Hostname: page-component-68945f75b7-l9cl4 Total loading time: 0 Render date: 2024-08-05T16:41:44.729Z Has data issue: false hasContentIssue false

Formation of discontinuous Al2O3 layers during high-temperature oxidation of RuAl alloys

Published online by Cambridge University Press:  01 January 2006

P.J. Bellina*
Affiliation:
Max-Planck-Institute für Metallforschung, 70569 Stuttgart, Germany
A. Catanoiu
Affiliation:
Max-Planck-Institute für Metallforschung, 70569 Stuttgart, Germany
F.M. Morales
Affiliation:
Max-Planck-Institute für Metallforschung, 70569 Stuttgart, Germany
M. Rühle
Affiliation:
Max-Planck-Institute für Metallforschung, 70569 Stuttgart, Germany
*
a)Address all correspondence to this author. e-mail: paul@mf.mpg.de
Get access

Abstract

Bond coats play a crucial role in the performance of thermal barrier coating systems. Ru alloys have been identified as promising candidates; therefore, systematic studies were performed on the oxidation behavior of bulk RuAl (50–50 at.%). Isothermal oxidation and thermogravimetric analyses were performed at 1100 °C for different times ranging from 0.1 h to 500 h. Microstructural characterization was performed by scanning and transmission electron microscopy. The results showed the formation of an α–Al2O3 layer on top of a δ–Ru layer. Interface instability between these layers and evaporation of gaseous Ru-oxides lead to the formation of large elongated cavities and alternating α–Al2O3/δ–Ru layers.

