International Journal of Corrosion The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . 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. Effect of Electrical Injection of Corrosion Inhibitor on the Corrosion of Steel Rebar in Chloride-Contaminated Repair Mortar Mon, 16 Nov 2015 14:00:12 +0000 The electrical rehabilitation treatments of repair mortar were performed with tetrabutylammonium bromide salt (TBAB) at an electrical current density of 5 A/m2, using two electrolytes (0.1 M NaOH and 0.1 M Na3BO3 solutions), and for two time periods (1 and 4 weeks), respectively. The average organic cation-based inhibitor’s concentration in cement mortars before and after this treatment was quantified using the UV-Vis spectroscopy. The experimental results reveal that the EICI treatment with 0.1 M Na3BO3 was more effective in injecting the inhibitor and in improving the chloride penetration resistance and compressive strength of the mortar, relative to using 0.1 M NaOH as electrolyte. In this case, after the 4-week EICI treatment, [TBA+] contents were 2.3 % and 2.4% by mass of cement mortar for uncontaminated and salt-contaminated mortars, respectively. After the 4-week EICI treatment, the apparent diffusion coefficients of chloride anion in cement mortar were decreased by 40% from 1.52 × 10−10 m2/s. The EICI treatment was able to halt the chloride-induced corrosion of the steel rebar by promoting its passivation. The 2-week EICI treatment using sodium hydroxide and sodium borate solutions decreased the corrosion current density of the rebar by 77.8% and 78.5%, respectively, approximately two months after the treatment. The Huyen Nguyen, Tuan Anh Nguyen, Thien Vuong Nguyen, Van Khu Le, Thi Mai Thanh Dinh, Hoang Thai, and Xianming Shi Copyright © 2015 The Huyen Nguyen et al. All rights reserved. Effect of High Temperature Sodium Hydroxide Immersion on Fusion Bond Epoxy Coating Mon, 28 Sep 2015 13:45:36 +0000 Fusion Bond Epoxy (FBE) coating system was exposed to 5% sodium hydroxide at elevated temperature for 30 days. The result of exposure showed formation of adhere deposit layer, a discolored zone underneath and remaining un-affected bulk of the coating. The deterioration of the coating was characterized using analytical techniques like scanning electron microscopy (SEM), energy-dispersive X-ray (EDAX) spectroscopy, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), pull-off adhesion, and electrochemical impedance spectroscopy (EIS). Results obtained indicated chemical deterioration of the coating in the discolored zone and leaching of low molecular weight coating component forming deposit layer. Although the adhesion strength and barrier property were not affected, the polymer matrix in the affected zone undergoes severe changes in its surface microstructure, primary chemical structure, and glass transition temperature. This may inflict serious impairment of the coating functional properties and premature failure of the coating in long term exposure. Amal Al-Borno, Xianyi Chen, and Shailesh Kewaldas Dhoke Copyright © 2015 Amal Al-Borno et al. All rights reserved. Corrosion Behaviour of a Silane Protective Coating for NdFeB Magnets in Dentistry Mon, 21 Sep 2015 12:24:22 +0000 The corrosion behavior of coated and uncoated Ni/Cu/Ni rare earth magnets was assessed at increasing steps with a multilayering silanization procedure. Magnets’ durability was analyzed in Fusayama synthetic saliva solution in order to evaluate their application in dental field. Corrosion performance was evaluated by using polarization and electrochemical impedance spectroscopy in synthetic saliva solution up to 72 hours of continuous immersion. The results show that the addition of silane layers significantly improved anticorrosion properties. The coating and aging effects, in synthetic saliva solution, on magnetic field were evaluated by means of cyclic force-displacement curves. Luigi Calabrese, A. Caprì, F. Fabiano, L. Bonaccorsi, C. Borsellino, and Edoardo Proverbio Copyright © 2015 Luigi Calabrese et al. All rights reserved. Smart Mesoporous Silica Nanocapsules as Environmentally Friendly Anticorrosive Pigments Tue, 15 Sep 2015 09:40:10 +0000 Nowadays there is a special interest to study and develop new smart anticorrosive pigments in order to increase