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Avaliação de soldagem de aço estrutural através do Ruído Magnético de Barkhausen; Evaluation of carbon steel welded plates with Magnetic Barkhausen Noise

Giraldo, Claudia Patricia Serna; Padovese, Linilson Rodrigues
Fonte: Associação Brasileira de Soldagem Publicador: Associação Brasileira de Soldagem
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
66.28%
Este trabalho apresenta resultados de avaliação de juntas soldadas de aço estrutural ASTM A36 por meio do Ruído Magnético de Barkhausen (RMB). A soldagem foi feita em chapas de 6 mm de espessura com preparação de chanfro em V, com um e dois passes. Foram feitas a caracterização de microestructuras e microdurezas através da junta soldada, e na superfície foram feitas medições de RMB. Os sinais de RMB foram analisados com o valor máximo, uma média de valores acima de 80% do pico máximo, o rms e o rms do envelope, dos quais foram obtidas curvas da variação com respeito ao centro do cordão e também foram obtidos mapas superficiais. Na caracterização microestructural obteve-se que as amostras de um e dois passes apresentaram tamanhos da zona afetada pelo calor (ZAC) diferente. As microdurezas mostraram que no limite de fusão tem-se a maior dureza enquanto que no fim da ZAC tem-se a menor dureza. O RMB mostrou que no limite de fusão tem o menor valor, enquanto que no fim da ZAC tem o maior valor. Este estúdio mostrou que as mudanças na microestrutura influenciam em todos os parâmetros analisados, sendo que a junta soldada ficou melhor representada pelo valor rms e rms do envelope do RMB.; This paper shows results for the evaluation of ASTM A36 carbon steel welded joints by Magnetic Barkhausen Noise (MBN). V-groove shape welded samples were made in a 6 mm thickness plates...

Formulação e otimização de uma mistura de inibidores de corrosão para aço carbono em meio de água de resfriamento industrial usando planejamento estatístico.; Obtention the optimum formulation of substances tested as corrosion inhibitors for carbon steel in water-cooling systems using design of experiments.

Bueno, Glorys Coromoto Villarroel de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 24/10/2008 PT
Relevância na Pesquisa
66.28%
O objetivo deste trabalho foi formular e otimizar uma mistura de quatro substâncias atóxicas como inibidores de corrosão para o aço carbono ABNT 1005 em meio de água de resfriamento industrial. As substâncias estudadas foram o molibdato de sódio, o tungstato de sódio, a ftalocianina de cobre e um tensoativo polimérico a base de silano de peso molecular 17.000 g.mol-1. As técnicas usadas neste estudo foram medidas de potencial de corrosão, espectroscopia de impedância eletroquímica e curva de polarização anódicas e catódicas. O tratamento dos resultados de espectroscopia de impedância eletroquímica foi feito por meio da modelagem com circuitos elétricos equivalentes, que permitiu quantificar parâmetros como resistência a transferência e carga (Rtc) e capacitância dupla camada elétrica, (Cdl). Para caracterizar a superfície do metal foram obtidas imagens por microscopia eletrônica de varredura, onde foi comprovada a alteração da superfície pela presença das substâncias estudadas. Pelas curvas de polarização foi verificado que todas as substâncias estudadas se comportam como inibidores de corrosão anódicos no meio estudado, isto é, diminuem a velocidade de dissolução do metal na presença de maiores concentrações. O uso de um projeto fatorial completo...

Métodos magnéticos não destrutivos para caracterização elasto-plástica em chapas de aços carbono.; Nondestructive magnetic methods for characterization of elastic-plastic Behavior in carbon steel plates.

Campos, Manuel Alberteris
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 22/06/2012 PT
Relevância na Pesquisa
66.32%
No presente trabalho se estuda a correlação de diferentes parâmetros de sinais de Ruído Magnético de Barkhausen (RMB) e de fluxo magnético com o comportamento elastoplástico em chapas de aço carbono, visando à aplicação dos resultados como técnica de Ensaio Não-Destrutivo. Comprovou-se que o comportamento de parâmetros como a energia (RMBenegia), o valor quadrático médio(RMBrms) e a envolvente dos sinais de RMB com os diferentes estados elastoplásticos do material resultou fortemente dependente da anisotropia de laminação, quantidade de Carbono e fases, gerados no processo de produção das chapas. Como novidade introduziu-se o parâmetro chamado de Área em baixo da curva da distribuição de pulsos do sinal de Barkhausen. A evolução deste parâmetro com a deformação identificou com boa aproximação a região de transição elasto-plástica do material. Harmônicos não lineares (HNL) do fluxo magnético apresentaram uma melhor correlação com a anisotropia do que com os estados elasto-plásticos do material, mas com alta dependência ao acoplamento sonda-amostra. Enquanto que o RMB apresentou elevados níveis de reprodutibilidade. Propriedades mecânicas e comportamentos característicos de ensaios de tração em regime discreto e contínuo foram reproduzidos e identificados com um alto grau de aproximação pelo RMB e os HNL. Outros métodos magnéticos e não magnéticos usados neste trabalho não apresentaram níveis altos de sensibilidade às mudanças microestruturais devido às deformações elasto-plásticas no material...

