International Journal of Corrosion The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. Effect of Grain Size on the Stress Corrosion Cracking of Ultrafine Grained Cu-10 wt% Zn Alloy in Ammonia Tue, 18 Jul 2017 07:54:43 +0000 The effect of grain size in the micron to submicron range on the stress corrosion cracking (SCC) of Cu-10 wt% Zn alloys was investigated using constant-load tests in ammonia vapor. The grain size was systematically varied from 4 μm to 0.12 μm by either cold-rolling or equal-channel angular pressing (ECAP), followed by annealing. The time to fracture increased with decreasing grain size above 1 μm but then began to decrease with decreasing grain size into the submicron range. This inverse trend in the submicron range is discussed in terms of a severe plastic deformation- (SPD-) induced ultrafine grain microstructure. Takuma Asabe, Muhammad Rifai, Motohiro Yuasa, and Hiroyuki Miyamoto Copyright © 2017 Takuma Asabe et al. All rights reserved. The Discrete Wavelet Transform and Its Application for Noise Removal in Localized Corrosion Measurements Sun, 04 Jun 2017 08:36:12 +0000 The present work discusses the problem of induced external electrical noise as well as its removal from the electrical potential obtained from Scanning Vibrating Electrode Technique (SVET) in the pitting corrosion process of aluminum alloy A96061 in 3.5% NaCl. An accessible and efficient solution of this problem is presented with the use of virtual instrumentation (VI), embedded systems, and the discrete wavelet transform (DWT). The DWT is a computational algorithm for digital processing that allows obtaining electrical noise with Signal to Noise Ratio (SNR) superior to those obtained with Lock-In Amplifier equipment. The results show that DWT and the threshold method are efficient and powerful alternatives to carry out electrical measurements of potential signals from localized corrosion processes measured by SVET. Rogelio Ramos, Benjamin Valdez-Salas, Roumen Zlatev, Michael Schorr Wiener, and Jose María Bastidas Rull Copyright © 2017 Rogelio Ramos et al. All rights reserved. The Effect of Graphene on the Protective Properties of Water-Based Epoxy Coatings on Al2024-T3 Thu, 25 May 2017 00:00:00 +0000 0.5 and 1% wt. of graphene nanoflakes were added to an anticorrosive additives-free water-based epoxy resin applied to Al2024-T3 samples. Calorimetric (DSC) and adhesion (cross-cut test) tests indicated that the presence of graphene did not affect the polymerization process of the resin or its adhesion to the substrate while it had some effect on its wettability. Electrochemical Impedance Spectroscopy (EIS) results obtained suggested that the addition of a small amount of graphene greatly enhanced the protective properties of the epoxy coating, retarding electrolytes absorption and reducing the total amount of adsorbed water. The latter occurrence suggests that the graphene effect on coating performances is related to both extended diffusion pathway length and graphene/matrix interaction due to the unique properties of graphene. T. Monetta, A. Acquesta, A. Carangelo, and F. Bellucci Copyright © 2017 T. Monetta et al. All rights reserved. Research of Microorganism Corrosion Properties of 2024-T31 Aluminum-Magnesium Alloy in Oil-Water System Tue, 11 Apr 2017 00:00:00 +0000 The surface analysis techniques and chemical technical means (polarization curves and AC impedance technique) were applied to research the corrosion characteristics of microorganisms SRB of 2024-T31 aluminum-magnesium alloy in the oil-water system, and the corrosion mechanism was finally analyzed. The results showed that SRB accelerate the corrosion process and cause uneven pitting on the surface of the metal matrix. Passive and biological films control the corrosion of the metal substrate in bacterial oil-water system. In the initial stage of immersion, a loose and uneven biofilm formed on the surface of substrate which accelerated its corrosion. In the midterm, the effect of biofilm gradually weakened while the protective effect of the passive film grew more insistently; the rate of corrosion slowed down. In the later period, localized corrosion cell of large cathode/small anode formed on the surface of the substrate which accelerates the corrosion. Yan-yu Cui, Jia Li, and Qing-miao Ding Copyright © 2017 Yan-yu Cui et al. All rights reserved. Electrodeposited Reduced Graphene Oxide Films on Stainless Steel, Copper, and Aluminum for Corrosion Protection Enhancement Sun, 02 Apr 2017 07:58:30 +0000 The enhancement of corrosion