Applicability of repassivation potential for long-term prediction of localized corrosion of Alloy 825 and type 316L stainless steel

Journal Article · Sun Oct 31 23:00:00 EST 1993 · Corrosion (Houston); (United States)

DOI:https://doi.org/10.5006/1.3316014· OSTI ID:5529601

Sridhar, N; Cragnolino, G A ^[1]

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1. Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses

Repassivation potential (E[sub rp]) was investigated for use as a parameter in the long-term prediction of pitting resistance of two Fe-Ni-Cr-Mo alloys that are candidate materials for high-level nuclear waste containers. This potential was found to be independent of the extent of prior pit growth for alloy 825 (UNS N08825) and type 316 L (UNS S31603) stainless steel (SS). Repassivation potential decreased by an increase in backward scan rate after pits were grown under potentiostatic conditions. This was related to the effect of potential on repassivation time. The corrosion potential (E[sup corr]) in simulated pit-crevice solutions increased with a decrease in pH and was independent of chloride (CL[sup [minus]]) concentration even to the point of depassivation. The depassivation pH (pH[sub D]) was independent of Cl[sup [minus]] concentration and increased slightly with an increase in temperature. The relationship between repassivation potential and E[sub corr] in simulated pit solutions was discussed. It was hypothesized that the repassivation potential for shallow pits was related to the time-dependent alteration of solution composition inside the pits and that the repassivation potential for deep pits was related to E[sub corr] of the depassivated metal inside the pit modified by the ohmic potential drop in the pit.

• OSTI ID: 5529601
• Journal Information: Corrosion (Houston); (United States), Journal Name: Corrosion (Houston); (United States) Vol. 49:11; ISSN 0010-9312; ISSN CORRAK
• Country of Publication: United States
• Language: English

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ALLOY-NI43FE30CR22MO3
ALLOYS
ALUMINIUM ADDITIONS
ALUMINIUM ALLOYS
AUSTENITIC STEELS
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
CHROMIUM ALLOYS
CHROMIUM-NICKEL STEELS
CHROMIUM-NICKEL-MOLYBDENUM STEELS
CONTAINERS
COPPER ALLOYS
CORROSION
CORROSION RESISTANCE
CORROSION RESISTANT ALLOYS
CREVICE CORROSION
HALIDES
HALOGEN COMPOUNDS
HEAT RES
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HIGH ALLOY STEELS
HIGH-LEVEL RADIOACTIVE WASTES
INCOLOY 825
INCOLOY ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
MANAGEMENT
MATERIALS
MOLYBDENUM ALLOYS
NICKEL ALLOY
NICKEL ALLOYS
NICKEL BASE ALLOYS
PASSIVATION
PH VALUE
PITTING CORROSION
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTE MANAGEMENT
RADIOACTIVE WASTES
STAINLESS STEEL-316L
STAINLESS STEELS
STEEL-CR17NI12MO3-L
STEELS
UNDERGROUND DISPOSAL
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES