ISSN 2305-6894

2016, Vol. 5, Issue 2 (pp. 100-189)

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N-Substituted amino acids as multifunctional additives used in cooling water. Part II: N-carboxymethyl and phosphonomethyl amino acids

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: The aim of research was to find additives with different capacities that can control the undesired corrosion and scale formation at the same time. Amino acids with different (carboxymethyl and/or phosphonomethyl) substituents were investigated to prove their multifunctional effectiveness. The most interesting parameters were the number of –COOH and –PO3H2 groups as well as the structure of the side chain in the amino acids. The experimental data proved that both the alkyl side chains (with or without additional carboxy and phosphonic groups) as well as the number of the ionizable substituents in the molecules influence the both efficacies.

Int. J. Corros. Scale Inhib., , 2, 183–189 PDF (580 K)
doi: 10.17675/2305-6894-2016-5-2-7

Electrochemistry in nanotechnology

  • M. Lakatos-Varsányi
Bay Zoltán Nonprofit Ltd, 1116 Budapest, Kondorfa utca 1., Hungary

Abstract: Corrosion results in short- or long-term deterioration of materials. All over the world, researchers and engineers try to find better and better resolution to inhibit these undesired processes. One of the very efficient techniques, when the metal surface is covered by nanolayers, that can control the corrosion, is the deposition of solids by metal layers with predefined characteristics (composition, thickness, etc.) Among the many electrochemical processes, we have applied the non-stationary electrochemical method, named pulse current electrochemical deposition (PC-technique) for nanostructured thin layers deposition. Applying a current interruption method, we produced pure metal and alloy coatings with various compositions and layer thickness developed from aqueous solutions, at ambient temperature. The exceptional advantage of pure metal coatings produced by PC technique is the pore free, nano-sized structure. All technical details are summarized in this paper and the anticorrosion efficiency of the nanocoatings is demonstrated, too.

Int. J. Corros. Scale Inhib., , 2, 172–182 PDF (963 K)
doi: 10.17675/2305-6894-2016-5-2-6

Argania spinosa (L.) as a source of new and efficient green corrosion inhibitor for copper in acidic medium: a comparative study of three green compounds

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1 Laboratoire Matériaux et Environnement, Faculté des Sciences d’Agadir, Morocco
2 Laboratory of Applied Chemistry and Environment, ENSA, Université Ibn Zohr, PO Box 1136, 80000 Agadir, Morocco
3 Department of Chemistry, An-Najah National University, P. O. Box 7, Nablus, Palestine

Abstract: The inhibition effect of three green inhibitors, Argan Oil (AO), Cosmetic Argan Oil (CAO) and Argan Hulls Extract (AHE), against copper corrosion in 2 M H3PO4 containing 3·10-1 M NaCl solutions were evaluated using conventional weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy. The weight loss results showed that all the three green inhibitors are excellent corrosion inhibitors, electrochemical polarizations data discovered the mixed mode of inhibition and the results of electrochemical impedance spectroscopy have shown that the change in the impedance parameters, charge transfer resistance and double layer capacitance, with the change in concentration of the inhibitors employed is due to the adsorption of the molecule leading to the formation of a protective layer on the surface of copper. The values of the inhibition efficiency calculated from these techniques are in reasonably good agreement.

Int. J. Corros. Scale Inhib., , 2, 159–171 PDF (661 K)
doi: 10.17675/2305-6894-2016-5-2-5

Protection of stainless steel in sulfuric acid solution containing hydrogen sulfide by inhibitors

  • , , , and
1 K.E. Tsiolkovsky Kaluga state university, Stepana Razina str., 26, Kaluga, 248023 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 1Kh18N9T in 2 М H2SO4 at t = 20–100°C was studied using the mass loss method. In addition, steel hydrogenation in the corrosive medium was measured by the vacuum extraction method. IFKhAN-92 (a 1,2,4-triazole derivative) and its combination with KI were studied as corrosion inhibitors. It was shown that 1Kh18N9T steel has low corrosion resistance in H2SO4 solutions, particularly at temperatures (t) close to 100°C. The steel corrosion rate is k = 1.7–727 g/(m2 h) under the conditions studied and increases with increasing t. Steel hydrogenation occurs at t = 40–100°C and is the strongest at 100°C (12 ml/100 g). The presence of 15 mM H2S in the H2SO4 solution slows down steel corrosion (k = 2.8–274 g/(m2 h)) but intensifies hydrogen absorption. The highest content of hydrogen absorbed in the metal (36 ml / 100 g) was observed at t = 40°C and 1 h exposure of the specimens. It has been shown that, by themselves, 5 mM IFKhAN-92 or 5 mM KI are not suitable for protection of 1Kh18N9T steel in the specified media, since IFKhAN-92 has low efficiency in H2SO4 solution without H2S, whereas, conversely, KI has low efficiency in H2SO4 solution containing H2S. However, their mixture shows versatile protection in these media. The formulation containing 2.5 mM IFKhAN-92 + 2.5 mM KI that suppresses steel corrosion in H2Scontaining medium up to 100°С and totally prevents hydrogen absorption up to 60°C, inclusive, has been recommended for steel protection in H2SO4, both in the absence and in the presence of H2S. This mixture is particularly efficient in solutions without H2S where it inhibits steel corrosion in the entire t range studied while keeping the content of hydrogen in the metal at metallurgical level.

