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Bells Corners, Canada

Dong Z.,University of Alberta | Liu Z.,University of Alberta | Li M.,University of Alberta | Luo J.-L.,University of Alberta | And 3 more authors.
Journal of Nuclear Materials | Year: 2015

Ferritic-Martensitic (F/M) steels are important candidate alloys to be used in the next generation (Generation-IV) SCWRs. In this work, two F/M steels with the same Cr content of around 12 wt.% and varied Si content from 0.6 wt.% to 2.2 wt.% were evaluated in supercritical water (SCW) at 500°C and 25 MPa for up to 1000 h. The effect of ultrasonic shot peening on the oxidation behavior of these F/M steels have been investigated. The results showed that the oxidation was affected by the Si content as well as the surface modification. The F/M steel with low Si concentration exhibited higher corrosion resistance than that of the alloy with high Si content. Shot peening, which could modify the microstructure at the surface, showed significantly beneficial effect to improving the oxidation resistance. A thin, uniform oxide layer formed on the peened sample could be attributed to the enhanced diffusion of Cr induced by the surface modification. © 2014 Elsevier B.V. All rights reserved.

Wang R.,University of Alberta | Dong Z.,University of Alberta | Luo J.,University of Alberta | Chen W.,University of Alberta | And 2 more authors.
Corrosion Science | Year: 2014

Various amounts of MgO, CeO2 and SiO2 additives were added into Cr2O3 ceramics for the purpose of investigating their effects on the stability of Cr2O3 in high-temperature supercritical water (SCW), which is being considered as the coolant used for the next generation Supercritical Water-cooled Reactor (SCWR). These ceramics were exposed to a Chalk River Laboratories SCW environment at 650°C and 25MPa for up to 600h. Gravimetric measurement, scanning electron microscope (SEM) analysis, X-ray diffraction (XRD) and mass spectrum analysis were conducted to characterize the corrosion behavior of these Cr2O3-based ceramics in high-temperature SCW. © 2014 Elsevier Ltd.

Wang R.,University of Alberta | Dong Z.,University of Alberta | Zheng W.,MTL NRCan | Guzonas D.,Chalk River Laboratories | And 2 more authors.
Canadian Nuclear Society - 33rd Annual Conference of the Canadian Nuclear Society and 36th CNS/CNA Student Conference 2012: Building on Our Past... Building for the Future | Year: 2012

In this investigation, Cr2O3 ceramics with different grain sizes were prepared and tested in supercritical water (SCW) environment at 650°C /25 MPa for 200 hours. The results show that the stability of Cr 2O3 in SCW was affected by its grain size. In addition, various amounts of CeO2 were added to Cr2O3 to examine the effect of CeO2 on the corrosion behaviour of the Cr 2O3 based ceramic under SCW condition. These Cr 2O3-based ceramics were exposed to an SCW environment at 650°C/ 25 MPa for up to 600 hours. The results showed that adding a proper amount (≤ 5 wt. %) of CeO2 increased the corrosion resistance of Cr2O3-based ceramics in SCW.

Dong Z.,University of Alberta | Chen W.,University of Alberta | Zheng W.,MTL NRCan | Guzonas D.,Chalk River Laboratories
Journal of Nuclear Materials | Year: 2012

The corrosion behavior of highly porous chromium carbide (Cr 3C 2) prepared by a reactive sintering process was characterized at temperatures ranging from 375 °C to 625 °C in a supercritical water environment with a pressure of 25-30 MPa. The test results show that porous chromium carbide is stable in SCW environments at temperatures under 425 °C, above which disintegration occurred. The porous carbide was also tested under hydrothermal conditions of pressures between 12 MPa and 50 MPa at constant temperatures of 400 °C and 415 °C, respectively. The pressure showed little effect on the stability of chromium carbide in the tests at those temperatures. The mechanism of disintegration of chromium carbide in SCW environments is discussed. © 2011 Elsevier B.V. All rights reserved.

Dong Z.,University of Alberta | Chen W.,University of Alberta | Zheng W.,MTL NRCan | Guzonas D.,Chalk River Laboratories
Corrosion Science | Year: 2012

The stability of chromium oxide (Cr 2O 3) ceramics with various amounts of yttrium oxide (Y 2O 3) or yttrium oxide-stabilized zirconium oxide (YSZ - 8mol.% Y 2O 3) added was evaluated in static and flowing supercritical water (SCW) environments. It was found that the corrosion behavior of Cr 2O 3-based ceramics was affected by their morphologies as well as SCW test variables. The results of loop tests showed that Cr 2O 3-based ceramics were stable at 650°C in flowing SCW with low to moderate oxygen concentration (8ppb to 8ppm). However, these ceramics suffered obvious degradation when exposed to SCW with higher oxygen concentrations (4vol.% hydrogen peroxide). © 2012 Elsevier Ltd.

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