ISSN 2305-6894

2015, Vol. 4, Issue 1 (pp. 1–107)

Another Giant passed away
(To the memory of Prof. Giordano Trabanelli)

With immense sadness the team of the Corrosion and Metallurgy Study Centre “Aldo Daccò” of the University of Ferrara announces the death of Prof. Giordano Trabanelli (retired, Emeritus Professor of the University of Ferrara), a well-known and highly esteemed scientist in the field of corrosion inhibition.

The science of corrosion inhibitors suffered a severe loss

The science of corrosion inhibitors suffered a severe loss: Professor Giordano Trabanelli passed away.

Protection of chromium-nickel steel in hydrochloric acid solution by a substituted triazole

      • Ya. G. Avdeev,1 D. S. Kuznetsov,2 M. V. Tyurina,1 A. Yu. Luchkin,2 and M. A. Chekulaev1
1 K. E. Tsiolkovsky Kaluga state university, 248023 Kaluga, Russian Federation
2 A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow, 119071 Russian Federation

Abstract: The corrosion of chromium-nickel steel 12Kh18N10T in 2.0 M HCl (t = 20–100°C) was studied using mass loss, potentiometric, and polarization methods. Efficient steel protection under these conditions can be achieved by inhibitors such as triazole derivative IFKhAN 92, alone or in combination with hexamethylenetetramine in a molar component ratio of 1 : 4. The proposed mixed inhibitor often protects steel 12Kh18N10T in HCl solutions in a broad temperature range, 20–100°C, more efficiently than IFKhAN-92 alone at the same concentrations. The triazole in question and its blend with urotropine ensure metal protection in acid solutions for at least 8 h. Since for IFKhAN-92 alone and its blend with urotropine the corrosion inhibition coefficients grow with an increase in temperature, at least to t = 100°C, they should be attributed to so-called “high-temperature inhibitors of acid corrosion”. The presence of inhibitors of interest in the solution considerably increases the fraction of diffusion control in the corrosion process, as indicated by the significant decrease in effective activation energy in the presence of these compounds. Steel corrosion occurs in the active dissolution region both in background and inhibited acid solutions. The corrosion potential of steel is more positive in solutions containing inhibitors because they predominantly slow down the anodic reaction. Addition of IFKhAN-92 or its mixture with urotropine to an HCl solution hinders considerably the electrode reactions on steel in the entire temperature range studied. In this case, the cathodic and anodic current densities decrease with time, while the inhibition coefficients of electrode reactions either increase or remain nearly constant. The corrosion potentials decrease with time in the presence of the additives in question at t = 20–60°C, which suggests that hindrance of the cathodic reaction is predominantly improved due to adsorption of inhibitors. It has been shown that the efficient inhibition of stainless steel corrosion in HCl solution by addition of IFKhAN-92 or IFKhAN-92 + urotropine results from strong hindrance of both electrode reaction on the metal by these inhibitors, which becomes stronger in time and remains in effect as the temperature increases.

Int. J. Corros. Scale Inhib., 2015, 4, no. 1, 1–14 (PDF 183 K)
doi: 10.17675/2305-6894-2015-4-1-001-014

Progress in the science of corrosion inhibitors

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

Abstract: The physicochemical features of corrosion inhibition of metals (alloys) strongly depend on the composition of the corrosive environment, its pH, temperature t, hydrodynamic conditions, the chemical nature of the metal to be protected, and the state of its surface, the presence of oxides, dirt, or corrosion products on it. This “multifactor” nature of corrosion seriously complicates the theoretical choice of an efficient corrosion inhibitor (CI), often requiring careful experimental studies and creating unjustified skepticism about the fundamental character of the physical chemistry area related to the study and development of CIs. Meanwhile, this skepticism can be proved wrong by the progress made over the past quarter century in various subareas.

Int. J. Corros. Scale Inhib., 2015, 4, no. 1, 15–34 (PDF 487 K)
doi: 10.17675/2305-6894-2015-4-1-015-034

Metal corrosion and its relation to other fields of science

      • S. Szabó
Institute of Materials and Environmental Chemistry, Research Center for Natural Sciences, Hungarian Academy of Sciences, Budapest H-1519, P.O. Box 286, Hungary

Abstract: Metal corrosion is a charge transfer process. Study of corrosion and corrosion protection requires manifold knowledge in he field of thermodynamics, reaction kinetics, catalysis, transport and surface phenomena. Dealloying, biocorrosion, corrosion effects of electric traction and energy systems are also very important scientific fields for understanding corrosion.

Int. J. Corros. Scale Inhib., 2015, 4, no. 1, 35–48 (PDF 135 K)
doi: 10.17675/2305-6894-2015-4-1-035-048

Residual protective effect of some intermediates in polyvinylpyrrolidone production

      • N. A Belousova, V. P. Grigor’ev and E. V. Plekhanova
Southern Federal University, Zorge st. 7, Rostov-on-Don, 344090 Russian Federation

Abstract: The regularities of changes in the residual protective effect (RPE) of wastes of polyvinylpyrrolidone production on the acid corrosion of steel were investigated. The duration of RPE increases with increasing duration of pre-adsorption. It was shown that the duration of the RPE (τ) is a function of the additive concentration in the pre-adsorption solution.

