Microstructural Evaluation of Stressed IN625 and NiCrAlY Coated IN625 Tested in High and Low Density SCW

Abstract

The goal of this study is to determine the corrosion resistance of NiCrAlY coatings for use in future supercritical water reactors (SCWR). The NiCrAlY coating was applied to IN 625 and was tested against bare IN 625, under stress, in high density supercritical water (HDSCW) and low density supercritical water (LDSCW). The IN 625 samples experienced intergranular corrosion in HDSCW but not in LDSCW; whereas the NiCrAlY sample experienced oxidation, with no other forms of corrosion observed. Thus, it is likely that NiCrAlY coatings are much more corrosion resistant than IN 625 in HDSCW.