Abstract The corrosion behavior of two commercial, nickel-based Inconel alloys, 625 (UNS N06625) and 718 (UNS N07718), has been evaluated after exposure to supercritical water (SCW) at 500°C and 600°C for periods of up to 1,026 h. The 500°C tests were performed in deaerated and 2 ppm dissolved oxygen SCW, while the 600°C tests were performed only in deaerated SCW. Evaluation of corrosion has been performed using weight-change measurements, scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD), Auger electron spectroscopy (AES), and a surface profilometer. Surface oxidation and pitting were the principal corrosion mechanisms for both alloys at 500°C; however, intergranular corrosion was also observed in the Alloy 625 sample exposed to deaerated oxygen SCW at 600°C for prolonged durations. Oxidation was more dominant compared to pitting for the samples exposed to higher oxygen content or higher temperature SCW. The oxide thickness was lower for the higher ch...
[1]
Z. Jiao,et al.
Corrosion of Austenitic Alloys in Supercritical Water
,
2006
.
[2]
T. Nishida,et al.
Corrosion Behavior of Nickel-Based Alloys and Type 316 Stainless Steel in Slightly Oxidizing or Reducing Supercritical Water
,
2006
.
[3]
George E. Totten,et al.
Steel Heat Treatment Handbook
,
2005
.
[4]
M. Anderson,et al.
Corrosion Behavior of Candidate Alloys for Supercritical Water Reactors
,
2004
.
[5]
D. Agarwal,et al.
Nickel and Nickel Alloys
,
2004
.
[6]
I. Wright,et al.
An Assessment of the High Temperature Oxidation Behavior of Fe-Cr Steels in Water Vapor and Steam
,
2002
.
[7]
Michael Schütze,et al.
Protective oxide scales and their breakdown
,
1997
.