SVET study of the corrosion protection of electrodeposited Zn and Zn‐Co‐Fe alloy coated steels

Abstract

The scanning vibrating electrode technique (SVET) was applied to study the corrosion resistance of partially coated (Zn and various Zn-Co-Fe alloys) and partially exposed steel samples in 10 mM NaCl solution. The sacrificial properties and the protection range decreases with increase in Co content in the alloy. For high Co content in the alloy, the coating becomes more noble to steel and loses its sacrificial protection. The barrier resistance of the coatings increases with the increase in Co content in the alloy coating. ZnCo-Fe alloys with high Co content (i.e., 32 wt% Co and 1 wt% Fe) showed excellent barrier properties due to passivation after dezincification protecting the underlying steel. An intermediate region of compositions can be distinguished in which the coatings provide a good combination of sacrificial and barrier resistance properties and also a reasonable protection range.

A virtual instrument for quantitative assessment of pitting corrosion

“…A fast research of the literature indicates that in recent investigations, the SVET was applied to determine the extent of corrosion protection imparted by metallic coating on steel. Oltra et al (2007), Desphane (2010), andLodhi et al (2008) used the SVET to study the protection of several coated alloys and found that they are corrosion resistant. These works demonstrated the usefulness of the SVET technique in corrosion studies for the selection of suitable materials for industrial plants, marine infrastructure and oil and gas installations, frequently affected by localized corrosion.…”

Heterogeneous electrochemical characteristics of biofilm/metal interface and local electrochemical techniques used for this purpose

“…This measurement is in proximity of the metal surface and the distance between the probe and metal surface is generally in about 100 mm range. This technique has been extensively used for localized corrosion research [29][30][31].…”