FERNANDA MARTINS QUEIROZ
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Artigo IPEN-doc 23662 On the effects of hydrothermal treatments on the corrosion resistance of the TSA anodized AA7475-T761 alloy2016 - ALMEIDA, THALLIS L.; QUEIROZ, FERNANDA M.; TERADA, MAYSA; COSTA, ISOLDA; CAPELOSSI, VERA R.The effect of hydrothermal treatment time on the sealing and corrosion resistance of the anodized AA7475-T761 aluminium alloy has been investigated in this study. The treatments tested are environmental compatible and has not chromium ions involved. Anodizing was carried out by tartaric-sulphuric anodizing (TSA) and this was followed by hydrothermal treatments for partial sealing, either with or without propyleneglycol (PRG) and/or cerium ions. Four different treatment times were tested, specifically, 2.5, 5.0, 7.5 and 10 min. The corrosion resistance of the treated samples was evaluated by Electrochemical Impedance Spectroscopy (EIS) and the anodic layers formed by anodizing and hydrothermal treatments were characterized by Scanning Electron Microscopy (SEM). The EIS results indicated that the best corrosion resistance was related to the treatments that combined hydrothermal treatments in boiling water with PRG for 10 minutes or boiling water with PRG and cerium ions for 5 min. The SEM images for the samples showed the formation of a homogeneous anodic layer and the thickness is approximately 3 m. It was noticed that the porosities were not completed sealed by the treatments tested and this was on purpose in order to allow coating adhesion to the anodic layer.Artigo IPEN-doc 23606 Avaliação da resistência a corrosão intergranular da liga AA2198-T82016 - ARAUJO, J.V.; MACHADO, C.S.C.; MILAGRE, M.X.; QUEIROZ, F.M.; COSTA, I.The intergranular corrosion is a form of corrosion which can result in loss of mechanical properties and might lead to rupture of the material. These properties are of fundamental importance for the materials used in aircraft for security reasons. It is important to characterize the intergranular corrosion resistance of materials used in aeronautical applications. This study investigated the intergranular corrosion resistance of the AA2198-T8 alloy that presents copper and lithium as the main alloying elements. The results showed that this alloys is susceptible to this form of corrosion.Artigo IPEN-doc 23605 Monitoramento da corrosão em ligas de alumínio dissimilares unidas por processo de soldagem por fricção e mistura (FSW) utilizadas no setor aeronáutico2016 - BUGARIN, A.F.S.; QUEIROZ, F.M.; TERADA, M.; MELO, H.G. de; COSTA, I.The corrosion behavior of the aluminum alloys ( AA2024 -T3 and AA7475 - T761 ) joined by the friction and mixing welding process (FSW) was monitored by immersion test in 10 mM NaCl solution as a function of exposure time to the test solution. The corrosion resistance was also evaluated by a gel test (agar- agar) by means of which the galvanic coupling between the two alloys was observed. The AA2024 alloy acted as the cathode and the AA7475 as the anode of the galvanically coupled pair. The immersion tests showed galvanic coupling in the mixed region (ZM) or nugget. The zone most affected by corrosion was the thermomechanically affected zone (ZTMA) at the interface with the thermally affected one (ZTA) on the side of the AA7475 alloy. At this interface, intergranular corrosion was seen from the first two hours of immersion.Artigo IPEN-doc 23603 Comparação do comportamento de corrosão da liga convencional AA2024-T351 e da liga Al-Li 2098-T3512016 - MILAGRE, M.X.; ARAUJO, J.V.; QUEIROZ, F.M.; MACHADO, C.S.C.; COSTA, I.In this work, the localized corrosion behavior of an Al-Li alloy (AA2098-T351) was compared with that of the AA2024-T351 conventional alloy by immersion test in 0.01 mol L-1 NaCl solution. The evolution of localized corrosion in both alloys was monitored by optical microscopy and scanning electron microscopy after several test periods from 2h to 24h. The results showed high susceptibility of the two alloys to pitting from the early hours of immersion. The corrosion mechanism in the two alloys, however, was different. Localized corrosion in the AA2024 alloy was associated with the microcells generation between micrometric precipitates and the matrix leading to superficial attack homogeneously distributed throughout the surface exposed to the corrosive environment. In the AA2098 alloy, however, a severe localized corrosion ascribed in the literature to the presence of phase T1 was also observed besides the localized corrosion type similar to that observed in the AA2024 alloy.Artigo IPEN-doc 09491 Aplicacao de tecnicas eletroquimicas a caracterizacao de revestimento 'galvanneal'2003 - QUEIROZ, F.M.; MELO, H.G.; COSTA, I.Artigo IPEN-doc 09486 Caracterizacao de revestimento 'galvannealed' por 'stripping' eletroquimico2003 - QUEIROZ, F.M.; COSTA, I.Artigo IPEN-doc 18126 Avaliação da proteção contra corrosão de aço eletrogalvanizado, passivado com cromo trivalente e pintado: sistema eletrogalvanizado - cromo III - pintura2011 - QUEIROZ, FERNANDA M.; ELSNER, CECILIA I.; SARLI, ALEJANDRO R. di; TOMACHUK, CELIA R.; COSTA, ISOLDAArtigo IPEN-doc 18127 Passivação, com camada espessa, à base de sais de cromo trivalente aplicada em temperatura ambiente sobre aço eletrozincado2011 - SANTOS, ALESSANDRA S.; TOMACHUK, CELIA R.; QUEIROZ, FERNANDA M.