Documents disponibles écrits par cet auteur

Effect of different thermochemical treatments on the electrochemical behaviour of a hot working steel / F. Rosalbino in Materials and corrosion, Vol. 62 N° 4 (Avril 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 4 (Avril 2011) . - pp. 357–361 Titre : Effect of different thermochemical treatments on the electrochemical behaviour of a hot working steel Type de document : texte imprimé Auteurs : F. Rosalbino, Auteur ; G. Scavino, Auteur ; E. Angelini, Auteur Année de publication : 2011 Article en page(s) : pp. 357–361 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Hot  working  steel  Nitriding  Nitrocarburising  Overcarburising  Polarisation  curves Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The X 37CrMoV5 1 KU hot working steel has been quenched and tempered, overcarburised, nitrided and nitrocarburised. The surface layers constituted after the thermochemical treatments were characterised by means of X-ray diffraction (XRD) analyses, optical and scanning electron microscope (SEM) observations, micro- and macrohardness indentations. The electrochemical behaviour was evaluated in two different aggressive environments: 0.1 M Na2SO4 and 0.1 M NaCl solutions. While the overcarburised and the nitrocarburised samples exhibit a poor electrochemical behaviour, the presence of a nitrided surface layer enhances the corrosion resistance. This is attributable to the protective action of the nitrided layer that hinders the anodic dissolution reaction of the matrix, whereas the presence of complex carbides in the overcarburised or nitrocarburised samples causes the preferential dissolution of the ferritic matrix due to galvanic coupling phenomena. Finally, the poor corrosion resistance exhibited by the nitrocarburised sample can be ascribed to the presence of a large amount of ferrite together with little ε solid solution in the surface layer. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905530/abstract [article] Effect of different thermochemical treatments on the electrochemical behaviour of a hot working steel [texte imprimé] / F. Rosalbino, Auteur ; G. Scavino, Auteur ; E. Angelini, Auteur . - 2011 . - pp. 357–361. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 4 (Avril 2011) . - pp. 357–361 Mots-clés : Hot  working  steel  Nitriding  Nitrocarburising  Overcarburising  Polarisation  curves Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The X 37CrMoV5 1 KU hot working steel has been quenched and tempered, overcarburised, nitrided and nitrocarburised. The surface layers constituted after the thermochemical treatments were characterised by means of X-ray diffraction (XRD) analyses, optical and scanning electron microscope (SEM) observations, micro- and macrohardness indentations. The electrochemical behaviour was evaluated in two different aggressive environments: 0.1 M Na2SO4 and 0.1 M NaCl solutions. While the overcarburised and the nitrocarburised samples exhibit a poor electrochemical behaviour, the presence of a nitrided surface layer enhances the corrosion resistance. This is attributable to the protective action of the nitrided layer that hinders the anodic dissolution reaction of the matrix, whereas the presence of complex carbides in the overcarburised or nitrocarburised samples causes the preferential dissolution of the ferritic matrix due to galvanic coupling phenomena. Finally, the poor corrosion resistance exhibited by the nitrocarburised sample can be ascribed to the presence of a large amount of ferrite together with little ε solid solution in the surface layer. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905530/abstract

Electrochemical corrosion behaviour of innovative mould steels in a chloride-containing environment / F. Rosalbino in Materials and corrosion, Vol. 63 N° 2 (Fevrier 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 105–110 Titre : Electrochemical corrosion behaviour of innovative mould steels in a chloride-containing environment Type de document : texte imprimé Auteurs : F. Rosalbino, Auteur ; G. Scavino, Auteur ; G. Mortarino, Auteur Année de publication : 2012 Article en page(s) : pp. 105–110 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : bainitic  microstructure;  corrosion  behaviour;  electrochemical  impedance  spectroscopy  (EIS);  mould  steels;  polarization  curves Résumé : Investigations concerning the electrochemical corrosion behaviour of mould steels are scarce and limited. In the present study the corrosion resistance of an innovative mould steel (a microalloyed steel, steel 2), devoted to the fabrication of large size moulds, and a steel having the same composition without microalloying elements (B, Zr, Nb, steel 3), proposed for small size moulds, was assessed in a chloride-containing environment and compared with that of the traditional 1.2738 steel. