Passivation Degradation of Alloy 800 in Boiling Solution Containing Thiosulphate

The effect of boiling bubbles on the passivation degradation of Alloy 800 in thiosulphate-containing aqueous electrolyte was experimentally investigated using corrosion potential, anodic polarization, combined with Secondary Ion Mass Spectrometry (SIMS) and X-ray Photoelectron Spectroscopy (XPS). The results showed that the boiling bubbles decreased the pitting potential by enhancing the mass transport. The specimen immersed in boiling electrolyte have a thicker anodic film and a greater amount of sulfur incorporation into the passive layer compared with the experiments at 99 °C. Moreover, a higher ratio of low valance sulfur species was detected on the specimen in boiling test electrolyte, indicating that the boiling bubbles reduced the corrosion resistance of Alloy 800.

Graphical abstractDownload high-res image (108KB)Download full-size image