the protection life time of organic coatings and, simultaneously, to find alternatives to conventional toxic and carcinogenic hexavalent chromium compounds. In this respect, the great development of nanotechnologies in recent years has opened up a range of possibilities in the field of anticorrosive paints through the integration of encapsulated nanoscale containers loaded with active components into coatings. By means of a suitable design of the capsule, the release of the encapsulated corrosion inhibitor can be triggered by different external or internal factors (pH change, mechanical damage, etc.) thus preventing spontaneous leakage of the active component and achieving more efficient and economical use of the inhibitor, which is only released upon demand in the affected area. In the present work, the improved anticorrosive behaviour achieved by encapsulated mesoporous silica nanocontainers filled with an environmentally friendly corrosion inhibitor has been evaluated. It has been proven that a change in the pH allows the rupture of the capsules, the release of the inhibitor, and the successful protection of the carbon steel substrate. C. Zea, R. Barranco-García, B. Chico, I. Díaz, M. Morcillo, and D. de la Fuente Copyright © 2015 C. Zea et al. All rights reserved. Bee Wax Propolis Extract as Eco-Friendly Corrosion Inhibitors for 304SS in Sulfuric Acid Tue, 15 Sep 2015 08:11:16 +0000 The inhibition properties of bee wax propolis (BWP) extract on the 304SS in 0.5 M sulfuric acid were conducted using potentiodynamic polarization, EIS, and XRD. Quercetin (2-(3.4-dihydroxy phenyl)-3.5.7-trihydroxy-4H-chromen-4-one) was identified as the main compound in the BWP extract based on FTIR and HPLC analysis. The results showed that the inhibitor could retard the corrosion rate of 304SS in 0.5 M sulfuric acid which reached 97.29% and 91.42% at 2000 ppm based on potentiodynamic polarization and EIS measurement, respectively. The inhibition efficiency decreased with increasing temperature. The inhibition mechanism of BWP extract on the 304SS was physisorption and obeyed Temkin adsorption isotherm equation. The thin protective layer on the 304SS surface was confirmed by XRD. Femiana Gapsari, Rudy Soenoko, Agus Suprapto, and Wahyono Suprapto Copyright © 2015 Femiana Gapsari et al. All rights reserved. Study on Corrosion of Macroporous Silicon in Sodium Hydroxide Solution by Electrochemical Methods and Scanning Electron Microscopy Mon, 07 Sep 2015 11:01:36 +0000 The fabricated macroporous silicon with a porosity of 26.33% corrosion in NaOH solution was systemically investigated by open circuit potential measurements, linear polarization measurements, potentiodynamic polarization measurements, and scanning electron microscopy, respectively. Results show that the potential open circuit and linear polarization resistance decreases with the NaOH concentration increasing. The corrosion potential shifts significantly to more negative potentials and corrosion current density increases with NaOH concentration increasing. Adding ethanol to 1.0 M NaOH can lead to the linear polarization resistance decrease, corrosion potentials shift in the positive direction, and corrosion current density increase. In addition, the scanning electron microscopy images demonstrate that the macroporous silicon samples are seriously damaged by 1.0 M NaOH and 1.0 M NaOH/EtOH (30%). Chuan Lai, Zhen Xiang, Changlu Liu, Chaoju Zhu, Hui Wang, and Hui Zhu Copyright © 2015 Chuan Lai et al. All rights reserved. Surface Corrosion Resistance in Turning of Titanium Alloy Thu, 27 Aug 2015 12:42:53 +0000 This work addresses the issues associated with implant surface modification. We propose a method to form the oxide film on implant surfaces by dry turning to generate heat and injecting oxygen-rich gas at the turning-tool flank. The morphology, roughness, composition, and thickness of the oxide films in an oxygen-rich atmosphere were characterized using scanning electron microscopy, optical profiling, and Auger electron spectroscopy. Electrochemical methods were used to study the corrosion resistance of the modified surfaces. The corrosion resistance trends, analyzed relative to the oxide film thickness, indicate that the oxide film thickness is the major factor affecting the