Spatially resolved measurement of electrochemical activity and pH distributions in corrosion processes by scanning electrochemical microscopy using antimony microelectrode tips

Abstract

A new method for the spatially resolved measurement of pH during corrosion processes with the scanning electrochemical microscope (SECM) is presented. Antimony tips are employed because the dual-function characteristics of this material allow the combined amperometric/potentiometric operation of the SECM. The applicability of this technique is illustrated by considering the galvanic corrosion of a model zinc–iron pair immersed in 0.1 M NaCl aqueous solution. Spatially resolved images of pH and oxygen concentration above the metal specimens could be obtained in the same experiment.