V. Pinela, L. A. de Oliveira, M. C. L. de Oliveira, R. A. Antunes
{"title":"Study of the Corrosion Process of AZ91D Magnesium Alloy during the First Hours of Immersion in 3.5 wt.% NaCl Solution","authors":"V. Pinela, L. A. de Oliveira, M. C. L. de Oliveira, R. A. Antunes","doi":"10.1155/2018/8785154","DOIUrl":"https://doi.org/10.1155/2018/8785154","url":null,"abstract":"The AZ91D magnesium alloy was immersed in 3.5 wt.% NaCl solution at room temperature for times ranging from 1 minute up to 72 hours. The aim was to investigate the evolution of the corrosion process using confocal laser scanning microscopy (CLSM), electrochemical impedance spectroscopy, and X-ray photoelectron spectroscopy. The microstructure of the as-received alloy was initially characterized by optical microscopy and scanning electron microscopy (SEM). The crystalline phases were identified by X-ray diffractometry. The main phases were primary-α, eutectic-α, and β (Mg17Al12). Vickers microhardness markings were made on the surface of one etched sample to facilitate the identification of the same region at each different immersion time, thus enabling the observation of the corrosion process evolution. Corrosion initiates at the grain boundaries of the eutectic microconstituent and, then, propagates through primary α-grains. The β-phase was less severely attacked.","PeriodicalId":13893,"journal":{"name":"International Journal of Corrosion","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2018-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/8785154","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47651265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hot Corrosion of SrTiO3 Perovskite in Na2SO4 + 50 wt.% V2O5 and Na2SO4 + 10 wt.% NaCl Environments at 900°C","authors":"M. Prasad, K. S. Rao, M. Reddy, G. Sreedhar","doi":"10.1155/2018/4763085","DOIUrl":"https://doi.org/10.1155/2018/4763085","url":null,"abstract":"This study examines the phase stability of perovskite SrTiO3 in Na2SO4 + 50 wt.% V2O5 and Na2SO4 + 10 wt.% NaCl environments at 900°C. Hot corrosion results show the formation of Sr2VO4, SrV2O6, and SrTiV5O11 phases in Na2SO4 + 50 wt.% V2O5 environment and Sr3Ti2O7, Na4TiO4, and TiO2 phases in Na2SO4 + 10 wt.% NaCl environment. Morphological observations revealed the austerity of hot corrosion attack on SrTiO3. The Sr2+ ions leached out from SrTiO3 and reacted with corrosive environments. These observations clearly indicate the destabilization of SrTiO3 in both environments.","PeriodicalId":13893,"journal":{"name":"International Journal of Corrosion","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2018-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/4763085","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43179109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Red Sea as a Corrosive Environment: Corrosion Rates and Corrosion Mechanism of Aluminum Alloys 7075, 2024, and 6061","authors":"A. Al-Moubaraki, Hind H. Al-Rushud","doi":"10.1155/2018/2381287","DOIUrl":"https://doi.org/10.1155/2018/2381287","url":null,"abstract":"Corrosion behavior of Al 7075, Al 2024, and Al 6061 in the Red Sea water was studied using weight loss (WL) measurements and potentiodynamic polarization (PDP) technique. The corrosion patterns and corrosion products formed on Al alloys were characterized using optical photography (OP), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). The results showed that WL data were consistent with bimodal model rather than the power law function and the corrosion rates exhibit a continuous decrease with exposure time. The increasing order of the Red Sea corrosivity on the studied Al alloys can be given as follows: Al 6061 < Al 2024 < Al 7075. The results of temperature effect revealed that an increase in temperature resulted in an increase in both anodic and cathodic current density and a decrease in corrosion potential. Al 7075 was less influenced by temperature than the other alloys. Pitting corrosion was the predominant corrosion pattern detected on all Al alloy surfaces after prolonged immersion in the Red Sea water. The appearance of S peak in EDS spectra of Al 7075 after corrosion gives an indication of the contribution of bacteria in the corrosion process.","PeriodicalId":13893,"journal":{"name":"International Journal of Corrosion","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2018-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/2381287","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42576157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rodrigo Monzon Figueredo, Mariana Cristina de Oliveira, Leandro Jesus de Paula, H. A. Acciari, E. N. Codaro
