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Investigation of the kinetics of intergranular corrosion in iron
Author(s) -
Pyun Sull,
Choe JaiHoon
Publication year - 1985
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.198500606
Subject(s) - passivation , intergranular corrosion , grain boundary , dissolution , chemistry , kinetics , corrosion , metallurgy , analytical chemistry (journal) , materials science , crystallography , microstructure , layer (electronics) , chromatography , physics , organic chemistry , quantum mechanics
Corrosion experiments on iron were performed in boiling 55% Ca(NO 3 ) 2 solution (115°C) to elucidate the kinetics of intergranular corrosion ( IGC) of iron. After the time‐current curve was recorded for the specimen exposed for 30 h to the IGC test solution at 1000 mV SHE (passive region), the specimen was examined for IGC by optical microscopy. The current‐time curves and optical micrographic observations suggested that the kinetics of IGC of iron is based upon the periodic passivation‐grain boundary dissolution process. IGC occurs mainly between the first passivation and the second repassivation periods. Average current density during this period can be regarded as a measure of the susceptibility to IGC . The excess dissolved nitrogen or nitride at the grain boundaries does not lead to a definite IGC .