Microelectrochemical surface and product investigations during electrochemical machining (ECM) in NaNO3

A transition from predominant oxygen evolution to predominant iron dissolution was found in the range from 5 to 30 A/cm2. At current densities >35 A/cm2 the oxygen evolution is reduced to some percent of the total current. The Fe3+/Fe2+ formation ratio increases to 2, corresponding to a dissolution of Fe3O4.