{"title":"A Comparative Study of Hydrogen-Induced Cracking Resistances of API 5L B and X52MS Carbon Steels","authors":"Rodrigo Monzon Figueredo, Mariana Cristina de Oliveira, Leandro Jesus de Paula, H. A. Acciari, E. N. Codaro","doi":"10.1155/2018/1604507","DOIUrl":"https://doi.org/10.1155/2018/1604507","url":null,"abstract":"Susceptibility to hydrogen-induced cracking of API 5L B and X52MS low-carbon steels in NACE 177-A, 177-B, and 284-B solutions has been investigated by the present work. A metallographic analysis of these steels was performed before and after NACE TM0284 standard testing. Corrosion products were characterized by scanning electron microscopy and X-ray dispersive energy spectrometry, which were subsequently identified by X-ray diffraction. Thus it was found that pH directly affects the solubility of corrosion products and hydrogen permeation. Both steels showed generalized corrosion in solution 177-A, and a discontinuous film was formed on their surfaces in solution 177-B; however, only the API 5L B steel failed the HIC test and exhibited greater crack length ratio in solution 177-A. In solution 284-B whose pH is higher, the steels exhibited thick mackinawite films with no internal cracking.","PeriodicalId":13893,"journal":{"name":"International Journal of Corrosion","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2018-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/1604507","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48454291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Pitting Corrosion of the Resistance Welding Joints of Stainless Steel Ventilation Grille Operated in Swimming Pool Environment","authors":"M. Szala, D. Łukasik","doi":"10.1155/2018/9408670","DOIUrl":"https://doi.org/10.1155/2018/9408670","url":null,"abstract":"This work focuses on the pitting corrosion of ventilation grilles operated in swimming pool environments. The ventilation grille was made by resistance welding of stainless steel rods. Based on the macroscopic and microscopic examinations, the mechanism of the pitting corrosion was confirmed. Chemical composition microanalysis of sediments as well as base metal using scanning electron microscopy and energy-dispersive spectroscopy (SEM-EDS) method was carried out. The weldments did not meet the operating conditions of the swimming pool environment. The wear due to the pitting corrosion was identified in heat affected zones of stainless steel weldment and was more severe than the corrosion of base metal. The low quality finish of the joints and influence of the welding process on the weld metal microstructure lead to accelerated deposition of corrosion effecting elements such as chlorine.","PeriodicalId":13893,"journal":{"name":"International Journal of Corrosion","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2018-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/9408670","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47354152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Victória da Costa Marba, N. N. Regone, E. N. Codaro, H. A. Acciari
{"title":"Effect of Pulsed Current Frequency and Anodisation Time on Surface Properties of Electropolished and Nonelectropolished Titanium Substrates","authors":"Victória da Costa Marba, N. N. Regone, E. N. Codaro, H. A. Acciari","doi":"10.1155/2018/3204301","DOIUrl":"https://doi.org/10.1155/2018/3204301","url":null,"abstract":"Surface characteristics of anodic films formed on electropolished and nonelectropolished titanium substrates have been evaluated using different sets of anodisation parameters at room temperature. Surfaces were analysed by light microscopy, Raman spectroscopy, scanning electron microscopy, and X-ray diffraction. The formation of TiO2 anatase phase was only detected on nonelectropolished substrates and there seems to be a larger amount of anatase as samples are anodised; consequently, the smallest crystals were obtained at the highest frequency of pulsed current. EIS results showed that there is no difference in the degree of compactness along the layer thickness.","PeriodicalId":13893,"journal":{"name":"International Journal of Corrosion","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2018-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/3204301","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44366656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jan-Ervin C. Guerrero, D. Camacho, O. Mokhtari, H. Nishikawa
{"title":"Corrosion and Leaching Behaviours of Sn-0.7Cu-0.05Ni Lead-Free Solder in 3.5 wt.% NaCl Solution","authors":"Jan-Ervin C. Guerrero, D. Camacho, O. Mokhtari, H. Nishikawa","doi":"10.1155/2018/6580750","DOIUrl":"https://doi.org/10.1155/2018/6580750","url":null,"abstract":"The corrosion and leaching behaviour of a new ternary Sn-0.7Cu-0.05Ni alloy in 3.5 wt.% NaCl solution is reported herein. Potentiodynamic polarization measurements show that Sn-0.7Cu-0.05Ni has the highest corrosion rate. Results of the 30-day Sn leaching measurement show that Sn-Cu-Ni joint has slight decrease attributed to the formation of thin passivation film after 15 days. The leaching amounts of Sn are observed to be higher in solder joint than in solder alloy due to the galvanic corrosion happening on the surface. EDS and XRD results of the corroded surface confirm that the corroded product is made up of oxides of tin.","PeriodicalId":13893,"journal":{"name":"International Journal of Corrosion","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2018-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/6580750","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45087760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An Electrochemical Synthesis of Reduced Graphene Oxide/Zinc Nanocomposite Coating through Pulse-Potential Electrodeposition Technique and the Consequent Corrosion Resistance","authors":"S. Asl, A. Afshar, Y. Yaghoubinezhad","doi":"10.1155/2018/3028693","DOIUrl":"https://doi.org/10.1155/2018/3028693","url":null,"abstract":"Pulse-potential coelectrodeposition