protection of metals and alloys by coating with simple, low cost, and highly adhered layer is still a main goal of many workers. In this research graphite flakes converted into graphene oxide using modified Hammers method and then reduced graphene oxide was electrodeposited on stainless steel 316, copper, and aluminum for corrosion protection application in seawater at four temperatures, namely, 20, 30, 40, and 50°C. All corrosion measurements, kinetics, and thermodynamics parameters were established from Tafel plots using three-electrode potentiostat. The deposited films were examined by FTIR, Raman, XRD, SEM, and AFM techniques; they revealed high percentages of conversion to the few layers of graphene with confirmed defects. Abdulkareem Mohammed Ali Al-Sammarraie and Mazin Hasan Raheema Copyright © 2017 Abdulkareem Mohammed Ali Al-Sammarraie and Mazin Hasan Raheema. All rights reserved. Semiempirical Theoretical Studies of 1,3-Benzodioxole Derivatives as Corrosion Inhibitors Mon, 20 Mar 2017 07:54:55 +0000 The efficiency of 1,3-benzodioxole derivatives as corrosion inhibitors is theoretically studied using quantum chemical calculation and Quantitative Structure Activity Relationship (QSAR). Different semiempirical methods (AM1, PM3, MNDO, MINDO/3, and INDO) are applied in order to determine the relationship between molecular structure and their corrosion protection efficiencies. Different quantum parameters are obtained as the energy of highest occupied molecular orbital , the energy of the lowest unoccupied molecular orbital , energy gap , dipole moment μ, and Mulliken charge on the atom. QSAR approach is applied to elucidate some important parameters as the hydrophobicity (Log P), surface area (S.A), polarization , and hydration energy (). Omnia A. A. El-Shamy Copyright © 2017 Omnia A. A. El-Shamy. All rights reserved. Chloride-Induced Corrosion of Steel in Concrete: An Overview on Chloride Diffusion and Prediction of Corrosion Initiation Time Wed, 22 Feb 2017 00:00:00 +0000 Initiation of corrosion of steel in reinforced concrete (RC) structures subjected to chloride exposures mainly depends on coefficient of chloride diffusion, , of concrete. Therefore, is one of the key parameters needed for prediction of initiation of reinforcement corrosion. Fick’s second law of diffusion has been used for long time to derive the models for chloride diffusion in concrete. However, such models do not include the effects of various significant factors such as chloride binding by the cement, multidirectional ingress of chloride, and variation of with time due to change in the microstructure of concrete during early period of cement hydration. In this paper, a review is presented on the development of chloride diffusion models by incorporating the effects of the key factors into basic Fick’s second law of diffusion. Determination of corrosion initiation time using chloride diffusion models is also explained. The information presented in this paper would be useful for accurate prediction of corrosion initiation time of RC structures subjected to chloride exposure, considering the effects of chloride binding, effect of time and space on , and interaction effect of multidirectional chloride ingress. Muhammad Umar Khan, Shamsad Ahmad, and Husain Jubran Al-Gahtani Copyright © 2017 Muhammad Umar Khan et al. All rights reserved. Sealing of PEO Coated AZ91 Magnesium Alloy Using La-Based Solutions Mon, 30 Jan 2017 00:00:00 +0000 In this work, solutions containing lanthanum salts were used for a post-treatment of sealing to increase the corrosion resistance of PEO coated AZ91 alloy. PEO coatings were produced on samples of AZ91 magnesium alloy using an alkaline solution containing sodium hydroxide, sodium phosphates, and sodium silicates. The sealing treatment was performed in a solution containing 12 g/L of La(NO3)3 at pH 4 at different temperatures and for different treatment times. Potentiodynamic polarization test, an EIS test, showed that the sealing treatment with solution containing lanthanum nitrate caused a remarkable increase in the corrosion resistance. The corrosion behavior was correlated with the surface morphology and elemental composition evaluated with scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). In particular, the sealing treatment at 50°C for 30 min resulted in being the most promising to increase the corrosion properties of PEO treated samples because of the formation of a homogeneous sealing layer, mainly composed of La(OH)3. Luca Pezzato, Katya Brunelli, Riccardo