ISRN Corrosion The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Development and Performance Evaluation of Corrosion Resistance Self-Healing Coating Wed, 23 Apr 2014 13:48:54 +0000 Polymer based nanocapsule was developed using core-cell approach, where the core material was methyl diphenyl diisocyanate and the cell material was urea-formaldehyde. The synthesized capsules of 100 to 800 nm size were incorporated into sol-gel matrix to prepare a final coating for steel protection. This coating was found protecting the steel at the damage or crack locations in 3.5% NaCl solution. SEM micrographs confirmed healing of the coating at the damage or crack points. Akshya Kumar Guin, Suryakanta Nayak, Manish Kumar Bhadu, Veena Singh, and Tapan Kumar Rout Copyright © 2014 Akshya Kumar Guin et al. All rights reserved. Surface Protection of Carbon Steel by Hexanesulphonic Acid-Zinc Ion System Wed, 19 Mar 2014 10:38:17 +0000 Inhibition of corrosion of carbon steel in dam water by hexanesulphonic acid as its sodium salt C6H13SO3Na (SHXS) in the absence and presence of a bivalent cation zinc ion (Zn2þ) has been investigated using weight loss method. Results of weight loss method indicate that inhibition efficiency (IE) increased with increase of inhibitor concentration. Polarization study reveals that SHXS-Zn2+ system controls the cathodic reaction predominantly. AC impedance spectra reveal that a protective film is formed on the metal surface. The nature of the metal surface has been analysed by Fourier Transform Infrared Spectroscopy (FTIR) and Atomic Force Microscopy (AFM). C. Mary Anbarasi and Susai Rajendran Copyright © 2014 C. Mary Anbarasi and Susai Rajendran. All rights reserved. Adsorption and Corrosion Inhibition Characteristics of Some Nicotinamide Derivatives on Mild Steel in Hydrochloric Acid Solution Mon, 10 Mar 2014 14:02:31 +0000 The present investigation includes the study of corrosion inhibition effect of N-(1H-Indol-3-ylmethylene)-nicotinamide (IMN) and N-(3,4,5-trimethoxy-benzylidene)-nicotinamide (TMN) on mild steel in 0.5 M HCl by mass loss and electrochemical measurements. The obtained results showed that inhibition efficiency increased with the increasing concentration of inhibitors and decreased with increase in temperature and immersion time. Potentiodynamic polarization curves indicate that both IMN and TMN were acting as mixed type of inhibitors. Langmuir adsorption isotherm model was employed to determine the equilibrium of adsorption for inhibiting process in both inhibitors. Nyquist plots revealed that, as the concentration of the inhibitors increases, double layer capacitance () and corrosion current () decreases, while polarization resistance () increases. Various thermodynamic parameters for the adsorption of inhibitors on mild steel were computed and discussed. The passive film formed on the metal surface was characterized by FTIR, EDX, and SEM. M. P. Chakravarthy and K. N. Mohana Copyright © 2014 M. P. Chakravarthy and K. N. Mohana. All rights reserved. Corrosion Behavior of Zinc-Graphite Metal Matrix Composite in 1 M of HCl Sun, 09 Mar 2014 12:37:06 +0000 This paper is aimed at investigating the corrosion behavior of Pure and Zinc-graphite particles with percentage of 1, 3, and 5%, respectively. The composites were fabricated by powder metallurgy method. Corrosion tests were performed according to ASTM standard. Corrosion rate was calculated and it is found that in all cases the corrosion rate was decreasing with the increase in exposure time. Meanwhile, the microstructure of composites was imaged and analyzed using optical microscope and scanning electron microscope. It is observed that the best corrosion resistance was zinc with 1% Graphite while Zinc with 3% and 5% Graphite composites did not enhance the corrosion resistance comparing to pure Zinc. M. A. Afifi Copyright © 2014 M. A. Afifi. All rights reserved. Characterization of Corrosive Bacterial Consortia Isolated from Water in a Cooling Tower Tue, 04 Mar 2014 00:00:00 +0000 An analysis of a culturable corrosive bacterial community in water samples from a cooling tower was performed using traditional cultivation techniques and its identification based on 16S rRNA gene sequence. Seven aerobic bacterial species were identified: Pseudomonas putida ARTYP1, Pseudomonas aeruginosa ARTYP2, Massilia timonae ARTYP3, Massilia albidiflava ARTYP4, Pseudomonas mosselii ARTYP5, Massilia sp. ARTYP6, and Pseudomonas sp. ARTYP7. Although some of these species have commonly been observed and reported in biocorrosion studies, the genus Massilia is identified for the first time in water from