Chemistry on the low field anodes and cathodes of air corona gaps

Surface effects of electrical coronas have been studied on the low field electrodes of point-to-plane air gaps with discharges burning in negative and positive glow regimes, i.e., mainly producing chemical effects without significant sputtering or thermal effects. Most of these chemical effects are due to oxidation and reduction processes taking place in aqueous microdroplets formed by the discharge where oxides, nitrates, and cyanides, are mainly found. Generally oxidation prevails providing very high oxidation states, but using preoxidized gold samples as cathodes enabled the separate observation of reduction phenomena.