CORROSION PERFORMANCE OF NICRALY COATED IN 625 AND 304 SS IN SUPERCRITICAL WATER

摘要

In this study, NiCrAlY plasma spray coated IN 625 and 304 SS samples were tested in SCW for940 hours. The weight and surface microstructure changes were evaluated after testing. Visualobservation showed that NiCrALY coated surface was more resistant to corrosion than bare 304SS and IN 625. SEM and EDS analyses of the samples also found that NiCrAlY coating sufferedvery little corrosion and heat treatment of NiCrAlY coating prior to SCW testing providedfurther corrosion protection due to the formation of alumina on the surface. The qualitativeweight change measurements also indicated that heat treatment led to the least weight gain onNiCrAlY coated IN 625 samples. NiCrAlY coated 304 SS was the only sample that hadsubstantial weight loss and this weight loss occurred on the bare 304 SS surrounding NiCrAlYcoating.