The Corrosion Behaviors of the Cerium Conversion Coatings on the Zinc Coating in a 5 % NaCl Solution

Abstract

The present paper investigated the impact of cerium on the corrosion resistance of zinc coating in a 5 % NaCl solution. Electrochemistry was used to measure the electrochemical parameters to compare the corrosion resistance of the zinc coating with that of the cerium conversion coating on the galvanized layer. SEM/EDS and XRD were adopted to analyze the appearance and phases of corrosion products of the cerium conversion coating and to probe the impact of cerium on the corrosion behavior of zinc coating in the Cl– media. The results showed that the cerium conversion coating formed on the zinc coating increased the zinc’s corrosion resistance effectively, conversion coating with lower cerium content protected the substrate poorly, resulting in easy erosion of the zinc coating in the Cl– media. The corrosion products mainly consist of complexes, such as Zn(OH)xCly and Ce(OH)xCly.

Keywords

• cerium
• zinc coating
• sodium chloride
• corrosion resistance
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