THE CORROSION BEHAVIOR OF NICKEL-BASED ALLOYS 182 AND 52 AND 316 STAINLESS STEEL IN CYCLIC HYDROGENATED AND OXYGENATED WATER CHEMISTRY IN HIGH TEMPERATURE AQUEOUS ENVIRONMENT

摘要

In the present work, Ni based Alloys 52 and 182 and solution-annealed 316 stainless steel (SS) were exposed to a cyclic hydrogenated and oxygenated water chemistry in the high temperature aqueous environment. The corresponding corrosion behavior was examined by in situ technologies of contact electric resistance (CER) and electrochemical impedance spectroscopy (EIS) and ex situ surface analysis methods including scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. It was found that the film resistance in DO periods is much higher than that in DH periods for all the materials. The difference of electrochemical corrosion potential (E_(corr)) in DO and DH periods is also huge (about 0.7 V) for all the materials. The evolution of the oxide film (morphology and composition etc.) with cyclic changing environment seems to be varied with material. For 316 SS and Alloy 52 the oxide film seems not changeable while for Alloy 182 some cyclic changes can be found with cyclic changing environment.