The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Violeta Barranco - One of the best experts on this subject based on the ideXlab platform.
-
eis study of the corrosion behaviour of zinc based coatings on steel in quiescent 3 nacl solution part 1 directly exposed coatings
Corrosion Science, 2004Co-Authors: Violeta Barranco, S. FeliuAbstract:Abstract The possibilities offered by the EIS technique for studying the progress of corrosion in several types of galvanised coatings were investigated. Corrosion tests were performed in a 3 wt.% NaCl aqueous solution, at approximately neutral pH, without stirring and in contact with the air. A tendency was seen towards an electrochemical overestimation of the corrosion values of essentially pure zinc and Zn–5%Al (Galfan) coatings compared with the gravimetric reference values. In contrast, the opposite tendence was revealed with the Zn–10%Fe (Galvanneal) coating. These deviations have made it necessary to use empirical values of the constant B of the Stern–Geary equation. The approximately linear progress of the attack with immersion time suggests a slight barrier effect of the corrosion products layer.
-
Comparative EIS and XPS studies of the protective character of thin lacquer films containing CR or P salts formed on galvanised steel, Galvanneal and galfan substrates
Electrochimica Acta, 2004Co-Authors: Sebastián Feliu, Violeta BarrancoAbstract:Abstract X-ray photoelectron spectroscopy (XPS) is used to analyse variations during exposure to humidity and UV radiation (UVCON test) in the chemical composition of the outer surface of organic coatings (lacquers) containing phosphating or chromating reagents applied on galvanised steel, Galvanneal and galfan substrates. By means of electrochemical impedance spectroscopy (EIS) measurements the protective character of the coatings analysed by XPS is studied and an attempt is made to establish possible relationships between the chemical composition of the surface of the lacquered substrates after exposure to the UVCON test and their electrochemical characterisation in immersion in a 3% NaCl solution. In general, the formation of defects or the loss of adhesion of the lacquer film leads to a significant reduction in charge transfer resistance values and, at the same time, an increase in interfacial capacitance values. The special behaviour of the galfan/lacquer “with chromating reagents” system is associated with the presence of a thin insulating film of chromium and aluminium oxides at the base of the pores in the lacquer. Interfacial capacitance values tend to evolve in close correspondence with the content of some elements on the surface of the materials.
-
effect of the incorporation of chromating reagents in an acrylic lacquer applied on galvanised steel Galvanneal and galfan during the uvcon test
Surface & Coatings Technology, 2003Co-Authors: S. Feliu, Violeta BarrancoAbstract:Abstract This paper analyses the effect of the exposure to humidity and UV radiation (UVCON test) of an organic coating (lacquer) containing chromating reagents applied on galvanised steel, Galvanneal and galfan substrates. An attempt is made to establish possible relationships between the degradation of the lacquered surface during its exposure and the presence or absence of alloying elements on the original zinc-based substrate. With the galvanised steel and galfan coatings, 60 days of exposure to the UVCON test are necessary for a slight reduction in the lacquer content to be observed. Removal of the lacquer leaves the Cr(III) formed on the surface of the zinc-based substrate exposed. With the galfan coating, the chromate layer grows on the initial aluminium oxide film. With the Galvanneal coating, in contrast to the lacquered galvanised steel and galfan, 15 days are sufficient for detachment of the lacquer to be observed. Longer exposure times lead to an appreciable increase in the percentage of lacquer removed. Surprisingly, the chromate layer remains on the surface of the Galvanneal coating, preventing its corrosion, even after 60 days of exposure. XPS data suggest the presence of CrOC type bonds at the interface, due to the oxidation of the lacquer surface associated with the reduction of Cr(VI) to Cr(III), which contribute significantly to the increase in lacquer adhesion.
