Automated Methods of Corrosion Measurements: Imaging corrosion by scanning probe microscopy

Scanning probe microscopy (SPM) techniques rely on computer recordings of interactions between the tip of a minute probe and the surface of the small specimen as a function of position; the measurements are used to depict an image of the atomic-scale surface topography on the computer screen. Mechanical control, recording, and data processing must therefore be automated to a high level of precision and reliability. These general techniques and the apparatus involved have been described extensively. The automated methods of such high-resolution microscopy coordinated with computerized electrochemical measurements as well as elemental analysis look very promising for elucidating corrosion reaction mechanisms. The study of initial surface reactions at the atomic or submicron level is becoming an important field of research in the understanding of corrosion processes. At present, mainly two scanning microscope techniques are employed investigating corrosion processes, and usually in situ: in situ scanning tunneling microscopy (in situ STM) and in situ scanning force microscopy (in situ AFM). It is these techniques to which attention is directed here.