a cooling tower. The biocorrosion behaviour of copper metal by the new species Massilia timonae ARTYP3 was selected for further investigation using a weight loss method, as well as electrochemical and surface analysis techniques (SEM, AFM, and FTIR). In contrast with an uninoculated system, thin bacterial biofilms and pitting corrosion were observed on the copper metal surface in the presence of M. timonae. The use of a biocide, bronopol, inhibited the formation of biofilm and pitting corrosion on the copper metal surface. Rajasekar Aruliah and Yen-Peng Ting Copyright © 2014 Rajasekar Aruliah and Yen-Peng Ting. All rights reserved. Corrosion Inhibition of Carbon Steel in 0.5 M H2SO4 by Phtalocyanine Blue Mon, 03 Feb 2014 09:53:27 +0000 Phthalocyanine blue dye has been investigated as a carbon steel corrosion inhibitor in 0.5 M sulfuric acid by using polarization curves, electrochemical impedance spectroscopy, and gravimetric tests. Dye concentrations included 0, 100, 200, 400, 600, 800, and 1000 ppm, whereas testing temperatures were 25, 40, and 60°C. Results indicated that phtalocyanine blue is a good corrosion inhibitor with its efficiency increasing with the concentration up to 40°C, but it increases at 60°C. Inhibitor improves the passive film properties and it forms an adherent, compact, protective film, acting, therefore, as an anodic-type inhibitor. At 25 and 40°C the corrosion process was under charge transfer, whereas at 60°C the adsorption/desorption of some species from the metal surface controlled the corrosion process. J. C. Valle-Quitana, G. F. Dominguez-Patiño, and J. G. Gonzalez-Rodriguez Copyright © 2014 J. C. Valle-Quitana et al. All rights reserved. One-Step Anodization/Sol-Gel Deposition of -Doped Silica-Zirconia Self-Healing Coating on Aluminum Thu, 12 Dec 2013 08:57:25 +0000 A novel process was used for the preparation of dense, thick, and stable silica-zirconia coatings on aluminum by an in situ anodization along with sol-gel deposition. Anodic electrophoretic deposition was carried on aluminum using a SiO2-ZrO2 sol that was synthesized from an epoxy modified silane and zirconium n-propoxide along with a cerium salt (Ce(NO3)3·6H2O). Current density and time were varied during the deposition. The optimal parameters that yielded uniform coatings were determined. Coatings were characterized for their crystallinity, scratch hardness, and microstructure. The barrier properties of the coatings were tested using potentiodynamic polarization studies, electrochemical impedance spectroscopy, and neutral salt spray tests. Grazing angle incidence X-ray diffraction studies revealed that the coating comprised crystalline Al2SiO5 along with an amorphous phase. The novelty of the process was that the crystalline aluminosilicate phase was formed even at room temperature and could be deposited on aluminum by a simultaneous anodization of aluminum and sol-gel deposition. The coated substrates withstood more than 400 hours of salt spray tests. Polarization measurements reveal that the composite layer of aluminosilicate along with the Ce3+-doped silica-zirconia sol enhances the corrosion properties by forming a passive layer, which acts as a good barrier against corrosion. N. Kumar, A. Jyothirmayi, K. R. C. Soma Raju, V. Uma, and R. Subasri Copyright © 2013 N. Kumar et al. All rights reserved. Study of Synergistic Effect of Iodide on the Corrosion Antagonistic Behaviour of a Heterocyclic Phenylhydrazone in Sulphuric Acid Medium on Carbon Steel Tue, 03 Dec 2013 10:49:42 +0000 Synergistic effect of KI on the corrosion inhibition efficiency of 3-acetylpyridine phenylhydrazone (3APPH) on carbon steel (CS) in 0.5 M sulphuric acid solution has been investigated using gravimetric studies, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization studies. Gravimetric corrosion studies revealed that 3APPH showed moderate corrosion inhibition efficiency up to 8 h and beyond this period it showed corrosion accelerating behavior. This antagonistic effect of 3APPH is due to the hydrolysis of the molecule in acidic medium. A very high percentage of inhibition efficiency at 24 h was obtained on the addition of KI due to the synergistic effect of iodide ions. The adsorption of 3APPH and 3APPH + KI on the surfaces of the corroding metal obey Langmuir isotherm as obtained by impedance measurements. Polarization studies revealed that 3APPH act as a mixed type inhibitor. Thermodynamic parameters () were derived from the adsorption isotherms. Surface morphology of the corroding metal was investigated by SEM analysis. Vinod P. Raphael, Joby Thomas Kakkassery, Shaju