Behaviour of the metal-oxide-fluid-interface

Surface phenomena at electrodes play a major role in streamer inception. Metal-electrodes are always covered with oxide-layers, changing the electrical and chemical properties of the metal-surface. Semiconducting metal-oxide structures arise at the surface. For experiments, oxide covered metal electrodes are dipped into the liquid. A double layer-structure with an inner and outer Helmholtz plane and a subsequent diffuse layer are established at the metal-oxide-liquid interface. Charge transport from and into the liquid is controlled by the electrical properties of the metal-oxide-double-layer structure. Streamer inception modifies the structure of these surface layers and leads to restructuring at the interface and in the liquid bulk. A model for the behaviour of the metal-oxide-liquid interface using percolation theory concepts is presented as well as experimental investigations of surface structures of electrodes used in experiments. Oxide layers found on brass electrodes as well as the impact of streamer inception on electrode surfaces is presented.