EIS characterisation of the layer of corrosion products on various substrates in differing atmospheric environments

Abstract

The layer of corrosion products forming on zinc in atmospheric environments of varying aggressivity have been characterised and compared with previous results obtained for carbon steel. The characteristics of said layers have been linked to the nature of the products found. Likewise, we have found that EIS is a useful tool towards characterising the layers of corrosion products of carbon steel and zinc. The equivalent circuit which gives the best fit of impedance data for both metals is type R(C(R(C(R(CR))))), where the Nyquist diagrams are composed of two time constants. It is observed that the value of the capacitance of the corrosion product layer (C pc ) diminishes as the time of exposure increases, which is directly related with an increase in the thickness of the corrosion product layer. Also, it is observed that when the nature of the corrosion products doesn't vary with the time of exposure, the decrease of the charge transfer resistance is related with the increase in the thickness of the corrosion product layer.

Electrodeposited Zn–TiO2 nanocomposite coatings and their corrosion behavior

“…The decreases of the C d values in the case of the composite coatings could be attributed to a decrease of the active area directly in contact with the corrosive media as a consequence of the incorporation of TiO 2 in Zn deposit, or to an increase in the thickness of the corrosion products formed on the surface [27]. This tendency was found in accordance with other data reported in the literature [5] for Zn-TiO 2 composites.…”

Study of corrosion evolution of carbon steel exposed to an industrial atmosphere

“…(3) the influence of pollution factors on the corrosion behaviour of steel [6][7][8]; and/or (4) the protective properties of the corrosion products [9,10]. However, previous studies usually adopted long sampling intervals, which can result in possibly missing some information about long-term corrosion behaviour.…”

“…Taking into account that atmospheric corrosion is a complex interaction between steel and its surrounding environment, scholars have focused on the corrosion mechanism of steels exposed to a variety of environments. Research on the atmospheric corrosion of steels is mainly concentrated on one of the following four aspects: (1) the corrosion kinetics, and the composition and structure of corrosion products formed on the steel surface, for a corresponding corrosion mechanism [1–3]; (2) the effect of alloying on the corrosion behaviour of steel [4,5]; (3) the influence of pollution factors on the corrosion behaviour of steel [6–8]; and/or (4) the protective properties of the corrosion products [9,10]. However, previous studies usually adopted long sampling intervals, which can result in possibly missing some information about long-term corrosion behaviour.…”

Electrochemical and Raman analysis of the corrosion products formed over hot dip galvanised steel wires exposed in different environmental sites

“…EIS is also employed for investigating atmospheric corrosion behaviour of galvanised steel. However, the study is mainly done for a short term (0-2 year) atmospheric exposure [6,17,18], or under model atmospheric conditions in the laboratory [19][20][21][22], or under thin layers of electrolytes [23][24][25][26]. This work focuses on aged materials obtained under different atmospheres after typically 4.5 years.…”