K. Shanmughan, and Aby Paul Copyright © 2013 Vinod P. Raphael et al. All rights reserved. Copper Corrosion by Atmospheric Pollutants in the Electronics Industry Wed, 02 Oct 2013 18:36:03 +0000 Hydrogen sulphide (H2S) is considered one of the most corrosive atmospheric pollutants. It is a weak, diprotic, reducing acid, readily soluble in water and dispersed into the air by winds when emitted from natural, industrial, and anthropogenic sources. It is a pollutant with a high level of toxicity impairing human health and the environment quality. It attacks copper forming thin films of metallic sulphides or dendrite whiskers, which are cathodic to the metal substrate, enhancing corrosion. H2S is actively involved in microbially influenced corrosion (MIC) which develops in water, involving sulphur based bacteria, in oxidizing and reducing chemical reactions. H2S is found in concentrated geothermal brines, in the atmosphere of geothermal fields, and in municipal sewage systems. Other active atmospheric pollutants include SOX, NOX, and CO. This investigation reports on the effects of H2S on copper in microelectronic components of equipment and devices, with the formation of nonconductive films that lead to electrical failures. Benjamin Valdez Salas, Michael Schorr Wiener, Roumen Zlatev Koytchev, Gustavo López Badilla, Rogelio Ramos Irigoyen, Monica Carrillo Beltrán, Nicola Radnev Nedev, Mario Curiel Alvarez, Navor Rosas Gonzalez, and Jose María Bastidas Rull Copyright © 2013 Benjamin Valdez Salas et al. All rights reserved. Evaluation of Corrosion Growth on SS304 Based on Textural and Color Features from Image Analysis Thu, 19 Sep 2013 14:24:55 +0000 Corrosion surface damage in the form of pitting and microcracks is observed in many systems and affects the integrity of steel structures in nuclear, civil, and industrial engineering. In order to gain a better understanding and develop nondestructive and automatic detection/assessment of corrosion damage and its growth, an image analysis based on texture using wavelet transforms and color features was carried out. Experiments were conducted on steel 304 panels under three different electrolyte solutions, and periodic scans were used to obtain the images for analysis over time. The results obtained from the image analysis are presented to illustrate the metrics which best characterize early stage corrosion damage growth behavior. The results obtained indicate that textural features in combination with color features are more effective and may be used for correlating service/failure conditions based on corrosion morphology. Ramana M. Pidaparti, Brian Hinderliter, and Darshan Maskey Copyright © 2013 Ramana M. Pidaparti et al. All rights reserved. Morphology Characterisation of Pitting Corrosion on Sensitized Austenitic Stainless Steel by Digital Image Analysis Tue, 27 Aug 2013 13:53:52 +0000 Pit morphology on sensitized 310S stainless steel has been studied using an image processing method based on reflected light microscopy. Salt Spray (fog) test has been used to induce the pitting corrosion. Morphological pits characters do not depend on sensitization heat treatments applied here. Nucleation rates and growth may be associated with quantity and distribution of chromium carbides. This being so, condition I (heating up to 1065°C during 1 h and air cooling) and condition II (heating up to 1065°C during 1 h and air cooling followed by reheating up to 670°C during 5 h and again air cooling) are the most susceptible to pitting, in particular the first one. In these two conditions, pits are nucleated in grains and in grain boundaries, while in condition III (heating up to 1065°C during 1 h and air cooling followed by reheating up to 620°C during 24 h and again air cooling), pits are preferentially nucleated in boundaries of small grains. Thence, pits usually grow more rapidly in depth than in width, being able to occur partial or total grains separation. Pits are mainly hemispherical, near-hemispherical, near-conical, and near-cylindrical without significant geometric transition associated with an increasing exposure period. R. B. Ribeiro, J. W. J. Silva, L. R. O. Hein, M. C. Pereira, E. N. Codaro, and N. T. Matias Copyright © 2013 R. B. Ribeiro et al. All rights reserved. Microstructural Characteristics and Mechanical Properties of Nanostructured and Conventional TiAlN and AlCrN Coatings on ASTM-SA210 Grade A-1 Boiler Steel Sun, 18 Aug 2013 11:26:42 +0000 Nanostructured and conventional TiAlN and AlCrN coatings were deposited on ASTM-SA210 Grade A-1 boiler steel. The present work has been focused to characterize the conventional