-
Study of degradation mechanisms of a protective lacquer film formulated with phosphating reagents applied on galvanised steel, Galvanneal and galfan in exposure to UV/condensation test
Surface & Coatings Technology, 2003Co-Authors: Sebastián Feliu, Violeta BarrancoAbstract:Abstract This paper analyses the effect of exposure to humidity and UV radiation (UVCON test) of an organic coating (lacquer) containing phosphating reagents applied on galvanised steel, Galvanneal and galfan substrates. An attempt is made to establish possible relationships between the degradation of the lacquered surface due to the effects of its exposure and the presence or absence of alloying elements on the original zinc substrate. After 15 days of exposure to the UVCON test, XPS has revealed an important reduction in the carbon content on the surface of the material, accompanied by an increase in the zinc, phosphorus and titanium contents. This change in surface composition suggests the rapid removal of a very considerable percentage of the lacquered coating. On the galvanised steel and Galvanneal coatings, sufficiently long exposure times to the UVCON test (60 days) have led to the elimination of the zinc phosphate layer and its replacement by a layer of zinc carbonate. Surprisingly, the zinc phosphate layer has remained on the surface of the galfan coating (95%Zn–5%Al) even after 60 days of exposure. The attack of this substrate in exposure to the UVCON test seems to be preferentially focused on its aluminium-rich phases.
-
XPS study of the surface chemistry of conventional hot-dip galvanised pure Zn, Galvanneal and Zn-Al alloy coatings on steel
Acta Materialia, 2003Co-Authors: Sebastián Feliu, Violeta BarrancoAbstract:This study uses X-ray photoelectron spectroscopy (XPS) to analyse the outer surfaces of galvanised, galfan and Galvanneal metallic coatings obtained by hot dipping. Considerable aluminium segregation towards the surface, principally as Al2O3, has been seen in all the studied coatings. The aluminium content on the surface was surprisingly similar to or even greater than the zinc content, which is the major element in the chemical composition of these coatings. The formation of Al2O3 seems to prevent the oxidation of the zinc in the metallic coating.
Sebastián Feliu - One of the best experts on this subject based on the ideXlab platform.
-
Correlation between the surface chemistry of annealed IF steels and the growth of a Galvanneal coating
Acta Materialia, 2005Co-Authors: Sebastián Feliu, M. L. Pérez-revengaAbstract:Abstract An attempt is made to establish possible relationships between the quantity of oxides and hydroxides of the alloying elements on the outer interstitial-free steel surface after the annealing process and the characteristics of the Galvanneal coating formed. XPS measurements reflect a clear influence of the alloying element contents and the water vapour content or dew point (DP) of the atmosphere on the oxide and hydroxide coverage of the steel surface. In general, much less Fe–Zn intermetallic formation is seen on the Ti steel substrate than on the Ti–Nb steel. The reason for this may be related with the higher oxide/(Fe + Mn) atomic ratio on the external surface of the Ti steel substrate. With the Ti–Nb–P steel, an absence of Fe was observed in the coatings obtained on the surface of this steel annealed in atmospheres with a DP of −45 or −10 °C. A clear direct relationship has been found between the inhibition of growth of Fe–Zn intermetallic compounds and the fraction of the steel substrate surface covered by manganese oxides as a result of the annealing process. For the Ti–Nb–P steel the increase in the DP of the Galvannealing atmosphere to 10 °C resulted in the incorporation of a significant Fe content in the coating. XPS analysis suggests a change in the surface film, and the formation of a phosphate enriched layer, instead of manganese oxide. A lower fraction of oxide coverage on the annealed steel substrate resulted in less of an impediment to the diffusion of iron atoms from the steel substrate to the zinc coating in the Galvannealing process.
-
Comparative EIS and XPS studies of the protective character of thin lacquer films containing CR or P salts formed on galvanised steel, Galvanneal and galfan substrates
Electrochimica Acta, 2004Co-Authors: Sebastián Feliu, Violeta BarrancoAbstract:Abstract X-ray photoelectron spectroscopy (XPS) is used to analyse variations during exposure to humidity and UV radiation (UVCON test) in the chemical composition of the outer surface of organic coatings (lacquers) containing phosphating or chromating reagents applied on galvanised steel, Galvanneal and galfan substrates. By means of electrochemical impedance spectroscopy (EIS) measurements the protective character of the coatings analysed by XPS is studied and an attempt is made to establish possible relationships between the chemical composition of the surface of the lacquered substrates after exposure to the UVCON test and their electrochemical characterisation in immersion in a 3% NaCl solution. In general, the formation of defects or the loss of adhesion of the lacquer film leads to a significant reduction in charge transfer resistance values and, at the same time, an increase in interfacial capacitance values. The special behaviour of the galfan/lacquer “with chromating reagents” system is associated with the presence of a thin insulating film of chromium and aluminium oxides at the base of the pores in the lacquer. Interfacial capacitance values tend to evolve in close correspondence with the content of some elements on the surface of the materials.
