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Comparison of corrosion mechanism of low‐alloy pipeline steel used for flexible pipes at vapor‐saturated CO 2 and CO 2 ‐saturated brine conditions
Author(s) -
Liu Z.G.,
Gao X.H.,
Du L.X.,
Li J.P.,
Yu C.,
Wang Y.X.,
Wang X.N.
Publication year - 2017
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/maco.201709604
Subject(s) - corrosion , brine , materials science , metallurgy , alloy , water vapor , microstructure , saturation (graph theory) , chemistry , mathematics , organic chemistry , combinatorics
Immersion experiment was carried out to illustrate the corrosion behavior of low‐alloy pipeline steel exposed to vapor‐saturated CO 2 and CO 2 ‐saturated brine conditions in terms of microstructure, corrosion kinetics, corrosion phases, macroscopic and microscopic surface morphologies. Experimental results indicate that the corrosion rate of vapor‐saturated CO 2 condition is greatly lower than that of CO 2 ‐saturated brine condition. The corrosion products of CO 2 ‐saturated brine condition are formed uniformly on coupons surface and the ones of vapor‐saturated CO 2 condition deposit in cluster. Vapor‐saturated CO 2 condition is beneficial for the formation of fine corrosion products compared with CO 2 ‐saturated brine condition. The corrosion mechanisms of vapor‐saturated CO 2 and CO 2 ‐saturated brine conditions are different, which contribute to the distinction in water chemistry. The schematic models of corrosion mechanisms of the two corrosion conditions are proposed based on experimental results.