It has been demonstrated that intermetallic thin films usually show different oxidation rates compared to those of bulk materials. Within the intermetallic phases, RuAl thin films have not been thoroughly investigated. Thereby, new studies of these systems are needed. Single-phase RuAl was found to be a promising candidate for protective coating material in applications that demand oxidation resistance. An important advantage of this system over other B2-aluminides arises on the coefficient of thermal expansion (CTE), which is substantially lower than that of FeAl, CoAl and NiAl, and it is closer to that of the α-Al2O3, thus increasing the adherence to the alumina protective layer, by decreasing the CTE mismatch between each other. In the present work, the isothermal oxidation behaviour of single-phase RuAl thin films deposited onto austenitic stainless steel substrates was studied in ambient air at 750 and 900 °C for short times (up to 60 min.). Scanning transmission electron microscopy and X-ray diffraction were performed for the subsequent analysis of the oxide scale. A protective α-Al2O3 scale was formed and in comparison to other aluminides, no evidence of the formation of transient alumina was found even at temperatures as low as 750 °C, being this fact an advantage over the most studied aluminides. The presence of particles at the metal/oxide interface is an indication that the oxide growth is dominated by the outward diffusion of Al cations. Moreover, this growth is described by a parabolic law showing an oxidation rate k x = 1.3 × 10−13 cm2/s at 900 °C and the corresponding oxidation activation energy is 116.4 ± 7.5 kJ/mol. The sufficient Al flux to the oxidation front, in combination with the narrow inter-nuclei spacing lead to a faster formation of continuous α-Al2O3 compared to bulk RuAl, as a consequence of the high density of grain boundaries.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Price includes VAT (USA)
Tax calculation will be finalised during checkout.
F. Mücklich, N. Ilić, and K. Woll, Intermetallics 16, 593 (2008).
F. Soldera, N. Ilic, S. Brännström, I. Barrientos, H. Gobran, and F. Mücklich, Oxidation of Metals 59, 529 (2003).
B. Tryon, T. M. Pollock, M. F. X. Gigliotti, and K. Hemker, Scripta Materialia 50, 9 (2003).
F. Soldera, N. Ilić, N. Manent Conesa, I. Barrientos, and F. Mücklich, Intermetallics 13, 101 (2005).
N. Ilić, F. Soldera, and F. Mücklich, Intermetallics 13, 444 (2005).
P. J. Bellina, A. Catanoiu, F. M. Morales, and M. Rühle, Journal of Material Research 2, 276 (2006).
F. Cao, T. K. Nandy, D. Stobbe, and T. M. Pollock, Intermetallics 15, 34 (2007).
F. Cao and T. M. Pollock, Acta Materialia 55, 2715 (2007).
N. Zotov, K. Woll, and F. Mücklich, Intermetallics 18, 1507 (2010).
K. Woll, R. Chinnam, and F. Mücklich. MRS Proceedings (2008), p. 1128.
D. Zhong, G. G. Mustoe, J. Moore, and J. Disam, Surface and Coatings Technology 146–147, 312 (2001).
A. Y. Yi and A. Jain, Journal of the American Ceramic Society 88, 579 (2005).
M. A. Guitar, K. Woll, E. Ramos-Moore, and F. Mücklich, Thin Solid Films 527, 1 (2013).
A. Huntz, Journal of Materials Science Letters 8, 1981 (1999).
H. Hindam and D. P. Whittle, Oxidation of Metals 18, 245 (1982).
G. H. Meier, Materials and Corrosion 47, 595 (1996).
R. Prescott and M. J. Graham, Oxidation of Metals 38, 73 (1992).
H. J. Grabke, Materials Science Forum 251–254, 149 (1997).
C. Choux, A. J. Kulińska, and S. Chevalier. Intermetallics 16, 1 (2008).
R. Prescott and M. J. Graham, Oxidation of Metals 38, 233 (1992).
H. J. Grabke, Intermetallics 7, 1153 (1999).
D. Barber, Philosophical Magazine 10, 75 (1964).
F. Mücklich and N. Ilić, Intermetallics 13, 5 (2005).
ASM Handbook, Vol. 3. Alloy Phase Diagrams (1992).
J. Doychak and M. Rühle, Oxidation of Metals 31, 431 (1989).
G. Cao, L. Geng, Z. Zheng, and M. Naka, Intermetallics 15, 1672 (2007).
F. Wang, Oxidation of Metals 48, 215 (1997).
J. G. Goedjen and D. A. Shores, Oxidation of Metals 37, 125 (1992).
V. Trindade, U. Krupp, and B. Hanjari, Materials Research 8, 371 (2005).
H. Lou, F. Wang, S. Zhu, B. Xia, and L. Zhang. Surface and Coatings Technology 63, 105 (1994).
Z. Liu, W. E. I. Gao, K. L. Dahm, and F. Wang, Acta Materialia 46, 1691 (1998).
S. Choi, H. Cho, and D. Lee, Oxidation of Metals 46, 109 (1996).
D. R. Clarke, Acta Materialia 51, 1393 (2003).
M. Schütze, Protective Oxide Scales and Their Breakdown. ISBN 0-471-95904 9 (1991).
G. C. Rybicki and J. L. Smialek, Oxidation of Metals 31, 275 (1989).
A. Kumar, M. Nasrallah, and D. Douglass, Oxidation of Metals 8, 227 (1974).
K. Reddy, J. Smialek, and A. Cooper, Oxidation of Metals 17, 429 (1982).
S. Choi, H. Cho, Y. Kim, D. Lee. Oxidation of Metals 46, 51 (1996).
J. Smialek, J. Doychak, and D. Gaydosh, Oxidation of Metals 34, 259 (1990).
P. Hou, Journal of the American Ceramic Society 86, 660 (2003).
C. Xu, W. Gao, and H. Gong, Intermetallics 8, 769 (2000).
R. Klumpes, C. Maree, E. Schramm, and J. Wit, Materials and Corrosion 47, 619 (1996).
H. Grabke, M. Brumm, and B. Wagemann, Materials and Corrosion 47, 675 (1996).
D. Zhong, J. J. Moore, E. Sutter, and B. Mishra, Surface and Coatings Technology 200, 1236 (2005).
C. H. Xu, W. Gao, and Y. D. He, Scripta Materialia 42, 975 (2000).
K. N. Lee and W. L. Worrell, Oxidation of Metals 32, 357 (1989).
H. X. Dong, Y. Jiang, Y. H. He, J. Zou, N. P. Xu, B. Y. Huang, et al., Materials Chemistry and Physics 122, 417 (2010).
This study was funded within a research project MU 959/24-1 of the Deutsche Forschungsgemeinschaft (DFG). The authors would like to thank the EFRE Funds of the European Commission for support of activities within the AME-Lab project. The authors are also grateful to Prof. Seidel, from the Department of Mechatronics, Saarland University, for the use of the magnetron sputtering device; and to Dr. F. Soldera, Dr. C. Gachot, Dipl.-Ing. N. Souza, Dipl.-Ing. C. Pauly and Dipl.-Ing. Sebastián Suarez for the usefully comments and discussion. A.Guitar is grateful to the German Academic Exchange Service (DAAD) for the financial support.
About this article
Cite this article
Guitar, M.A., Mücklich, F. Isothermal Oxidation Behaviour of Nanocrystalline RuAl Intermetallic Thin Films. Oxid Met 80, 423–436 (2013). https://doi.org/10.1007/s11085-013-9409-8
- Thin films