Navegação por Autores IPEN "MACHADO, CARULINE de S.C."

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  • IPEN-DOC 26650

    MACHADO, CARULINE de S.C. ; DONATUS, UYIME ; MILAGRE, MARIANA X. ; MOGILI, NAGA V.V.; GIORJÃO, RAFAEL A.R.; KLUMPP, RAFAEL E. ; ARAUJO, JOAO V. de S. ; FERREIRA, RAPHAEL O.; COSTA, ISOLDA . Correlating the modes of corrosion with microstructure in the friction stir welded AA2198-T8 alloy in aqueous hydrogen peroxide-chloride medium. Corrosion, v. 75, n. 6, p. 628-640, 2019. DOI: 10.5006/3054

    Abstract: In this study, different types of localized corrosion in the friction stir welding (FSW) zones of an AA2198-T8 when the alloy is subjected to a corrosion test in a hydrogen peroxide–chloride solution (according to ASTM G110 standard) has been investigated. The corrosion modes were correlated with microstructure, especially with respect to the T1 phase and coarse Al-Cu-Fe phase distribution across the weldment. Simulated thermal profile and microhardness measurements were used to establish the variations in T1 phase distribution. Two types of corrosion were observed in the FSW zones: intense pitting and intergranular corrosion—type I; and the formation of cavities and trenches—type II. Type I is associated with the T1 phase while type II is associated with Al-Cu-Fe coarse intermetallics. Both types were found on the base metal (BM) and heat affected zone, but the type I reduced in the latter toward the stir zone (SZ). The SZ/thermomechanically affected zone (TMAZ) exhibited only type II. Also, Cu enrichment was observed around the type II sites in the SZ/TMAZ. Furthermore, an inverse correlation between microhardness and corrosion resistance which was related to T1 phase concentration in the different zones was also observed. Moreover, the SZ and BM were isolated and evaluated by an immersion test and electrochemical analysis using the ASTM G110 test solution. The results indicated galvanic coupling effects, as the SZ was strongly attacked when exposed separately compared to when it was coupled with the other zones.

    Palavras-Chave: corrosion; friction welding; stirring; aluminium alloys; corrosion resistance; microhardness; microstructure; hydrogen peroxide; chlorides

  • IPEN-DOC 27712

    KLUMPP, RAFAEL E. ; DONATUS, UYIME ; SILVA, REJANE M.P. da ; ANTUNES, RENATO A.; MACHADO, CARULINE de S.C. ; MILAGRE, MARIANA X. ; ARAUJO, JOAO V. de S. ; VIVEIROS, BARBARA V.G. de ; COSTA, ISOLDA . Corrosion protection of the AA2198-T8 alloy by environmentally friendly organic-inorganic sol-gel coating based on bis-1,2-(triethoxysilyl) ethane. Surface and Interface Analysis, v. 53, n. 3, p. 314-329, 2021. DOI: 10.1002/sia.6919

    Abstract: In this work, a surface coating composed of organic‐inorganic hybrid sol‐gel based on bis‐1,2‐(triethoxysilyl) (BTSE) ethane was applied on AA2198‐T8 samples, and its effect on corrosion resistance was investigated and compared with that of a chromate layer formed in a solution with hexavalent chromium ions. The corrosion resistance of BTSE coated samples was evaluated by immersion tests in sodium chloride solution (0.005 mol/L NaCl) and monitored by global electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and local electrochemical techniques such as scanning vibrating electrode technique (SVET) and scanning electrochemical microscopy (SECM). The formed coating layers were characterized by X‐ray photoelectron spectroscopy (XPS). The results pointed out that the BTSE is an effective alternative coating for corrosion protection of new generation Al‐Cu‐Li alloys and could replace chromates obtained in toxic and carcinogenic CrVI containing solutions leading to improved corrosion protection.

