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Two forms of high resolution X-ray tomographic experiments (i.e. synchrotron based X-ray microtomography and desktop microfocus computed X-ray tomography) are demonstrated in the present paper to illustrate the wide application of these techniques for qualitative and quantitative studies of localised corrosion and environmentally assisted cracking. Specifically, synchrotron based X-ray tomography was used to investigate the localised corrosion morphology within aluminium specimens when exposed in situ to a chloride environment while microfocus computed X-ray tomography was used to investigate the morphology and quantify the transition from localised corrosion to stress corrosion cracking in steel specimens exposed ex situ to a simulated corrosive condensate environment.

Monitoring the early stages of environmentally assisted cracking under light water reactor conditions is a challenging task but is getting more important in the context of a proactive aging management approach. From a rather large number of available corrosion monitoring techniques, only very few appear suitable for the detection of crack initiation and application in high temperature water environments (y300uC). The most promising of these techniques (electrochemical noise, acoustic emission, electrochemical impedance spectroscopy, alternating/direct current potential drop and high temperature imaging autoclave) are summarised and assessed in the current paper.