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Oxidation of stoichiometric poly- and single-crystalline MoSi2 at 773K

Authors :
Zhang, Fang
Zhang, Lanting
Shan, Aidang
Wu, Jiansheng
Source :
Intermetallics. Apr2006, Vol. 14 Issue 4, p406-411. 6p.
Publication Year :
2006

Abstract

Abstract: Pest oxidation and oxidation kinetics of MoSi2 at 773K were investigated and compared using as-cast, spark plasma sintered poly-crystalline MoSi2 and MoSi2 single crystal. Specimens (either poly- or single-crystalline) containing cracks are liable to pest disintegration after a certain period of exposure. High temperature in situ observation shows that new cracks tend to nucleate at the pre-existing cracks'' tip but not at grain boundary or porosity. The MoSi2 single crystal shows a much lower weight gain compared to the dense poly-crystal during a 300h exposure. The oxidation kinetics changes from a linear law for the poly-crystalline specimen to a parabolic-like law for the single crystal. A protective compact oxide scale is formed on the MoSi2 single crystal. However, the oxide scale formed on the poly-crystalline specimen is porous and full of cracks. This difference is discussed in the light of different diffusion rates in the bulk matrix and at the grain boundary. [Copyright &y& Elsevier]

Details

Language :
English
ISSN :
09669795
Volume :
14
Issue :
4
Database :
Academic Search Index
Journal :
Intermetallics
Publication Type :
Academic Journal
Accession number :
19126782
Full Text :
https://doi.org/10.1016/j.intermet.2005.08.001