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements were carried out on the investigated steel samples in a 0.1 M NaCl solution at 25 °C. Scanning electron microscopy and electron probe microanalysis were used to characterize the specimens surface after the electrochemical tests. Despite having a bainitic microstructure, the electrochemical corrosion behaviour of the investigated steels is quite different. Results showed that the steel 3 and the 1.2738 steel samples exhibit the best and the worst electrochemical corrosion behaviours compared to the steel 2 sample. The presence of pearlite is considered as the main reason for the poor corrosion behaviour showed by the 1.2738 steel sample, due to galvanic coupling phenomena between this phase and the bainitic matrix which experiences preferential dissolution. The coarse bainitic microstructure characterizing the steel 2 sample is responsible for its lower corrosion resistance as compared with the steel 3 sample exhibiting a finer bainitic microstructure. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005794/abstract [article] Electrochemical corrosion behaviour of innovative mould steels in a chloride-containing environment [texte imprimé] / F. Rosalbino, Auteur ; G. Scavino, Auteur ; G. Mortarino, Auteur . - 2012 . - pp. 105–110. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 2 (Fevrier 2012) . - pp. 105–110 Mots-clés : bainitic  microstructure;  corrosion  behaviour;  electrochemical  impedance  spectroscopy  (EIS);  mould  steels;  polarization  curves Résumé : Investigations concerning the electrochemical corrosion behaviour of mould steels are scarce and limited. In the present study the corrosion resistance of an innovative mould steel (a microalloyed steel, steel 2), devoted to the fabrication of large size moulds, and a steel having the same composition without microalloying elements (B, Zr, Nb, steel 3), proposed for small size moulds, was assessed in a chloride-containing environment and compared with that of the traditional 1.2738 steel. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements were carried out on the investigated steel samples in a 0.1 M NaCl solution at 25 °C. Scanning electron microscopy and electron probe microanalysis were used to characterize the specimens surface after the electrochemical tests. Despite having a bainitic microstructure, the electrochemical corrosion behaviour of the investigated steels is quite different. Results showed that the steel 3 and the 1.2738 steel samples exhibit the best and the worst electrochemical corrosion behaviours compared to the steel 2 sample. The presence of pearlite is considered as the main reason for the poor corrosion behaviour showed by the 1.2738 steel sample, due to galvanic coupling phenomena between this phase and the bainitic matrix which experiences preferential dissolution. The coarse bainitic microstructure characterizing the steel 2 sample is responsible for its lower corrosion resistance as compared with the steel 3 sample exhibiting a finer bainitic microstructure. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005794/abstract

Electrochemical corrosion behaviour of Sn–Ag–Cu (SAC) eutectic alloy in a chloride containing environment / F. Rosalbino in Materials and corrosion, Vol. 63 N° 6 (Juin 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 6 (Juin 2012) . - pp. 492–496 Titre : Electrochemical corrosion behaviour of Sn–Ag–Cu (SAC) eutectic alloy in a chloride containing environment Type de document : texte imprimé Auteurs : F. Rosalbino, Auteur ; G. Zanicchi, Auteur ; R. Carlini, Auteur Année de publication : 2012 Article en page(s) : pp. 492–496 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Electrochemical  impedance  spectroscopy  (EIS);  NaCl  solution;  polarization  curves;  Sn–Ag–Cu  eutectic  alloy;  tin  oxy-chloride Résumé : The corrosion behaviour of the Sn94.5Ag3.8Cu1.5 (SAC) eutectic alloy was investigated in 0.1 M NaCl solution by potentiodynamic polarization and impedance spectroscopy measurements and compared with that of the conventional Sn73.9Pb23.1 eutectic solder employed for a long time in the packaging of microelectronic components and devices. Scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) were used to characterize the SAC eutectic alloy prior to and after the electrochemical tests. The electrochemical results indicated that the Sn–Ag–Cu eutectic alloy exhibits better corrosion behaviour than the Sn–Pb eutectic solder in NaCl solution. The presence of a corrosion products layer constituted by tin oxy-chloride was detected at the surface of both alloys investigated after the electrochemical tests. The better corrosion behaviour of SAC eutectic alloy compared to Sn–Pb eutectic solder is ascribed to the formation of a more compact surface film of corrosion products with improved protective properties owing to the presence of copper and silver, as revealed by EPMA. