Article ID Journal Published Year Pages File Type
190599 Electrochimica Acta 2011 8 Pages PDF
Abstract

The mechanism of corrosion of oxygen-free copper has been studied in stagnant aqueous sulfide solutions using corrosion potential and electrochemical impedance spectroscopy (EIS) measurements. Film structure and composition were examined on surfaces and on cross-sections prepared by focused ion beam (FIB) milling using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Experiments were conducted in anaerobic 5 × 10−5 mol dm−3 Na2S + 0.1 mol dm−3 NaCl solutions for exposure periods up to 4000 h (∼167 days) to mimic (at least partially) the conditions that could develop on a copper nuclear fuel waste container in a deep geologic repository. The corrosion film formed was a single cellular Cu2S layer with a non-uniform thickness. The film thickness increased approximately linearly with immersion time, which implied that the sulfide film formed on the Cu surface is non-protective under these conditions up to this exposure time. The film growth process was controlled by HS− diffusion partially in the aqueous solution in the pores in the cellular sulfide film and partially in the bulk of the aqueous solution.

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Physical Sciences and Engineering Chemical Engineering Chemical Engineering (General)
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