    Palavras-Chave: corrosion; corrosion protection; surface coating; silanes; aluminium alloys; sol-gel process; hybrid systems; corrosion resistance

  • IPEN-DOC 25861

    MACHADO, CARULINE de S.C. ; KLUMPP, RAFAEL E. ; AYUSSO, VICTOR H. ; DONATUS, UYIME ; MILAGRE, MARIANA X. ; ARAUJO, JOAO V. de S. ; MACHADO, GLAUSON A.F. ; COSTA, ISOLDA . Effect of surface treatments on the localized corrosion resistance of the AA2198‐T8 aluminum lithium alloy welded by FSW process. Surface and Interface Analysis, v. 51, n. 12, SI, p. 1231-1239, 2019. DOI: 10.1002/sia.6622

    Abstract: In this work, the effect of eight types of surface treatments on the corrosion resistance of friction stir welded samples of an AA2198‐T8 Al‐Cu‐Li alloy were tested and compared in an attempt to find suitable alternatives to toxic and carcinogenic hexavalent chromium treatments. All the samples were anodized and subjected to different post‐anodizing treatments. The post‐anodizing treatments were (1) hydrothermal treatment in Ce (NO3)3 6H2O solution; (2) hydrothermal treatment in Ce (NO3)3 6H2O solution with H2O2; (3) hydrothermal treatment in boiling water; (4) hexavalent chromium conversion coating; and (5) immersion in BTSE (bis‐1,2‐(triethoxysilyl) ethane. The corrosion resistance of the treated samples was evaluated by immersion tests in sodium chloride solution (0.1 mol L−1 NaCl) and electrochemical impedance spectroscopy (EIS) of the friction stir weldment. The results showed that among the alternative treatments, the Ce‐containing solutions presented the best corrosion resistance, especially when used without peroxide.

    Palavras-Chave: aluminium alloys; corrosion; corrosion resistance; lithium alloys; corrosion protection; friction welding; anodization; copper alloys; chromium; scanning electron microscopy

  • IPEN-DOC 26823

    MACHADO, CARULINE de S.C. ; SILVA, REJANE M. da ; ARAUJO, JOAO V. de S. ; DONATUS, UYIME ; MILAGRE, MARIANA X. ; KLUMPP, RAFAEL E. ; ROSSI, JESUALDO L. ; COSTA, ISOLDA . Effects of chloride ion concentration on the corrosion behavior of the AA2198-T8 alloy. In: EUROPEAN CORROSION CONGRESS, September 9-13, 2019, Seville, Spain. Proceedings... 2019.

    Abstract: In this work, the influence of chloride ions concentration on the corrosion behavior of the AA2198-T8 alloy was evaluated. Immersion test and electrochemical analyses were performed in sodium chloride solutions of three concentrations, 0.001 mol L-1, 0.005 mol L-1 and 0.01 mol L-1. The results showed that the AA2198-T8 alloy was susceptible to localized corrosion (LC) and to severe localized corrosion (SLC) in all conditions investigated. The electrochemical results obtained by open circuit potential measurements, cyclic voltammetry and potentiodynamic polarization curves were associated with the corroded microstructure of the alloy. Although electrochemical techniques allowed differentiating the corrosion resistance as a function of chloride concentration, the result was strongly influenced by the corroded/uncorroded area ratio related to the SLC.

  • IPEN-DOC 26639

    MACHADO, CARULINE de S.C. . Estudo da corrosão localizada da liga de alumínio 2198-T8 soldada por fricção e mistura / Study of localized corrosion on 2198-T8 aluminum alloy welded by friction stir welding . 2019. Tese (Doutorado em Tecnologia Nuclear) - Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP, São Paulo. 159 p. Orientador: Isolda Costa. DOI: 10.11606/T.85.2020.tde-06022020-102545