corrosion resistance of titanium alloys in a simulated body fluid (SBF). Turning in an oxygen-rich atmosphere can form a thick oxide film on the implant surface. The thickness of surface oxide films processed at an oxygen concentration of 80% was improved to 4.6 times that of films processed at an oxygen concentration of 21%; the free corrosion potential shifted positively by 0.357 V, which significantly improved the corrosion resistance of titanium alloys in the SBF. Therefore, the proposed method may (partially) replace the subsequent surface oxidation. This method is significant for biomedical development because it shortens the process flow, improves the efficiency, and lowers the cost. Rui Zhang, Xing Ai, Yi Wan, Zhanqiang Liu, Dong Zhang, and Sheng Feng Copyright © 2015 Rui Zhang et al. All rights reserved. Novel Synthesis of Vegetable Oil Derived Corrosion Inhibitors Wed, 15 Jul 2015 06:33:04 +0000 Two different naturally occurring vegetable oils, Cress seed oil, and Linseed oil were chemically modified via novel one pot synthesis to produce fatty acid derived amides. These were characterized by their ability to prevent corrosion of carbon steel in vigorously stirred, aerated seawater, one of the most corrosive naturally occurring environments. Corrosion inhibitor efficiencies of up to 99.6% or a corrosion rate reduction factor of 250 in this medium is reported. The one pot synthetic strategy means that the corrosion inhibitors can be made at very low cost. Paul Rostron and Sonia Kasshanna Copyright © 2015 Paul Rostron and Sonia Kasshanna. All rights reserved. The Pitting Susceptibility Investigation of Passive Films Formed on X70, X80, and X100 Pipeline Steels by Electrochemical Noise and Mott-Schottky Measurements Sun, 05 Jul 2015 14:01:51 +0000 The pitting susceptibility of passive films formed on X70, X80, and X100 pipeline steels was investigated by means of electrochemical noise (EN) and Mott-Schottky measurements. The EN results were analyzed according to the shot-noise theory and stochastic theory. Pit initiation process was analyzed quantitatively using the Weibull distribution function. Pit growth process was simulated by Gumbel distribution function. The experimental results of Mott-Schottky plots showed that the passive films formed on the three pipeline steels displayed an n-type semiconductor character, and the passive film for X100 pipeline steel has the lowest donor density () among the three passive films. The EN results demonstrated that X100 pipeline steel had the lowest pit initiation rate and pit growth probability, which implied that the X100 pipeline steel had the lowest pitting susceptibility. Yang Zhao, Ping Liang, Yanhua Shi, Yunxia Zhang, and Tao Yang Copyright © 2015 Yang Zhao et al. All rights reserved. An Investigation of a Combined Thiourea and Hexamethylenetetramine as Inhibitors for Corrosion of N80 in 15% HCl Solution: Electrochemical Experiments and Quantum Chemical Calculation Mon, 25 May 2015 14:07:49 +0000 The inhibition mechanism of thiourea (TU) and hexamethylenetetramine (HMTA) mixed in 15% HCl solution on N80 surface was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy measurements, and surface morphology analysis. Quantum chemical calculations and molecular dynamics simulations were performed to study the properties of TU and HMTA. The results showed that the inhibitors can form strong bonds and stable films on the surface, which inhibits the cathodic and anodic reactions in HCl solution and reduces the diffusion coefficients of corrosive particles. Jun Hu, Yun Wang, Lijun Yu, Yongqiang Zou, and Yuqi Wang Copyright © 2015 Jun Hu et al. All rights reserved. Eco-Friendly Corrosion Inhibition of Pipeline Steel Using Brassica oleracea Thu, 19 Feb 2015 06:26:59 +0000 The inhibition capacity of Brassica oleracea (BO) extract on the corrosion of pipeline steel in 0.5 M H2SO4 was evaluated using electrochemical techniques. The results showed an excellent inhibition efficiency which increased with initial increase in extract concentration and temperature to a point and decreased with further increase in BO extract concentration and temperature. Mixed inhibition behaviour was proposed for the action of BO. The unique behaviour of BO was attributed to the organic entities present in the