| Titre : |
Analysis of the various processes downstream cathodic hydrogen charging, I: Diffusion, laboratory permeation and measurement of hydrogen content and diffusion coefficient |
| Type de document : |
texte imprimé |
| Auteurs : |
Jean-Louis Crolet, Auteur |
| Année de publication : |
2016 |
| Article en page(s) : |
17 p. |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Tags : |
'Charge d'hydrogène cathodique' 'Coefficient de diffusion' transitoire' 'Laboratoire perméation' 'Teneur en hydrogène' |
| Index. décimale : |
620.11 Matériaux (propriétés, résistance) |
| Résumé : |
The new views of 2000 on cathodic hydrogen charging are introduced in the numerical modelling of the downstream hydrogen diffusion, and this Part I deals with artificial laboratory permeation with electrochemical measurements on a Pd coated exit face. The “true” transients and steady state are thus calculated for the concentration profiles c(x,t) and the permeation flux Jperm, as well as the permeation efficiency Ep. The former nomenclature in term of thin vs thick membranes is indeed altered by high vs low charging fluxes, or high, medium and low, or still better, very high and moderately high, and very low and moderately low. Results are then compared to the historical calculation tools based on the boundary condition of a constant surface concentration c0 at the entry face. These mathematical tools had been developed a long time ago for permeation under gaseous charging, and they are still valid in this case, but since the abandonment of the Bockris mechanism of discharge-recombination, they are basically invalid for the new cathodic charging by direct proton transfer. More generally, it is emphasised how the two charging modes are different for any subsequent transport process, and more will be addressed in Part II. Then, the totally unexpected consequences on the mechanism of sulfide stress cracking (SSC) will be addressed in Parts III and IV. |
| Note de contenu : |
- INTRODUCTION : The role of time and fortuity - The "old" hydrogen - The "new" hydrogen
- NUMERICAL MODELLING : Diffusion basics - Artificial laboratory permeation - Joined measurement of the hydrogen content co and diffusion coefficient DH |
| Référence de l'article : |
205 |
| DOI : |
http://dx.doi.org/10.1051/mattech/2016007 |
| En ligne : |
http://www.mattech-journal.org/articles/mattech/pdf/2016/02/mt150085.pdf |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26656 |
in MATERIAUX & TECHNIQUES > Vol. 104, N° 2 (2016) . - 17 p.
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Analysis of the various processes downstream cathodic hydrogen charging, I: Diffusion, laboratory permeation and measurement of hydrogen content and diffusion coefficient in MATERIAUX & TECHNIQUES, Vol. 104, N° 2 (2016)