    Abstract: Neste estudo, a microestrutura e a resistência à corrosão da liga AA2198-T8 soldada pelo processo FSW foram investigadas por técnicas microscópicas, ensaios de imersão e eletroquímicos em soluções contendo íons cloreto. Diferentes tipos de corrosão localizada foram observados na liga, os quais foram correlacionados com a microestrutura, principalmente com a presença da fase T1 (Al2CuLi) e de precipitados micrométricos compostos de Al-Cu-Fe. A simulação do perfil térmico, medidas de microdureza, medidas de calorimetria exploratória diferencial e microscopia eletrônica de transmissão foram usadas para estudar a concentração e distribuição da fase T1 ao longo das zonas afetadas pela solda e vizinhanças. Uma correlação inversa entre a microdureza e a resistência à corrosão localizada severa (CLS) foi obtida e relacionada à concentração da fase T1 nas diferentes zonas da liga soldada. A CLS foi predominante na zona não afetada pela solda, ou metal base (MB), quando testada isoladamente ou acoplada galvanicamente às demais zonas. Quando acopladas galvanicamente, a zona de mistura (ZM) atuou como catodo em relação às zonas vizinhas. No entanto, quando esta zona foi testada isoladamente das demais, a CLS foi observada, entretanto, esta foi associada a fase T2/TB. Diferenças na morfologia e cinética de ataque foram observadas entre a ZM e o MB. As técnicas locais mostraram-se apropriadas para o estudo de corrosão dessas ligas, enquanto que as técnicas eletroquímicas convencionais não apresentaram resolução suficiente para diferenciar os tipos de ataque localizado típicos destas ligas.

    Palavras-Chave: microhardness; corrosion resistance; aluminium alloys; welded joints; friction; electrochemical cells; sweep circuits; polarization; calorimetry; microstructure; solid state physics; x-ray spectroscopy; electric impedance; electron microscopy; microscopy; scanning electron microscopy; transmission electron microscopy

  • IPEN-DOC 27430

    ARAUJO, JOAO V. de S. ; MILAGRE, MARIANA X. ; FERREIRA, RAPHAEL O.; MACHADO, CARULINE de S.C. ; BUGARIN, ALINE de F.S. ; MACHADO, IZABEL F.; COSTA, ISOLDA . Exfoliation and intergranular corrosion resistance of the 2198 Al–Cu–Li alloy with different thermomechanical treatments. Materials and Corrosion, v. 71, n. 12, p. 1957-1970, 2020. DOI: 10.1002/maco.202011839

    Abstract: In this study, the resistance to exfoliation and intergranular corrosion (IGC) of the 2198 Al–Cu–Li alloy submitted to different thermomechanical treatments (T3, T8, and T851) was investigated. The tests were carried out following the standard practices, ASTM G34‐18 and ASTM G110‐15, respectively. All the tested alloys showed susceptibility to exfoliation and some alloys showed susceptibility to IGC, but the artificially aged alloys presented a higher tendency to exfoliation. The extensive hydrogen evolution reaction (HER) was observed on the surfaces of artificially aged alloys when immersed in the EXCO solution. The HER resulted in an increase in solution pH with the time of immersion. Also, the weight losses related to the artificially aged alloys were higher than that of the naturally aged ones. The T8 treatment was the only condition that resulted in susceptibility to both, intergranular and transgranular corrosion, whereas the T851 treatment did not show IGC susceptibility, only transgranular corrosion. Finally, the 2198‐T3 condition showed the highest corrosion resistance among the thermomechanical treatments tested. The results of the 2198 alloy subjected to various treatments were compared with that of the 2024‐T3 alloy. This last alloy showed higher resistance to exfoliation and IGC as compared with the 2198 alloy.

    Palavras-Chave: corrosion; corrosion resistance; intergranular corrosion; thermomechanical treatments; aluminium alloys; copper alloys; lithium alloys; optical systems; emission spectroscopy; plasma; friction welding

  • IPEN-DOC 27812

    MACHADO, CARULINE de S.C. ; DONATUS, UYIME ; MILAGRE, MARIANA X. ; ARAUJO, JOAO V. de S. ; VIVEIROS, BARBARA V.G. de ; KLUMPP, RAFAEL E. ; PEREIRA, VICTOR F.; COSTA, ISOLDA . How microstructure affects localized corrosion resistance of stir zone of the AA2198-T8 alloy after friction stir welding. Materials Characterization, v. 174, p. 1-14, 2021. DOI: 10.1016/j.matchar.2021.111025