Caracterização da resistência à deformação a quente do aço baixo carbono microligado ao vanádio; Carachterization of the hot deformation resistance of a low carbon steel microalloyed with vanadium

Cunha, Emerson Fernandes da
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
66.37%
Este trabalho, realizado em cooperação com a Gerdau Riograndense, tem por finalidade avaliar o comportamento do aço GG1013-M, um aço baixo teor de carbono microligado com vanádio e manganês, na laminação a quente no que tange a sua resistência à deformação, possibilitando assim a tomada de decisão em relação a modificações no processo. Foram realizados testes em simulador termomecânico Gleeble™ para determinação das temperaturas a serem usadas no teste prático no laminador, onde testou-se lotes que cobrissem toda a amplitude da faixa de composição química da qualidade do aço em estudo. No teste prático no laminador, foram retiradas amostras para os ensaios mecânicos, onde identificou-se, por intermédio do tratamento de dados em software estatístico, a influência da variação dentro da faixa da composição química sobre os limites de escoamento e resistência. Como resultado, conseguiu-se determinar a faixa de temperatura mais provável, onde a resistência a deformação a quente é menor, minimizando ou eliminando as conseqüências da redução de ductilidade a quente por conta do endurecimento da matriz por precipitação dos elementos de liga em forma de compostos.; This work was conducted in cooperation with Gerdau Riograndense aiming at the evaluation of the hot rolling behavior of a low carbon steel microalloyed with manganese and vanadium (internally GG1013-M steel).The deformation resistance was evaluated...

Effect of citrate ions on the electrochemical behaviour of low-carbon steel in borate buffer solutions

Modiano, S.; Fugivara, C. S.; Benedetti, A. V.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 529-545
ENG
Relevância na Pesquisa
66.28%
The electrochemical behaviour of cold-rolled low carbon steel was studied on both active and passive potential regions in borate buffer solutions with and without the addition of sodium citrate (NaCit). In the active region anodic charges increased significantly and RCT values decreased with citrate, due to the formation of soluble complexes. In the passive potential region the film formed at +0.4 V in borate buffer solution with and without 0.010 M NaCit is probably enriched by Fe3O4 oxide, while films formed at +0.8 V are probably enriched by gamma-Fe2O3. The equivalent circuit [R-s(R(CT)Q)] fitted all experimental impedance data. (C) 2003 Elsevier Ltd. All rights reserved.

Determination of the volume fraction of retained austenite in a 300m steel by heat tinting technique

Silva, Gisele Bonfiette; Dian, Gustavo Henrique; Brandão, Sirlei Aparecida Araujo; Abdalla, Antonio Jorge; Hashimoto, Tomaz Manabu; Pereira, Marcelo dos Santos
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
56.4%
Applying the Heat Tinting Technique the microestrutural characterization of a 300M steel (medium carbon steel) was accomplished. The steel was austenitized for 20 min to 900°C, followed by holding at 400°C (in the bainitic temperature), with maintenance time of the material in the temperature of 1min, 5min and 30min, aiming at the formation of a multiphase structure. Through the metallographic analysis it is verified that, with the use of this technique, it is possible the determination of the volume fraction of the present phases in the 300M steel, especially in the identification and quantification of the retained austenite. Copyright © 2007 SAE International.

