Chapter 57. An Investigation of the Microstructure in the Pest Oxide of a MoSi2- Based Composite
- Todd Jessen,
- Ersan Ustundag
Published Online: 28 MAR 2008
DOI: 10.1002/9780470294635.ch57
Copyright © 2000 The American Ceramic Society
Book Title
24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 21, Issue 4
Additional Information
How to Cite
Tang, J. E., Halvarsson, M., Kvist, A., Hansson, K., Svensson, J.-E. and Pompe, R. (2008) An Investigation of the Microstructure in the Pest Oxide of a MoSi2- Based Composite, in 24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 21, Issue 4 (eds T. Jessen and E. Ustundag), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294635.ch57
Publication History
- Published Online: 28 MAR 2008
- Published Print: 1 JAN 2000
Book Series:
ISBN Information
Print ISBN: 9780470375693
Online ISBN: 9780470294635
- Summary
- Chapter
- References
Keywords:
- microanalysis;
- pest oxide layer;
- molybdenum;
- catastrophic oxidation;
- thermo gravimetric analysis
Summary
The pesting of MoSi2 was investigated by performing detailed microanalysis on the pest oxide layer. The studied material was a MoSi2-Mo5i3-clay composite which had undergone pest-oxidation for 4000 hours at 450°C. Results from detailed SEM and TEM studies, including quantitative EDX analysis, on the various features in the pest oxide are presented. It was found that MoSi2, as well as the MosSi3, transforms immediately into an oxide mixture of MoO3 nanocrystals and amorphous SiO2 with significant loss in molybdenum upon oxidation. With time, part of the oxide mixture cluster into lamellar MoO3 aggregates. These aggregates disappear from the oxide after even longer times, leaving voids in the oxide structure. This allows even quicker depletion of MoO3 from the oxide, leaving dark grey regions containing mostly SO2.