Abstract
Aluminide coatings are of interest for fusion energy applications both for compatibility with liquid Pb-Li and to form an alumina layer that acts as a tritium permeation barrier. Oxide dispersion strengthened (ODS) ferritic steels are a structural material candidate for commercial reactor concepts expected to operate above 600 °C. Aluminizing was conducted in a laboratory scale chemical vapor deposition reactor using accepted conditions for coating Fe- and Ni-base alloys. However, the measured mass gains on the current batch of ODS Fe-14Cr were extremely low compared to other conventional and ODS alloys. After aluminizing at two different Al activities at 900 °C and at 1100 °C, characterization showed that the ODS Fe-14Cr specimens formed a dense, primarily AlN layer that prevented Al uptake. This alloy batch contained a higher (> 5000. ppma) N content than the other alloys coated and this is the most likely reason for the inhibited aluminization. Other factors such as the high O content, small (~. 140. nm) grain size and Y-Ti oxide nano-clusters in ODS Fe-14Cr also could have contributed to the observed behavior. Examples of typical aluminide coatings formed on conventional and ODS Fe- and Ni-base alloys are shown for comparison.
Original language | English |
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Pages (from-to) | 5036-5041 |
Number of pages | 6 |
Journal | Surface and Coatings Technology |
Volume | 206 |
Issue number | 24 |
DOIs | |
State | Published - Aug 15 2012 |
Funding
The authors would like to thank J. A. Haynes, K. M. Cooley, G. W. Garner, T. Lowe, H. Longmire, K. Unocic and H. Meyer for assistance with the experimental work. D. Hoelzer provided the 14YWT material and ODM 401 was provided by the manufacturer, Dour Metal sro, Slovak Republic. J. A. Haynes and K. A. Unocic provided helpful comments on the manuscript. This research was sponsored by the Office of Fusion Energy Sciences, U. S. Department of Energy (DOE) .
Funders | Funder number |
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U. S. Department of Energy | |
U.S. Department of Energy | |
Fusion Energy Sciences |
Keywords
- Aluminide coatings
- Chemical vapor deposition
- Ferritic steels
- Fusion energy
- ODS alloys