Comportement électrochimique de l’alliage 904L en milieux phosphoriques pollués par les ions sulfurés
Written by sctunisie no commentsThe effect of sulphide ions on the corrosion behaviour of an austenitic alloy 904L (Z1CNDU 25-20) in phosphoric media and especially on the nature and the composition of the layer formed at the material surface has been studied using electrochemical methods (polarization curves) and spectroscopic techniques (XPS, Auger and IR). The electrochemical study shows that the sulphide ions induce the depolarization of anodic processes resulting in a increase of material dissolution kinetics and hence a decrease of corrosion resistance. In such conditions, information obtained on the passivity film using surface analysis techniques revealed enrichment or impoverishment in some elements. So, the external layer is characterized by the presence of phosphate and metallic sulphide, while the internal layer contains some oxides and hydroxides. The micrographic test obtained by SEM showed localized attacks at the material surface in the presence of sulphide ions.
A. Bellaouchou, A. Guenbour, A. Benbachir, L. Aries
Corrosion, Stainless Steel, Phosphoric Medium, Sulphides ions
Pages 1389-1398