thick (by plasma spraying and gas nitrided) and nanostructured thin (by physical vapor deposition process) TiAlN and AlCrN coatings developed on ASTM-SA210 Grade A-1 boiler steel. The surface morphology of the coated samples was studied using FE-SEM with EDAX attachment, XRD analysis, AFM analysis, and the X-ray mapping analysis. The presence of metal nitride phases as identified by XRD analysis indicates that the desired coatings were successfully developed. The bond strength, surface roughness, and microhardness of the gas nitrided plasma sprayed conventional coatings were measured. A good adhesion of the conventional thick TiAlN and AlCrN coatings was evident from bond test results. Vikas Chawla Copyright © 2013 Vikas Chawla. All rights reserved. Synergistic Effect of Iodide Ion and 4-Hydroxy Coumarin on the Corrosion Inhibition of Mild Steel in Hydrochloric Acid Thu, 27 Jun 2013 08:46:48 +0000 No discussion of the use of inhibitors in acid solution is complete without mentioning the phenomenon of synergism. Synergism also operates in corrosion protection where an enhanced inhibition may be related to interaction between inhibitor compounds. This effect has been observed since the earlier days of inhibitor technology and continues to be a potent tool in the development of acid inhibitors for specialized uses. Hence, in this paper, the corrosion inhibition behavior of mild steel (MS) in 1 M hydrochloric acid in the presence of 4-hydroxy coumarin (4HC) and potassium iodide (KI) has been investigated using the mass loss method and electrochemical techniques. The inhibitive performance of 4HC is considerably enhanced by the addition of KI. The addition of KI to different concentrations of 4HC has intensified its efficiency through considerable reduction in the mass loss, corrosion current density , double layer capacitance , and increase in charge transfer resistance . The calculated synergism parameter “” is greater than unity, thereby proving the fact that the improvement in inhibition efficiency of 4HC, generated by the addition of KI, is due to synergism. Shyamala R. Krishnamurthy and Meenakshi H. N. Parameswaran Copyright © 2013 Shyamala R. Krishnamurthy and Meenakshi H. N. Parameswaran. All rights reserved. The Effect of Achyranthes aspera Extracts on Mild Steel Corrosion in Industrial Water Medium Tue, 28 May 2013 16:30:55 +0000 Achyranthes aspera (AA) extracts were studied as corrosion inhibitor for mild steel (MS) in industrial water medium using mass loss and electrochemical techniques. The results of the study revealed that AA extracts inhibit MS corrosion through adsorption process following Langmuir adsorption isotherm model. The protection efficiency increased with increase in inhibitor concentration and decreased with temperature. The electrochemical impedance spectroscopy (EIS) measurements showed that the charge transfer resistance increases with increase in the concentration of AA extracts. The polarization curves obtained indicate that AA extracts act as mixed type of inhibitor. Scanning electron microscopy (SEM) was used to analyze the surface adsorbed film. Chikkur B. Pradeep Kumar and Kikkeri N. Mohana Copyright © 2013 Chikkur B. Pradeep Kumar and Kikkeri N. Mohana. All rights reserved. An Investigation on Dislocation Density in Cold-Rolled Copper Using Electrochemical Impedance Spectroscopy Mon, 25 Mar 2013 11:54:24 +0000 Variation of electrochemical impedance with dislocation density was investigated using electrochemical impedance spectroscopy (EIS). For this purpose, EIS measurements were carried out on 10, 20, 30, 40, and 50% cold-rolled commercially pure copper in 0.1 M NaCl (pH = 2) solution. Nyquist plots illustrated that the electrochemical reactions are controlled by both charge transfer and diffusion process. Increasing dislocation density, the magnitude of electrochemical impedance of samples was decreased. Decreasing magnitude of impedance at intermediate frequencies indicated increasing double-layer capacitance. Charge transfer resistance decreased from value 329.6 Ωcm2 for annealed sample to 186.3 Ωcm2 for sample with maximum dislocation density ( ). Phase angles were lower for samples that contained more dislocation density, indicating more tendencies to loss of electrons and releasing atoms into electrolyte. Elyas Rafiee, Mansour Farzam, Mohammad Ali Golozar, and Ali Ashrafi Copyright © 2013 Elyas Rafiee et al. All rights reserved. Corrosion Study of Powder-Coated Galvanised Steel Sun, 24 Mar 2013 08:45:04 +0000 In general, steel is protected from corrosive environments by conversion coatings, that