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Microstructure and thermal diffusivity of La2Zr2O7 powder for TBC aplications

Grzegorz J. Moskal ,  Aleksandra Rozmysłowska 

Silesian University of Technology, Department of Materials Science, Krasińskiego 8, Katowice 40-019, Poland

Abstract

From the beginning of construction of contemporary aircraft engines, in order to improve life and use properties of applied materials to a maximum, the systems of protective coatings are used. Contemporary constructions of engines, and development in technologies as well, lead to evolution of new protective coatings and to improvement of ones, which were sooner applied. The thermal barrier coatings TBC (thermal barrier coating) enable to lower temperature (at approx. 170°C) of operating elements, exposed to creeping, in a hot section of gas turbine (e. g. combustion chambers and directing and rotating blades) to a range, which enables to operate for a long time in conditions of high temperature influence and prolongs operation of them even three or four times, simultaneously reducing consumption of fuel. The results of microstructure tests performed on the powders intended for thermally sprayed TBCs with APS method were presented in this article. The tests of phase and chemical composition of the analysed powder were performed. The carbon, sulphur and gas nitrogen contents were, among other things, determined during those tests. The x-ray powder diffraction phase identification in as received material was determined. The tested material showed the presence of La2Zr2O7 compound as the predominant one and ZrO2 oxides. The surface morphology analysis of the powder was carried out and its internal structure was characterized. The tested material shows porous structure typical for agglomerated powders. The second testing area applied to analysis of the powder thermal properties. The thermal diffusivity of the compressed samples with density similar to the solid material was determined with the laser flash (LF) method. The measurement results show that requirements for the materials used for new generation TBCs are met.  

This work was supported by the Polish Ministry of Education and Science under the research project No PBZ-MNiSW-01/I/2007

 

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Related papers

Presentation: Poster at E-MRS Fall Meeting 2009, Symposium G, by Aleksandra Rozmysłowska
See On-line Journal of E-MRS Fall Meeting 2009

Submitted: 2009-04-17 14:26
Revised:   2009-08-19 13:18