Babbolin, Paolo Dolcet, and Manuele Dabalà Copyright © 2017 Luca Pezzato et al. All rights reserved. Fire-Side Corrosion: A Case Study of Failed Tubes of a Fossil Fuel Boiler Sun, 15 Jan 2017 00:00:00 +0000 The failures of superheater and reheater boiler tubes operating in a power plant utilizing natural gas or mazut as a fuel have been analysed and the fire-side corrosion has been suggested as the main reason for the failure in boiler tubes. The tubes have been provided by a fossil fuel power plant in Iran and optical and electron microscopy investigations have been performed on the tubes as well as the corrosion products on their surfaces. The results showed that the thickness of the failed tubes is not uniform which suggests that fire-side corrosion has happened on the tubes. Fire-side corrosion is caused by the reaction of combustion products with oxide layers on the tube surface resulting in metal loss and consequently tubes fracture. However, the tubes corrosion behaviour did not follow the conventional models of the fire-side corrosion. Given that, using the corrosion monitoring techniques for these boiler tubes seems essential. As a result, the thickness of the boiler tubes in different parts of the boiler has been recorded and critical points are selected accordingly. Such critical points are selected for installation of corrosion monitoring probes. Majid Asnavandi, Mohaddeseh Kahram, Milad Rezaei, and Davar Rezakhani Copyright © 2017 Majid Asnavandi et al. All rights reserved. Corrosion Behavior of Brazed Zinc-Coated Structured Sheet Metal Sun, 15 Jan 2017 00:00:00 +0000 Arc brazing has, in comparison to arc welding, the advantage of less heat input while joining galvanized sheet metals. The evaporation of zinc is reduced in the areas adjacent to the joint and improved corrosion protection is achieved. In the automotive industry, lightweight design is a key technology against the background of the weight and environment protection. Structured sheet metals have higher stiffness compared to typical automobile sheet metals and therefore they can play an important role in lightweight structures. In the present paper, three arc brazing variants of galvanized structured sheet metals were validated in terms of the corrosion behavior. The standard gas metal arc brazing, the pulsed arc brazing, and the cold metal transfer (CMT®) in combination with a pulsed cycle were investigated. In experimental climate change tests, the influence of the brazing processes on the corrosion behavior of galvanized structured sheet metals was investigated. After that, the corrosion behavior of brazed structured and flat sheet metals was compared. Because of the selected lap joint, the valuation of damage between sheet metals was conducted. The pulsed CMT brazing has been derived from the results as the best brazing method for the joining process of galvanized structured sheet metals. A. Nikitin, L. Schleuss, R. Ossenbrink, and V. Michailov Copyright © 2017 A. Nikitin et al. All rights reserved. Corrigendum to “A Study of N,N-Diethylammonium O,O′-Di(p-methoxyphenyl)dithiophosphate as New Corrosion Inhibitor for Carbon Steel in Hydrochloric Acid Solution” Mon, 09 Jan 2017 11:41:13 +0000 Chuan Lai, Bin Xie, Changlu Liu, Wan Gou, Lvshan Zhou, Xiulan Su, and Like Zou Copyright © 2017 Chuan Lai et al. All rights reserved. The Inhibition Effect of Sodium Glutarate towards Carbon Steel Corrosion in Neutral Aqueous Solutions Wed, 28 Dec 2016 14:23:06 +0000 The inhibition effect of sodium glutarate towards corrosion of carbon steel in neutral 0.02 M NaCl solution was investigated with potentiodynamic polarization and electrochemical impedance measurements. Results of electrochemical measurements revealed a poor inhibitive action for low concentrations (1 mM and 5 mM) and a significant improvement in efficiency for concentrations of 32 mM or higher. The protective film exhibited excellent stability in the temperature range 22°C–55°C. Full chemical passivation was accomplished and analysis of the impedance spectra for the high concentrations of glutarate was consistent with the inhibition mechanism which assumes that the carboxylates support the passivation of carbon steel in aerated solutions by plugging the defect sites and that the passivation process is enhanced by adsorption of the carboxylates on the oxide-covered surface. Such mechanism was confirmed by the XPS analysis. G. Chan-Rosado and M. A. Pech-Canul Copyright © 2016 G. Chan-Rosado and M. A. Pech-Canul. All rights reserved. Monitoring the Interaction