is, phosphating, chromating, and so forth, and then followed by different layers of paints. Nowadays, strict pollution laws and regulations are creating significant challenges for coating experts to develop an environmentally friendly product. Powder coatings have demonstrated their ability as alternative to traditional solvent-borne coatings. In the present work, polyester-based two coating systems have been investigated and their performances have been evaluated for surface topographical properties by Scanning electron microscope (SEM), and energy dispersive spectrometry (EDX), accelerated corrosion resistance by salt spray test, and impedance property by electrochemical impedance spectroscopy. Coating adhesion with the steel and hardness were evaluated by bond strength, cross cut adhesion, and pencil hardness. This paper explains the results and performance of the coatings by the above two systems. Manish Kumar Bhadu, Akshya Kumar Guin, Veena Singh, and Shyam K. Choudhary Copyright © 2013 Manish Kumar Bhadu et al. All rights reserved. Effect of Serine and Methionine on Electrochemical Behavior of the Corrosion of Mild Steel in Aqueous Solutions Wed, 06 Mar 2013 13:54:38 +0000 The pitting corrosion behaviour of mild steel in Na2HPO4 solutions contains chloride ion as an aggressive ion and serine and methionine as inhibitors were investigated using open-circuit potential (OCP), potentiodynamic polarization measurements, and pitting corrosion current measurements; both inhibitors shift the potential in the positive direction. The corrosion rate of the mild steel was measured in the absence and presence of the inhibitors, and the inhibition efficiency of the amino acids at a concentration of 0.02 M was calculated. The pitting corrosion current shows that increasing concentration of the inhibitor causes a decrease in pitting current density, and inhibition efficiency increases with increasing concentration of the inhibitors. The adsorption of these inhibitors on the mild steel surface obeys Langmuir isotherm, and the calculated adsorption free energy (Δ) for the inhibitors on the mild steel in 0.1 M (Na2HPO4 + NaCl) solutions was found to be (−24.61, −29.34) kJ/mol for serine and methionine, respectively, which reveals strong physical adsorption of the amino acids molecules on the mild steel surface. Mohamed N. Rahuma, Mohamed B. EL-Sabbah, and Imperiyka M. Hamad Copyright © 2013 Mohamed N. Rahuma et al. All rights reserved. Corrosion Inhibition and Adsorption Properties of Ethanolic Extract of Calotropis for Corrosion of Aluminium in Acidic Media Tue, 05 Mar 2013 10:39:37 +0000 The corrosion inhibition of aluminium in sulfuric acid solution in the presence of different plant parts, namely, leaves, latex, and fruit was studied using weight loss method and thermometric method. The ethanolic extracts of Calotropis procera and Calotropis gigantea act as an inhibitor in the acid environment. The inhibition efficiency increases with increase in inhibitor concentration. The plant parts inhibit aluminium, and inhibition is attributed, due to the adsorption of the plant part on the surface of aluminium. Sudesh Kumar and Suraj Prakash Mathur Copyright © 2013 Sudesh Kumar and Suraj Prakash Mathur. All rights reserved. The Corrosion Resistance of Nickel Electrocomposite Coating Containing BaFe12O19 Particles Sun, 24 Feb 2013 09:32:58 +0000 Electroplating composite coating is an effective method to prepare composite coating through the codeposition of metallic, nonmetallic, or polymer particles with metal to improve properties such as corrosion resistance, hardness, and wear performance. This paper reports the synthesis of a novel Ni-BaFe12O19 magnetic nanocomposite coating exhibiting improved corrosion resistance. In the present paper, BaFe12O19 particles were synthesized by a single-step solution combustion method and characterized for phase, particle size, and morphology. These particles were incorporated in a nickel metal matrix, and the properties of the coatings like nanohardness and corrosion resistance were investigated. The coating microstructure was also studied using field emission scanning electron microscope. A Vickers hardness of 777 HV was exhibited by Ni-BaFe12O19, and plain Ni coating exhibited a hardness of 517 HV. The Ni-BaFe12O19 composite coating exhibited improved corrosion resistance compared to plain Ni coating with an value of 0.034 μA/cm2 compared to 0.361 μA/cm2 for plain Ni. The Ni-BaFe12O19 coating also exhibited higher charge transfer and polarization resistance compared to plain Ni coating. S. T. Aruna, G. Savitha, Jyothi Shedthi, and V. K. William