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005979/abstract [article] Electrochemical corrosion behaviour of Sn–Ag–Cu (SAC) eutectic alloy in a chloride containing environment [texte imprimé] / F. Rosalbino, Auteur ; G. Zanicchi, Auteur ; R. Carlini, Auteur . - 2012 . - pp. 492–496. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 6 (Juin 2012) . - pp. 492–496 Mots-clés : Electrochemical  impedance  spectroscopy  (EIS);  NaCl  solution;  polarization  curves;  Sn–Ag–Cu  eutectic  alloy;  tin  oxy-chloride Résumé : The corrosion behaviour of the Sn94.5Ag3.8Cu1.5 (SAC) eutectic alloy was investigated in 0.1 M NaCl solution by potentiodynamic polarization and impedance spectroscopy measurements and compared with that of the conventional Sn73.9Pb23.1 eutectic solder employed for a long time in the packaging of microelectronic components and devices. Scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) were used to characterize the SAC eutectic alloy prior to and after the electrochemical tests. The electrochemical results indicated that the Sn–Ag–Cu eutectic alloy exhibits better corrosion behaviour than the Sn–Pb eutectic solder in NaCl solution. The presence of a corrosion products layer constituted by tin oxy-chloride was detected at the surface of both alloys investigated after the electrochemical tests. The better corrosion behaviour of SAC eutectic alloy compared to Sn–Pb eutectic solder is ascribed to the formation of a more compact surface film of corrosion products with improved protective properties owing to the presence of copper and silver, as revealed by EPMA. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005979/abstract

Electrochemical corrosion response of a precipitation hardening moulds steel in a NaCl solution / F. Rosalbino in Materials and corrosion, Vol. 63 N° 3 (Mars 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 3 (Mars 2012) . - pp. 247–253 Titre : Electrochemical corrosion response of a precipitation hardening moulds steel in a NaCl solution Type de document : texte imprimé Auteurs : F. Rosalbino, Auteur ; G. Scavino, Auteur ; G. Mortarino, Auteur Année de publication : 2012 Article en page(s) : pp. 247–253 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Corrosion  behavior;  electrochemical  impedance  spectroscopy;  polarization  curves;  precipitation  hardening  moulds  steel Résumé : Investigations concerning the electrochemical corrosion behavior of mould steels are scarce and limited. In the present study, the corrosion resistance of a precipitation hardening moulds steel submitted to aging treatments has been assessed in a 0.1 M NaCl aqueous solution by means of potentiodynamic polarization and electrochemical impedance spectroscopy measurements. The electrochemical characterization of the steel not submitted to hardening treatments was also examined and a comparative study was made between the different specimens. Scanning electron microscopy and electron probe microanalysis were used to obtain information about the morphology and chemical composition of the steels surface after the electrochemical tests. Increasing the aging temperature an increase of secondary hardness is observed, attributable to an increase of secondary phases (re-precipitated carbides and metastable GP zones) amount, positively reflecting on the mechanical properties. However, the electrochemical results show a progressive worsening of the corrosion behavior, the as-received steel sample exhibiting the best corrosion resistance. The observed decrease of corrosion resistance with increasing the aging temperature is ascribed to enhanced galvanic coupling phenomena between the secondary phases, acting as cathodes, and the surrounding matrix which, consequently, experiences preferential dissolution. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005820/abstract [article] Electrochemical corrosion response of a precipitation hardening moulds steel in a NaCl solution [texte imprimé] / F. Rosalbino, Auteur ; G. Scavino, Auteur ; G. Mortarino, Auteur . - 2012 . - pp. 247–253. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 3 (Mars 2012) . - pp. 247–253 Mots-clés : Corrosion  behavior;  electrochemical  impedance  spectroscopy;  polarization  curves;  precipitation  hardening  moulds  steel Résumé : Investigations concerning the electrochemical corrosion behavior of mould steels are scarce and limited. In the present study, the corrosion resistance of a precipitation hardening moulds steel submitted to aging treatments has been assessed in a 0.1 M NaCl aqueous solution by means of potentiodynamic polarization and electrochemical impedance spectroscopy measurements. The electrochemical characterization of the steel not submitted to hardening treatments was also examined and a comparative study was made between the different specimens. Scanning electron microscopy and electron probe microanalysis were used to obtain information about the morphology