Int. J. Corros. Scale Inhib., , 2, 147–158 PDF (301 K)
doi: 10.17675/2305-6894-2016-5-2-4

Mild steel protection in acidic media using Mucuna pruriens seed extract

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1 Electrochemical and Material Science Unit (EMRU), Department of Chemistry, School of Sciences, Federal University of Technology Owerri, PMB 1526 Owerri, Nigeria
2 Department of Chemistry; School of Physical Sciences, Federal University of Technology Owerri, PMB 1526 Owerri, Nigeria

Abstract: The inhibition of corrosion of mild steel in 1 molar hydrochloric acid solution (1 M HCl) by Mucuna pruriens seed extract (MPSE) was investigated by weight-loss and electrochemical techniques. A significant decrease in the corrosion rate of mild steel was observed in the presence of the investigated additive and the inhibition efficiency was found to depend on the concentration of the MPSE. The potentiodynamic polarization data indicated that this additive was of mixed type, but the anodic effect was more pronounced. Nyquist plots showed that on increasing the MPSE concentration, the charge transfer resistance increased and double layer capacitance decreased. The thermodynamic parameters of adsorption revealed a strong interaction between the MPSE constituents and the corroding metal surface. MPSE lowered the corrosion reaction by blocking the mild steel surface through chemical adsorption. The mechanism of inhibition was discussed in the light of the chemical structure of the four major components of MPSE.

Int. J. Corros. Scale Inhib., , 2, 132–146 PDF (392 K)
doi: 10.17675/2305-6894-2016-5-2-3

Study on corrosion inhibition efficiency of some quinazoline derivatives on stainless steel 304 in hydrochloric acid solutions

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1 Department of chemistry, Faculty of Science, Mansoura University, Mansoura-35516, Egypt
2 Department chemistry, Faculty of Science, Tanta University, Tanta, Egypt

Abstract: The effect of the addition of some quinazoline derivatives on the corrosion of stainless steel 304 (SS 304) in hydrochloric acid medium was investigated using electrochemical frequency modulation (EFM), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and weight reduction measurements, The inhibition efficiency increases with increasing the inhibitor concentration, but decreases with increasing the temperature. The adsorption of these compounds on the stainless steel 304 surface follows Langmuir isotherm. Potentiodynamic polarization studies showed that these compounds are mixed-type inhibitors. The results obtained from all the measurements are in good agreement. The effect of temperature in the range 298–328 K on the corrosion of stainless steel 304 in 1 M HCl was tested and thermodynamic parameters were computed and discussed.

Int. J. Corros. Scale Inhib., , 2, 112–131 PDF (403 K)
doi: 10.17675/2305-6894-2016-5-2-2

Silica scale control by non-ionic polymers: The influence of water system impurities

  • Z. Amjad
School of Arts and Sciences, Walsh University, N. Canton, Ohio, 44720, USA

Abstract: Silica and metal silicate are perhaps the most undesirable deposit encountered in industrial water systems including cooling, desalination, and geothermal. Conventional anionic scale and deposit control agents are not effective in controlling silica-based scales. The complexity of controlling silica laden waters stem from the limited solubility of both amorphous (polymerized) silica and metal silicates. Once formed, silica scale is extremely difficult to remove and often requires the use of mechanical and/or chemical methods. Several laboratory evaluations were conducted to better understand the performance of non-ionic polymers as silica polymerization inhibitors. The impact of system impurities such as trivalent metal ions (Al3+, Fe3+) and suspended matter (clay) on the performance of silica inhibitors was also evaluated.

Int. J. Corros. Scale Inhib., , 2, 100–111 PDF (211 K)
doi: 10.17675/2305-6894-2016-5-2-1

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