Grips Copyright © 2013 S. T. Aruna et al. All rights reserved. Corrosion Inhibition of Cu-Ni (90/10) Alloy in Seawater and Sulphide-Polluted Seawater Environments by 1,2,3-Benzotriazole Tue, 12 Feb 2013 13:26:32 +0000 The inhibiting effect of 1,2,3-benzotriazole (BTAH) against the corrosion of Cu-Ni (90/10) alloy in seawater and seawater polluted with inorganic sulphide was studied by electrochemical impedance studies (EISs), potentiodynamic polarization studies, and cyclic voltammetric (CV) and weight-loss studies. Surface examination studies were carried out by X-ray photo electron spectroscopy (XPS) and scanning electron microscopy (SEM)/energy dispersive X-ray analysis (EDX). EIS studies have been carried out in seawater and 10 ppm of inorganic sulphide containing seawater in the absence and presence of BTAH at different concentrations, different immersion periods, and at different temperatures. Appropriate equivalent circuit model was used to calculate the impedance parameters. The potentiodynamic polarization studies inferred that BTAH functions as a mixed inhibitor. The impedance, polarization, and weight-loss studies showed that the inhibition efficiency of BTAH is in the range between 99.97 and 99.30% under different conditions. Cyclic voltammeric studies show the stability of the protective BTAH film even at anodic potentials of +550 mV versus Ag/AgCl. All these studies infer that BTAH functions as an excellent inhibitor for Cu-Ni (90/10) alloy in seawater and sulphide-polluted seawater. XPS and SEM-EDX studies confirm the presence of protective BTAH film on the alloy surface. Venkata Appa Rao Boyapati and Chaitanya Kumar Kanukula Copyright © 2013 Venkata Appa Rao Boyapati and Chaitanya Kumar Kanukula. All rights reserved. Corrosion Behaviour of Ti-6Al-4V Alloy with Nitride Coatings in Simulated Body Fluids at and Mon, 11 Feb 2013 15:19:15 +0000 Nitride coatings were formed on Ti-6Al-4V alloy by thermodiffusion treatment. The corrosion-electrochemical behaviour of Ti-6Al-4V alloy with nitride coatings I and II was investigated in physiological solutions (0.9% NaCl and Tyrode's) at temperatures of and . It is determined that nitride coating I provides Ti-6Al-4V alloy the higher corrosion resistance in Tyrode's solution at both temperatures of solution while nitride coating II in isotonic 0.9% NaCl. I. M. Pohrelyuk, O. V. Tkachuk, and R. V. Proskurnyak Copyright © 2013 I. M. Pohrelyuk et al. All rights reserved. The Development of a Mathematical Model for the Prediction of Corrosion Rate Behaviour for Mild Steel in 0.5 M Sulphuric Acid Sun, 10 Feb 2013 14:45:30 +0000 The effect of varying temperature, concentration, and time on the corrosion rate of mild steel in 0.5 M H2SO4 acid with and without (wild jute tree) grewia venusta plant extract has been investigated by weight loss. The temperature, concentration of inhibitor and time were varied in the range of 0–10% v/v at 2% v/v interval, 30–70∘C at 20∘C interval, and 45–270 minutes at 45 minutes interval respectively. Scanning electron microscope was used to analyze the morphology of the sample surface. Linear regression equation and analysis of variance (ANOVA) were employed to investigate the influence of process parameters on the corrosion rate of the samples. The predicted corrosion rate of the samples was found to lie close to those experimentally observed ones. The confirmation of the experiment conducted using ANOVA to verify the optimal testing parameters shows that the increase in inhibitor concentration above 2% v/v and time would reduce the corrosion rate. The results also showed that the increase in temperature would also increase the corrosion rate greatly and that the plant extract was very effective for the corrosion inhibition of mild steel in acidic medium. I. Y. Suleiman, O. B. Oloche, and S. A. Yaro Copyright © 2013 I. Y. Suleiman et al. All rights reserved. Cuminum cyminum Extracts as Eco-Friendly Corrosion Inhibitor for Mild Steel in Seawater Thu, 07 Feb 2013 17:05:44 +0000 The inhibitive effect of Jeera (Cuminum cyminum) plant extracts on the corrosion of mild steel in an aqueous solution of seawater was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The stability of the inhibition efficiency of Jeera extracts was examined by weight-loss method. Potentiodynamic polarization curves indicated that the Jeera extract behaves as an anodic type inhibitor. EIS measurements showed that the dissolution process occurs under activation control. The corrosion rates of steel and the inhibition efficiencies of the extract obtained from impedance and polarization measurements were