Int. J. Corros. Scale Inhib., 2015, 4, no. 1, 49–56 (PDF 365 K)
doi: 10.17675/2305-6894-2015-4-1-049-056

Enhanced corrosion inhibition of mild steel in CO2-saturated solutions containing some novel green surfactants based on cottonseed oil

      • I. T. Ismayilov,1,2 Hany M. Abd El-Lateef,2 V. M. Abbasov,1 E. N. Efremenko,3 L. I. Aliyeva1 and Ch. K. Salmanova1
1 Mamedaliev Institute of Petrochemical Processes, National Academy of Sciences of Azerbaijan, AZ1025 Baku, Azerbaijan
2 Chemistry Department, Faculty of Science, Sohag University, 82524 Sohag, Egypt
3 Faculty of Chemistry, Lomonosov Moscow State University, 119991, GSP-1, 1-3 Leninskiye Gory, Moscow, Russia

Abstract: Some novel green surfactants based on cottonseed oil were synthesized and tested as inhibitors for the corrosion of mild steel in CO2-saturated 1% NaCl solution by potentiodynamic polarization and linear polarization resistance corrosion rate measurements at 50°C. Their critical micelle concentrations at equilibrium in water at 25°C were also determined. Inhibition efficiency increased with increase in the concentration of the studied surfactants, reached the maximum (99.34%) at 100 ppm. The Tafel polarization results indicate that the inhibitors act as mixed inhibitors. The adsorption of the inhibitors on the steel surface obeys Langmuir isotherms. The thermodynamic parameters of adsorption revealed a strong interaction between the inhibitors and the corroding mild steel surface.

Int. J. Corros. Scale Inhib., 2015, 4, no. 1, 57–74 (PDF 559 K)
doi: 10.17675/2305-6894-2015-4-1-057-074

Performance of phosphonates as copper(II) ions stabilization agents for industrial water systems

      • Z. Amjad
Walsh University, School of Arts and Sciences, North Canton, OH 44720, USA

Abstract: Copper(II) salts have long been used to kill algae in water systems, but they can precipitate as insoluble salts and form deposits on equipment surface. It is important to remove toxic metal from industrial waste because of contamination and toxicity issues. This paper discusses the testing and effects of various phosphonates to control copper-based fouling in the industrial water systems. It has been found that Cu(II) ions stabilization (complexation, precipitation, dispersion, etc.) strongly depends on solution pH, reaction time, and phosphonate concentration. Results on the evaluation of various phosphonates suggest the following order, in terms of decreasing effectiveness: HEDP ≈ HPA > PAPEMP > AMP >> PBTC.

Int. J. Corros. Scale Inhib., 2015, 4, no. 1, 75–84 (PDF 383 K)
doi: 10.17675/2305-6894-2015-4-1-075-084

Profound “turn-off” effects of anionic polymers on the inhibitory activity of cationic polyallylamine in the prevention of silica scale

      • A. Spinthaki, A. Stathoulopoulou and K. D. Demadis
Crystal Engineering, Growth and Design Laboratory, Department of Chemistry, University of Crete, Voutes Campus, Crete, GR -71003, Greece

Abstract: Colloidal/amorphous silica (SiO2·nH2O, n is variable) is considered as the most undesirable inorganic precipitate that forms during various processes in silica-supersaturated industrial waters. In this paper we present how certain polymeric chemical additives can prevent silicic acid polymerization to form colloidal silica, which may lead to deposition onto industrial equipment. More specifically, stabilization of silicic acid is accomplished by using a cationic polymer, polyallylamine hydrochloride (PALAM), in supersaturated silica solutions (starting silica concentration in the form of silicate 500 ppm, or 8.3 mM sodium orthosilicate, Na2SiO3·5H2O, expressed as SiO2) at pH = 7. PALAM is a linear homopolymer that carries one amine side functional group every two carbon atoms, so it becomes protonated at circumneutral pH, rendering the molecule cationic. Its blends with anionic polymers such as carboxymethylinulin (CMI), poly(acrylamide-co-acrylic acid) (PAM-co-AA) and phosphonomethylated chitosan (PCH) are also studied for their silica scale inhibition efficiency.

Int. J. Corros. Scale Inhib., 2015, 4, no. 1, 85–95 (PDF 457 K)
doi: 10.17675/2305-6894-2015-4-1-085-095

Alkyl-benzotriazole derivatives as inhibitors of iron and copper corrosion

      • G. Trabanelli, A. Frignani, C. Monticelli and F. Zucchi
Corrosion Study Centre “A. Daccò”, University of Ferrara, via A. Saragat 1, 44122 Ferrara, Italy

Abstract: 5-Alkyl derivatives of benzotriazole (1–12 carbon atom long alkyl chain) were tested as inhibitors of pure iron corrosion in sulphuric or hydrochloric acid at 25°C and pure copper corrosion in acidic sulphate and saline solutions at 30°C. This series of compounds was more efficient in contrasting copper than iron corrosion and, generally, the longer the alkyl chain the higher the inhibiting performances and the longer the persistency of the inhibiting action. However, due to a decrease in the solubility, the maximum inhibiting effects were produced by the hexyl derivative. In the case of iron, these compounds were more efficient in the hydrochloric acid solution than in the sulphuric one, while for copper they were more effective in the acidic sulphate solution than in the acidic chloride solution. The higher inhibiting effects for copper can be justified by the mode of BTA adsorption, that consists in chemisorption, instead of physisorption occurring on iron.

Int. J. Corros. Scale Inhib., 2015, 4, no. 1, 96-107 (PDF 270 K)
doi: 10.17675/2305-6894-2015-4-1-096-107