Electrochemical noise analysis of PbSCC of Alloy 600 SG tube in caustic environments at high temperature

An electrochemical noise (EN) monitoring technique was applied to analyse an initiation and a propagation of Pb-assisted stress corrosion cracking (PbSCC) of Alloy 600 material in a simulated environment of steam generator (SG) sludge piles at high temperature. A typical electrochemical potential decrease concurrent with a current increase was observed during the EN measurements, indicating the occurrence of localized corrosion events. The EN data were analysed for the processes of a uniform corrosion, an initiation and a propagation of PbSCC using a stochastic theory and microscopy.