-
Study of degradation mechanisms of a protective lacquer film formulated with phosphating reagents applied on galvanised steel, Galvanneal and galfan in exposure to UV/condensation test
Surface & Coatings Technology, 2003Co-Authors: Sebastián Feliu, Violeta BarrancoAbstract:Abstract This paper analyses the effect of exposure to humidity and UV radiation (UVCON test) of an organic coating (lacquer) containing phosphating reagents applied on galvanised steel, Galvanneal and galfan substrates. An attempt is made to establish possible relationships between the degradation of the lacquered surface due to the effects of its exposure and the presence or absence of alloying elements on the original zinc substrate. After 15 days of exposure to the UVCON test, XPS has revealed an important reduction in the carbon content on the surface of the material, accompanied by an increase in the zinc, phosphorus and titanium contents. This change in surface composition suggests the rapid removal of a very considerable percentage of the lacquered coating. On the galvanised steel and Galvanneal coatings, sufficiently long exposure times to the UVCON test (60 days) have led to the elimination of the zinc phosphate layer and its replacement by a layer of zinc carbonate. Surprisingly, the zinc phosphate layer has remained on the surface of the galfan coating (95%Zn–5%Al) even after 60 days of exposure. The attack of this substrate in exposure to the UVCON test seems to be preferentially focused on its aluminium-rich phases.
-
XPS study of the surface chemistry of conventional hot-dip galvanised pure Zn, Galvanneal and Zn-Al alloy coatings on steel
Acta Materialia, 2003Co-Authors: Sebastián Feliu, Violeta BarrancoAbstract:This study uses X-ray photoelectron spectroscopy (XPS) to analyse the outer surfaces of galvanised, galfan and Galvanneal metallic coatings obtained by hot dipping. Considerable aluminium segregation towards the surface, principally as Al2O3, has been seen in all the studied coatings. The aluminium content on the surface was surprisingly similar to or even greater than the zinc content, which is the major element in the chemical composition of these coatings. The formation of Al2O3 seems to prevent the oxidation of the zinc in the metallic coating.
Manuel Morcillo - One of the best experts on this subject based on the ideXlab platform.
-
Lap-joint corrosion testing of precoated steel sheets
Journal of Coatings Technology, 2003Co-Authors: Belén Chico, Manuel Morcillo, Daniel Fuente, José Antonio González, Eduardo OteroAbstract:In industry, and particularly in the building construction and automotive industries, lapjoint technology for precoated steel sheet assembly has undergone rapid development. However, the durability problems associated with joints of this type are well known, i.e., premature deterioration of protective coatings (metallic, organic) and accelerated metallic corrosion of the base steel by moisture retention in the joint, crevice corrosion, etc. The authors have been involved in researching lap-joint corrosion testing to learn the behavior of materials in these joints. The precoated steel sheet materials studied were divided into two groups according to their use in two well-defined industrial sectors: building (55% Al-Zn and hot-dip galvanized, painted and unpainted) and car manufacturing (electrogalvanized and Galvanneal).
