Modeling of the factors contributing to the initiation and propagation of the crevice corrosion of alloy 625

Journal Article · Tue Nov 01 04:00:00 EST 1994 · Journal of the Electrochemical Society; (United States)

DOI:https://doi.org/10.1149/1.2059273· OSTI ID:6977507

Lillard, R S; Scully, J R ^[1]

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1. Univ. of Virginia, Charlottesville, VA (United States)

Crevice corrosion of alloy 625 in both chlorinated and nonchlorinated American Society for Testing and Materials (ASTM) artificial ocean water was modeled. Secondary current and potential distributions as a function of crevice depth were obtained from the model using the following crevice initiation criteria (1) E < E[sub Flade], (2) i[sub diss] = 10 [mu]A/cm[sup 2], and (3) pH [approximately]0.46 at the site where the first two criteria are met. For alloy 625 in nonchlorinated ASTM artificial ocean water these criteria are satisfied at depths which are near the mouth of the crevice. These depths are incompatible with the mass-transport conditions governing the development of the critical crevice solution. In the chlorinated system the model predicts that initiation occurs at greater depths which are compatible with all the critical crevice solution. In the chlorinated system the model predicts that initiation occurs at greater depths which are compatible with all the criteria including mass-transport considerations. The model results are in agreement with remote crevice assembly experiments which show that crevice corrosion occurs more readily in the chlorinated ASTM artificial ocean water. Propagation of the crevice corrosion of alloy 625 is shown to be ohmically controlled by the resistance between the mouth of the crevice and the initiation site.

• OSTI ID: 6977507
• Journal Information: Journal of the Electrochemical Society; (United States), Journal Name: Journal of the Electrochemical Society; (United States) Vol. 141:11; ISSN JESOAN; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360105* -- Metals &amp; Alloys-- Corrosion &amp; Erosion
ALLOY-NI61CR22MO9NB4FE3
ALLOYS
ALUMINIUM ADDITIONS
ALUMINIUM ALLOYS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHLORINATION
CHROMIUM ALLOYS
COMPUTERIZED SIMULATION
CORROSION
CORROSION RESISTANT ALLOYS
CORROSIVE EFFECTS
CREVICE CORROSION
HALOGENATION
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HYDROGEN COMPOUNDS
INCONEL 625
INCONEL ALLOYS
IRON ALLOYS
KINETICS
MASS TRANSFER
MATERIALS
MATHEMATICAL MODELS
MOLYBDENUM ALLOYS
NICKEL ALLOYS
NICKEL BASE ALLOYS
NIOBIUM AL
OXYGEN COMPOUNDS
REACTION KINETICS
SEAWATER
SIMULATION
VOLTAGE DROP
WATER