of Two Heterocyclic Compounds on Carbon Steel by Electrochemical Polarization, Noise, and Quantum Chemical Studies Mon, 19 Dec 2016 13:02:01 +0000 A heterocyclic phenylhydrazone 2-[(E)-(2-phenylhydrazinylidene)methyl]pyridine (P2APH) and its reduced form 2-[(2-phenylhydrazinyl)methyl]pyridine (RP2APH) were synthesized, characterized, and subjected to corrosion inhibition investigation on carbon steel (CS) in 1 M HCl using gravimetric, polarization, electrochemical noise, quantum chemical, and surface studies. P2APH showed more inhibition capacity than RP2PPH. But RP2PPH was very stable in acid medium and showed pronounced corrosion inhibition efficacy for days. Energy of HOMO and LUMO, their difference, number of electrons transferred, electronegativity, chemical hardness, and so forth were evaluated by quantum chemical studies. Agreeable correlation was observed between the results of quantum chemical calculations and other corrosion monitoring techniques. Vinod P. Raphael, Shaju K. Shanmughan, and Joby Thomas Kakkassery Copyright © 2016 Vinod P. Raphael et al. All rights reserved. Microbiologically Influenced Corrosion of Carbon Steel Exposed to Biodiesel Sun, 18 Dec 2016 13:32:43 +0000 Environmental concerns over worsening air pollution problems caused by emissions from vehicles and depletion of fossil fuels have forced us to seek fuels such as biodiesel which can supplement petrofuels. Biodiesels have the ability to retain water and provide a conducive environment for microbiologically influenced corrosion (MIC) which may cause difficulties during transportation, storage, and their use. This paper analyses the influence of bacteria on the corrosivity of biodiesel obtained from Jatropha curcas on carbon steel using mass loss method. Carbon steel showed the highest corrosion rates in B100 (100% biodiesel) both in the presence and in absence of bacteria. The surface analysis of the metal was carried out using SEM. S. Malarvizhi and Shyamala R. Krishnamurthy Copyright © 2016 S. Malarvizhi and Shyamala R. Krishnamurthy. All rights reserved. Investigation of Stress Concentration and Casing Strength Degradation Caused by Corrosion Pits Wed, 09 Nov 2016 14:11:49 +0000 Downhole casing and tubing are subjected to corrosion in many cases because of the exposure to corrosive environment. A more serious problem is that pitting corrosion occurs in the casing inner surface. Meanwhile, downhole strings are subjected to various forms of mechanical loads, for example, internal pressure load, external collapse load, or both. These loads acting on the corrosion pits will cause stress concentration and degrade the casing strength. Thus, it is essential to evaluate the stress concentration degree reasonably. The SCF (stress concentration factor) is usually used to characterize the degree of stress concentration induced by corrosion pits. This paper presented a comparison on the SCFs regarding the analytical method for a single pit and experimental method for double pits. The results show that the SCF of a single pit depends mainly on the depth of the corrosion pit; however, the SCF of the double pits strongly depends on the pits distance. A correction factor of 1.3 was recommended in the double pits SCF prediction model. Wei Yan, Yun Xu, Yi Zhou, and Kongyang Wang Copyright © 2016 Wei Yan et al. All rights reserved. Protection against Corrosion of Aluminum Alloy in Marine Environment by Lawsonia inermis Wed, 09 Nov 2016 09:20:55 +0000 The corrosion performance of aluminum alloy 5083 (AA5083) was investigated in the splash zone area simulated in salt spray cabinet at ambient temperature. Three paint formulations were prepared in accordance with different percentages of henna extract. FTIR method was used to determine the constituent of henna while weight loss and electrochemical method were applied to investigate the inhibition behaviour. The findings show that corrosion rate of aluminum alloy decreased with the increases of henna extract in the coating formulation. The rise of charge transfer resistance () value has contributed to the greater protection of the coated aluminum. The decrease in double layer capacitance value () is another indicator that a better protective barrier has been formed in the presence of henna in the coating matrix. H. M. Hajar, F. Zulkifli, M. G. Mohd Sabri, and W. B. Wan Nik Copyright © 2016 H. M. Hajar et al. All rights reserved. Experimental Investigation on Corrosion Effect on Mechanical Properties of Buried Metal Pipes Thu, 08 Sep 2016 09:17:13 +0000 Corrosion has