The oxidation behavior of model binary and ternary alloys in supercritical water (SCW) was examined. Binary alloys contained 9 or 14 at% Cr. Ternary alloys had 1.5 at% of one of the following elements: Si, Al, V, Mn or Ti. Samples with different surface finishes were exposed to SCW for up to 500 hours. The oxidized samples were characterized using gravimetry, SEM, HRTEM and EDX. After exposure, a uniform double layer oxide with outwardly grown magnetite inwardly grown Fe-Cr mixed oxide was detected on most of samples. Alloys contains 14 at% Cr or/and 1.5 at% Si showed a mixed oxidation mode, where relatively thick double layer oxides coexisted with thin protective oxide. The coverage with the thin oxide increased with the increase of deformation and/or Cr and/or Si content. A 20 nm thick Si-enriched layer was detected at such alloy/oxide interfaces. This behavior is very similar to “third element effect”.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/33288 |
| Date | 20 November 2012 |
| Creators | Li, Weimi |
| Contributors | Newman, Roger C. |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
Page generated in 0.002 seconds