Electrochemical impedance and conductivity measurements in a heterogeneous Fe powder particle—electrolyte system with or without electrochemical reaction

The participation of solid Fe powder particles in the transfer of charge through a heterogeneous system consisting of an electrolyte and conducting powder particles was studied by means of electrochemical impedance spectroscopy and conductivity measurements. Different behaviour was encountered in electroinactive Na2SO4 electrolyte without metal electrodeposition on the Fe particles and in NiSO4 electrolyte where Ni electrodeposition occurs on the Fe particle surfaces. From impedance diagrams and the proposed model the formation of aggregates and chains of Fe particles is deduced. The important role of electrochemical reaction proceeding at the particle surface in the charge transfer behaviour in stirred heterogeneous systems was also demonstrated.