Effect of Thiosulfate on Pitting Corrosion of Ni-Cr-Fe Alloys in Chloride Solutions

Pitting corrosion of Alloys 600, 690, and 800 (UNS N06600, N06690, and N08800) was studied in 1 M NaCl solution with different concentrations of thiosulfate (). Alloys exhibited vastly different electrochemical behavior, depending on the concentration and chromium content of the alloy. Alloy 600 exhibited a breakdown and repassivation potential that decreased with decreasing concentration, in the range from 1 M to 10−4 M. Breakdown and...