Microstructural effects on fatigue crack growth behavior of a microalloyed steel

Laurito, D. F.; Baptista, C. A R P; Torres, M. A S; Abdalla, A. J.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 1915-1925
ENG
Relevância na Pesquisa
56.4%
Thermal transformations on microalloyed steels can produce multiphase microstructures with different amounts of ferrite, martensite, bainite and retained austenite. These different phases, with distinct morphologies, are determinant of the mechanical behavior of the steel and can, for instance, affect the crack path or promote crack shielding, thus resulting in changes on its propagation rate under cyclic loading. The aim of the present work is to evaluate the effects of microstructure on the tensile strength and fatigue crack growth (FCG) behaviour of a 0.08%C-1,5%Mn (wt. pct.) microalloyed steel, recently developed by a Brazilian steel maker under the designation of RD480. This steel is being considered as a promising alternative to replace low carbon steel in wheel components for the automotive industry. Various microstructural conditions were obtained by means of heat treatments followed by water quench, in which the material samples were kept at the temperatures of 800, 950 and 1200 °C. In order to describe the FCG behavior, two models were tested: the conventional Paris equation and a new exponential equation developed for materials showing non-linear FCG behavior. The results allowed correlating the tensile properties and crack growth resistance to the microstructural features. It is also shown that the Region II FCG curves of the dual and multiphase microstructural conditions present crack growth transitions that are better modeled by dividing them in two parts. The fracture surfaces of the fatigued samples were observed via scanning electron microscopy in order to reveal the fracture mechanisms presented by the various material conditions. © 2010 Published by Elsevier Ltd.

Carbon nanotube-reinforced siloxane-PMMA hybrid coatings with high corrosion resistance

Hammer, P.; Dos Santos, F. C.; Cerrutti, B. M.; Pulcinelli, S. H.; Santilli, C. V.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 601-608
ENG
Relevância na Pesquisa
56.5%
Siloxane-polymethyl methacrylate hybrid films containing functionalized multiwall carbon nanotubes (CNTs) were deposited by dip-coating on carbon steel substrates from a sol prepared by radical polymerization of methyl methacrylate and 3-methacryloxy propyl-trimethoxysilane, followed by hydrolytic co-polycondensation of tetraethoxysilane. The correlation between the structural properties and corrosion protection efficiency was studied as a function of the molar ratio of nanotubes carbon to silicon, varied in the range between 0.1% and 5%. 29Si nuclear magnetic resonance and thermogravimetric measurements have shown that hybrids containing carbon nanotubes have a similar degree of polycondensation and thermal stability as the undoped matrix and exhibit and excellent adhesion to the substrate. Microscopy and X-ray photoelectron spectroscopy results revealed a very good dispersion of carbon nanotubes in the hybrid matrix and the presence of carboxylic groups allowing covalent bonding with the end-siloxane nodes. Potentiodynamic polarization curves and electrochemical impedance spectroscopy results demonstrate that CNTs containing coatings maintain the excellent corrosion protection efficiency of the hybrids, showing even a superior performance in acidic solution. The nanocomposite structure acts as efficient corrosion barrier...

Visualisation of the Galvanic Effects at Welds on Carbon Steel

Pagotto,Josias F.; Montemor,Maria F.; Recio,Francisco J.; Motheo,Artur J.; Simões,Alda M.; Herrasti,Pilar
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2015 EN
Relevância na Pesquisa
66.28%
Non-destructive classical techniques, such as electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP) measurement, were complemented with advanced techniques, including the scanning vibrating electrode technique (SVET) and localised electrochemical impedance spectroscopy (LEIS) to examine galvanic effects at welds on carbon steel. The classical techniques indicated that corrosion processes are accelerated in the weld. The advanced techniques revealed admittance values related to more severe corrosion along the weld than in the base metal and higher corrosion currents in the weld. When the weld and base metal are electrically connected, the weld serves as a cathodic protector for the base metal.

Kinetics of austenite formation during continuous heating in a low carbon steel

Oliveira, Fernando Lucas Gon?alves e; Andrade, Margareth Spangler; Cota, Andr? Barros
Fonte: Universidade Federal de Ouro Preto Publicador: Universidade Federal de Ouro Preto
Tipo: Artigo publicado em periodico
EN_US
Relevância na Pesquisa
66.28%
The kinetics and microstructural evolution of austenite formation in a low carbon steel, with initial microstructure composed of ferrite and pearlite, were studied during continuous heating, by using dilatometric analysis and measurements of microstructural parameters. The formation of austenite was observed to occur in two stages: (a) pearlite dissolution and (b) ferrite to austenite transformation. The critical temperatures of austenite formation in continuous heating increase with increasing heating rate, with greater influence on the finishing temperature of austenite formation. For both the 1 ?C/s and 0.1 ?C/s heating rates, the formation rate of austenite reaches a maximum at approximately the finishing temperature of pearlite dissolution, and the formation rate of austenite as a function of the temperature is greater at the higher heating rate.

