as of the double bond was elucidated and explained. The effect of electrophilic or nucleophilic groups in the phenyl ring was demonstrated by efficacy and roughness parameters

Int. J. Corros. Scale Inhib., , 4, 360–366 PDF (350 K)
doi: 10.17675/2305-6894-2016-5-4-6

Control of thermal conditions as a method of protecting iron against local dissolution

  • , and
1 Federal State Budgetary Educational Institution of Higher Professional Education Voronezh State University, 1 Universitetskaya Square, Voronezh, 394006, Russian Federation
2 Federal State Budgetary Educational Institution of Higher Professional Education Voronezh State Pedagogical University, 86 Lenina Street, Voronezh, 394043, Russian Federation

Abstract: Using a model setup reproducing various operation conditions of heat transfer equipment, the temperature conditions at the metal/solution interface that may inhibit the local violation of passive iron in soft water in the presence of Cl, Br, I, SO42-, and NO3- anions have been determined. It has been demonstrated that the presence of a positive heat flow directed from the solid to the liquid phase protects the metal from local damage in all the systems studied, in contrast to the conditions of thermal equilibrium where a similar effect can be observed only at a certain temperature of the metal surface.

Int. J. Corros. Scale Inhib., , 4, 367–375 PDF (666 K)
doi: 10.17675/2305-6894-2016-5-4-7

Corrosion inhibition potentiality of some benzimidazole derivatives for mild steel in hydrochloric acid: Electrochemical and weight loss studies

  • , and
1 Laboratory of separation processes, Faculty of Science, University Ibn Tofail, PO Box 242, Kenitra, Morocco
2 Laboratory of Applied Chemistry and Environment, ENSA, Ibn Zohr University, PO Box 1136, 80000 Agadir, Morocco
3 Department of Chemistry, An-Najah National University, PO Box 7, Nablus, Palestine

Abstract: The adsorption and inhibition effects of three benzimidazole derivatives (BDD), namely: 2-(2-pyridyl)benzimidazole (PBD), 2-bromo-1H-benzimidazole (BrBD), and 2-chlorobenzimidazole (ClBD) on mild steel corrosion in 1 M HCl have been studied by electrochemical and weight loss methods. Results showed that inhibition efficiency increases with concentration and maximum value was obtained at 5·10–3 M concentration. From the results, it is concluded that the BDD inhibited mild steel corrosion in 1 M HCl by adsorbing on the metal surface. Polarization results showed that the BDD act as mixed type inhibitors. The adsorption of BDD onto the mild steel surface was described by the Langmuir adsorption isotherm.

Int. J. Corros. Scale Inhib., , 4, 347–359 PDF (361 K)
doi: 10.17675/2305-6894-2016-5-4-5

Corrosion inhibition of a composite inhibitor containing imidazoline on carbon steel in simulated reverse osmosis product water of seawater

  • , , , and
1 Shanghai University of Electric Power, Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power, Shanghai 20009, China
2 Shanghai Fakai Chemical Industry Co. Ltd., Shanghai 201505, China

Abstract: The synergistic performance of corrosion inhibition of 2-undecyl-N-carboxymethyl-Nhydroxyethyl imidazoline (UHCI) and ZnSO4 on 20# carbon steel surface in simulated reverse osmosis product water of seawater was investigated by electrochemical methods, scanning atomic force microscopy (AFM) and X-ray diffraction (XRD). The results show that the composite inhibitor acts as a mixed type inhibitor, reducing the corrosion of carbon steel effectively and the inhibition efficiency reaches the best values when the mass concentration ratio of UHCI and ZnSO4 is 50 : 50 at the total concentration of the solution is 100 mg/L where the corrosion inhibition efficiency reaches 96.99%. The UHCI molecules adsorbed on metal surfaces, controlling the anodic reaction. ZnSO4 is deposited on the metal surface in the form of Zn(OH)2, controlling the cathodic reaction.

Int. J. Corros. Scale Inhib., , 4, 325–332 PDF (454 K)
doi: 10.17675/2305-6894-2016-5-4-3

Environmental testing of the efficiency of IFKhAN-80, an inhibitor for corrosion protection of steel reinforcement in concrete

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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: Environmental tests of the efficiency of IFKhAN-80, a corrosion inhibitor for steel reinforcement in concrete, have been carried out. It has been found that the electrochemical criteria for the estimation of the corrosion behavior of steel reinforcement in concrete recommended by GOST (RF State Standard) 31383-2008 are not informative under the test conditions used. In view of this, the effect of IFKhAN-80 on the kinetics of corrosion spot growth on steel surface has been analyzed. In the absence of an inhibitor, corrosion of reinforcement steel already occurs in the course of hardening of chloride-containing concrete. Once hardening is completed, the growth rate of corrosion spots decreases abruptly. The area of corroded surface remains unchanged for 6 months, then the growth of corrosion spots on the metal surface resumes. Addition of IFKhAN-80 with tempering water in amounts recommended by the developers slows down corrosion in the course of concrete hardening and during exposure under natural conditions. Application of IFKhAN80 onto the surface of concrete samples in amounts recommended by the developers can arrest the growth of corrosion spots for a long time.

Int. J. Corros. Scale Inhib., , 4, 319–324 PDF (195 K)
doi: 10.17675/2305-6894-2016-5-4-2

Organic corrosion inhibitors: where are we now? A review. Part II. Passivation and the role of chemical structure of carboxylates

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

Abstract: This article provides an overview of works (2006–2016) devoted to the passivation of various metals and the influence of organic carboxylic acids and their salts thereon. The results of corrosion and electrochemical studies, as well studies on the composition and structural features of surface layers on the metals being protected by a variety of physicochemical methods are considered.

Int. J. Corros. Scale Inhib., , 4, 282–318 PDF (848 K)
doi: 10.17675/2305-6894-2016-5-4-1

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