of reduced graphene oxide/zinc (rGO-Zn) nanocomposite coating is directly controlled upon a steel substrate from a one-pot aqueous mixture containing [GO−/Zn2+]δ+ nanoclusters. GO nanosheets are synthesized by modified Hummer’s approach while Zn cations are produced in the solution and deposited on GO nanosheets using anodic dissolution technique. Eventually, nanoclusters are reduced to rGO-Zn film through an electrochemical process. Chemical composition, surface morphology, and corrosion resistance of the thin film are characterized. Results show that the corrosion resistance of rGO-Zn coating is approximately 10 times more than the bare steel.","PeriodicalId":13893,"journal":{"name":"International Journal of Corrosion","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2018-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/3028693","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47819207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of Deformation Structure and Annealing Temperature on Corrosion of Ultrafine-Grain Fe-Cr Alloy Prepared by Equal Channel Angular Pressing","authors":"M. Rifai, M. Yuasa, H. Miyamoto","doi":"10.1155/2018/4853175","DOIUrl":"https://doi.org/10.1155/2018/4853175","url":null,"abstract":"The effect of the deformation structure and annealing temperature on the corrosion of ultrafine-grain (UFG) Fe-Cr alloys with 8 to 12% Cr prepared by equal channel angular pressing (ECAP) was investigated with particular emphasis on the stability of the passivation layer. Fe-Cr alloys were processed by ECAP using up to eight passes at 423 K by the Bc route, followed by annealing at temperatures of 473 to 1173 K for 1 h. Passivity appeared in all alloys as a result of ECAP, and the stability of the passivation layer was evaluated by anodic polarization measurements in a 1000 mol·m−3 NaCl solution. The stability of the passivation layer increased as the degree of deformation became more extensive with successive ECAP passes, and distinct escalation occurred with the formation of a UFG microstructure. In the early stages of annealing at moderate temperatures, the stability of the passivation layer deteriorated, although no visible grain growth occurred, and this effect increased monotonically with increasing annealing temperature. The high degree of stability of the passivation layer on UFG alloys following ECAP can be attributed to the large number of high-angle nonequilibrium grain boundaries, which may lead to Cr enrichment of the surface region. The deterioration of the passivation layer in the early stages of annealing may be attributed to a change in the grain boundaries to an equilibrium state. The present results show that the superiority of as-ECAPed materials of the Fe-Cr alloy to recovered ones by heat treatment can be achieved with 8–10% Cr as observed in 20% Cr.","PeriodicalId":13893,"journal":{"name":"International Journal of Corrosion","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2018-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/4853175","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41480742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cymbopogon citratus and NaNO2 Behaviours in 3.5% NaCl-Immersed Steel-Reinforced Concrete: Implications for Eco-Friendly Corrosion Inhibitor Applications for Steel in Concrete","authors":"J. Okeniyi, A. Popoola, E. T. Okeniyi","doi":"10.1155/2018/5949042","DOIUrl":"https://doi.org/10.1155/2018/5949042","url":null,"abstract":"This paper studies behaviours of Cymbopogon citratus leaf-extract and NaNO2, used as equal-mass admixture models, in 3.5% NaCl-immersed steel-reinforced concrete by nondestructive electrochemical methods and by compressive-strength improvement/reduction effects. Corrosion-rate, corrosion-current, and corrosion-potential constitute electrochemical test-techniques while compressive-strength effect investigations followed ASTM C29 and ASTM C33, in experiments using positive-controls for the electrochemical and compressive-strength studies. Analyses of the different electrochemical test-results mostly portrayed agreements on reinforcing-steel anticorrosion effects by the concentrations of natural plant and of chemical admixtures in the saline/marine simulating-environment and in the distilled H2O (electrochemical positive control) of steel-reinforced concrete immersions. These indicated that little amount (0.0833% cement for concrete-mixing) of Cymbopogon citratus leaf-extract was required for optimal inhibition efficiency, η = 99.35%, on reinforcing-steel corrosion, in the study. Results of compressive-strength change factor also indicated that the 0.0833% Cymbopogon citratus concentration outperformed NaNO2 admixture concentrations also in compressive-strength improvement effects on the NaCl-immersed steel-reinforced concrete. These established implications, from the study, on the suitability of the eco-friendly Cymbopogon citratus leaf-extract for replacing the also highly effective NaNO2 inhibitor of steel-in-concrete corrosion in concrete designed for the saline/marine service-environment.","PeriodicalId":13893,"journal":{"name":"International Journal of Corrosion","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/5949042","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44121333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}