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Corrosion of tinplate T54S and T61 in humid atmosphere and saline solution
Author(s) -
Zhu Xiaolong,
Sandenbergh R. F.
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(200109)52:9<685::aid-maco685>3.0.co;2-h
Subject(s) - chemistry , corrosion , metallurgy , layer (electronics) , coating , cathodic protection , anode , materials science , organic chemistry , electrode
The initial corrosion mechanism and corrosion behaviors of tinplate T54S and T61 were investigated by chemical stripping layer by layer, humid atmosphere exposure, SEM and potentiodynamic method in saline solutions with the addition of a small amount of components simulating foods and tomato sauce. The results show that T54S initially corroded in the form of pitting at the bottom of grease marks on the surface while T61 displayed the initial corrosion along the steel base on the interface of the tin coating and steel, and both were driven by galvanic corrosion between tin coating as a cathode and base steel as an anode. In the solution of 3.5% NaCl, the free corrosion potential from the outer layer to steel base shifted to negative with an addition of 100 ppm HNO 3 but the potential order reversed as HNO 2 replaced HNO 3 at equivalent content. With an addition of 100 ppm NaHS, a high cathodic peak for either the middle or the inner layers was ascribed to the involvement of the reduction of extra hydrogen, i.e. HS − . T54S displayed a wider anodic passive zone and lower passive current density than T61, which resulted from the effect of the alloy layer.