extract. N. C. Ngobiri, E. E. Oguzie, Y. Li, L. Liu, N. C. Oforka, and O. Akaranta Copyright © 2015 N. C. Ngobiri et al. All rights reserved. Effect of Piperidin-4-ones on the Corrosion Inhibition of Mild Steel in 1 N H2SO4 Sun, 15 Feb 2015 14:32:03 +0000 The corrosion inhibition of mild steel in 1 N sulphuric acid solution by 2,6-diphenylpiperidin-4-ones with various substituents at 3- and 3,5-positions (01–06) has been tested by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopic methods, and FTIR and UV absorption spectra. The surface morphology of the mild steel specimen has been analyzed by SEM. The effect of temperature (300 to 323 ± 1 K) on the corrosion behavior of mild steel in the presence of the inhibitors (01–06) was studied using weight loss techniques. The effect of anions (Cl−, Br−, and I−) on the corrosion behavior of mild steel in the presence of the same inhibitors was also studied by weight loss method and the synergism parameters were calculated. The adsorption characteristics of the inhibitors have been determined from the results. Glory Tharial Xavier, Brindha Thirumalairaj, and Mallika Jaganathan Copyright © 2015 Glory Tharial Xavier et al. All rights reserved. Effects of Strain Energy and Grain Size on Corrosion Resistance of Ultrafine Grained Fe-20%Cr Steels with Extremely low C and N Fabricated by ECAP Tue, 06 Jan 2015 09:33:38 +0000 Effect of strain energy and grain size on corrosion resistance of ultrafine grained (UFG) Fe-20%Cr steels with extremely low C and N fabricated by equal channel angular pressing (ECAP) was investigated. UFG structures of initial grain size of 144 nm exhibited the typical three-stage softening comprising recovery, recrystallization, and grain growth. Potentiodynamic polarization measurements were carried out with a conventional three-electrode cell to evaluate pitting potential. Pitting potential in 1000 molm−3 NaCl solution was nobler in UFG state, but pitting potential started to decrease monotonously at lower temperature compared to hardness. The degradation of corrosion resistance in the early stage of annealing is attributed to stability change of passivation by recovery of dislocation structures inside grains and in nonequilibrium grain boundaries. We therefore conclude that nobler potentials of UFG states were realized by not only grain size reduction but also defective deformation-induced UFG. Muhammad Rifai, Hiroyuki Miyamoto, and Hiroshi Fujiwara Copyright © 2015 Muhammad Rifai et al. All rights reserved. Corrosion Potential Profile Simulation in a Tube under Cathodic Protection Thu, 18 Dec 2014 12:27:56 +0000 The potential distribution in tubes of a heat exchanger is simulated when applying cathodic polarization to its extremes. The comparison of two methods to achieve this goal is presented: a numeric solution based on boundary elements carried out with the commercial software Beasy-GID and a semianalytical method developed by the authors. The mathematical model, the simplifications considered, and the problem solving are shown. Since both approaches use polarization curves as a boundary condition, experimental polarization curves (voltage versus current density) were determined in the laboratory under flow conditions and cylindrical cell geometry. The results obtained suggest the impossibility of extending the protection along the whole tube length; therefore, other protection methods are considered. Mauricio Ohanian and Víctor Martínez-Luaces Copyright © 2014 Mauricio Ohanian and Víctor Martínez-Luaces. All rights reserved. Corrosion Inhibition Effect of 4-Hydroxy-N′-[(E)-(1H-indole-2-ylmethylidene)] Benzohydrazide on Mild Steel in Hydrochloric Acid Solution Thu, 11 Dec 2014 11:11:47 +0000 The inhibition performance and adsorption behaviour of 4-hydroxy-N′-[(E)-(1H-indole-2-ylmethylidene)] benzohydrazide (HIBH) on mild steel in 1 M HCl solution were tested by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The inhibition efficiency of HIBH increases with increase in inhibitor concentration in the temperature range 30–60°C. Polarisation curves indicate that HIBH is a mixed inhibitor, affecting both cathodic and anodic corrosion currents. The adsorption process of HIBH at the mild steel/hydrochloric acid solution interface obeyed Langmuir adsorption isotherm