In order to investigate the influence of the confinement on the corrosion behaviour of metallic materials, an innovative thin layer electrochemical cell was developed. The cell includes a device which allows a continuous gas supply within the electrolyte film covering the metallic specimen under study. A procedure based on high frequency impedance measurements is also proposed to control and precisely adjust the setting of the electrolyte film geometry. The experimental set-up was validated by performing measurements of the stationary limiting cathodic current on a steel disk immersed in a K2SO4 aerated solution for various electrolyte layer thicknesses. The results obtained demonstrate the reliability of the experimental method. (c) 2007 Elsevier Ltd. All rights reserved.