Documents disponibles écrits par cet auteur

Effect of grain refinement on corrosion of ferritic–martensitic steels in supercritical water environment / X. Ren in Materials and corrosion, Vol. 61 N° 9 (Septembre 2010) 

Public ISBD [article]  in Materials and corrosion > Vol. 61 N° 9 (Septembre 2010) . - pp. 748–755 Titre : Effect of grain refinement on corrosion of ferritic–martensitic steels in supercritical water environment Type de document : texte imprimé Auteurs : X. Ren, Auteur ; Sridharan, K., Auteur ; T. R. Allen, Auteur Année de publication : 2011 Article en page(s) : pp. 748–755 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Ferritic–martensitic  steels Résumé : The effects of grain refinement on the corrosion behavior of three ferritic–martensitic (F/M) steels, HT9, T91, and NF616, and two binary model alloys Fe-15%Cr and Fe-18%Cr in supercritical water (SCW) have been investigated. Grain refinement down to a size of about one micron in the surface regions, was achieved by introducing severe plastic deformation by shot peening. After exposure to SCW with 25 ppb oxygen at 500 °C for up to 3000 h, an improvement in corrosion resistance was observed in grain-refined samples because of the enhanced diffusion of chromium on the surface, through a high density of grain boundaries. The chromium content in the steels and the exposure durations in SCW were determined to be important factors influencing the efficacy of the grain refinement effects. These results are supported by both experimental evidence and theoretical predictions. Another approach for grain refinement, equal channel angular pressing (ECAP), was also investigated for T91 steel. ECAP resulted in lower weight gain due to corrosion compared to the untreated samples, but exhibited a slightly higher weight gain compared to the shot-peened samples after long-term exposures in SCW which is probably caused by different fractions of high-angle grain boundaries in grain-refined regions, introduced by different grain refinement techniques. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905446/abstract [article] Effect of grain refinement on corrosion of ferritic–martensitic steels in supercritical water environment [texte imprimé] / X. Ren, Auteur ; Sridharan, K., Auteur ; T. R. Allen, Auteur . - 2011 . - pp. 748–755. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 61 N° 9 (Septembre 2010) . - pp. 748–755 Mots-clés : Ferritic–martensitic  steels Résumé : The effects of grain refinement on the corrosion behavior of three ferritic–martensitic (F/M) steels, HT9, T91, and NF616, and two binary model alloys Fe-15%Cr and Fe-18%Cr in supercritical water (SCW) have been investigated. Grain refinement down to a size of about one micron in the surface regions, was achieved by introducing severe plastic deformation by shot peening. After exposure to SCW with 25 ppb oxygen at 500 °C for up to 3000 h, an improvement in corrosion resistance was observed in grain-refined samples because of the enhanced diffusion of chromium on the surface, through a high density of grain boundaries. The chromium content in the steels and the exposure durations in SCW were determined to be important factors influencing the efficacy of the grain refinement effects. These results are supported by both experimental evidence and theoretical predictions. Another approach for grain refinement, equal channel angular pressing (ECAP), was also investigated for T91 steel. ECAP resulted in lower weight gain due to corrosion compared to the untreated samples, but exhibited a slightly higher weight gain compared to the shot-peened samples after long-term exposures in SCW which is probably caused by different fractions of high-angle grain boundaries in grain-refined regions, introduced by different grain refinement techniques. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905446/abstract

Synthesis of a water-soluble siloxane copolymer and its application for antimicrobial coatings / L. Kou in Industrial & engineering chemistry research, Vol. 48 N° 14 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6521–6526 Titre : Synthesis of a water-soluble siloxane copolymer and its application for antimicrobial coatings Type de document : texte imprimé Auteurs : L. Kou, Auteur ; J. Liang, Auteur ; X. Ren, Auteur Année de publication : 2009 Article en page(s) : pp. 6521–6526 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : N-halamine  siloxane  Quaternary  ammonium  salt  siloxane  Copolymers  5,5-dimethylhydantoin  Trimethylamine Résumé : Copolymers of an N-halamine siloxane and a quaternary ammonium salt siloxane were prepared using 5,5-dimethylhydantoin and trimethylamine as functional groups. The solubility of this siloxane copolymer in water was dramatically improved over that of a hydantoinyl siloxane homopolymer developed earlier. The biocidal activity of cotton swatches coated with the copolymer was evaluated against S. aureus and E. coli O157:H7; the antimicrobial fabric with 0.23%−0.26% chlorine loading could inactivate 107 colony forming units (CFU) of bacteria within 1−5 min of contact. It was observed that a 1 wt % coating bath could provide a coating that could be chlorinated to greater than a 0.20% chlorine loading for a copolymer having a 9:1 ratio of hydantoin to quat moieties. The stability of the oxidative chlorine loading on the cotton swatches was not affected by the presence of the very hydrophilic quat functional group. Use of the copolymer in an antimicrobial coating application will be desirable because no organic solvent is needed for the preparation of a coating bath for textile materials. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017302 [article] Synthesis of a water-soluble siloxane copolymer and its application for antimicrobial coatings [texte imprimé] / L. Kou, Auteur ; J. Liang, Auteur ; X. Ren, Auteur . - 2009 . - pp. 6521–6526. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6521–6526 Mots-clés : N-halamine  siloxane  Quaternary  ammonium  salt  siloxane  Copolymers  5,5-dimethylhydantoin  Trimethylamine Résumé : Copolymers of an N-halamine siloxane and a quaternary ammonium salt siloxane were prepared using 5,5-dimethylhydantoin and trimethylamine as functional groups. The solubility of this siloxane copolymer in water was dramatically improved over that of a hydantoinyl siloxane homopolymer developed earlier. The biocidal activity of cotton swatches coated with the copolymer was evaluated against S. aureus and E. coli O157:H7; the antimicrobial fabric with 0.23%−0.26% chlorine loading could inactivate 107 colony forming units (CFU) of bacteria within 1−5 min of contact. It was observed that a 1 wt % coating bath could provide a coating that could be chlorinated to greater than a 0.20% chlorine loading for a copolymer having a 9:1 ratio of hydantoin to quat moieties. The stability of the oxidative chlorine loading on the cotton swatches was not affected by the presence of the very hydrophilic quat functional group. Use of the copolymer in an antimicrobial coating application will be desirable because no organic solvent is needed for the preparation of a coating bath for textile materials. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017302