Corrosion Behavior of Steels in LiBr–H2O–CaCl2–LiNO3 Systems

Abstract

Conventional absorption and refrigeration systems use a LiBr/H2O mixture, which causes corrosion problems to the metallic components. In order to avoid this and some other problems such as crystallization and vapor pressure, some additives such as CaCl2 and/or LiNO3 are added to the LiBr/H2O mixture. In the present work, the corrosion behavior of 1018 carbon steel as well as of type 304 and 316L stainless steels was evaluated in LiBr/H2O at 80 °C with the addition of CaCl2, LiNO3, and CaCl2+LiNO3. Potentiodynamic polarization curves and electrochemical impedance spectroscopy were used for this purpose. The results showed that the corrosion current density values of all tested steels decreased with the addition of CaCl2 and/or LiNO3, which induced the formation of a passive film on carbon steel. Both types of stainless steels showed a passive film in all tested conditions, but the passive current density was the lowest, whereas the passive zone was the widest, for 316L steel. The corrosion mechanism remained unaltered for both stainless steels but was changed with the addition of CaCl2 and/or LiNO3 for carbon steel.