model and inhibition takes place by mixed adsorption, predominantly chemisorption. The activation and thermodynamic parameters for the corrosion inhibition process were calculated to elaborate the mechanism of corrosion inhibition. Preethi Kumari, Prakash Shetty, and Suma A. Rao Copyright © 2014 Preethi Kumari et al. All rights reserved. Electrochemical Investigation of Corrosion Behavior Heat Treated Al-6Si-0.5Mg-xCu (x = 0, 0.5, 1, 2, and 4 wt%) Alloys Sun, 07 Dec 2014 06:59:39 +0000 The corrosion behaviour of heat treated Al-6Si-0.5Mg-xCu (, 1, 2, and 4 wt%) alloys in 0.1 M NaCl solution was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization curves reveal that 2 wt% Cu (Alloy-4) and 4 wt% Cu (Alloy-5) content alloys are more prone to corrosion than the other alloys investigated. But the EIS test results showed that charge transfer resistance () increases with increasing Cu content into Al-6Si-0.5Mg. Maximum charge transfer resistance () is reported with the addition of 2 wt% Cu and minimum value is for 4 wt% Cu content Al-6Si-0.5Mg alloy. Due to additions of Cu into Al-6Si-0.5Mg alloy, the magnitudes of open circuit potential (OCP), corrosion potential (), and pitting corrosion potential () in NaCl solution were shifted to the more noble direction. A. Hossain, F. Gulshan, and A. S. W. Kurny Copyright © 2014 A. Hossain et al. All rights reserved. Exploratory Study of Sensitization in Cryogenically Cooled Ferritic Stainless Steel Welds Sun, 07 Dec 2014 00:10:13 +0000 Enhanced cooling via forced convection using cryogenic liquid is an option for controlling grain growth in the heat affected zone (HAZ) of ferritic stainless steel welds which improves joint strength. However, this technique seems to alter the martensite distribution in the high-temperature heat affected zone (HTHAZ) which is a critical constituent in rating the susceptibility to sensitization in ferritic stainless steel grades; any such information is not available in the literature. Thus, it is imperative to establish the influence of cryogenic cooling on sensitization dynamics in the HTHAZ. This paper discusses the influence of cryogenic cooling on sensitization in an AISI 430 ferritic stainless steel weld. It is established that cryogenic cooling increases the cooling rate in the HTHAZ and reduces the martensite volume percent by an average of 20%. This reduction in martensite content in the HTHAZ increases the level of ditched structure in cryogenically cooled welds and yields more ferrite-martensite ditched grain boundaries than in conventional welds. Although the cryotreated welds exhibit greater ditched boundary, the structure is still classified as nonsensitized, since no single grain boundary is completely surrounded by ditches. M. O. H. Amuda and S. Mridha Copyright © 2014 M. O. H. Amuda and S. Mridha. All rights reserved. Investigation on the Effect of Green Inhibitors for Corrosion Protection of Mild Steel in 1 M NaOH Solution Sun, 23 Nov 2014 09:26:36 +0000 Alkaline corrosion is one of the main issues faced by the industries. The main chemicals abundantly used in industries are NaOH, H3PO4, HCl, and H2SO4. Corrosion control of metals has technical, economical, environmental, and aesthetical importance. The use of inhibitors is one of the best options to protect metals and alloys against corrosion. The corrosion protection of mild steel in 1 M NaOH solution by mix of Henna/Zeolite powder was studied at different temperatures by weight loss technique. Adsorption, activation, and statistical studies were addressed in this work. Adsorption studies showed that inhibitor adsorbed on metal surface according to Langmuir isotherm. Surface studies were performed by using UV-spectra and SEM. The adsorption of inhibitor on the steel surface was found to obey Langmuir’s adsorption isotherm. The inhibition efficiency increased with increasing concentration of the inhibitor in NaOH medium. Inhibition mechanism is deduced from the concentration and temperature dependence of the inhibition efficiency, Langmuir’s adsorption isotherm, SEM, and UV spectroscopic results. Premjith Jayakumar Ramakrishnan, Vishnu Deth Kaleekal Janardhanan, Ramkumar Sreekumar, and Keerthy Parayil Mohan Copyright © 2014 Premjith Jayakumar Ramakrishnan et al. All rights reserved. Corrosion