been found to be the most predominant cause for failures of buried metal pipes. A review of published literature on pipe corrosion reveals that little research has been undertaken on the effect of corrosion on mechanical properties of pipe materials and almost no research has been conducted on corrosion effect on fracture toughness. The intention of this paper is to present a comprehensive test program designed to investigate the effect of corrosion on mechanical properties of metals in soil. Two types of metals, namely, cast iron and steel, are tested under corrosion in three different environments. A relationship between corrosion and deterioration of mechanical property of metals is developed. It is found in the paper that the more acidic the environment is, the more corrosion the metal undergoes and that the corrosion reduces both the tensile strength and fracture toughness of the metal. The results presented in the paper can contribute to the body of knowledge of corrosion behavior and its effect on mechanical properties of metals in soil environment, which in turn enable more accurate prediction of failures of buried metal pipes. Yingbo Hou, Deqing Lei, Shujin Li, Wei Yang, and Chun-Qing Li Copyright © 2016 Yingbo Hou et al. All rights reserved. Inhibition of Corrosion of Carbon Steel in 3.5% NaCl Solution by Myrmecodia Pendans Extract Wed, 31 Aug 2016 16:15:14 +0000 Inhibitor is a substance that is added to the corrosive media to inhibit corrosion rate. Organic inhibitors are preferred to inorganic ones since they are environmentally friendly. One of the organic compounds which is rarely reported as a corrosion inhibitor is Myrmecodia Pendans. The organic compounds can be adsorbed on the metal surface and block the active surface to reduce the rate of corrosion. In this study, the used pipe was carbon steel API 5L Grade B with 3.5% NaCl solution as the corrosion medium. The objective of this research was to analyze the inhibition mechanism Myrmecodia Pendans towards carbon steel in a corrosion medium. Concentration variations of extract Myrmecodia Pendans were 0–500 ppm. Fourier Transform Infrared (FTIR) was used for chemical characterization of Myrmecodia Pendans. Polarization and Electrochemical Impedance Spectroscopy (EIS) were used to measure the corrosion rate and behaviour. From the electrochemical measurements, it was found that the addition of 400 mg/L inhibitor gave the highest inhibition efficiency. Myrmecodia Pendans acted as a corrosion inhibitor by forming a thin layer on the metal surface. Atria Pradityana, Sulistijono, Abdullah Shahab, Lukman Noerochim, and Diah Susanti Copyright © 2016 Atria Pradityana et al. All rights reserved. Electrochemical and Microstructural Analysis of FeS Films from Acidic Chemical Bath at Varying Temperatures, pH, and Immersion Time Tue, 23 Aug 2016 13:55:29 +0000 The corrosion resistance and corrosion products of 4130 alloy steel have been investigated by depositing thin films of iron sulfide synthesized from an acidic chemical bath. Tests were conducted at varying temperatures (25°C–75°C), pH levels (2–4), and immersion time (24–72 hours). The corrosion behavior was monitored by linear polarization resistance (LPR) method. X-ray Diffraction (XRD), Energy Dispersive X-ray (EDX) spectroscopy, and Scanning Electron Microscopy (SEM) have been applied to characterize the corrosion products. The results show that, along with the formation of an iron sulfide protective film on the alloy surface, increasing temperature, increasing immersion time, and decreasing pH all directly increase the corrosion rate of steel in the tested experimental conditions. It was also concluded that increasing temperature causes an initial increase of the corrosion rate followed by a large decrease due to transformation of the iron sulfide crystalline structure. Ladan Khaksar, Gary Whelan, and John Shirokoff Copyright © 2016 Ladan Khaksar et al. All rights reserved. Effect of Additional Sulfide and Thiosulfate on Corrosion of Q235 Carbon Steel in Alkaline Solutions Mon, 15 Aug 2016 09:16:28 +0000 This paper investigated the effect of additional sulfide and thiosulfate on Q235 carbon steel corrosion in alkaline solutions. Weight loss method, scanning electron microscopy (SEM) equipped with EDS, X-ray photoelectron spectroscopy (XPS), and electrochemical measurements were used in this study to show the corrosion behavior and electrochemistry of Q235 carbon steel. Results indicate that the synergistic corrosion rate of Q235 carbon steel in alkaline solution containing