Type
Articles
Copyright
Copyright © Materials Research Society 2006

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1.Levi, C.G.: Emerging materials and processes for thermal barrier systems. Curr. Opin. Solid St. Mater. Sci. 8, 77 (2004).Google Scholar
2.Clarke, D.R. and Levi, C.G.: Materials design for the next generation thermal barrier coatings. Ann. Rev. Mater. Res. 33, 383 (2003).CrossRefGoogle Scholar
3.Leyens, C., Pint, B.A. and Wright, I.G.: Effect of composition on the oxidation and hot corrosion resistance of NiAl doped with precious metals. Surf. Coat. Technol. 133–134, 15 (2000).Google Scholar
4.Brickey, M.R. and Lee, J.L.: Structural and chemical analyses of a thermally grown oxide scale in thermal-barrier coatings containing a platinum-nickel aluminide bondcoat. Oxid. Met. 54, 237 (2000).Google Scholar
5.Angenete, J., Stiller, K. and Langer, V.: Oxidation of simple and Pt-modified aluminide diffusion coatings on Ni-base superalloys—I. Oxide scale microstructure. Oxid. Met. 60, 47 (2003).Google Scholar
6.Mennicke, C., Clarke, D.R. and Rühle, M.: Stress relaxation in thermally grown alumina scales on heating and cooling FeCrAl and FeCrAlY alloys. Oxid. Met. 55, 551 (2001).Google Scholar
7.Tolpygo, V.K. and Clarke, D.R.: Spalling failure of alpha-alumina films grown by oxidation. II. Decohesion nucleation and growth. Mater. Sci. Eng. A 278, 151 (2000).Google Scholar
8.Lee, W.E. and Lagerlof, K.P.D.: Structural and electronic-diffraction data for sapphire (alpha-Al2O3). J. Elec. Micr. Technol. 2, 247 (1985).CrossRefGoogle Scholar
9.Levi, C.G., Sommer, E., Terry, S.G., Catanoiu, A. and Rühle, M.: Alumina grown during deposition of thermal-barrier coatings on NiCrAlY. J. Am. Ceram. Soc. 86, 676 (2003).Google Scholar
10.Leyens, C., Schulz, U., Pint, B.A. and Wright, L.G.: Influence of electron beam physical vapor deposited thermal barrier coating microstructure on thermal barrier coating system performance under cyclic oxidation conditions. Surf. Coat. Technol. 120–121, 68 (1999).Google Scholar
11.Haynes, J.A., Ferber, M.K., Porter, W.D. and Rigney, E.D.: Characterization of alumina scales formed during isothermal and cyclic oxidation of plasma-sprayed TBC systems at 1150 °C. Oxid. Met. 52, 31 (1999).Google Scholar
12.Prins, S.N., Cornish, L.A., Stumpf, W.E. and Sundman, B.: Thermodynamic assessment of the Al–Ru system. Calphad 27, 79 (2003).Google Scholar
13.Fleischer, R.L., Field, R.D. and Briant, C.L.: Mechanical-properties of high temperature alloys of AlRu. Metall. Trans. A 22, 403 (1991).CrossRefGoogle Scholar
14.Tryon, B., Pollock, T.M., Gigliotti, M.F.X. and Hemker, K.: Thermal expansion behavior of ruthenium aluminides. Scripta Mater. 50, 845 (2004).Google Scholar
15.Lu, D.C. and Pollock, T.M.: Low temperature deformation and dislocation substructure of ruthenium aluminide polycrystals. Acta Mater. 47, 1035 (1999).Google Scholar
16.Soldera, F., Ilić, N., Brännström, S., Barrientos, I., Gobram, H. and Mücklich, F.: Formation of Al2O3 scales on single-phase RuAl produced by reactive sintering. Oxid. Met. 59, 529 (2003).Google Scholar
17.Massalski, T.B.: Binary Alloy Phase Diagrams, 2nd ed. (ASM International, Materials Park, OH, 1990).Google Scholar
18.Chou, T.C.: The formation of discontinuous Al2O3 layers during high temperature oxidation of IrAl alloys. J. Mater. Res. 5, 378 (1990).CrossRefGoogle Scholar
19.Jehn, H.: High temperature behaviour of platinum group metals in oxidizing atmospheres. J. Less-Comm. Met. 100, 321 (1984).Google Scholar
20.Tolpygo, V.K. and Clarke, D.R.: Microstructural study of the theta-alpha transformation in alumina scales formed on nickel-aluminides. Mater. High Temp. 17, 59 (2000).Google Scholar
21.Birks, N. and Meier, G.H.: Introduction to High Temperature Oxidation of Metals, 1st ed. (Edward Arnold, London, U.K., 1983).Google Scholar
22.Wolff, I.M. and Sauthoff, G.: Role of an intergranular phase in RuAl with substitutional additions. Acta Mater. 45, 2949 (1997).Google Scholar
23.Fleischer, R.L. and McKee, D.W.: Mechanical and oxidation properties of AlRu-based high temperature alloys. Metall. Trans. A 24, 759 (1993).Google Scholar
24.Strecker, A. and Salzberger, U.: Specimen preparation for transmission electron microscopy: Reliable method for cross-section and brittle materials. Mayer J. Prakt Metallogr. 30, 482 (1993).CrossRefGoogle Scholar
25.Barin, I.: Thermochemical Data of Pure Substances (VCH, Weinheim, Germany, 1989).Google Scholar
26.Miller, R.A.: Oxidation-based model for thermal barrier coating life. J. Am. Ceram. Soc. 67, 517 (1984).Google Scholar
27.Williams, D.B. and Carter, C.B.: Transmission Electron Microscopy: A Textbook for Material Science (Plenum Press, New York, 1996).Google Scholar
28.Ahn, C.C.: Transmission Electron Energy Loss Spectroscopy In Material Science & the EELS Atlas (VCH, Weinheim, Germany, 2004).Google Scholar
29.Reimer, L., Zepke, U., Mösch, J., Ross-Messemer, M., Probst, W. and Weimer, E.: EELSpectroscopy (Carl Zeiss, Electron Optics Division, Order No. G34-640, Oberkochen, Germany, 1983).Google Scholar
30.Hindam, H. and Whittle, D.P.: Microstructure, adhesion and growth-kinetics of protective scales on metals and alloys. Oxid. Met. 18, 245 (1982).Google Scholar
31.Tolpygo, V.K., Clarke, D.R. and Murphy, K.S.: Oxidation-induced failure of EB-PVD thermal-barrier coatings. Surf. Coat. Technol. 146, 124 (2001).Google Scholar
32.Pint, B.A., Wright, I.G., Lee, W.Y., Zhang, Y., Prüssner, K. and Alexander, K.B.: Substrate and bond coat compositions: Factors affecting alumina scale adhesion. Mater. Sci. Eng. A 245, 201 (1998).Google Scholar
33.Pint, B.A.: Experimental observations in support of the dynamic-segregation theory to explain the reactive-element effect. Oxid. Met. 45, 1 (1996).Google Scholar
34.Schumann, E., Yang, J.C., Rühle, M. and Graham, M.J.: High resolution SIMS and analytical TEM evaluation of alumina scales on beta-NiAl containing Zr or Y. Oxid. Met. 46, 37 (1996).Google Scholar
35.Kingery, W.D., Bowen, H.K. and Uhlmann, D.R.: Introduction to Ceramics (J. Wiley & Sons, New York, 1976).Google Scholar
36.Pint, B.A., Martin, J.R. and Hobbs, L.W.: The oxidation mechanism of theta-Al2O3 scales. Solid State Ionics 78, 99 (1995).CrossRefGoogle Scholar
37.Yang, J.C., Schumann, E., Levin, I. and Rühle, M.: Transient oxidation of NiAl. Acta Mater. 46, 2195 (1998).Google Scholar
38.Prescott, R. and Graham, M.J.: The formation of aluminum-oxide scales on high-temperature alloys. Oxid. Met. 38, 233 (1992).Google Scholar
39.Clarke, D.R.: The lateral growth strain accompanying the formation of thermally grown oxide. Acta Mater. 51, 1393 (2003).Google Scholar
40.Meier, G.H. and Pettit, F.S.: The oxidation behaviour of intermetallic compounds. Mater. Sci. Eng. A 153, 548 (1992).Google Scholar
41.Rebollo, N.R., He, M.Y., Levi, C.G. and Evans, A.G.: Mechanism governing the distortion of alumina-forming alloys upon cyclic oxidation. Zeit für Metall. 3, 171 (2003).Google Scholar