Corrosion of carbon steel has been investigated for 200h in concentrated aqueous solution of mixed LiBr-LiNO
3-KCl-LiOH salts at elevated temperatures as functions of temperature and concentration of LiNO
3 and Li
2MoO
4O. The structure and composition of the surface films were analyzed by XRD, SEM and XPS. At 463K, addition of LiNO
3 (>0.0125mol/kg) decreased the total amount of iron corroded (
WT), amount of iron ions in the oxide (
WF) and amount of Fe
2+ ions dissolved into the water (
WD) drastically, however pits were observed. At LiNO
3=3.01mol/kg,
WT and
WF increased as temperature rises, whereas
WD decreased as temperature rises. Pit was observed at LiNO
3=3.01mol/kg between 363K and 463K. Below 403K, pit depth was less than 15μm, while above 433K the pit depth was more than 80μm. These corrosion behavior did not depend on the addition of Li
2MoO
4. Outermost parts of oxide films formed at LiNO
3=3.01mol/kg, were composed of γ-Fe
2O
3 and the decrease in the LiNO
3 concentration changed the composition from γ-Fe
2O
3 to Fe
3O
4. The role of surface film in the corrosion behavior was discussed in terms of its ion-selectivity and OH
- ion stabilizing ability.
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