ISSN 2305-6894

2018, Vol. 7, Issue 2 (pp. 112-tbd)

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Assessment of inhibiting features of some commercial bactericides

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1 Gasprom VNIIGAZ, Proektiruemiy proezd 5537, vlad. 15, str. 1, Razvilka village, 142717Moscow region, Russia
2 Gasprom PJSC, 16 Nametkina St., 117997Moscow, Russia
3 Gubkin Russian State University of Oil and Gas, 65 Leninsky Prospekt, 119991 Moscow, Russia

Abstract: The study deals with bacteriological and anti-corrosion features of three domestic bactericidal corrosion inhibitors (CI) in presence of sulphate-reducing bacteria in an oxygen-depleted and CO2-containing nutritent medium. Efficacy of compositions under study in both inhibiting bacterial growth in an environment and decreasing total corrosion rate in structural steel was measured experimentally. Particular attention in discussion of results was paid to applicability conditions of optical evaluation method for bactericidal features of additives.

Int. J. Corros. Scale Inhib., , 2, 112-125 PDF (2 661 K)
doi: 10.17675/2305-6894-2018-7-2-1

Volatile corrosion inhibitors for ferrous and non-ferrous metals and alloys: A review

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1 Department of Applied Chemistry, JETGI, Faculty of Engineering, Barabanki, India-225203
2 Department of Chemistry, School of Mathematical & Physical Sciences, Faculty of Agriculture, Science and Technology, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho 2735, South Africa
3 Material Science Innovation & Modelling (MaSIM) Research Focus Area, Faculty of Agriculture, Science and Technology, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho 2735, South Africa
4 Assistant Professor, Department of Civil Engineering, JETGI, Faculty of Engineering, Barabanki, India-225203
5 Center of Research Excellence in Corrosion, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia

Abstract:

Int. J. Corros. Scale Inhib., , 2, 126-150 PDF (1 453 K)
doi: 10.17675/2305-6894-2018-7-2-2

Effect of binary mixtures on chloride induced corrosion of rebars in concrete

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Politecnico di Milano, Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta” Via Mancinelli 7, 20131 Milano, Italy

Abstract: Rebar corrosion is one of the most important phenomena affecting the durability of reinforced concrete structures. Corrosion inhibitors can be used as a preventative method, able to delay corrosion, or as repair method, to reduce corrosion rate. During more than 15 years in our laboratories an intense experimental research was carried out: the aim of the research was to identify new organic substances or mixtures thereof that might have inhibiting effectiveness. In the paper the effect of binary mixtures on chloride induced corrosion of rebars in concrete is studied; the mixtures are based on two amines, dimethylethanolamine (DMEA) and triethylenetetramine (TETA), and a carboxylate (benzoate); the tests were carried out for comparison purpose also in concrete containing nitrite, acknowledged to be the most effective product. The best results among the binary mixtures were shown by the benzoate–TETA, while the mixtures based on DMEA–TETA were not satisfactory. The performance of the mixtures is not comparable to nitrites.

Int. J. Corros. Scale Inhib., , 2, 151-164 PDF (1 094 K)
doi: 10.17675/2305-6894-2018-7-2-3

A study on the desorption of phosphonic acids, corrosion inhibitor precursors, from polymer microcapsules

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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 National Research Moscow State University of Civil Engineering (NRU MGSU), Yaroslavskoye shosse 26, Moscow, 129337 Russian Federation

Abstract: Salts of phosphonic acids are known as efficient corrosion inhibitors in anticorrosive coatings. Incorporation of phosphonates in microscopic capsules into a coating makes it possible to initiate desorption from capsules and diffusion of the inhibitor to the substrate “on demand”. The desorption kinetics of phosphonic acids at the initial stage of contact of a capsule with a water flow and until establishment of a stable inhibitor flux has been studied. The diffusion coefficients of the acid extracted from capsules have been estimated. The efficiency of granulation and extraction processes for building microcapsule walls resistant to water and organic solvents has been shown.

