Microstructural Evolution of Thermal Barrier Coatings during Isothermal Oxidation


Article Preview

This paper analyses the degradation of a ceramic top coating 70%ZrO2 – 30%CaO deposited onto a stainless steel AISI 304 by thermal spray, using Ni-6%Al-5%Mo as overlay coating. These thermal barrier coatings were heat treated for 48, 120 and 288 h at 800 °C to evaluate the degradation of these materials by isothermal oxidation. The microstructure evolution during oxidation was analysed by environmental scanning electron microscopy, transmission electron microscopy and X ray microanalysis. A thermally grown oxide layer was observed between the overlay coating and the ceramic top coating after oxidation. This layer was formed by a mixed Al, Ni and Mo oxides.



Edited by:

Marc Anglada et al.




A. Salazar et al., "Microstructural Evolution of Thermal Barrier Coatings during Isothermal Oxidation", Key Engineering Materials, Vol. 333, pp. 269-272, 2007

Online since:

March 2007




[1] R. A. Miller, J. Thermal Spray Technol., Vol. 6, Nº 1, 35-42 (1997).

[2] S. Bose, J. DeMasi-Marcin, J. Thermal Spray Technol., Vol. 6, Nº 1, 99-104 (1997).

[3] W. E. Lee, W. M. Rainforth, in: Ceramic microstructures, edited by Chapman and Hall, London (1994).

[4] V. Sergo, D. R. Clarke, J. Am. Ceram. Soc., Vol. 81, 3237-3242 (1998).

[5] J. Gómez-García, P. Poza, V. Utrilla, Bol. Soc. Esp. Ceram. V., Vol. 45, Nº 2, 70-74 (2006).

[6] F. Nagata, T. Shimotsu, H. Kakibayashi, in: Approach to Atomic Structure (High Resolution Transmission Electron Microscopy), Supplemental Issue of Hitachi Instrument News, March (1989).

[7] M. J. Stiger, M. N. Yanar, M. G. Topping, F. S. Pettit, G. H. Meier, Zeitschrift fur Metallkunde, Vol. 90, Nº 12, 1069-1078 (1999).

[8] P. Poza, P. S. Grant, Surf. Coat. Tech., accepted. 200 nm200 nm (b) NiO CaZrO3 2 µm2 µm NiAl2O4 γ/γ' (a) Fig. 5. BF images of the TGO associated to the oxidized TBC at 800ºC for 48 h: (a) NiAl2O4 spinel grain formed close to the bond coat. SADP with B=<102> is included, (b) NiO grains formed close to the ceramic coating. NBDP with B=<01 1> is included.