Effects on the Strength Properties of Steel Fibre Reinforced Concrete Containing Slag and Corrosion Inhibitor Mon, 17 Nov 2014 11:50:35 +0000 Corrosion in steel can be detrimental in any steel rebar reinforced concrete as well as in the case of steel fibre reinforced concrete. The process of corrosion occurring in steel fibre incorporated concrete subjected to corrosive environment was systematically evaluated in this study. Concrete specimens were prepared with steel fibre inclusions at 1.5% (volume fraction) of concrete and were added in slag based concrete (containing manufactured sand) and replaced with cement at 20%, 40%, and 60% of total binder. Accelerated corrosion studies were carried out using alternate wetting and drying cycle accompanied with initial stress at 40% and 60% of ultimate stress. Concrete specimens were then immersed in chloride-free water and sodium chloride solution (3.5%) after subjecting to initial stress. The alternate wetting and drying process of different concrete mixes was continued for longer exposure (6 months). Later, the strength degradation during the accelerated corrosion process was then assessed in compressive and flexural tests. Test results indicated that the strength degradation was marginal in the case of steel fibre reinforced concrete containing higher slag content and for the concretes containing corrosion inhibitors. The maximum strength reduction was noticed in the case of plain concrete containing steel fibres and, with the slag addition, a considerable reduction in corrosion potential was noticed. Also, with the increase in slag replacement up to 60%, a significant increase in strength was noticed in flexural test. Experimental test results also showed that the corrosion process in steel fibre reinforced concrete can be controlled with the incorporation of corrosion inhibitors in cementitious system. Sivakumar Anandan, Sounthararajan Vallarasu Manoharan, and Thirumurugan Sengottian Copyright © 2014 Sivakumar Anandan et al. All rights reserved. Electrochemical Impedance and Modelling Studies of the Corrosion of Three Commercial Stainless Steels in Molten Carbonate Thu, 06 Nov 2014 09:20:49 +0000 The corrosion induced by molten carbonates on the metallic structure materials is a problem constraining the life span of molten carbonate fuel cell (MCFC) at elevated temperatures. The reaction between the outgrowing oxide scale and lithium carbonate in the electrolyte is generally a slow process and very important to the passivation behaviour of the underlying steel. The corrosion behaviour of three commercial alloys (P92, SS304, and SS310) with different Cr contents in molten (0.62Li, 0.38K)2CO3 at 650°C was monitored by electrochemical impedance spectroscopy (EIS) for 120 hours to investigate the lithiation process. With SEM images and extensive XRD analysis of the oxides, equivalent circuits were proposed to interpret the impedance data and explain the corrosion behaviour of the three alloys at different stage with respect to lithiation process. C. S. Ni and L. Y. Lu Copyright © 2014 C. S. Ni and L. Y. Lu. All rights reserved. Electroless Deposition of Ni-Cu-P Coatings Containing Nano-Al2O3 Particles and Study of Its Corrosion Protective Behaviour in 0.5 M H2SO4 Wed, 05 Nov 2014 08:58:31 +0000 Ni-Cu-P/nano-Al2O3 composite coatings are prepared on mild steel from an alkaline electroless plating bath containing different concentrations of Al2O3 nanoparticles. The protective effect of codeposited nanoparticles on the corrosion behaviour of the coatings is studied in 0.5 M H2SO4 solution. The electrochemical methods, that is, electrochemical noise (ECN), electrochemical impedance spectroscopy (EIS), and polarization measurements, are used to characterize the corrosion properties of the coatings. The results show that the inclusion of nanosized particles leads to significant improvement of corrosion resistance of the coatings. The highest corrosion resistance is obtained at 20 ppm of nanoparticles concentration in the plating bath. The ECN measurements results are in good agreement with results obtained from two other electrochemical methods after trend removal. The SEM images prove that nano-Al2O3 particles were embedded in the Ni-Cu-P matrix and are dispersed uniformly on the