Study of Corrosion Behavior of Copper Beneath a Droplet by Means of Wire Beam Electrode Technology

Abstract

The corrosion behavior of copper beneath a droplet of 0.6 mol/L NaCl solution was studied by means of wire beam electrode technique combined with electrochemical impedance spectroscopy (EIS). The results show that the distribution of galvanic current remains negative at the center and positive at the periphery of copper surface covered by the droplet at the initial stage. And the polarity reversed with the extension of time, i.e. the positive one at the center and the negative one at the periphery. To study more comprehensively, the EIS measurement was conducted at an interval of 2 h for two copper wires selected separately at the center and the periphery, and the change of the local impedances was found consistent with that of the current distributions. Meanwhile, the surface morphology of the electrode and the composition of the corrosion products were also examined by using scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). At the beginning, reddish brown oxide products formed much quickly and earlier at the periphery rather than at the center. Then, with the extension of time, the electrode surface was totally covered by corrosion products from the periphery to the center. But, the corrosion products film at the center 定稿日期:2013-11-15 基金项目:国家自然科学基金项目 (51131005和40906039)、山东省优秀中青年科学家奖励基金项目 (BS2012HZ021)及山东 省自然科学基金项目 (ZR2010DQ006)资助 作者简介:张彭辉,男,1989年生,硕士生,研究方向为金属腐蚀与防护 通讯作者:王燕华,E-mail:wyhazz@163.com DOI:10.11902/1005.4537.2013.197