Accurate Control of Oxide Ions Content for Corrosion Studies: Application to SS316L and Its Alloying Elements in Molten LiCl-KCl  

作　　者：Thibaut Fourès Mathieu Gibilaro Laurent Massot Elisa Capelli Bertrand Morel Pierre Chamelot Thibaut Fourès;Mathieu Gibilaro;Laurent Massot;Elisa Capelli;Bertrand Morel;Pierre Chamelot(Laboratoire de Gnie Chimique, Universit de Toulouse, Toulouse, France;Orano, Chtillon, France)

机构地区：[1]Laboratoire de Gnie Chimique, Universit de Toulouse, Toulouse, France [2]Orano, Chtillon, France

出　　处：《Materials Sciences and Applications》2024年第12期572-586,共15页材料科学与应用期刊(英文)

摘　　要：The aim of this work was to study the influence of oxide ions concentration on the stability of 316L stainless steel and its alloying compounds (chromium, iron, nickel and molybdenum) in molten LiCl-KCl-Li2O at 550˚C. An in-situ oxide ions titration method using square wave voltammetry was developed to quantify oxide ions, to accurately control the experimental conditions. The influence of oxide ions concentration was then studied by linear sweep voltammetry and long-term immersions followed by SEM-EDS analysis on pure elements and SS316L. Results showed that chromium was stabilized in presence of O2−, iron was dissolved independently of [O2−], nickel was resistant to corrosion and molybdenum, which was stable in oxide-free media, was found reactive towards O2−. On SS316L, a passivation layer was observed and an enriched chromium-oxygen layer was observed by SEM-EDS. Almost all the iron was dissolved and a small depletion of molybdenum was visible while nickel remained resistant to corrosion. Linear sweep voltammetry studies were consistent with SEM-EDS analysis and each alloying compound exhibited a similar behaviour in the SS316L as its pure form.The aim of this work was to study the influence of oxide ions concentration on the stability of 316L stainless steel and its alloying compounds (chromium, iron, nickel and molybdenum) in molten LiCl-KCl-Li2O at 550˚C. An in-situ oxide ions titration method using square wave voltammetry was developed to quantify oxide ions, to accurately control the experimental conditions. The influence of oxide ions concentration was then studied by linear sweep voltammetry and long-term immersions followed by SEM-EDS analysis on pure elements and SS316L. Results showed that chromium was stabilized in presence of O2−, iron was dissolved independently of [O2−], nickel was resistant to corrosion and molybdenum, which was stable in oxide-free media, was found reactive towards O2−. On SS316L, a passivation layer was observed and an enriched chromium-oxygen layer was observed by SEM-EDS. Almost all the iron was dissolved and a small depletion of molybdenum was visible while nickel remained resistant to corrosion. Linear sweep voltammetry studies were consistent with SEM-EDS analysis and each alloying compound exhibited a similar behaviour in the SS316L as its pure form.

关 键 词：CHROMIUM Iron Nickel MOLYBDENUM Molten Salts SS316L Stainless Steel Oxide Ions 

分 类 号：TG1[金属学及工艺—金属学]