Determination of electrochemical parameters and corrosion rate for carbon steel in un-buffered sodium chloride solutions using a superposition model

Herrera, Leandro; Vargas Valero, José Tomás; Cáceres, Luis
Fonte: Universidade do Chile Publicador: Universidade do Chile
Tipo: Artículo de revista
EN
Relevância na Pesquisa
56.41%
Publicación ISI; Corrosion of carbon steel in un-buffered NaCl solutions was studied applying linear potential sweep technique to a rotating disk electrode. Current-potential curves were obtained from linear potential sweep at a rate of 1 mV s(-1) in solution with concentrations in the range 0.02-1 M NaCl and rotation rates in the range 170-370 rad s(-1), at 22 degrees C. Potential sweeps, which were conducted in the potential range -700 to -100 mV/SHE, were started from the cathodic limit in order to approach the measurement of corrosion under rust-free conditions. Polarization curves were analyzed with a superimposition model developed ad hoc and implemented in a computer program, which enabled determining the corrosion rate and kinetics parameters of the underlying anodic and cathodic sub-processes. The anodic sub-process, dissolution of iron, was well described in terms of a pure charge transfer controlled reaction, while the cathodic sub-process, oxygen reduction on iron, was well described in terms of mixed mass transfer and charge transfer control. Increase of electrode rotation rate increases the limiting current of oxygen reduction, which results in an enhanced corrosion rate of carbon steel. Increase of NaCl concentration has a dual effect: the limiting current of oxygen reduction decreases as a result of the influence of NaCl concentration on solution viscosity and the anodic dissolution of iron increases due to the influence of NaCl on pitting formation. However...

Comparación de la microestructura y propiedades de impacto de dos materiales compuestos laminados de acero de ultraalto contenido de carbono; Microstructure and impact properties comparison of two ultrahigh carbon steel laminated composites

Pozuelo, M.; Carreño, Fernando; Ruano, Oscar Antonio
Fonte: Sociedad Española de Cerámica y Vidrio Publicador: Sociedad Española de Cerámica y Vidrio
Tipo: Artículo Formato: 326789 bytes; application/pdf
SPA
Relevância na Pesquisa
66.37%
[ES] Se procesaron mediante laminación en caliente dos materiales compuestos laminados de acero de ultraalto contenido de carbono (AUAC, 1,3%C) de seis capas cada uno: El primero está compuesto por tres capas de AUAC alternadas con tres capas de un acero microaleado, y el segundo con tres del mismo AUAC alternadas con tres de un acero suave. Se ha realizado un estudio de sus microestructuras, dureza Vickers y propiedades de impacto. Se han mejorado los valores de energía absorbida de los dos materiales compuestos laminados respecto al del AUAC.; [EN] Two ferrous laminated composites containing six layers have been processed by roll bonding. One of them consists of three layers of an ultrahigh carbon steel (1.3%C UHCS) interlayered with other three layers of a microalloyed steel. The other composite consists of three layers of UHCS and three layers of a mild steel. Microstructure, Vickers hardness and impact properties have been studied. The absorbed energy values of the two laminated composites were higher than that of the UHCS.; Peer reviewed

Inhibitory Action of Camellia sinensis Extract on the Corrosion of Carbon Steel in 0.1 mol L-1 HCl; Estudo da Ação Inibidora do Extrato de Camellia sinensis na Corrosão do Aço-carbono 1020 em HCl 1 mol L-1

Viviane M. Teixeira; Universidade Federal do Rio de Janeiro; Érica C. dos Santos; Universidade Federal do Rio de Janeiro; Michelle Jakeline C. Rezende; Universidade Federal do Rio de Janeiro; Eliane D'Elia; Universidade Federal do Rio de Janeiro
Fonte: Revista Virtual de Química Publicador: Revista Virtual de Química
Tipo: ; Formato: binary/octet-stream
Publicado em 18/09/2015 PT
Relevância na Pesquisa
66.37%
The effect of Camellia sinensis extracts on the corrosion of carbon steel in 1 mol L-1 HCl was examined. Polarization curves show that this extract act as mixed-type inhibitor with predominantly cathodic characteristic. The inhibition efficiency obtained from the polarization curves and electrochemical impedance increases with the extract concentration, with 89 % in the presence of 1500 ppm of the extract. The apparent activation energy (Ea) for the dissolution of C-steel slightly increased when the extract was used. This result could be attributed to the physisorption of the inhibitor on the steel surface. DOI: 10.5935/1984-6835.20150102; O efeito do extrato da Camellia sinensis na corrosão do aço-carbono em HCl 1 mol L-1 foi investigado. As curvas de polarização mostram que este extrato age como inibidor misto com característica predominantemente catódica. A eficiência de inibição obtida a partir das curvas de polarização e da técnica de impedância eletroquímica aumentou com a concentração do extrato, chegando a 89 % na presença de 1500 ppm do extrato. A energia de ativação aparente para a dissolução do aço-carbono aumentou ligeiramente quando o extrato foi usado. Este resultado pode ser atribuído à fisissorção do inibidor sobre a superfície do aço. DOI: 10.5935/1984-6835.20150102