    Abstract: In this study, the microstructure and corrosion resistance of the stir zone (SZ) of the AA2198-T8 Al-Cu-Li alloy welded by friction stir welding (FSW) were investigated by microscopy, immersion tests and electrochemical techniques such as measurements of open circuit potential variation with time, and scanning vibrating electrode technique (SVET) measurements. A low chloride-containing solution (0.005 mol L−1 NaCl) was employed in the corrosion studies and severe localized corrosion (SLC) was observed in the SZ related to intergranular attack. The results were compared to those of the non-affected areas by FSW, also known as base metal (BM). In the BM, SLC was found and the type of attack related to it was intragranular. In both zones, BM and SZ, SLC was due to precipitates of high electrochemical activity, specifically T1 (Al2CuLi) phase in the BM, whereas TB (Al7Cu4Li) / T2 (Al6CuLi3) in the SZ. Scanning vibrating electrode technique (SVET) analysis was very useful in the study of SLC in the AA2198-T8 alloy showing the development of high anodic current densities at the mouth of the SLC sites.

    Palavras-Chave: electrochemistry; friction welding; stir reactor; corrosion resistance; microstructure

  • IPEN-DOC 27705

    SILVA, ROSANA V. da; VOLTZ, HIURY; ITMAN FILHO, ANDRE; MILAGRE, MARIANA X. ; MACHADO, CARULINE de S.C. . Hybrid composites with glass fiber and natural fibers of sisal, coir, and luffa sponge. Journal of Composite Materials, v. 55, n. 5, p. 717-728, 2021. DOI: 10.1177/0021998320957725

    Abstract: Hybrid composites with synthetic and natural fibers are a good choice in the field of composites, as they combine the good mechanical performance of synthetic fibers with the advantages of natural fibers. In this work, polymeric hybrid composites associating glass fiber and natural fibers were developed. Three hybrid composites were developed: sisal/ glass, coir/glass and Luffa/glass. The composites are five-layer laminate, three layers of E-glass interspersed with two layers of natural fibers that can be sisal, coir, or Luffa sponge (Luffa Cylindrica). In addition to hybrid composites, a five-layer fiberglass composite was also manufactured. The composites were manufactured by compression molding technique using orthophthalic polyester resin as matrix. Tensile and flexural tests were performed to characterize the composites. Considering the three hybrid composites, the best behavior was observed for the sisal/glass composite, being a potential replacement for fiberglass. The order of performance was the same in the tensile and flexural tests, sisal/glass, coir/glass, and luffa/glass, in this order. In the specimen’s fracture analysis, for both tests, it was observed that the fracture was quite located with no damage in regions far from the fracture. This behavior indicates good adhesion between the layers of natural and synthetic fibers, despite the discrepancy of their properties.

    Palavras-Chave: hybridization; composite materials; fibers; coconuts; microstructure; fiberglass

  • IPEN-DOC 25535

    KLUMPP, RAFAEL E. ; SILVA, REJANE M.P. da; DONATUS, UYIME ; MACHADO, CARULINE de S.C. ; AYUSSO, VICTOR H. ; MILAGRE, MARIANA X. ; ARAUJO, JOAO V. de S. ; COSTA, ISOLDA . Influência da composição da solução de tratamento de superfície na resistência à corrosão da liga AA2024-T3. Tratamento de Superfície, n. 212, p. 23-28, 2019.

    Abstract: Os tratamentos de superfície de ligas de alumínio em soluções contendo íons de terras raras têm se mostrado promissores para a substituição dos tratamentos que utilizam íons de cromo hexavalente em sua composição. A composição das soluções de tratamento com terras raras é um fator importante na propriedade de proteção à corrosão da camada superficial formada. Neste trabalho, o efeito da adição de peróxido de hidrogênio à solução de tratamento para proteção à corrosão da liga AA2024-T3 foi investigado por técnicas eletroquímicas e microscópicas. Os resultados mostraram que a adição do peróxido de hidrogênio altera a morfologia da camada, o mecanismo de formação desta e resulta em propriedades de proteção levemente inferiores às da camada formada na ausência de peróxido.

