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Electrochemical corrosion behaviors and protective properties of Ni–Co–TiO2 composite coating prepared on sintered NdFeB magnet / X. K. Yang in Materials and corrosion, Vol. 61 N° 7 (Juillet 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 7 (Juillet 2010) . - pp. 618–625 Titre : Electrochemical corrosion behaviors and protective properties of Ni–Co–TiO2 composite coating prepared on sintered NdFeB magnet Type de document : texte imprimé Auteurs : X. K. Yang, Auteur ; Q. Li, Auteur ; S. Y. Zhang, Auteur Année de publication : 2010 Article en page(s) : pp. 618–625 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Electrochemical  impedance  spectroscopy;  NdFeB  magnet;  Ni–Co–TiO2  composite  coating;  potentiodynamic  polarization Résumé : In this paper, a protective Ni–Co–TiO2 composite coating was prepared on the sintered NdFeB magnet by direct current electrodeposition. The surface morphologies, microstructure, and chemical composition of the composite coating were studied using scanning electron microscope (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS), respectively. The surface morphologies and microstructure analysis showed that the composite coating possessed cauliflower-like grain colonies, and formed face-centered cubic (fcc) solid solution. The electrochemical corrosion behaviors of the composite coating in 0.5 mol/L H2SO4, 0.6 mol/L NaOH, 0.6 mol/L Na2SO4, and neutral 3.5 wt% NaCl solutions were evaluated by potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS), showing good protection for NdFeB magnet. In order to further investigate the protective properties of the composite coating for NdFeB magnet and the practicability of the composite coating, the long-term immersion test was carried out in neutral 3.5 wt% NaCl solutions using EIS. The results of long-term corrosion test showed that the Ni–Co–TiO2 composite coating could provide long-term protection in neutral 3.5 wt% NaCl solutions for NdFeB magnet. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905449/abstract [article] Electrochemical corrosion behaviors and protective properties of Ni–Co–TiO2 composite coating prepared on sintered NdFeB magnet [texte imprimé] / X. K. Yang, Auteur ; Q. Li, Auteur ; S. Y. Zhang, Auteur . - 2010 . - pp. 618–625. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 7 (Juillet 2010) . - pp. 618–625 Mots-clés : Electrochemical  impedance  spectroscopy;  NdFeB  magnet;  Ni–Co–TiO2  composite  coating;  potentiodynamic  polarization Résumé : In this paper, a protective Ni–Co–TiO2 composite coating was prepared on the sintered NdFeB magnet by direct current electrodeposition. The surface morphologies, microstructure, and chemical composition of the composite coating were studied using scanning electron microscope (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS), respectively. The surface morphologies and microstructure analysis showed that the composite coating possessed cauliflower-like grain colonies, and formed face-centered cubic (fcc) solid solution. The electrochemical corrosion behaviors of the composite coating in 0.5 mol/L H2SO4, 0.6 mol/L NaOH, 0.6 mol/L Na2SO4, and neutral 3.5 wt% NaCl solutions were evaluated by potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS), showing good protection for NdFeB magnet. In order to further investigate the protective properties of the composite coating for NdFeB magnet and the practicability of the composite coating, the long-term immersion test was carried out in neutral 3.5 wt% NaCl solutions using EIS. The results of long-term corrosion test showed that the Ni–Co–TiO2 composite coating could provide long-term protection in neutral 3.5 wt% NaCl solutions for NdFeB magnet. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905449/abstract

Electrodeposition of zinc on AZ91D magnesium alloy pre-treated by stannate conversion coatings / S. Y. Zhang in Materials and corrosion, Vol. 61 N° 10 (Octobre 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 10 (Octobre 2010) . - pp. 860–865 Titre : Electrodeposition of zinc on AZ91D magnesium alloy pre-treated by stannate conversion coatings Type de document : texte imprimé Auteurs : S. Y. Zhang, Auteur ; Q. Li, Auteur ; B. Chen, Auteur Année de publication : 2011 Article en page(s) : pp. 860–865 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : AZ91D  magnesium  alloy;  corrosion  resistance;  stannate  conversion  coating;  zinc  electrodeposition Résumé : A stannate chemical conversion process followed by an activation procedure was employed as the pre-treatment process for AZ91D magnesium alloy substrate. Zn was electroplated onto the pre-treated AZ91D magnesium alloy surface from pyrophosphate bath to improve the corrosion resistance and the solderability. The surface morphologies of conversion coating and zinc coating were examined with scanning electron microscope (SEM). The phase composition of conversion coating was investigated by X-ray diffraction (XRD). The electrochemical corrosion behavior of the coatings in the corrosive solution was investigated by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The experimental results showed that the activated stannate chemical conversion coating provided a suitable interface between zinc coating and the AZ91D magnesium alloy substrate. The corrosion resistance of the AZ91D substrate was improved by the zinc coating. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905435/abstract [article] Electrodeposition of zinc on AZ91D magnesium alloy pre-treated by stannate conversion coatings [texte imprimé] / S. Y. Zhang, Auteur ; Q. Li, Auteur ; B. Chen, Auteur . - 2011 . - pp. 860–865. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 10 (Octobre 2010) . - pp. 860–865 Mots-clés : AZ91D  magnesium  alloy;  corrosion  resistance;  stannate  conversion  coating;  zinc  electrodeposition Résumé : A stannate chemical conversion process followed by an activation procedure was employed as the pre-treatment process for AZ91D magnesium alloy substrate. Zn was electroplated onto the pre-treated AZ91D magnesium alloy surface from pyrophosphate bath to improve the corrosion resistance and the solderability. The surface morphologies of conversion coating and zinc coating were examined with scanning electron microscope (SEM). The phase composition of conversion coating was investigated by X-ray diffraction (XRD). The electrochemical corrosion behavior of the coatings in the corrosive solution was investigated by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The experimental results showed that the activated stannate chemical conversion coating provided a suitable interface between zinc coating and the AZ91D magnesium alloy substrate. The corrosion resistance of the AZ91D substrate was improved by the zinc coating. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905435/abstract

Partially substituting MgO for NaOH as the alkali source in the second-stage Impregnation of triploid poplar P-RC APMP / X. Q. Hu in Industrial & engineering chemistry research, Vol. 49 N° 7 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3088–3093 Titre : Partially substituting MgO for NaOH as the alkali source in the second-stage Impregnation of triploid poplar P-RC APMP Type de document : texte imprimé Auteurs : X. Q. Hu, Auteur ; W. Yuan, Auteur ; S. Y. Zhang, Auteur Année de publication : 2010 Article en page(s) : pp. 3088–3093 Note générale : Indystrial Chemistry Langues : Anglais (eng) Mots-clés : MgO  NaOH  Alkali  Triploid  Triplor Résumé : In the conventional preconditioning followed by refiner chemical treatment, alkaline peroxide mechanical pulping (P-RC APMP) process, sodium hydroxide (NaOH) is used as the alkali source. In this study, magnesium oxide (MgO) was used to partially substitute for NaOH as the alkali source (substitution ratio of up to 50%) in the second-stage impregnation of the triploid poplar P-RC APMP process. The changes in pH values of the residual bleaching liquor, yields, and chemical components of the treated wood chips in the second-stage impregnation and also the physical properties of the resultant P-RC APMP pulps with and without MgO substitution were investigated to explore the potential advantages of the process. The results showed that the partial MgO substitution for NaOH resulted in a lower pH of residual bleaching liquor and a higher treated wood chips yield than those of the NaOH-based process. In addition, the dissolution of benzene alcohol extractives, lignin, pentosans, and carbohydrates were all decreased. The resultantly yielded P-RC APMP pulp has a higher bulk, opacity, and light-scattering coefficient, but lower strength properties and a slightly lower brightness. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901639p [article] Partially substituting MgO for NaOH as the alkali source in the second-stage Impregnation of triploid poplar P-RC APMP [texte imprimé] / X. Q. Hu, Auteur ; W. Yuan, Auteur ; S. Y. Zhang, Auteur . - 2010 . - pp. 3088–3093. Indystrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3088–3093 Mots-clés : MgO  NaOH  Alkali  Triploid  Triplor Résumé : In the conventional preconditioning followed by refiner chemical treatment, alkaline peroxide mechanical pulping (P-RC APMP) process, sodium hydroxide (NaOH) is used as the alkali source. In this study, magnesium oxide (MgO) was used to partially substitute for NaOH as the alkali source (substitution ratio of up to 50%) in the second-stage impregnation of the triploid poplar P-RC APMP process. The changes in pH values of the residual bleaching liquor, yields, and chemical components of the treated wood chips in the second-stage impregnation and also the physical properties of the resultant P-RC APMP pulps with and without MgO substitution were investigated to explore the potential advantages of the process. The results showed that the partial MgO substitution for NaOH resulted in a lower pH of residual bleaching liquor and a higher treated wood chips yield than those of the NaOH-based process. In addition, the dissolution of benzene alcohol extractives, lignin, pentosans, and carbohydrates were all decreased. The resultantly yielded P-RC APMP pulp has a higher bulk, opacity, and light-scattering coefficient, but lower strength properties and a slightly lower brightness. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901639p

Preparation and characterization of inorganic and organic coatings on AZ91D magnesium alloy with electroless plating pretreatment / S. Y. Zhang in Materials and corrosion, Vol. 62 N° 9 (Septembre 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 9 (Septembre 2011) . - pp. 841–847 Titre : Preparation and characterization of inorganic and organic coatings on AZ91D magnesium alloy with electroless plating pretreatment Type de document : texte imprimé Auteurs : S. Y. Zhang, Auteur ; Q. Li, Auteur ; X. K. Yang, Auteur Année de publication : 2011 Article en page(s) : pp. 841–847 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : AZ91D  magnesium  alloy  Corrosion  protection  Electrochemical  impedance  spectroscopy  Potentiodynamic  polarization Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In this paper, a protective coating scheme was applied for the corrosion protection of AZ91D magnesium alloy. Electroless Ni coating (EN coating) as bottom layer, electrodeposited Ni coating (ENN coating), and silane-based coating (ENS coating) as top layer, respectively, were successfully prepared on AZ91D magnesium alloy by combination techniques. Scanning electron microscopy and X-ray diffraction were employed to investigate the surface and phase structure of coatings, respectively. The electrochemical corrosion behaviors of coatings in neutral 3.5 wt% NaCl solution were evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The corrosion testing showed that the three kinds of coatings all could provide corrosion protection for AZ91D magnesium alloy to a certain extent, and the corrosion resistance of ENN and ENS was superior to EN. In order to further study the corrosion protection properties of ENN and ENS, a comparative investigation on the evolution of EIS of ENN and ENS was carried out by dint of immersion test in neutral 3.5 wt% NaCl solution. The results indicated that, compared with ENN, the ENS could provide longer corrosion protection for AZ91D magnesium alloy. It is significant to determine the barrier effect of each coating, which could provide reference for industry applications. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005958/abstract [article] Preparation and characterization of inorganic and organic coatings on AZ91D magnesium alloy with electroless plating pretreatment [texte imprimé] / S. Y. Zhang, Auteur ; Q. Li, Auteur ; X. K. Yang, Auteur . - 2011 . - pp. 841–847. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 9 (Septembre 2011) . - pp. 841–847 Mots-clés : AZ91D  magnesium  alloy  Corrosion  protection  Electrochemical  impedance  spectroscopy  Potentiodynamic  polarization Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In this paper, a protective coating scheme was applied for the corrosion protection of AZ91D magnesium alloy. Electroless Ni coating (EN coating) as bottom layer, electrodeposited Ni coating (ENN coating), and silane-based coating (ENS coating) as top layer, respectively, were successfully prepared on AZ91D magnesium alloy by combination techniques. Scanning electron microscopy and X-ray diffraction were employed to investigate the surface and phase structure of coatings, respectively. The electrochemical corrosion behaviors of coatings in neutral 3.5 wt% NaCl solution were evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The corrosion testing showed that the three kinds of coatings all could provide corrosion protection for AZ91D magnesium alloy to a certain extent, and the corrosion resistance of ENN and ENS was superior to EN. In order to further study the corrosion protection properties of ENN and ENS, a comparative investigation on the evolution of EIS of ENN and ENS was carried out by dint of immersion test in neutral 3.5 wt% NaCl solution. The results indicated that, compared with ENN, the ENS could provide longer corrosion protection for AZ91D magnesium alloy. It is significant to determine the barrier effect of each coating, which could provide reference for industry applications. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005958/abstract