-
Lap-joint corrosion testing of precoated steel sheets
Journal of Coatings Technology, 2003Co-Authors: Belén Chico, Manuel Morcillo, Daniel Fuente, José Antonio González, Eduardo OteroAbstract:In industry, and particularly in the building construction and automotive industries, lap-joint technology for precoated steel sheet assembly has undergone rapid development. However, the durability problems associated with joints of this type are well known, i.e., premature deterioration of protective coatings (metallic, organic) and accelerated metallic corrosion of the base steel by moisture retention in the joint, crevice corrosion, etc. The authors have been involved in researching lap-joint corrosion testing to know the behaviour of materials in these joints. The precoated steel sheet materials studied were divided into two groups according to their use in two well-defined industrial sectors: building (55% Al-Zn and hot-dip galvanised, painted and unpainted) and car manufacturing (electrogalvanised and Galvanneal).Peer Reviewe
-
Lap-joint corrosion of automotive coated materials in chloride media. Part 2 – Galvannealed steel
Surface & Coatings Technology, 2000Co-Authors: Elisabete Almeida, Manuel MorcilloAbstract:The main aim of this work is to study the lap-joint corrosion of present-day zinc-coated automotive painting substrates, namely electrogalvanized steel, Galvanneal, and electrogalvanized/Galvanneal assemblies. The first part of the work (E. Almeida, M. Morcillo, Surf. Coat. Technol., in press) was dedicated to specific aspects concerning electrogalvanized steel. In this second part, Galvannealed steel is studied using special specimens with spot-welded lap-joints, before and after salt-spray exposure. The corrosion mechanisms proposed as a consequence of this study have been based on results obtained by visual observation, scanning electron microscopy (SEM) associated with X-ray energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Auger spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). The experimental results obtained showed that the use of Galvannealing did not alter the main mechanisms or chemical reactions involved in lap-joint corrosion already observed for electrogalvanized steel. However, in the case of Galvanneal, the corrosion propagation step seems to be significantly moderate.
-
lap joint corrosion of automotive coated materials in chloride media part 3 electrogalvanized steel Galvanneal interface
Surface & Coatings Technology, 2000Co-Authors: Elisabete Almeida, Manuel MorcilloAbstract:The aim of this work is to study the lap-joint corrosion of zinc-coated automotive painting substrates namely electrogalvanized steel, Galvanneal, and electrogalvanized/Galvanneal assemblies. Parts 1 and 2 of the work were dedicated specifically to aspects concerning electrogalvanized steel and Galvanneal, respectively. In this final part, the special case of mixed lap joints involving electrogalvanized steel and Galvanneal is studied. By means of salt-spray exposure and SEM/EDS and XRD analysis, the study suggests that the coupling of Galvanneal with electrogalvanized steel contributes to decreasing Galvanneal corrosion inside lap joints, while electrogalvanized steel suffers an increase in lap-joint corrosion. These phenomena seem to be due to significant transformations among the alloy phases and corrosion products, which seem to start with zinc consumption of the electrogalvanized steel surface and, only subsequently, of the Galvanneal surface.
-
Lap-joint corrosion of automotive coated materials in chloride media. Part 3 : Electrogalvanized steel/Galvanneal interface
Surface and Coatings Technology, 2000Co-Authors: Elisabete Almeida, Manuel MorcilloAbstract:The aim of this work is to study the lap-joint corrosion of zinc-coated automotive painting substrates namely electrogalvanized steel, Galvanneal, and electrogalvanized/Galvanneal assemblies. Parts 1 and 2 of the work were dedicated specifically to aspects concerning electrogalvanized steel and Galvanneal, respectively. In this final part, the special case of mixed lap joints involving electrogalvanized steel and Galvanneal is studied. By means of salt-spray exposure and SEM/EDS and XRD analysis, the study suggests that the coupling of Galvanneal with electrogalvanized steel contributes to decreasing Galvanneal corrosion inside lap joints, while electrogalvanized steel suffers an increase in lap-joint corrosion. These phenomena seem to be due to significant transformations among the alloy phases and corrosion products, which seem to start with zinc consumption of the electrogalvanized steel surface and, only subsequently, of the Galvanneal surface.
S. Feliu - One of the best experts on this subject based on the ideXlab platform.
-
eis study of the corrosion behaviour of zinc based coatings on steel in quiescent 3 nacl solution part 1 directly exposed coatings
Corrosion Science, 2004Co-Authors: Violeta Barranco, S. FeliuAbstract:Abstract The possibilities offered by the EIS technique for studying the progress of corrosion in several types of galvanised coatings were investigated. Corrosion tests were performed in a 3 wt.% NaCl aqueous solution, at approximately neutral pH, without stirring and in contact with the air. A tendency was seen towards an electrochemical overestimation of the corrosion values of essentially pure zinc and Zn–5%Al (Galfan) coatings compared with the gravimetric reference values. In contrast, the opposite tendence was revealed with the Zn–10%Fe (Galvanneal) coating. These deviations have made it necessary to use empirical values of the constant B of the Stern–Geary equation. The approximately linear progress of the attack with immersion time suggests a slight barrier effect of the corrosion products layer.