Int. J. Corros. Scale Inhib., , 2, 165-174 PDF (684 K)
doi: 10.17675/2305-6894-2018-7-2-4

Protection of carbon steel against atmospheric corrosion by volatile inhibitors of IFKhAN series at high concentrations of CO2, H2S and NH3

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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, ul. Sovetskaya, 106, Tambov, 392000, Russian Federation
3 Derzhavin State University, ul. Internatsyonalnaya, 33, Tambov, 392000, Russian Federation

Abstract: The protective efficacy of volatile inhibitors (VCI) of IFKhAN-A series (A-8, 112, 114, 118) against atmospheric corrosion of carbon steel St3 was studied at room temperature in air in the presence of corrosion stimulants (CS) at specified concentrations: CO2 (0.2–0.6) vol.%, H2S (10–30) mg/m3 and NH3 (20–60) mg/m3. The relative humidity was 100%. Corrosion tests were carried out in sealed containers of 7 liters in volume (desiccators) in two versions. In one version, only one CS was introduced into the air atmosphere. In the other, two or all three used CS were simultaneously injected into the gas phase. To create equilibrium concentrations of the CS in the air atmosphere, a special technique has been developed. The duration of the corrosion tests was 240–528 hours. Potentiodynamic polarization measurements were performed at a potential sweep rate of 0.66 mV/s immediately after immersing the electrodes in the solution and after 24 to 96 hours of their stay in the corrosive medium (in situ). In the presence of CO2 in air atmosphere, the protective efficiency of all the VCIs studied is close to 100%. In the presence of NH3 (20 mg/m3), it is within 74% (IFKhAN-8) to 21% (IFKhAN-118). In the presence of H2S, the protective effect of the VCIs increases again, amounting to 93–97%. In uninhibited systems containing simultaneously two stimulants of corrosion, intense pitting is observed. When CO2 and NH3 are introduced simultaneously, the protective effect of the investigated VCIs is in the range of 76–87%, with CO2+H2S it is 81% (A-112 and 118) to 100% (A-114), and with H2S+NH3, it is 67–85%. The most effective is IFKhAN-114, which not only reduces the corrosion rate, but also eliminates pitting (CO2+NH3). Introduction of IFKhAN-114 allows one to achieve the protective effect of 95% in the presence of all three CS simultaneously. The corrosion rate of steel in the uninhibited background solution is limited by the cathodic reaction. In the presence of (NH4)2S as an NH3 and H2S reaction product, the IFKhAN-114 inhibitor effectively inhibits the anodic process. As a result, the corrosion potential of steel is increased by 0.070 V. The protective effect of IFKhAN-114 obtained from the data of potentiodynamic measurements in this medium immediately after immersing the electrode in the solution, is about 50%. This is lower than the value calculated from the results of gravimetric measurements, due to the different duration of steel aging in the corrosive environment.

Int. J. Corros. Scale Inhib., , 2, 175-184 PDF (515 K)
doi: 10.17675/2305-6894-2018-7-2-5

A comprehensive study of grape pomace extract and its active components as effective vapour phase corrosion inhibitor of mild steel

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1 National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Ave Peremogy 37, Kiev, 03056 Ukraine
2 Ukrainian State Chemical-Engineering University, Gagarin Ave. 8, Dnipro, 49005 Ukraine
3 Chernihiv National T.G. Shevchenko Pedagogical University, 53 Hetmana Polubotka str., 14013 Chernihiv, Ukraine

Abstract: The inhibition efficiency of grape pomace extract (GPE) and its main constituents (2-phenylacetaldehyde, hexanal) as a green volatile corrosion inhibitor for the temporary protection of mild steel was investigated. Weight loss measurements and potentiodynamic polarization techniques were all used for this assessment. The major constituents of GPE were identified by GC-MS analysis. Grape pomace extract inhibited mild steel corrosion under conditions of periodic condensation of moisture with a protection efficiency of ~92%. The gravimetric measurement indicates that inhibition efficiency shows direct proportional relation with concentration of inhibitor. The corrosion rate reduction is time dependent, and the highest protection values were achieved only in 48 h. Inhibition efficiency increases in the order: grape pomace extract > 2-phenylacetaldehyde > hexanal. The grape pomace extract and main components acted as a mixed-type inhibitor with predominant cathodic effectiveness. Structural characterization by using SEM, AFM images and FT-IR analysis further supported the electrochemical and weight loss measurements results obtained.

Int. J. Corros. Scale Inhib., , 2, 185-202 PDF (1 415 K)
doi: 10.17675/2305-6894-2018-7-2-6

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