Thin layers of iron corrosion products electrochemically deposited on inert substrates: synthesis and behaviour

The deterioration of iron-based materials due to corrosion is a well-known problem. A variety of corrosion products can be formed depending on the species present in the medium (soil, water, etc.). Understanding the transformation pathways during the evolution of a corrosion layer is a hard challenge since it is difficult to clearly identify the contributions of each corrosion product. That is why the development of electrodes with only one iron corrosion product deposited as thin layers on inert substrates (gold, silver) presents many advantages to carry out electrochemical studies. In this way, the present paper reports successful electrochemical synthesis of thin layers deposited on inert substrates (gold, silver) of commonly occurring iron corrosion products as siderite, green rusts incorporating carbonate or sulphate anions, magnetite and goethite. The films are characterised by usual ex-situ techniques: FTIR, SEM, and XRD. The study of the electrochemical behaviour of thin films of green rust deposited on silver illustrates the potential application of such electrodes. (C) 2004 Elsevier Ltd. All rights reserved.