Corrosion of galvanised steel under an electrolytic drop

Emilie Dubuisson (1) , Philippe Lavie (1, 2) , Francis Dalard (1) , Jean-Pierre Caire (1) , Sabine Szunerits (1)

1 LEPMI - Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces
2 PSA Peugeot-Citroen

Described here for the first time is an investigation of the local corrosion behaviour of galvanized steel using an electrolytic droplet comprising chloride and sulphate ions. The maximal height of the electrolytic layer and the diameter varied between 500–1100 μm with a total diameter between 1.47–3.35 mm, respectively. These measurements were possible by using microelectrodes as reference and counter electrodes, which could be inserted into the electrolyte droplet thus forming an electrochemical microcell. Polarization curves as well as electrochemical impedance spectroscopy plots were recorded under the electrolyte droplet configuration allowing the determination of the polarisation resistance R_p and the proportionality constant k of the Stern and Geary equation. The influence of temperature, chloride concentration, pH and the thickness of the electrolytic layer on the corrosion rate of galvanised steel were studied.

Mots clés: Atmospheric corrosion; Galvanised steel; Electrochemical impedance spectroscopy; Thin electrolyte layer; Microelectrodes

Domaines: Matériaux

Emilie Dubuisson, Philippe Lavie, Francis Dalard, Jean-Pierre Caire, Sabine Szunerits. Corrosion of galvanised steel under an electrolytic drop. Corrosion Science, 2007, 49 (2), pp. 910-919. ⟨10.1016/j.corsci.2006.05.027⟩. ⟨hal-00333717⟩