| Scratch test and scanning electrochemical microscopy (SECM) were applied to study the effects of thiosulfate on stress corrosion cracking (SCC) of Alloy 800 in simulated crevice solutions. The results showed that thiosulfate cathodically shifted the pitting potential of Alloy 800 significantly and the pitting morphology on the electrode surface was also different from that formed in the absence of thiosulfate. The synergistic effect between thiosulfate and stress was also observed, which was mainly promoting enhanced anodic dissolution at active sites.;In the lead-induced stress corrosion crackings (PbSCC) work, the crack propagation rate (CPR) of Alloy 800 double cantilever specimen were estimated in neutral crevice chemistries solutions at 300 degree Celsius. The PbSCC of alloy 800 at high temperature were investigated by comparing the CPR rate of Pb-contaminated and Pb-free conditions. A repetitive behavior of crack advance was observed from the measurement. This observation is consistent with the film rupture model. |
