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Seawater corrosion of 70Cu‐30Ni alloy of incomplete recrystallization of intermittent and full immersion
Author(s) -
Zhu X.,
Lei T.
Publication year - 2001
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/1521-4176(200105)52:5<368::aid-maco368>3.0.co;2-4
Subject(s) - alloy , intergranular corrosion , metallurgy , corrosion , recrystallization (geology) , cathodic protection , seawater , materials science , chemistry , electrochemistry , electrode , paleontology , oceanography , biology , geology
The corrosion of 70Cu‐30Ni alloy of incomplete recrystallization was investigated by electrochemical technique, intermittent and full immersion in natural seawater, SEM and AES. Exposed to seawater for a short time, 70Cu‐30Ni alloy formed uniform and compact corrosion product films, which were rich in nickel, oxygen and seawater species for intermittent immersion; while the alloy fully immersed displayed loose and thick films, which were of denickelification and intergranular corrosion occurred to the underlying substrate. It was found that some regular crystals situated at the intersection of boundaries or the outer layer of the film and the crystals are ascribed to the reduction of cuprous ions to compensate the deficiency of oxygen for the cathodic process. Intergranular corrosion was observed in the underlying substrate for intermittent immersion after a long‐term exposure. Intermittent immersion can, to some degree, slow down the corrosion but not prevent the alloy of incomplete recrystallization from intergranular corrosion. Consequently, the corrosion mechanism of 70Cu‐30Ni alloy is proposed to be determined by its microstructure, independent of exposure conditions.