This paper deals with oxidation phenomena observed on surfaces
submitted to the action of corona-activated ambient air. The study was
mainly performed with gold and silicon surfaces chosen for their great
material stability. During the discharge, the surfaces become covered with
micronic water droplets which look like granules. They grow in number with
the duration of the sample exposure to the discharge, their mean size
depending on the material, and they resist the vacuum of the electron
scanning microscope, but not its electron beam, especially when it is
focused on them. From a chemical point of view, the surfaces are now
oxidized in a way comparable with what can be obtained in liquid
electrochemical solutions and, apart from the electrode material oxides or
hydroxides observed, one can also find nitrogen oxides, but in clearly
smaller quantities.