Inhibition of Corrosion of Carbon Steel in Sea Water by Sodium Gluconate-Zn2+ System

Rajendran,S.; Anuradha,K.; Kavipriya,K.; Krishnaveni,A.; Jeyasundari,J.; Sribharathy,V.
Fonte: Sociedade Portuguesa de Electroquímica Publicador: Sociedade Portuguesa de Electroquímica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2013 EN
Relevância na Pesquisa
66.28%
The inhibition efficiency of sodium gluconate (SG)-Zn2+ system in controlling corrosion of carbon steel in sea water has been evaluated by weight-loss method. The formulation consisting of 250 ppm of SG and 75 ppm of Zn2+ has 98% IE. Influence of duration of immersion on the IE of SG-Zn2+ has been evaluated. The mechanistic aspects of corrosion inhibition have been investigated by polarization study and AC impedance spectra. The protective film has been analysed by FTIR and luminescence spectra. The surface morphology and the roughness of the metal surface have been analysed by atomic force microscopy. The protective film consists of Fe2+-SG complex and Zn(OH)2. It is found to be UV-fluorescent.

Fennel (Foeniculum Vulgare) Essential Oil as Green Corrosion Inhibitor of Carbon Steel in Hydrochloric Acid Solution

Lahhit,N.; Bouyanzer,A.; Desjobert,J.-M.; Hammouti,B.; Salghi,R.; Costa,J.; Jama,C.; Bentiss,F.; Majidi,L.
Fonte: Sociedade Portuguesa de Electroquímica Publicador: Sociedade Portuguesa de Electroquímica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 EN
Relevância na Pesquisa
66.33%
Essential oil from fennel (Foeniculum vulgare) (FM) was tested as corrosion inhibitor of carbon steel in 1 M HCl using electrochemical impedance spectroscopy (EIS), Tafel polarisation methods and weight loss measurements. The results show that the increase of the charge-transfer resistance (Rct) with the oil concentration supports the molecules of oil adsorption on the metallic surface. The polarization plots reveal that the addition of natural oil shifts the cathodic and anodic branches towards lower currents. Such shifts indicate that FM oil acts as a mixed-type inhibitor. The global rate of corrosion estimated by weight loss measurements confirms the above results. The inhibition efficiency attains a maximum of 76 % at 3 mL/L, but decreases with the rise of temperature. The analysis of FM oil, obtained by hydro-distillation, using Gas Chromatography (GC) and Gas Chromatography/Mass Spectrometry (GC/MS) showed that the major components were limonene (20.8 %) and β-pinene (17.8%). The adsorption of FM on the steel surface has been discussed according to the chemical composition of the oil, giving an explanation to the obtained results.

Electrochemical Evaluation of Linseed Oil as Environment-friendly Inhibitor for Corrosion of Steel in HCl Solution

Afia,L; Salghi,R; Benali,O; Jodeh,S; Warad,I; Ebensod,E; Hammoutie,B
Fonte: Sociedade Portuguesa de Electroquímica Publicador: Sociedade Portuguesa de Electroquímica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2015 EN
Relevância na Pesquisa
56.44%
The effect of linseed oil (LO) on the corrosion of carbon steel in 1 M HCl solution was investigated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) technique and weight loss measurements. The inhibiting action increases with the concentration of the tested inhibitor. The highest efficiency (98.2%) is obtained at 3g/L of LO. The influence of temperature on the corrosion behavior of carbon steel in 1 M HCl, with the addition of LO was also studied. The obtained data from EIS measurements were analyzed to model the corrosion inhibition process through an appropriate equivalent circuit model; a constant phase element (CPE) has been used. Polarization measurements show also that LO acts as a good mixed inhibitor. The inhibition process is attributed to the formation of an adsorbed film of the inhibitor on the metal surface which protects the metal against corrosion. LO is adsorbed on the steel surface according to a Langmuir isotherm adsorption model. The results obtained showed that the linseed oil could serve as an effective green inhibitor of the corrosion of carbon steel in hydrochloric acid medium.