coating surface. H. Ashassi-Sorkhabi, H. Aminikia, and R. Bagheri Copyright © 2014 H. Ashassi-Sorkhabi et al. All rights reserved. Study on Polymer Modified Cement-Based Coating with Healing Effect on Rusty Carbon Steel Tue, 30 Sep 2014 11:35:44 +0000 The anticorrosion properties of polymer emulsion modified cement-based coating with healing effect on carbon steel were investigated. The change of linear polarization resistance () and electrochemical impedance spectroscopy (EIS) have been used to measure the inhibitive and curative effect of electrodes painted with the coating in 3.5% NaCl solution. The results indicated the high alkalinity of filler (cement) in coating can obviously improve the anticorrosion performance of coated steel electrodes. And the inhibitive ability of cement-based coating with fluoride acrylic emulsion is superior to that of the coating with epoxy emulsion. Moreover, by adding antirust pigments and rust converters in the fluoride acrylic emulsion modified cement-based coating, the inhibitive property was improved and the curative effect can be observed. Kunrong Wang, Zhiyong Liu, Zixiao Wang, and Weibin Yang Copyright © 2014 Kunrong Wang et al. All rights reserved. Evaluation of Corrosion Inhibition of Mild Steel in 1 M Hydrochloric Acid Solution by Mollugo cerviana Mon, 21 Jul 2014 08:33:18 +0000 The inhibiting effect of methanolic extract of Mollugo cerviana plant on the corrosion of mild steel in 1 M HCl solution has been investigated by different techniques like potentiodynamic polarization, electrochemical impedance spectroscopy, and weight loss methods for five different concentrations of plant extract ranging from 25 to 1000 mg/L. The results indicated that the corrosion inhibition efficiency increased on increasing plant extract concentration till 500 mg/L and decreased on further increasing concentration. The extract was a mixed type inhibitor with the optimum inhibition concentration of 500 mg/L in potentiodynamic polarization. The adsorption of the plant extract on the mild steel surface was found to obey Langmuir adsorption isotherm. Surface analysis was also carried out to find out the surface morphology of the mild steel in the presence and in the absence of the inhibitor to find out its efficiency. The obtained results showed that the Mollugo cerviana extract acts as a good inhibitor for the corrosion of mild steel in 1 M HCl solution. P. Arockiasamy, X. Queen Rosary Sheela, G. Thenmozhi, M. Franco, J. Wilson Sahayaraj, and R. Jaya Santhi Copyright © 2014 P. Arockiasamy et al. All rights reserved. Corrosion Behavior of A356-10 Vol.% SiC Composites Cast by Gravity and Squeeze Casting in H2SO4 Solutions Tue, 08 Jul 2014 00:00:00 +0000 Corrosion behavior of A356-10 vol.% SiC composites cast by gravity and squeeze casting is evaluated. For this purpose, prepared samples were immersed in H2SO4 solution for 2 hrs. at open circuit potential. Tafel polarization and electrochemical impedance spectroscopy (EIS) were carried out to study the corrosion resistance of composites. The results showed that corrosion resistance of composites cast by squeeze casting is higher than that of the gravity cast composites. The micrographs of scanning electron microscope (SEM) clearly showed the squeeze casting composites exhibit a good dispersion/matrix interface when compared with composites produced by gravity casting. A. Fattah-alhosseini, M. Ranjbaran, and S. Vajdi Vahid Copyright © 2014 A. Fattah-alhosseini et al. All rights reserved. Effect of Cold-Rolled Thickness Reduction Degree on Characteristics of Hydrogen Diffusion in Silicon Steel Tue, 17 Jun 2014 08:17:38 +0000 The characteristic of hydrogen uptake and diffusion in the cold-rolled silicon steel was investigated by electrochemical hydrogen permeation technique performed under different cathodic charging current density and cold-rolled thickness reduction degree. The results indicated that anodic permeation current density increased with increasing cathodic charging current for the specimens. Moreover, the anodic steady state permeation current density and the solubility increased with an increase in the cold-rolled thickness reduction degrees. The breakthrough time of hydrogen in the specimens was shortened with increasing thickness reduction degrees, and