کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1470401 990324 2009 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Characterization of the corrosion products of electrodeposited Zn, Zn–Co and Zn–Mn alloys coatings
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Characterization of the corrosion products of electrodeposited Zn, Zn–Co and Zn–Mn alloys coatings
چکیده انگلیسی

The morphology, composition, phase composition and corrosion products of coatings of pure Zn (obtained from two types of electrolytic bath: an acidic bath (Znacid) and a cyanide-free alkaline bath (Znalkaline)) and of Zn–Mn and Zn–Co alloys on steel substrates were studied. To achieve this, diverse techniques were used, including polarization curves, atomic force microscopy (AFM), scanning electron microscopy (SEM), glow discharge spectroscopy (GDS), X-ray diffraction (XRD), and the salt spray test. In the salt spray test, the exposure time required for the coatings to exhibit red corrosion (associated with the oxidation of steel) decreased in the following order: Zn–Mn(432h) > Zn–Co(429h) > Znalkaline(298h) > Znacid(216h). The shorter exposure times required for corrosion of the pure Zn coatings are related to the coating composition and the crystallographic structure. Analysis of the corrosion products disclosed that Zn5(OH)8Cl2·H2O was a corrosion product of all of the coatings tested. However, the formation of oxides of manganese (MnO, Mn0.98O2, Mn5O8) in the Zn–Mn coating, and the formation of the hydroxide Zn2Co3(OH)10·2H2O in the Zn–Co coating, produced more compact and stable passive layers, with lower dissolution rates.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Corrosion Science - Volume 51, Issue 11, November 2009, Pages 2703–2715
نویسندگان
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