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Localized corrosion resistance of corrosion-resistant Ni based alloys in hot concentrated seawater

Conference ·
OSTI ID:351822
;  [1]
  1. Mitsubishi Materials Corp., Omiya, Saitama (Japan). Central Research Inst.

Localized corrosion resistance of stainless steel (Type 316L), a titanium-based alloy (Ti-0.15Pd) and corrosion-resistant nickel-based alloys (a new alloy MAT-21 (Alloy T) and Alloy C-276) was evaluated in four simulated seawater solutions containing 1.8 to 22.0 wt% of chloride ions concentrated by evaporation. Stress corrosion cracking was observed on the 316L stainless steel but not on Alloy T and Alloy C-276 in the solutions. Pitting attack occurred on the surface of the 316L stainless steel base metal in all the solutions. Alloy C-276 suffered pitting attack on the surface including the welded section only in the solutions containing 18.9 and 22.0 wt% of chloride ions, respectively. No pitting attack occurred over any part of the surface including the welded section of Alloy T in any of the solutions. No crevice corrosion was observed in an immersion test of Alloy T and the Ti-0.15 5Pd alloy using test pieces with crevices although crevice corrosion was seen the creviced test pieces of Alloy C-276 and the 316L stainless steel. It was found that both Alloy T and the Ti-0.15Pd alloy, which exhibit high repassivation potentials for crevice corrosion (E{sub r,CREV})corresponding to crevice corrosion potentials, have excellent crevice corrosion resistance, while these alloys which exhibit corrosion potentials greater than E{sub r,CREV}in a solution with a high chloride ion concentration and a high dissolved oxygen concentration in open air may be corroding in the crevices.

OSTI ID:
351822
Report Number(s):
CONF-980316--
Country of Publication:
United States
Language:
English