-
Persistence of superficial contamination of rolled steel during successive treatments up to the formation of a Galvanneal coating
Metallurgical and Materials Transactions A, 2004Co-Authors: S. Feliu, M. L. Pérez-revenga, V. BarrancoAbstract:With the assistance of X-ray photoelectron spectroscopy (XPS) the outer surface (approx. 3 nm) of IF steels that have to react with zinc in order to produce the Galvanneal coating has been characterized. In particular, attention has been focused on the nature and content of carbon-rich impurities on the surface of these steels, which have been cold rolled and annealed. The study has found a type of superficial contamination in which the elements C and Ca are associated and which persists throughout the annealing and Galvannealing processes. In this case, the contamination surprisingly seemed to shift from the surface of the steel substrate to the otuer surface of the Galvanneal coating. The present communication is intended to report this unexpected fact.
-
effect of the incorporation of chromating reagents in an acrylic lacquer applied on galvanised steel Galvanneal and galfan during the uvcon test
Surface & Coatings Technology, 2003Co-Authors: S. Feliu, Violeta BarrancoAbstract:Abstract This paper analyses the effect of the exposure to humidity and UV radiation (UVCON test) of an organic coating (lacquer) containing chromating reagents applied on galvanised steel, Galvanneal and galfan substrates. An attempt is made to establish possible relationships between the degradation of the lacquered surface during its exposure and the presence or absence of alloying elements on the original zinc-based substrate. With the galvanised steel and galfan coatings, 60 days of exposure to the UVCON test are necessary for a slight reduction in the lacquer content to be observed. Removal of the lacquer leaves the Cr(III) formed on the surface of the zinc-based substrate exposed. With the galfan coating, the chromate layer grows on the initial aluminium oxide film. With the Galvanneal coating, in contrast to the lacquered galvanised steel and galfan, 15 days are sufficient for detachment of the lacquer to be observed. Longer exposure times lead to an appreciable increase in the percentage of lacquer removed. Surprisingly, the chromate layer remains on the surface of the Galvanneal coating, preventing its corrosion, even after 60 days of exposure. XPS data suggest the presence of CrOC type bonds at the interface, due to the oxidation of the lacquer surface associated with the reduction of Cr(VI) to Cr(III), which contribute significantly to the increase in lacquer adhesion.
Elisabete Almeida - One of the best experts on this subject based on the ideXlab platform.
-
Lap-joint corrosion of automotive coated materials in chloride media. Part 2 – Galvannealed steel
Surface & Coatings Technology, 2000Co-Authors: Elisabete Almeida, Manuel MorcilloAbstract:The main aim of this work is to study the lap-joint corrosion of present-day zinc-coated automotive painting substrates, namely electrogalvanized steel, Galvanneal, and electrogalvanized/Galvanneal assemblies. The first part of the work (E. Almeida, M. Morcillo, Surf. Coat. Technol., in press) was dedicated to specific aspects concerning electrogalvanized steel. In this second part, Galvannealed steel is studied using special specimens with spot-welded lap-joints, before and after salt-spray exposure. The corrosion mechanisms proposed as a consequence of this study have been based on results obtained by visual observation, scanning electron microscopy (SEM) associated with X-ray energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Auger spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). The experimental results obtained showed that the use of Galvannealing did not alter the main mechanisms or chemical reactions involved in lap-joint corrosion already observed for electrogalvanized steel. However, in the case of Galvanneal, the corrosion propagation step seems to be significantly moderate.
-
lap joint corrosion of automotive coated materials in chloride media part 3 electrogalvanized steel Galvanneal interface
Surface & Coatings Technology, 2000Co-Authors: Elisabete Almeida, Manuel MorcilloAbstract:The aim of this work is to study the lap-joint corrosion of zinc-coated automotive painting substrates namely electrogalvanized steel, Galvanneal, and electrogalvanized/Galvanneal assemblies. Parts 1 and 2 of the work were dedicated specifically to aspects concerning electrogalvanized steel and Galvanneal, respectively. In this final part, the special case of mixed lap joints involving electrogalvanized steel and Galvanneal is studied. By means of salt-spray exposure and SEM/EDS and XRD analysis, the study suggests that the coupling of Galvanneal with electrogalvanized steel contributes to decreasing Galvanneal corrosion inside lap joints, while electrogalvanized steel suffers an increase in lap-joint corrosion. These phenomena seem to be due to significant transformations among the alloy phases and corrosion products, which seem to start with zinc consumption of the electrogalvanized steel surface and, only subsequently, of the Galvanneal surface.