Malonic Acid as Transporter of Zn2+ Towards: Carbon Steel Surface

Jayashree,A.; Selvarani,F. Rajammal; Sahayaraj,J. Wilson; Amalraj,A. John; Rajendran,S.
Fonte: Sociedade Portuguesa de Electroquímica Publicador: Sociedade Portuguesa de Electroquímica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 EN
Relevância na Pesquisa
66.28%
The inhibition efficiency (IE) of malonic acid (MA)-Zn2+ system in controlling corrosion of carbon steel immersed in well water has been evaluated by weight-loss method. The formulation consisting of 50 ppm of MA and 50 ppm of Zn2+ has 85% IE. The influence of N-cetyl-N,N,N-trimethylammonium bromide (CTAB) and N-cetyl pyridinium chloride (CPC) on the IE of the MA- Zn2+ system has been studied. At lower pH value (pH=6) IE decreases and in alkaline medium (pH=8) IE increases. Polarization study reveals that MA-Zn2+ system functions as a mixed inhibitor. AC impedance spectra reveal that a protective film is formed on the metal surface. FTIR spectra reveal that the protective film consists of Fe2+-MA complex and Zn(OH)2.

Inhibition and biocide actions of sodium dodecyl sulfate-Zn2+ system for the corrosion of carbon steel in chloride solution

Antony,Noreen; Sherine,H. Benita; Rajendran,Susai
Fonte: Sociedade Portuguesa de Electroquímica Publicador: Sociedade Portuguesa de Electroquímica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
Relevância na Pesquisa
66.28%
The inhibition efficiency of sodium dodecyl sulfate (SDS) in controlling corrosion of carbon steel in aqueous solution containing 120 ppm of Cl− in the presence and absence of Zn2+ has been evaluated by weight loss method. The formulation consisting of 300 ppm of SDS and 75 ppm of Zn2+ gives 93 % inhibition efficiency. A synergistic effect exists between SDS and Zn2+. As the immersion period increases, the inhibition efficiency of SDS-Zn2+ decreases. Polarization study reveals that this formulation controls both the anodic and cathodic reactions. AC impedance spectra reveal that a protective film is formed on the metal surface.

Corrosion Inhibition by Amino Trimethylene Phosphonic Acid (ATMP) -Zn2+ System for Carbon Steel in Ground Water

Muthumani,N.; Rajendran,Susai; Pandiarajan,M.; Christyd,J. Lydia; Nagalakshmie,R.
Fonte: Sociedade Portuguesa de Electroquímica Publicador: Sociedade Portuguesa de Electroquímica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2012 EN
Relevância na Pesquisa
66.28%
The inhibition efficiency (IE) of Amino Trimethylene phosphonic acid (ATMP) in controlling corrosion of carbon steel immersed in ground water in the absence and presence of Zn2+ has been evaluated by weight loss method. It is observed that the synergistic formulation consisting of 250 ppm ATMP and 10 ppm of Zn2+ has 98% IE. Polarization study reveals that ATMP-Zn2+ system functions as a cathodic inhibitor system. AC impedance study reveals that a protective film is formed on the metal surface.

Corrosion Inhibition of Carbon Steel in HCl Solutions Using Aminopyrimidine Derivatives

Mahmoud,S.S.; Ahmed,M.M.
Fonte: Sociedade Portuguesa de Electroquímica Publicador: Sociedade Portuguesa de Electroquímica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2006 EN
Relevância na Pesquisa
66.38%
This work aimed to study the corrosion inhibition of carbon steel in 2 M HCl solutions using some aminopyrimidine derivatives. In this investigation the techniques of measurements were: weight loss, linear polarization, impedance and corrosion penetration. The inhibitory effect of the investigated compounds resulted from their adsorption onto the carbon steel. Their adsorption on the metallic surface obeyed Frumkin’s model of adsorption. The inhibition efficiency of the compound greatly depends on the electron density on the molecules, which in turn depends on its structure. The values of activation energy were determined in 2 M HCl in the absence and in the presence of inhibitors. The presence of inhibitors increases the values of the activation energy of corrosion. The adsorption of these compounds onto the metallic surface occurs via the N-atoms of amino-groups, O-atoms of hydroxy-groups, and S-atoms of mercapto group present in the compound. For this reason the inhibitory effect of the inhibitors varied according to the number and nature of adsorption centers in the molecules.