Applications of microelectrodes in impedance spectroscopy

Using a simple method for manufacturing of micro-tips, numerous microelectrodes with reasonably small electroactive area were produced by insulating the micro-tips into glass capillaries. Microelectrode characterisation was carried out with steady state diffusion limited current measurements in acidic FeCl3 solution. The microelectrodes were used for different purposes, the simplest of which was measuring the impedance in the region of a small conductive area placed in an insulating surrounding. Other measurements were carried out by generating impedance profiles in different electrolytes, as a microelectrode approached a conversion-coated metal surface, in order to gain information about the properties of the coating.