in good agreement. Inhibition was found to increase with an increasing concentration of the plant extract. The results obtained show that the Jeera extract could serve as an effective inhibitor for the corrosion of mild steel in seawater. V. Sribharathy and Susai Rajendran Copyright © 2013 V. Sribharathy and Susai Rajendran. All rights reserved. Corrosion of WC-VC-Co Hardmetal in Neutral Chloride Containing Media Tue, 29 Jan 2013 14:11:51 +0000 The effect of varying VC content on the corrosion behavior of WC-10 wt% Co hardmetals in sodium chloride (NaCl) and synthetic mine water (SMW) solutions has been investigated using anodic polarization scans and surface analytical methods. It is shown that the polarization behavior is active-pseudopassive in NaCl and active in SMW regardless of the VC content, while the corrosion resistance is poorer and independent of VC content in NaCl but better at high VC contents in SMW. The corrosion behavior of samples is explained using the effect of VC on the chemical composition of the binder. C. N. Machio, D. S. Konadu, J. H. Potgieter, S. Potgieter-Vermaak, and J. Van der Merwe Copyright © 2013 C. N. Machio et al. All rights reserved. Improvement in Corrosion Inhibition Efficiency of Molybdate-Based Inhibitors via Addition of Nitroethane and Zinc in Stimulated Cooling Water Tue, 25 Dec 2012 15:55:46 +0000 An investigation was conducted to improve the corrosion inhibition efficiency of molybdate-based inhibitors for mild steel which is the main construction material of cooling water systems, using nitroethane as an organic compound beside zinc. In this study a new molybdate-based inhibitor was introduced with the composition of 60 ppm molybdate, 20 ppm nitrite, 20 ppm nitroethane, and 10 ppm zinc. Inhibition efficiency of molybdate alone and with nitrite, nitroethane, and zinc on the uniform corrosion of mild steel in stimulated cooling water (SCW) was assessed by electrochemical techniques such as potentiodynamic polarization and electrochemical impedance (AC impedance) measurements. Weight loss measurements were made with coupon testing specimens in the room temperature for 48 h. Studies of electron microscopy, including scanning electron microscopy (SEM) photograph and X-ray energy dispersive spectrometry (EDS) microanalysis, were used. The results obtained from the polarization and AC impedance curves were in agreement with those from the corrosion weight loss results. The results indicate that the new inhibitor is as effective as molybdate alone, though at one-ninth of the concentration range of molybdate, which is economically favorable. Saeed Mohammadi, Fatemeh Baghaei Ravari, and Athareh Dadgarinezhad Copyright © 2012 Saeed Mohammadi et al. All rights reserved. The Performance of Carbon Fibre Composites as ICCP Anodes for Reinforced Concrete Structures Thu, 20 Dec 2012 10:13:06 +0000 Cathodic protection has been proven to be one of the most widely applicable and cost-effective solutions for tackling steel corrosion in reinforced concrete. In this study, the possible use of carbon fibre composites, which are primarily used to strengthen concrete members, has been investigated as impressed current cathodic protection anodes. Carbon fibre anodes have been assessed in both concrete and calcium hydroxide solution. Two bonding mediums incorporating epoxy and geopolymer have also been investigated. The results demonstrate that epoxy resin can be used for bonding carbon fibre fabric anodes to reinforced concrete structures while geopolymer is more effective for bonding carbon fibre reinforced polymer (CFRP) rod into preformed grooves in the concrete surface. The dissolution of carbon fibre anode appears to stablise after a period of time, dependent upon the size and shape of the anode and applied voltage and current. Based on the present results, a maximum current density of 128 mA/m2 of reinforcing steel area is recommended for the operation of CFRP fabric anode and 64 mA/m2 of reinforcing steel area for that of CFRP rod anode. Chinh Van Nguyen, Paul Lambert, Pal Mangat, Fin O’Flaherty, and Graeme Jones Copyright © 2012 Chinh Van Nguyen et al. All rights reserved. Inhibitory Mechanism of Carbon Steel Corrosion in Sea Water by an Aqueous Extract of Henna Leaves Sun, 16 Dec 2012 14:15:44 +0000 The inhibition efficiency (IE) of an aqueous extract of henna leaves in controlling corrosion of carbon steel in seawater has been evaluated by weight-loss method. The weight loss study reveals that the formulation consisting of 8 mL of henna extract (HE) and 25 ppm of Zn2+ has 94% inhibition efficiency in controlling corrosion of