sulfide and thiosulfate is larger than that of sulfide and thiosulfate alone, which could be due to redox reaction of sulfide and thiosulfate. The surface cracks and pitting characteristics of the specimens after corrosion were carefully examined and the corrosion products film is flake grains and defective. The main corrosion products of specimen induced by S2− and S2 are FeS, FeS2, Fe3O4, and FeOOH. The present study shows that the corrosion mechanism of S2− and S2 is different for the corrosion of Q235 carbon steel. Bian Li Quan, Jun Qi Li, and Chao Yi Chen Copyright © 2016 Bian Li Quan et al. All rights reserved. Long Term Corrosion Experiment of Steel Rebar in Fly Ash-Based Geopolymer Concrete in NaCl Solution Mon, 15 Aug 2016 06:05:53 +0000 This research focuses on an experimental investigation to identify the effects of fly ash on the electrochemical process of concrete during the curing time. A rebar was analysed using potentiostat to measure the rest potential, polarization diagram, and corrosion rate. Water-to-cement ratio and amount of fly ash were varied. After being cured for 24 hours at a temperature of 65°C, the samples were immersed in 3.5% of NaCl solution for 365 days for electrochemical measurement. Measurements of the half-cell potential and corrosion current density indicated that the fly ash has significant effects on corrosion behaviour of concrete. Although fly ash tends to create passivity on anodic current, it increases corrosion rate. The corrosion potential of this concrete mixture decreases compared to concrete without fly ash. From the result, it can be summarized that concrete mixture with 70% of OPC (Ordinary Portland Cement) and 30% fly ash has shown the best corrosion resistance. Y. P. Asmara, J. P. Siregar, C. Tezara, Wan Nurlisa, and J. Jamiluddin Copyright © 2016 Y. P. Asmara et al. All rights reserved. A Probabilistic Physics of Failure Approach for Structure Corrosion Reliability Analysis Sun, 14 Aug 2016 11:15:14 +0000 Corrosion is recognized as one of the most important degradation mechanisms that affect the long-term reliability and integrity of metallic structures. Studying the structural reliability with pitting corrosion damage is useful for risk control and safety operation for the corroded structure. This paper proposed a structure corrosion reliability analysis approach based on the physics-based failure model of pitting corrosion, where the states of pitting growth, pit-to-crack, and cracking propagation are included in failure model. Then different probabilistic analysis methods such as Monte-Carlo Simulation (MCS), First-Order Reliability Method (FORM), Second-Order Reliability Method (SORM), and response surface method are employed to calculate the reliability. At last, an example is presented to demonstrate the capability of the proposed structural reliability model and calculating methods for structural corrosion failure analysis. Chaoyang Xie and Hong-Zhong Huang Copyright © 2016 Chaoyang Xie and Hong-Zhong Huang. All rights reserved. Seismic Behavior of Corroded RC Bridges: Review and Research Gaps Thu, 19 May 2016 16:25:49 +0000 Chloride-induced corrosion and its effect on structural and seismic performance of reinforced concrete (RC) structures have been the topic of several research projects in past decades. This literature review summarizes the state of the art by presenting a brief description of chloride-induced corrosion, its main characteristics and influencing factors, a summary of experimental published data, and existing corrosion-induced deterioration models together with numerical and experimental methods used to evaluate corroded RC bridge pier. This literature review highlights the need for reliable deterioration models for RC structures and appropriate analysis methods are needed for design of new structures or assessment of existing civil engineering structures especially in seismic areas. Kaveh Andisheh, Allan Scott, and Alessandro Palermo Copyright © 2016 Kaveh Andisheh et al. All rights reserved. Simulation of the Ill-Posed Problem of Reinforced Concrete Corrosion Detection Using Boundary Element Method Wed, 06 Apr 2016 09:29:17 +0000 Many studies have suggested that the corrosion detection of reinforced concrete (RC) based on electrical potential on concrete surface was an ill-posed problem, and thus it may present an inaccurate interpretation of corrosion. However, it is difficult to prove the ill-posed problem of the RC corrosion detection by experiment. One promising technique is using a numerical