Imaging localised corrosion of NiTi shape memory alloys by means of alternating current scanning electrochemical microscopy (AC-SECM)

This communication aims at the investigation of NiTi shape memory alloys (nitinol) with respect to visualisation of localised corrosion phenomena. Alternating current scanning electrochemical microscopy (AC-SECM) has been used as an approach to detect inhomogeneities in the passive oxide layer of nitinol with high spatial resolution. The appearance of microscopic corroding spots on the surface can be imaged due to the decreasing solution resistance between the sample and the used scanning tip. These spots bear a high reactivity towards the onset of pitting corrosion.