-
Lap-joint corrosion of automotive coated materials in chloride media. Part 3 : Electrogalvanized steel/Galvanneal interface
Surface and Coatings Technology, 2000Co-Authors: Elisabete Almeida, Manuel MorcilloAbstract:The aim of this work is to study the lap-joint corrosion of zinc-coated automotive painting substrates namely electrogalvanized steel, Galvanneal, and electrogalvanized/Galvanneal assemblies. Parts 1 and 2 of the work were dedicated specifically to aspects concerning electrogalvanized steel and Galvanneal, respectively. In this final part, the special case of mixed lap joints involving electrogalvanized steel and Galvanneal is studied. By means of salt-spray exposure and SEM/EDS and XRD analysis, the study suggests that the coupling of Galvanneal with electrogalvanized steel contributes to decreasing Galvanneal corrosion inside lap joints, while electrogalvanized steel suffers an increase in lap-joint corrosion. These phenomena seem to be due to significant transformations among the alloy phases and corrosion products, which seem to start with zinc consumption of the electrogalvanized steel surface and, only subsequently, of the Galvanneal surface.
-
Lap-joint corrosion of automotive coated materials in chloride media. Part 2 – Galvannealed steel
Surface and Coatings Technology, 2000Co-Authors: Elisabete Almeida, Manuel MorcilloAbstract:The main aim of this work is to study the lap-joint corrosion of present-day zinc-coated automotive painting substrates, namely electrogalvanized steel, Galvanneal, and electrogalvanized/Galvanneal assemblies. The first part of the work (E. Almeida, M. Morcillo, Surf. Coat. Technol., in press) was dedicated to specific aspects concerning electrogalvanized steel. In this second part, Galvannealed steel is studied using special specimens with spot-welded lap-joints, before and after salt-spray exposure. The corrosion mechanisms proposed as a consequence of this study have been based on results obtained by visual observation, scanning electron microscopy (SEM) associated with X-ray energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Auger spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). The experimental results obtained showed that the use of Galvannealing did not alter the main mechanisms or chemical reactions involved in lap-joint corrosion already observed for electrogalvanized steel. However, in the case of Galvanneal, the corrosion propagation step seems to be significantly moderate. (C) 2000 Elsevier Science S.A. All rights reserved. | The main aim of this work is to study the lap-joint corrosion of present-day zinc-coated automotive painting substrates, namely electrogalvanized steel, Galvanneal, and electrogalvanized/Galvanneal assemblies. The first part of the work was dedicated to specific aspects concerning electrogalvanized steel. In this second part, Galvannealed steel is studied using special specimens with spot-welded lap-joints, before and after salt-spray exposure. The corrosion mechanisms proposed as a consequence of this study have been based on results obtained by visual observation, scanning electron microscopy (SEM) associated with X-ray energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Auger spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). The experimental results obtained showed that the use of Galvannealing did not alter the main mechanisms or chemical reactions involved in lap-joint corrosion already observed for electrogalvanized steel. However, in the case of Galvanneal, the corrosion propagation step seems to be significantly moderate.Peer Reviewe
-
Lap-joint corrosion of automotive coated materials in chloride media. Part 1 - Electrogalvanized steel
Surface and Coatings Technology, 2000Co-Authors: Elisabete Almeida, Manuel MorcilloAbstract:Lap-joint corrosion has been studied by several authors. However, the mechanisms involved in this type of corrosion, in the specific case of new painting substrates for the automotive industry, are not at all clear. The main purpose of this work is to study lap-joint corrosion in modern automotive painting substrates, namely electrogalvanized steel, Galvanneal and electrogalvanized/Galvanneal assemblies. In this first part of the work, electrogalvanized steel is studied using special specimens with spot-welded lap-joints, before and after salt-spray exposure. Special lap-joint spacements and positions were involved. The corrosion mechanisms proposed were based on the results obtained by visual observations, scanning electron microscopy (SEM) associated with X-ray energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Auger spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS).
