Start Publications Synergistic effect of Zn electrodeposition and cerium ...
Attension

Synergistic effect of Zn electrodeposition and cerium conversion coating on the corrosion performance of low carbon steel

Year: 2022

Journal: Appl. Surf. Sci., Volume 602, NOV 15

Authors: Kozhukharov, S.; Girginov, Ch.; Tsanev, A.; Boshkova, N.

Organizations: Bulgarian National Scientific Fund [??-06-H37/16]; Bulgarian Ministry of Education and Science [D01-382/2020]

Keywords: Zn galvanic layers; Ce-conversion coatings; Barrier ability; EIS; PDS

The present research is based on the comparison of the results obtained from low carbon steel samples treated by different approaches for formation of coating primers. The treatments included electrodeposition of a galvanic Zn-layer, spontaneous deposition of a cerium conversion coating (CeCC), and combination of them. The obtained layers were exposed for 24 h to a 0.01 M NaCl model corrosive medium (MCM) and were then assessed by two electrochemical methods: Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic Scanning (PDS). The formed protective layers were examined using a variety of instrumental analytical techniques. The composition of the surfaces was determined by performing X-Ray Photoelectron Spectroscopy (XPS) and Energy Dispersion X-ray (EDX) analyses. Their topologies were observed by means of Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM), which also enabled to define the roughness of the films. In addition, their color characteristics and surface hydrophobicity were also evaluated. As main result, the synergism be-tween the cerium conversion coating and the galvanically deposited Zn underlayer was evinced by all the used analytical methods. Finally, a conceptual model on the mechanism of the formation of the combined double layer coating primer was proposed.