کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10269763 459892 2005 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Passivity and passivity breakdown of a zinc electrode in aerated neutral sodium nitrate solutions
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Passivity and passivity breakdown of a zinc electrode in aerated neutral sodium nitrate solutions
چکیده انگلیسی
The passivation and pitting corrosion behaviour of a zinc electrode in aerated neutral sodium nitrate solutions was investigated by cyclic voltammetry and chronopotentiometry techniques, complemented by ex situ scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) examinations of the electrode surface. Measurements were conducted under different experimental conditions. The potentiodynamic anodic polarization curves do not exhibit active dissolution region due to spontaneous passivation. The passivity is due to the presence of thin film of ZnO on the anode surface. The passive region is followed by pitting corrosion as a result of breakdown of the passive film. SEM images confirmed the existence of pits on the electrode surface. The breakdown potential decreases with an increase in NO3− concentration and temperature, but increases with increasing potential scan rate. Addition of SO42− ions to the nitrate solution accelerates pitting corrosion, while addition of WO42− and MoO42− ions inhibits pitting corrosion. The chronopotentiometry measurements show that the incubation time for pitting initiation decreases with increasing NO3− concentration, temperature and applied anodic current density. Addition of SO42− ions decreases the rate of passive film growth and the incubation time, while the reverse changes produced by addition of either WO42− or MoO42− ions.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Electrochimica Acta - Volume 50, Issue 6, 30 January 2005, Pages 1265-1274
نویسندگان
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