期刊
CORROSION SCIENCE
卷 55, 期 -, 页码 107-115出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.corsci.2011.10.013
关键词
Steel; Polymer coatings; Modeling studies; Crevice corrosion; Cathodic protection
资金
- US Department of Transportation, Pipeline and Hazardous Materials Safety Administration [DTPH56-08-T-0003]
- Pipeline Research Council International
- CenterPoint Energy, New Orleans, Louisiana
A model developed in an earlier work was used in this work to investigate the effect of coating permeability on the evolution of solution chemistry, corrosion potential, and rate in a crevice formed between a steel surface and a coating disbonded from it. The crevice gap varies along distance from the mouth, and the coating is permeable to ions and/or oxygen (O-2). The earlier work focused specifically on modeling the effect of variable gap (on crevice corrosion) with the coating impermeable to either ions or O-2. In both works, the crevice chemistry was an aerated, diluted sodium chloride solution, which at the mouth was set to be different from that initially in the crevice. The results of this work show that a permeable coating behaves like a membrane, which, under a cathodic polarization at the crevice mouth, tends to raise the in-crevice sodium ion concentration and pH more rapidly relative to an impermeable coating. Later, as the sodium ion concentration and pH in the crevice become greater than at the mouth, the permeable coating tends to reverse the transport direction for ions. At a mouth potential of -0.900 V vs. saturated CulCuSO(4), the cathodic current is sufficient to suppress all O-2 penetrating the crevice both from the mouth and through the coating. The practical implication is that in the presence of sufficient cathodic polarization, a permeable coating, when disbonded, can still be capable of protecting the substrate steel from corrosion attack. (C) 2011 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据