    Palavras-Chave: aluminium alloys; corrosion protection; hydrogen peroxide; corrosion resistant alloys; layers; atomic force microscopy; scanning electron microscopy; spectroscopy; electric impedance; cerium nitrates

  • IPEN-DOC 26644

    DONATUS, UYIME ; SILVA, REJANE M.P. da ; ARAUJO, JOAO V. de S. ; MILAGRE, MARIANA X. ; ABREU, CAIO P. de ; MACHADO, CARULINE de S.C. ; COSTA, ISOLDA . Macro and microgalvanic interactions in friction stir weldment of AA2198-T851 alloy. Journal of Materials Research and Technology, v. 8, n. 6, p. 6209-6222, 2019. DOI: 10.1016/j.jmrt.2019.10.015

    Abstract: The galvanic interactions within and between the friction stir weld zones of the AA2198-T851alloy have been investigated using electrochemical and microscopy techniques. The parentmaterial (PM) was the most anodic region and exhibited pronounced severe localized corro-sion (SLC) both when coupled and isolated. The stir zone was the most resistant to corrosionand exhibited no SLC when coupled, but exhibited SLC when isolated. Profiles associatedwith dissolved oxygen consumption and hydrogen generation currents across the weldmentwere inversely related because the anodic (PM) region produced higher hydrogen bubblesand, interestingly, consumed more dissolved oxygen compared with the other regions.

    Palavras-Chave: friction welding; aluminium alloys; copper alloys; lithium alloys; interactions; electrochemical corrosion; polarization; scanning electron microscopy; pitting corrosion; redox reactions

  • IPEN-DOC 27686

    ARAUJO, JOAO V. de S. ; SILVA, REJANE M.P. da ; MILAGRE, MARIANA X. ; MACHADO, CARULINE de S.C. ; COSTA, ISOLDA . Mecanismo de evolução de hidrogênio durante a corrosão da liga 2198-T8 em meio contendo cloreto: uma abordagem eletroquímica / On the hydrogen evolution mechanism during corrosion of the 2198-T8 alloy in chloride solution: an electrochemical approach. Química Nova, v. 43, n. 8, p. 1058-1065, 2020. DOI: 10.21577/0100-4042.20170598

    Abstract: Corrosion is still one of the most serious and frequent problems in industries. The phenomena involved in the corrosion mechanism of Al-alloys may be explained by formation of galvanic cells between the metal matrix and heterogeneities, such as precipitates, intermetallic phases leading to potential differences and electrochemical reactions. In the cathodic sites, the main reactions are oxygen reduction reaction, in aerated neutral environments, and hydrogen evolution in acid media. This last type of reaction might also occur in neutral solutions inside pits (anodic region). In this study, the mechanism of hydrogen evolution during corrosion of the 2198-T8 Al-Cu-Li alloy exposed in a chloride solution was investigated. The mechanism was related to the presence of T1 phase (Al2CuLi), which is the main strengthening phase in this material. This phase is highly active and, when exposed to corrosive media, leads to severe localized corrosion (SLC). One of the main characteristics related to SLC is hydrogen gas evolution which was confirmed by gel visualization. In this study, the hydrogen evolution mechanism inside the SLC sites was studied by scanning electrochemical microscopy (SECM).

    Palavras-Chave: corrosion; corrosion resistant alloys; aluminium alloys; copper alloys; lithium alloys; hydrogen production; electrochemistry

  • IPEN-DOC 27418

    ARAUJO, JOAO V. de S. ; MILAGRE, MARIANA X. ; FERREIRA, RAPHAEL O.; MACHADO, CARULINE de S.C. ; ABREU, CAIO P. de ; COSTA, ISOLDA . Microstructural characteristics of the Al alloys: the dissimilarities among the 2XXX alloys series used in aircraft structures. Metallography, Microstructure, and Analysis, v. 9, n. 5, p. 744-758, 2020. DOI: 10.1007/s13632-020-00688-5

