Corrosion behavior of carbon steels and low alloy steels in concentrated LiBr-CaCl2 solution at elevated temperature

Corrosion behaviors of carbon steels and Cr and/or Mo modified low alloy steels were studied in concentrated LiBr-CaCl2 mixed solution. In solutions of CaCl2 up to 21 mol/kg&middotH2O, a concentration of CaCl2 indicating maximum corrosion weight loss of carbon steels was about 5 mol/kg&middotH2O at 120°C. In LiBr-CaCl2 mixed solution, the concentration varied with CaCl2/LiBr ratio and shifted to a higher concentration with decreasing CaCl2/LiBr ratio. The corrosion rate of carbon steel decreased with exposure time, while that of low alloy steel remained constant. These facts might be due to formation of a thick corrosion product layer with crevices, where crevice corrosion is accelerated by concentrated Cl- and dissolved Cr(III) to decrease pH.