Corrosion Behaviour of 1018 Carbon Steel in LiBr-H2O-CaCl2-LiNO3 Mixtures

A study on the effect of CaCl2, LiNO3 and CaCl2+LiNO3 to the LiBr-H2O system on the corrosion behaviour of 1018 carbon steel was performed with the aid of electrochemical techniques such as potentiodynamic polarization curves and electrochemical impedance spectroscopy. This system is used in conventional refrigeration absorption systems. LiBr was used at different concentrations (283.3, 425 and 825 g/L) and temperatures (25, 50 and 80 degrees C). Corrosion current density value, I-corr, obtained in the LiBr+H2O system decreased with the addition of these additives, obtaining the lowest value when CaCl2 was added. I-corr values increased with both an increase in the testing temperature and the LiBr concentration. In addition to this, corrosion process for the LiBr-H2O system was under desorption/desorption control, whereas in presence of these additives it was either under charge transfer or reactants diffusion control depending upon the testing temperature or LiBr concentration.