carbon steel in sea water. Polarization study reveals that HE and Zn2+ system functions as mixed type inhibitor. AC impedance spectra reveal that protective film is formed on the metal surface. The nature of the metal surface has been analysed by FTIR spectra, SEM, and AFM analysis. V. Johnsirani, J. Sathiyabama, Susai Rajendran, and A. Suriya Prabha Copyright © 2012 V. Johnsirani et al. All rights reserved. Predictive Modelling of Wellhead Corrosion due to Operating Conditions: A Field Data Approach Wed, 12 Dec 2012 15:58:48 +0000 The flow of crude oil, water, and gas from the reservoirs through the wellheads results in its deterioration. This deterioration which is due to the impact of turbulence, corrosion, and erosion significantly reduces the integrity of the wellheads. Effectively managing the wellheads, therefore, requires the knowledge of the extent to which these factors contribute to its degradation. In this paper, the contribution of some operating parameters (temperature, CO2 partial pressure, flow rate, and pH) on the corrosion rate of oil and gas wellheads was studied. Field data from onshore oil and gas fields were analysed with multiple linear regression model to determine the dependency of the corrosion rate on the operating parameters. ANOVA, value test, and multiple regression coefficients were used in the statistical analysis of the results, while in previous experimental results, de Waard-Milliams models and de Waard-Lotz model were used to validate the modelled wellhead corrosion rates. The study shows that the operating parameters contribute to about 26% of the wellhead corrosion rate. The predicted corrosion models also showed a good agreement with the field data and the de Waard-Lotz models but mixed results with the experimental results and the de Waard-Milliams models. Chinedu I. Ossai Copyright © 2012 Chinedu I. Ossai. All rights reserved. Effect of Plasma Surface Pretreatment on Ce3+-Doped GPTMS-ZrO2 Self-Healing Coatings on Aluminum Alloy Mon, 10 Dec 2012 17:05:09 +0000 A hybrid sol synthesized from an acid-catalyzed hydrolysis and condensation reaction of 3-glycidoxypropyltrimethoxysilane (GPTMS) and zirconium n-propoxide was used as a matrix nanocomposite sol. To this sol, 0.01 M Ce3+ was added as an inhibitor to provide a self-healing coating system. The effect of an atmospheric air plasma surface pretreatment of aluminum alloy substrates prior to coating deposition of Ce3+-doped/undoped GPTMS-ZrO2 sol was studied with respect to corrosion protection. Coatings were generated by a dip coating technique employing a withdrawal speed of 5 mm/s and thermally cured at 130° C for 1 h. The coated Al surfaces were characterized using potentiodynamic polarization studies and electrochemical impedance spectroscopy. They were also subjected to accelerated corrosion testing using neutral salt spray test with 5% NaCl solution after creating an artificial scratch for more than 200 hours to assess the self-healing ability of coatings. It was observed that cerium (III) doping was effective for corrosion protection during long-term exposure to the electrolyte solution, and a plasma surface pretreatment of substrates prior to coating deposition of Ce3+-doped coatings improved the adhesion of coatings that provides enhanced corrosion protection along with self-healing ability exhibited in case of damages/scratches caused in the coating. N. Kumar, A. Jyothirmayi, and R. Subasri Copyright © 2012 N. Kumar et al. All rights reserved. Synergistic Effect of KI on Corrosion Inhibition of Mild Steel by Polynuclear Schiff Base in Sulphuric Acid Wed, 05 Dec 2012 15:40:59 +0000 Synergistic effect of KI on the corrosion inhibition efficiency of polynuclear Schiff base, anthracene-9(10H)-one-3-aminopropanoic acid (A9O3AP), on mild steel (MS) in 0.5 M sulphuric acid solution has been investigated using weight loss measurements, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization studies. The results show that inhibition efficiencies on MS increase with increase in concentration of the inhibitor and enhancement in inhibition efficiency was observed on addition of potassium iodide due to synergism. The adsorptions, of inhibitor and inhibitor + KI on the surfaces of the corroding metal obey Freundlich and Langmuir isotherms, respectively. Polarization studies revealed that A9O3AP acts as a mixed type inhibitor. Thermodynamic parameters (; ) were calculated using the adsorption isotherms. A probable synergismtic mechanism is proposed. K. S. Shaju, K. Joby Thomas, Vinod P. Raphael, and Aby Paul Copyright © 2012 K. S. Shaju et al. All rights reserved.