Effect of temperature and concentration on the passive film properties of a duplex stainless steel in LiBr solutions

摘要

Lithium Bromide (LiBr) is one of the most widely used absorbents in refrigerationtechnology. However, the operating conditions in the absorption machines cangenerate serious corrosion problems in the structural materials. Duplex stainlesssteel could be employed in absorption machines due to their good mechanicalproperties and corrosion resistance. Cyclic potentiodynamic curves andelectrochemical impedance measurements were carried out with the as-received ansensitised (825 °C, 1h) Alloy 900 in LiBr solutions at two concentrations (400 g/l and992 g/l) and at different temperatures (25, 35, 45 and 55 °C). According to theresults, the polarisation resistance decreases with the solution temperature and theLiBr concentration. Additionally, the sensitisation process has a negative effect in thepolarisation resistance; these results are in agreement with those observed in thecyclic potentiodynamic curves.