Alloy 600 coupons were exposed to air-saturated water at pressures of 15.65 MPa and 25.4 MPa and temperatures ranging from 21 C to 543 C in an optically accessible flow cell. In situ Raman spectra were collected at a number of temperatures, as the metal coupons were heated and then cooled. The coupons also were characterized ex situ with Raman spectroscopy and scanning electron microscopy. A NiFe2O4 phase was identified on both coupon surfaces while α-CrOOH and Cr2O3 phases were identified on only one. The hydrothermal corrosion of one alloy 600 coupon and a 304L stainless steel coupon were compared. It was observed that the extent of formation and/or degree of crystallinity of both the NiFe2O4 and α-CrOOH phases were lower on the alloy 600 coupon than on the 304L stainless steel coupon.
Citation: Journal of Nuclear Materials
Pub Type: Journals
alloy 600, aqueous corrosion, corrosion product release, hydrothermal oxidation, in situ Raman spectroscopy, NiFe2O4