    Abstract: Microstructure characteristics of two high-strength aluminum alloys, the 2024-T3 Al–Cu–Mg, and the new generation Al–Cu–Li alloy 2198, in the T8 and T851 tempers, were investigated in this study. For this purpose, microstructural and statistical analyses were carried out. The results showed equiaxed grains for the 2024-T3 and 2198-T851 alloys, whereas, elongated grains for the 2198-T8. Besides, the 2198-T851 alloy displayed slip bands in the grains due to the stretching stage, “51”. The 2024-T3 alloy showed at least two types of constituent particles, Al–Cu–Mg and Al–Cu–Mn–Fe–(Si); whereas Al–Cu–Li alloys showed only one type, Al–Cu–Fe, in their composition. Statistical analyses showed that the percentage of area covered by constituent particles was larger in the 2024-T3 alloy compared to the 2198 in both tempers, T8 and T851. On the other hand, the Al–Cu–Li alloys showed higher microhardness values relatively to the Al–Cu one. The differences among the nanometric phases present in Al–Cu and Al–Cu–Li alloys were analyzed by transmission electron microscopy. All the results were related to the different chemical composition and industrial thermomechanical processing of each alloy.

    Palavras-Chave: alloys; microstructure; aluminium alloys; copper alloys; magnesium alloys; lithium alloys; statistics; systems analysis; corrosion; corrosion resistant alloys; scanning electron microscopy; transmission electron microscopy; nanoparticles

  • IPEN-DOC 27402

    ARAUJO, JOAO V. de S. ; SILVA, REJANE M.P. da ; DONATUS, UYIME ; MACHADO, CARULINE de S.C. ; COSTA, ISOLDA . Microstructural, electrochemical and localized corrosion characterization of the AA2198-T851 alloy. Materials Research, v. 23, n. 4, p. 1-10, 2020. DOI: 10.1590/1980-5373-MR-2020-0161

    Abstract: In the present work, the microstructure, electrochemical behavior and localized corrosion of the AA2198-T851 Al-Cu-Li alloy were studied. The microstructure was correlated with corrosion results obtained by immersion, gel visualization and scanning electrochemical microscopy (SECM) tests. Immersion and gel visualization tests showed high kinetics of corrosion attack during the first hours of immersion. SECM analyzes by means of surface generation/tip collection (SG/TC) mode detected hydrogen evolution generated during spontaneous corrosion from severe localized corrosion (SLC) sites on the metal surface. SECM results revealed sites of intense hydrogen evolution after 2 h of immersion and increased amounts of corrosion products after 4 h of immersion. Hydrogen evolution sites detected by SECM were associated with severe localized corrosion (SLC).

    Palavras-Chave: microstructure; corrosion; aluminium alloys; hydrogen; electrochemistry; scanning electron microscopy; copper alloys; lithium alloys; gels; data visualization

  • IPEN-DOC 26885

    KLUMPP, RAFAEL E. ; DONATUS, UYIME ; ARAUJO, JOAO V.S. ; REDÍGOLO, MARCELO M. ; MACHADO, CARULINE de S.C. ; COSTA, ISOLDA . The effect of acid pickling on the corrosion behavior of a cerium conversion-coated AA2198-T851 Al-Cu-Li alloy. Journal of Materials Engineering and Performance, v. 29, n. 1, p. 167-174, 2020. DOI: 10.1007/s11665-019-04551-9

    Abstract: The effect of acid pickling pretreatments prior to cerium conversion coating process on the corrosion behavior of AA2198-T851 alloy substrates was investigated. Three acid pretreatments were employed: nitric acid (HNO3), phosphoric acid (H3PO4) and sulfuric acid (H2SO4). The cerium conversion coating process was performed using a batch solution composed of cerium nitrate and hydrogen peroxide. Microscopic techniques, electrochemical impedance spectroscopy, polarization resistance and open-circuit potential measurements were employed to investigate the effect of each acid pretreatment. The untreated and nitric acid pretreated substrates presented more defective cerium conversion layers than the substrates treated with phosphoric and sulfuric acids. Accordingly, the corrosion resistance of the untreated and nitric acid-treated substrates was very low, while that of the substrates treated with phosphoric acid and sulfuric acids were greatly improved. The sulfuric acid pickling treatment was the best pretreatment before cerium conversion coating among the investigated pretreatments on the AA2198-T851 Al-Cu-Li alloy.

