ISSN 2305-6894

2014, Vol. 3, Issue 2 (pp. 78–148)

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Adsorption and passivation of copper by triazoles in neutral aqueous solution

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1 A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow, 119071 Russian Federation
2 Voronezh State University, Universitetskaya pl. 1, Voronezh, 394006 Russian Federation

Abstract: The relationship between hydrophobicity of triazoles and their adsorption and passivation ability in relation to copper is analyzed. Adsorption of triazoles on oxidized copper surface is polymolecular. Adsorption of the first monolayer is described by Frumkin equation with the free energy of adsorption in the range of 51–70 kJ/mol. Certain triazoles are able to effectively inhibit anodic dissolution of copper in neutral chloride solutions. The possible spatial arrangement of the triazoles on the surface of oxidized copper is revealed.

Int. J. Corros. Scale Inhib., , 2, 137–148 PDF (739 K)
doi: 10.17675/2305-6894-2014-3-2-137-148

Electrochemical investigations of aluminium alloys tribocorrosion

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G.V.Karpenko Physico-Mechanical Institute of National Academy of Sciences of Ukraine, 79603 Lviv, Ukraine

Abstract: Electrochemical methods based on corrosion potential and polarization current measurements are widely used in tribocorrosion research. However, most equipment types allow recording of integrated electrochemical parameters of metals during tribocorrosion, but little attention is paid to local processes that occur on friction surfaces. It was proposed to use a capillary probe as a reference electrode, which reduces the effect of cathodic sites on sample tribopotential and allows measurements in low-conductivity solutions. The study was carried out on an example of the widely used AA2024 alloy, and may relate to structural aluminum alloys. It was shown that the difference between tribopotential values of the alloy measured by classic electrochemical technique and capillary probe may be up to 0.6 V in a study in glycerin. It was established that correlation exists between the current of alloy polarization at the corrosion potential in distilled water and the volume of worn material. The empirical relationship found for a ball-on-flat tribometer with reversible sliding provides a possibility to estimate the amount of worn material based on polarization currents. This method may also be promising in studies on the efficiency of corrosion inhibitors on mechanically activated surface of passive metal.

Int. J. Corros. Scale Inhib., , 2, 129–136 PDF (1 114 K)
doi: 10.17675/2305-6894-2014-3-2-129-136

Influence of the ways of expression of the additivity of superficial protective film components on the estimation of their partial contributions to the total protective effect

  • R. V. Kashkovskiy
Gazprom VNIIGAZ LLC, Razvilka, Leninsky Rayon, Moscow Region, 142717 Russian Federation

Abstract: As studies directed at improvement of a method for estimation of the amount to which corrosion products and inhibitor films contribute to the total protection effects are being held, various approaches to express the additivity of superficial protective film components are considered, along with their influence on the estimation of the partial contributions of each individual component of a superficial protective film. The latter will be discussed in our subsequent study.

Int. J. Corros. Scale Inhib., , 2, 120–128 PDF (634 K)
doi: 10.17675/2305-6894-2014-3-2-120-128

Acetylenic alcohols as inhibitors of iron acid corrosion. Improvement of the inhibition efficiency of a class of substances based on their action mechanism

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Corrosion Study Centre “A. Daccò”, University of Ferrara, v. Saragat 1, 44122 Ferrara (I)

Abstract: This paper shows the results obtained in “A. Daccò” Corrosion Study Centre on the inhibition of iron acid corrosion by acetylenic alcohols. The improvement in the protective performances of this class of substances was obtained through base molecule modifications related to their action mechanism (i.e., initial adsorption onto the metal surface and successive polymeric layer formation). Therefore, in an attempt to favour molecular adsorption, some 3-methyl-1-butyne derivatives were modified by substituting the acetylenic hydrogen atom with halogen atoms (Cl, Br or I), while alkyn-3-ols were modified by increasing their alkyl chain length to determine the subsequent polymeric layer improvement. The presence of halo-atoms of increasing polarizability favoured the inhibiting action of 3-methyl-1-butyne derivatives to the anodic reaction, while the lengthening of the alkyl chain in alkyn-3-ols promoted a marked increase in the inhibiting effects due to the formation of a thick layer. In this latter class of substances the iodine atom significantly increased the persistence of the inhibiting action.

Int. J. Corros. Scale Inhib., , 2, 105–119 PDF (973 K)
doi: 10.17675/2305-6894-2014-3-2-105-119

Regularities of oilfield pipeline leak rate variation in time

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

Abstract: The dependence of the rate of corrosion-related oilfield pipeline leaks on operation time is analyzed. It is shown theoretically that the oilfield pipeline leak rate first increases and then decreases after reaching a maximum. The validity of this conclusion is demonstrated using data on the leak rate at various oilfield pipeline types

Int. J. Corros. Scale Inhib., , 2, 101–104 PDF (462 K)
doi: 10.17675/2305-6894-2014-3-2-101-104

Investigations on the influence of phosphonates in dispersing iron oxide (rust) by polymeric additives for industrial water applications

  • Z. Amjad
Division of Mathematics and Sciences, Walsh University, 2020 E. Maple Street, N. Canton, Ohio 44270, USA

Abstract: The performance of polymeric and non-polymeric additives as iron oxide (rust) dispersants in aqueous system has been investigated. The polymers evaluated include: homopolymers of acrylic acid, aspartic acid; copolymers of acrylic acid : vinyl acetate; acrylic acid : hydroxylpropyl acrylate, maleic acid :sulfonated styrene; and terpolymer of acrylic acid : 2-acrylamido-2-methyl propane sulfonic acid :sulfonated styrene. Phosphonates (or nonpolymeric additives) tested include: hydroxyphosphono acetic acid, HPA; aminotris(methylenephosphonic acid), AMP; hydroxyethylidene 1,1-diphosphonic acid, HEDP; 2-phosphonobutane 1,2,4-tricarboxylic acid, PBTC; and polyamino polyether methylene phosphonic acid, PAPEMP. Based on the performance data, polymers effectiveness as iron oxide dispersants is: terpolymer > copolymer > homopolymer. Under similar experimental conditions, phosphonates exhibit poor performance as iron oxide dispersants. It has also been observed that presence of phosphonates exhibit antagonistic effect on the performance of polymers.

Int. J. Corros. Scale Inhib., , 2, 89–100 PDF (871 K)
doi: 10.17675/2305-6894-2014-3-2-089-100

Electrochemical and XPS study of 2-merсaptobenzothiazole nanolayers on zinc and copper surface

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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: The electrochemical behavior of copper and zinc in neutral (рН 7.4) borate buffer solution with addition of 0.5 M NaCl and the effect of 2-merсaptobenzothiazole (MBT) on the electrochemical processes and adsorption on these metals has been studied by means of electrochemistry and X-ray photoelectron spectroscopy (XPS). The formation of MBT–metal cation complex films on copper and zinc surface has been shown. The effect of corrosive media composition and time-dependent relations of nanoscale film growth on the surface of the metals investigated have been determined. It was assumed that adsorbed MBT anion forms M(MBT)х, a polymeric complex where M = Cu+ (x = 1) or Zn2+ (x = 2).

Int. J. Corros. Scale Inhib., , 2, 78–88 PDF (1 241 K)
doi: 10.17675/2305-6894-2014-3-2-078-088

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