and chemical composition of the steels surface after the electrochemical tests. Increasing the aging temperature an increase of secondary hardness is observed, attributable to an increase of secondary phases (re-precipitated carbides and metastable GP zones) amount, positively reflecting on the mechanical properties. However, the electrochemical results show a progressive worsening of the corrosion behavior, the as-received steel sample exhibiting the best corrosion resistance. The observed decrease of corrosion resistance with increasing the aging temperature is ascribed to enhanced galvanic coupling phenomena between the secondary phases, acting as cathodes, and the surrounding matrix which, consequently, experiences preferential dissolution. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005820/abstract

Stability of the passive state of Zr–Nb crystalline alloys / F. Rosalbino in Materials and corrosion, Vol. 63 N° 7 (Juillet 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 7 (Juillet 2012) . - pp. 580–585 Titre : Stability of the passive state of Zr–Nb crystalline alloys Type de document : texte imprimé Auteurs : F. Rosalbino, Auteur ; D. Macciò, Auteur ; A. Saccone, Auteur Année de publication : 2012 Article en page(s) : pp. 580–585 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Electrochemical  impedance  spectroscopy  (EIS);  passive  state;  pitting  corrosion;  potentiodynamic  polarization  curves;  Zr–Nb  alloys Résumé : Stability of the passive state was assessed for pure Zr and four Zr–Nb alloys (2.5, 5.0, 10.0, 25.0 at.% Nb) after 24 h exposure to naturally aerated 3.5% NaCl solution (pH = 6). Open circuit potential values indicated that all the Zr–Nb alloys studied and the pure Zr undergo spontaneous passivation due to spontaneously formed oxide film passivating the metallic surface. It also indicated that the addition of increasing Nb contents to pure Zr seems to improve the protection characteristics of its spontaneous oxides. Potentiodynamic polarization curves showed an increase of the breakdown potential and the extent of the passive range following an increased niobium amount in the alloy. This leads to the conclusion that a progressive increase of niobium content positively affects the localized corrosion behaviour of the Zr–Nb alloys by enhancing the electrochemical stability of the passive film. Electrochemical impedance spectroscopy (EIS) studies showed high impedance values for all the samples, and its increase on increased niobium content in the alloy indicated an improvement in the corrosion resistance of the spontaneous oxide film. The fit obtained suggests a single passive film present on the metal surface, with resistance improving with the increase of niobium amount in the alloy. All these electrochemical results show the beneficial effect of increasing niobium contents on the passive state stability of the Zr–Nb alloys. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201006012/abstract [article] Stability of the passive state of Zr–Nb crystalline alloys [texte imprimé] / F. Rosalbino, Auteur ; D. Macciò, Auteur ; A. Saccone, Auteur . - 2012 . - pp. 580–585. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 7 (Juillet 2012) . - pp. 580–585 Mots-clés : Electrochemical  impedance  spectroscopy  (EIS);  passive  state;  pitting  corrosion;  potentiodynamic  polarization  curves;  Zr–Nb  alloys Résumé : Stability of the passive state was assessed for pure Zr and four Zr–Nb alloys (2.5, 5.0, 10.0, 25.0 at.% Nb) after 24 h exposure to naturally aerated 3.5% NaCl solution (pH = 6). Open circuit potential values indicated that all the Zr–Nb alloys studied and the pure Zr undergo spontaneous passivation due to spontaneously formed oxide film passivating the metallic surface. It also indicated that the addition of increasing Nb contents to pure Zr seems to improve the protection characteristics of its spontaneous oxides. Potentiodynamic polarization curves showed an increase of the breakdown potential and the extent of the passive range following an increased niobium amount in the alloy. This leads to the conclusion that a progressive increase of niobium content positively affects the localized corrosion behaviour of the Zr–Nb alloys by enhancing the electrochemical stability of the passive film. Electrochemical impedance spectroscopy (EIS) studies showed high impedance values for all the samples, and its increase on increased niobium content in the alloy indicated an improvement in the corrosion resistance of the spontaneous oxide film. The fit obtained suggests a single passive film present on the metal surface, with resistance improving with the increase of niobium amount in the alloy. All these electrochemical results show the beneficial effect of increasing niobium contents on the passive state stability of the Zr–Nb alloys. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201006012/abstract