    Palavras-Chave: inorganic acids; pickling; corrosion pickling; cerium; nitric acid; phosphoric acid; sulfuric acid; coatings; conversion; aluminium alloys; lithium alloys; copper alloys; electrochemistry; corrosion resistance

  • IPEN-DOC 25832

    DONATUS, UYIME ; ARAUJO, JOAO V. de S. ; MACHADO, CARULINE de S.C. ; MOGILI, NAGA V.V.; ANTUNES, RENATO A.; COSTA, ISOLDA . The effect of manufacturing process induced near-surface deformed layer on the corrosion behaviour of AA2198-T851 Al–Cu–Li alloy. Corrosion Engineering, Science and Technology, v. 54, n. 3, p. 205-215, 2019. DOI: 10.1080/1478422X.2018.1558932

    Abstract: The effect of the near-surface deformed layer on the corrosion behaviour of AA2198-T851 Al–Cu–Li alloy has been investigated using microscopy and electrochemical techniques. This shows that a deformed layer developed by rolling was more active but only exhibited superficial attack compared to a mechanically polished surface, which produced severe localised corrosion associated with the presence of hexagonal T1 particles. The rolled surface became increasingly corrosion resistant with time, but when coupled, galvanically enhanced severe localised corrosion sites developed on the surface over time.

    Palavras-Chave: corrosion; microstructure; transmission electron microscopy; metals; alloys; scanning electron microscopy; surfaces; interfaces; aluminium alloys; copper alloys; corrosion protection; lithium alloys

  • IPEN-DOC 25934

    ARAUJO, JOAO V. de S. ; BUGARIN, ALINE de F.S. ; DONATUS, UYIME ; MACHADO, CARULINE de S.C. ; QUEIROZ, FERNANDA M. ; TERADA, MAYSA ; ASTARITA, ANTONELLO; COSTA, ISOLDA . Thermomechanical treatment and corrosion resistance correlation in the AA2198 Al–Cu–Li alloy. Corrosion Engineering, Science and Technology, v. 54, n. 7, p. 575-586, 2019. DOI: 10.1080/1478422X.2019.1637077

    Abstract: The influence of T3, T8 and T851 thermomechanical treatments on the microstructure and corrosion resistance of the AA2198 was investigated. Differential scanning calorimetry and scanning electron microscopy were used for microstructural characterisation, whereas electrochemical methods were employed to analyse the corrosion behaviour of the alloy. The morphology and composition of constituent particles were similar for the T3 and T8 thermomechanical treatments but varied in the T851. There was an inverse relation between T1 phase density and corrosion resistance. The T3 treatment with the highest corrosion resistance was the one with the lowest density of T1 phase. The mechanisms of corrosion varied with the thermomechanical treatments.

    Palavras-Chave: thermomechanical treatments; aluminium alloys; lithium alloys; microstructure; copper alloys; corrosion resistant alloys; heat treatments

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ATENÇÃO!

ESTE TEXTO "AJUDA" ESTÁ SUJEITO A ATUALIZAÇÕES CONSTANTES, A MEDIDA QUE NOVAS FUNCIONALIDADES E RECURSOS DE BUSCA FOREM SENDO DESENVOLVIDOS PELAS EQUIPES DA BIBLIOTECA E DA INFORMÁTICA.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

1. Portaria IPEN-CNEN/SP nº 387, que estabeleceu os princípios que nortearam a criação do RDI, clique aqui.


2. A experiência do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP) na criação de um Repositório Digital Institucional – RDI, clique aqui.

O Repositório Digital do IPEN é um equipamento institucional de acesso aberto, criado com o objetivo de reunir, preservar, disponibilizar e conferir maior visibilidade à Produção Científica publicada pelo Instituto, desde sua criação em 1956.

Operando, inicialmente como uma base de dados referencial o Repositório foi disponibilizado na atual plataforma, em junho de 2015. No Repositório está disponível o acesso ao conteúdo digital de artigos de periódicos, eventos, nacionais e internacionais, livros, capítulos, dissertações, teses e relatórios técnicos.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.