INVESTIGATION OF ELECTROCHEMICAL PROCESSES BY AC QUARTZ ELECTROGRAVIMETRY

A general approach is proposed to investigate an electrochemical react ion mechanism by simultaneous electrochemical and electrogravimetric i mpedance measurements. Our approach shows that a.c. electrogravimetry may provide some useful information on the chemical nature of the spec ies involved, in addition to the information obtained by using electro chemical impedance analysis alone. Application of a.c. electrogravimet ry to passive iron in sulfuric acid solution showed that the major par t of the charge transferred during a transient potential change, withi n the Fe passive potential range, contributes to iron corrosion rather than to the film growth. In the case of electropolymerization of poly pyrrol in the presence of sodium dodecylsulfate, it was shown that the electropolymerization is followed by an oxidation process, which occu rred in pores crossing the polymer.