CORROSION STUDIES OF STAINLESS STEELS, TITANIUM AND ALLOY 33 IN AQUEOUS LITHIUM BROMIDE SOLUTIONS

摘要

The corrosion behaviour of three Stainless Steels, Alloy 33 and Titanium was studied in LiBr solutions (400 g/L, 700 g/L and 850 g/L chromate containing commercial solution). Chromate acts as inhibitor and its inhibitor influence was analyzed. Current corrosion for the materials was always higher in 400 g/L LiBr than in 700 g/L and the most negative corrosion potentials were obtained in the inhibited solution. The most effective action of the inhibitor was observed on titanium while the least inhibitor efficiency was obtained for Alloy 33. The critical potentials shifted towards more negative values when LiBr concentration increased in the solution. Chromate did not enhance the pitting resistance of the stainless steels. Galvanic behaviour of the pairs considered was analyzed by the Mixed Potential Theory. Alloy 33 was always the anodic element of the pairs so that its corrosion resistance in the three media decreases due to the galvanic effect produced by its coupling with a different material. AISI 316 is the cathodic element in the commercial solution.