method. The objective of this study is to simulate the ill-posed problem of RC corrosion detection based on electrical potential on a concrete surface using the Boundary Element Method (BEM). BEM simulates electrical potential within a concrete domain. In order to simulate the electrical potential, the domain is assumed to be governed by Laplace’s equation. The boundary conditions for the corrosion area and the noncorrosion area of rebar were selected from its polarization curve. A rectangular reinforced concrete model with a single rebar was chosen to be simulated using BEM. The numerical simulation results using BEM showed that the same electrical potential distribution on the concrete surface could be generated from different combinations of parameters. Corresponding to such a phenomenon, this problem can be categorized as an ill-posed problem since it has many solutions. Therefore, BEM successfully simulates the ill-posed problem of reinforced concrete corrosion detection. Syarizal Fonna, Israr M. Ibrahim, M. Ridha, Syifaul Huzni, and A. K. Ariffin Copyright © 2016 Syarizal Fonna et al. All rights reserved. Adaptive Corrosion Protection System Using Continuous Corrosion Measurement, Parameter Extraction, and Corrective Loop Thu, 17 Mar 2016 06:33:52 +0000 A simple current-sourced adaptive corrosion protection system (ACPS) along with a technology to extract the protection current from the Tafel plot is presented. For reliable protection of the target metal, first, the Tafel plot of the target metal is obtained. Subsequently, a novel technique proposed in this paper is used to extract the protection current from the Tafel plot. This extracted protection current is fed to the target metal to protect the metal in the existing corrosive environment. This three-part system is adaptively used to update the required protection current to effectively protect the target metal continuously. All these functionalities are integrated in a stand-alone ACPS that effectively diagnoses the corrosion status and updates the protection parameters without any manual interaction or physical modification of the set-up to offer modularity, reliability, and cost saving. To validate the technique, a laboratory scale system is realized and tested using various metal samples and various corrosive mediums. Using the experimental system, A36 metal coupons are effectively protected with protection (inhibition) efficiency of 40–100 in different corrosive mediums that can extend the life expectancy of the target metal from ~2 times to more than 100 times for the tested corrosive mediums. Jasbir N. Patel, Andre Chang, Haleh Shahbazbegian, and Bozena Kaminska Copyright © 2016 Jasbir N. Patel et al. All rights reserved. Study of New Thiazole Based Pyridine Derivatives as Potential Corrosion Inhibitors for Mild Steel: Theoretical and Experimental Approach Thu, 03 Mar 2016 13:07:16 +0000 Three new thiazole based pyridine derivatives 5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-2-ylmethylene-hydrazide (2-MTPH), 5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-3-ylmethylene-hydrazide (3-MTPH), and 5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-4-ylmethylene-hydrazide (4-MTPH) were synthesized and characterized. Corrosion inhibition performance of the prepared compounds on mild steel in 0.5 M HCl was studied using gravimetric, potentiodynamic polarisation, and electrochemical impedance techniques. Inhibition efficiency has direct relation with concentration and inverse relation with temperature. Thermodynamic parameters for dissolution and adsorption process were evaluated. Polarisation study reveals that compounds act as both anodic and cathodic inhibitors with emphasis on the former. Impedance study shows that decrease in charge transfer resistance is responsible for effective protection of steel surface by inhibitors. The film formed on the mild steel was investigated using FTIR, SEM, and EDX spectroscopy. Quantum chemical parameters like , , , hardness, softness, and ionisation potential were calculated. Higher value of and lower value of indicate the better inhibition efficiency of the compounds. Lower ionisation potential of inhibitors indicates higher reactivity and lower chemical stability. T. K. Chaitra, K. N. Mohana, and H. C. Tandon Copyright © 2016 T. K. Chaitra et al. All rights reserved. A Study of N,N-Diethylammonium O,O′-Di(p-methoxyphenyl)dithiophosphate as New Corrosion Inhibitor for Carbon Steel in Hydrochloric Acid Solution Thu, 18 Feb 2016 07:03:07 +0000 N,N-Diethylammonium