Microvisualization of corrosion

Localized corrosion continues to be a major cause of degradation failure in a wide variety of technological applications. The propagation stage of failure is no longer a fundamentally difficult job to characterize for pits and stress corrosion cracks, for example. It is the initiation stage that remains difficult to characterize, arising in part because of the difficulty in being able to predict where and when localized attack will occur. Recent developments in scanned probe techniques have created renewed interest in this problem. The present paper will describe some of the recent advances in optical, electrochemical and photoelectrochemical techniques that are directed at providing local information on precursor sites and vulnerable areas on metal and semiconductor surfaces.