Straining electrode behavior and corrosion resistance of nickel base alloys in high temperature acidic solution
- Sumitomo Metal Industries, Ltd., Hyogo (Japan)
Repassivation behavior and IGA resistance of nickel base alloys containing 0{approximately}30 wt% chromium was investigated in high temperature acid sulfate solution. (1) The repassivation rate was increased with increasing chromium content. And so the amounts of charge caused by the metal dissolution were decreased with increasing chromium content. (2) Mill-annealed Alloy 600 suffered IGA at low pH environment below about 3.5 at the fixed potentials above the corrosion potential in 10%Na{sub 2}SO{sub 4}+H{sub 2}SO{sub 4} solution at 598K. On the other hand, thermally-treated Alloy 690 was hard to occur IGA at low pH environments which mill-annealed Alloy 600 occurred IGA. (3) It was considered that the reason, why nickel base alloys containing high chromium content such as Alloy 690 (60%Ni-30%Cr-10%Fe) had high IGA/SCC resistance in high temperature acidic solution containing sulfate ion, is due to both the promotion of the repassivation and the suppression of the film dissolution by the formation of the dense chromium oxide film.
- OSTI ID:
- 48113
- Report Number(s):
- CONF-910808--
- Country of Publication:
- United States
- Language:
- English
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