Hydrogen embrittlement of duplex stainless steel under cathodic protection in acidic artificial sea water in the presence of sulphide ions

By slow strain rate technique, hydrogen embrittlement (HE) of a 2205 duplex stainless steel was studied in deaerated acidic (pH 6.5) artificial sea water, in the absence and in presence of sulphide ions (1–30 ppm). Strain rate tests (1 × 10−6 s−1) were performed on specimens polarized at −0.9; −1.0 and −1.2 VSCE at 25 ± 0.1 °C. HE was evaluated by R, the ratio between the % elongation to fracture in the aggressive solution and in air.Duplex stainless steel were subjected to HE in acidic artificial sea water at −0.9 VSCE. HE increased at −1.0 VSCE but it was reduced at −1.2 VSCE. This decrease was attributed to the influence of a calcareous deposit.Sulphide ions at 1 ppm were sufficient to stimulate HE of duplex stainless steel. The higher the sulphide amount and the more negative the cathodic potential, the higher HE was. In the presence of S2−, the shielding effect of the calcareous deposit was not evident.