Investigation of steel corrosion in MX80 bentonite at 120°C

Corrosion experiments were performed on two metallic substrates, a ferritic–pearlitic steel (P285NH) and a ferritic one (Armco), in silicate environment during 30 days at 120°C. Corrosion products were characterized in terms of morphology (scanning electron microscope and transmission electron microscopy), composition (energydispersive X‐ray spectroscopy) and structure (µ‐Raman, selected area electron diffraction, X‐ray absorption near edge structure). Results show a nanometric inner layer made of compact and adherent nanocrystallized magnetite with, locally a thickness up to several micrometers due to the metal microstructure. An outer layer of Fe‐rich phyllosilicate, smectite and serpentine, more porous than the inner one and poorly adherent is observed around both the samples. Corrosion experiments were performed on two metallic substrates, a ferritic–pearlitic steel (P285NH) and a ferritic one (Armco), in silicate environment during 30 days at 120°C. Results show a nanometric inner layer made of a compact and adherent nanocrystallized magnetite layer and an outer layer of Fe‐rich phyllosilicate, smectite and serpentine, more porous than the inner one and poorly adherent.