the value of the hydrogen diffusivity decreased gradually with increasing thickness reduction degrees. Yongfeng Li, Lian Cai, Guanjun Liu, and Lijie Ma Copyright © 2014 Yongfeng Li et al. All rights reserved. Characterization of Corrosion Products on Carbon Steel Exposed to Natural Weathering and to Accelerated Corrosion Tests Sun, 15 Jun 2014 05:09:10 +0000 The aim of this work was to compare the corrosion products formed on carbon steel plates submitted to atmospheric corrosion in urban and industrial atmospheres with those formed after accelerated corrosion tests. The corrosion products were characterized by X-ray diffraction, Mössbauer spectroscopy, and Raman spectroscopy. The specimens were exposed to natural weathering in both atmospheres for nine months. The morphologies of the corrosion products were evaluated using scanning electron microscopy. The main product found was lepidocrocite. Goethite and magnetite were also found on the corroded specimens but in lower concentrations. The results showed that the accelerated test based on the ASTM B117 procedure presented poor correlation with the atmospheric corrosion tests whereas an alternated fog/dry cycle combined with UV radiation exposure provided better correlation. Renato Altobelli Antunes, Rodrigo Uchida Ichikawa, Luis Gallego Martinez, and Isolda Costa Copyright © 2014 Renato Altobelli Antunes et al. All rights reserved. Corrosion Problems in Incinerators and Biomass-Fuel-Fired Boilers Mon, 12 May 2014 06:15:28 +0000 Incinerators are widely used to burn the municipal waste, biowaste, wood, straw, and biomedical waste. Combustion of these types of waste results in generation of chlorides of sodium and potassium which may attack the metallic part of the incinerator. In biofuel-fired boilers, similar type of highly corrosive environment is present. Attempt has been made to review the corrosion problems and their solutions as per the available literature. Deepa Mudgal, Surendra Singh, and Satya Prakash Copyright © 2014 Deepa Mudgal et al. All rights reserved. Hot Corrosion Behaviour of Detonation Gun Sprayed Stellite-6 and Stellite-21 Coating on Boiler Steel SAE 431 at 900°C Tue, 06 May 2014 07:35:13 +0000 Hot corrosion is the serious problem in gas turbines, superheaters, and economizers of coal-fired boilers. It occurs due to the usage of wide range of fuels such as coal, oil, and so on at the elevated temperatures. Protective coatings on boiler steels are used under such environments. In the present investigation, Stellite-6 and Stellite-21 coatings have been deposited on boiler steel SAE 431 by detonation gun method. The hot corrosion performance of Stellite-6 and Stellite-21 coated as well as uncoated SAE 431 steel has been evaluated in aggressive environment of Na2SO4-82%Fe2(SO4)3 under cyclic conditions at an elevated temperature of 900°C for total duration of 50 cycles. Thermogravimetric technique was used to approximate the kinetics of hot corrosion. Stellite-6 coating imparted better hot corrosion resistance than Stellite-21 coating in the given environment. Scanning electron microscopy was used to characterize the surface of hot corrosion products. N. K. Mishra, A. K. Rai, S. B. Mishra, and R. Kumar Copyright © 2014 N. K. Mishra et al. All rights reserved. Assessment of Automotive Coatings Used on Different Metallic Substrates Tue, 29 Apr 2014 08:54:14 +0000 Four epoxy primers commonly used in the automotive industry were applied by gravity pneumatic spray gun over metallic substrates, specifically, steel, electrogalvanized steel, hot-dip galvanized steel, and aluminum. A two-component polyurethane resin was used as topcoat. To evaluate the performance of the different coating systems, the treated panels were submitted to mechanical testing using Persoz hardness, impact resistance, cupping, lattice method, and bending. Tribological properties of different coating systems were conducted using pin on disc machine. Immersion tests were carried out in 5% NaCl and immersion tests in 3% NaOH solutions. Results showed which of the coating systems is more suitable for each substrate in terms of mechanical, tribological, and anticorrosive performance. W. Bensalah, N. Loukil, M. De-Petris Wery, and H. F. Ayedi Copyright © 2014 W. Bensalah et al. All rights reserved.