Mechanistic investigation of hydrogen-enhanced anodic dissolution of X-70 pipe steel and its implication on near-neutral pH SCC of pipelines

被引:148
作者
Li, M. C.
Cheng, Y. F. [1 ]
机构
[1] Univ Calgary, Dept Mech & Mfg Engn, Calgary, AB T2N 1N4, Canada
[2] Shanghai Univ, Inst Mat, Shanghai 200072, Peoples R China
基金
加拿大自然科学与工程研究理事会;
关键词
hydrogen; anodic dissolution; near-neutral pH stress corrosion cracking; pipelines;
D O I
10.1016/j.electacta.2007.07.015
中图分类号
O646 [电化学、电解、磁化学];
学科分类号
081704 ;
摘要
The effects of hydrogen-charging on anodic dissolution of pipe steel under near-neutral pH condition were studied by electrochemical techniques. Hydrogen-charging enhances the anodic dissolution rate of the steel. The hydrogen-enhanced dissolution increases with increasing charging current density. The hydrogen effect is attributed to the alteration of chemical potential and exchange current density of steel. Hydrogen-charging affects the corrosion process of the steel. In particular, at a high charging current density, a layer of corrosion product forms on the electrode surface to change corrosion potential and interfacial double-charge layer capacitance as well as charge-transfer resistance. The hydrogen effect factor for enhanced anodic dissolution of steel at an anodic potential of -0.4 V (SCE) is 1.53 only. Hydrogen-enhanced anodic dissolution of steel by itself may not be the major factor contributing to the high rate of crack growth in pipe steel in near-neutral pH electrolyte. A further investigation of the synergistic effect of hydrogen and stress on dissolution at the crack-tip is essential to determine the mechanism of near-neutral pH stress corrosion cracking of pipelines. (C) 2007 Elsevier Ltd. All rights reserved.
引用
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页码:8111 / 8117
页数:7
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