Micro-electrochemical techniques for studies of localized processes on metal surfaces in the nanometer range

Micro- and nano-electrochemical techniques using microcapillaries as microcells are powerful methods to study local phenomenas on metal surfaces. Since most of the large-scale electrochemical techniques provide only average data integrating over a relatively large surface area (square millimeters–square centimeters) they are often inadequate for studying localized corrosion processes on passive metal surfaces. Due to the enhanced current resolution of micro- and nano-electrochemical methods down to picoampere and femtoampere local processes in the nanometer range can easily be studied. Results obtained from stainless steel are presented and discussed with respect to the corrosion resistance of these alloys. Furthermore, micro-electrochemical noise measurements also allow evaluation of the experimental data with respect to their statistical relevance. Based on the microcapillary technique new methods have been developed, such as the non-contact scanning capillary microscopy and the Micro-Tribocorrosion Electrochemistry (MTE).