O,O′-di(p-methoxyphenyl)dithiophosphate (EAPP) as a new corrosion inhibitor was synthesized in the present work. The corrosion inhibition of EAPP in hydrochloric acid for carbon steel was evaluated by potentiodynamic polarization measurements, electrochemical impedance spectroscopy, weight loss measurements, and scanning electron microscopy. The results indicate that the EAPP is mixed type inhibitor, and the adsorption of EAPP on carbon steel surface obeys Langmuir isotherm. In addition, the inhibition efficiency increases with increasing the concentration of inhibitor and decreases with increasing the hydrochloric acid concentration, temperature, and storage time. Chuan Lai, Bin Xie, Changlu Liu, Wan Gou, Lvshan Zhou, Xiulan Su, and Like Zou Copyright © 2016 Chuan Lai et al. All rights reserved. Corrosion Behavior of Carbon Steels in CCTS Environment Thu, 04 Feb 2016 07:38:42 +0000 The paper reports the results of an experimental work on the effect of steel microstructures on morphology and protectiveness of the corrosion scale formed in water saturated by supercritical CO2. Two HSLA steels were tested. The microstructures were modified by means of different heat treatments. Weight loss was measured after exposure at CO2 partial pressure of 80 bar and 60°C temperature. The morphology of the scale was analyzed by means of scanning electron microscope (SEM) energy-dispersive X-ray spectroscopy (EDX). Cathodic potentiodynamic tests were carried out on precorroded specimens for evaluating the effect of preformed scales on cathodic polarization curves in CO2 saturated sulphuric acid solution at pH 3, which is the value estimated for water saturated by supercritical CO2. The results are discussed in order to evaluate the effect of iron carbide network on scale growth and corrosion rate. Weight loss tests evidenced average corrosion rate values in the range 1–2.5 mm/y after 150-hour exposure. The presence of thick siderite scale significantly reduces the corrosion rate of carbon steel. A slight decrease of the corrosion rate was observed as the scale thickness increases and moving from martensite to microstructures containing carbides. M. Cabrini, S. Lorenzi, and T. Pastore Copyright © 2016 M. Cabrini et al. All rights reserved. Experimental Study on the Influence of AC Stray Current on the Cathodic Protection of Buried Pipe Tue, 19 Jan 2016 13:57:38 +0000 The size of the damaged area of the coating and its position on the pipeline impacted the cathodic protection potential, and there was a damaged area of the greatest impact value. When damaged area was 300 mm2, the IR drop was the largest, and this situation could easily lead to inadequate protection; when the parallel spacing between pipeline and interference source was unchanged, the measured value curves of cathodic protection potential presented “U” shaped trend with the increasing stray current interference intensity. Under certain parallel spacing between pipeline and interference source, high alternating stray current intensity would cause serious negative offsets, so that the overprotection of the pipeline occurred, and make the coating crack; there was a parallel threshold length. When less than the threshold, the pipe-ground potential increases rapidly with the parallel length increasing. In order to judge whether a pipeline was interference by AC stray current and the risk of stray current corrosion, we should make a comprehensive analysis of the cathodic protection energizing potential, the switch-off potential, AC pipe-soil potential, IR drops, and so on. Qingmiao Ding and Yueming Fan Copyright © 2016 Qingmiao Ding and Yueming Fan. All rights reserved. Pomegranate (Punica granatum) Peel Extract as a Green Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Solution Tue, 24 Nov 2015 08:17:10 +0000 The inhibition effect of pomegranate peel extract (PPE) on the corrosion of mild steel in hydrochloric acid (HCl) solution was investigated. The polarization, mass loss, and electrochemical impendence techniques were used to evaluate the corrosion inhibition performance of the pomegranate peel extract. The results revealed that PPE acts as a corrosion inhibitor in HCl solution. The inhibition efficiency increased with the increase of extract concentration. The inhibition action was attributed to the adsorption of the chemical compounds present in the extract solution, on mild steel surface. Habib Ashassi-Sorkhabi, Shoja Mirzaee, Taghi Rostamikia, and Robabeh Bagheri Copyright © 2015 Habib Ashassi-Sorkhabi et al. All rights reserved.