Corrosion behavior of chromium oxide based ceramics in supercritical water (SCW) environments

The stability of chromium oxide (Cr2O3) ceramics with various amounts of yttrium oxide (Y2O3) or yttrium oxide-stabilized zirconium oxide (YSZ – 8 mol.% Y2O3) added was evaluated in static and flowing supercritical water (SCW) environments. It was found that the corrosion behavior of Cr2O3-based ceramics was affected by their morphologies as well as SCW test variables. The results of loop tests showed that Cr2O3-based ceramics were stable at 650 °C in flowing SCW with low to moderate oxygen concentration (8 ppb to 8 ppm). However, these ceramics suffered obvious degradation when exposed to SCW with higher oxygen concentrations (4 vol.% hydrogen peroxide).

► Corrosion behavior of Cr2O3 ceramics in various SCW environments was investigated.
► The corrosion of Cr2O3 was affected by ceramic morphologies and testing variables.
► Grain boundaries of Cr2O3 are susceptible for occurring of cracks and disintegration.
► Adding proper amounts of Yttria or YSZ can enhance the stability of Cr2O3 ceramics.