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XRD characterization of new type of pyrochlore powders for TBC applications

Grzegorz J. Moskal 

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


Zirconium oxide, modified with yttrium oxide (YSZ) is a main material of a ceramic layer in TBC systems. Although, the TBC layers, which are based on ceramics type YSZ, have been used for 30 years, their life is a basic problem, because it limits wider application of them.  Considering very limited possibilities to increase operation temperature of gas turbines, what results from achieving similar operation parameters of turbines to a melting point of superalloys, one can state that development is necessary, from the one hand on  high temperature creep resisting materials, on a base of high-melting metals,  and on the other hand materials, provided for a new type of thermal barriers, which are used to high temperature creep resisting alloys on a base of nickel and high-melting metals.  Zirconates modified with elements of rare-earths type RE2Zr2O7 of pyrochlore structure - these materials demonstrate considerably low thermal conduction than the YSZ and high structural stability up-to temperature 1,500°C. Here, zirconates La, Gd, Nd, Sm are the most promising. Diffraction analyses of the powders with pyrochlore structure on the basis of Gd, La, Sm and Nd zirconates were performed in this article. Phase composition was determined in the initial state and after annealing at temperatures within the range 1100-1500°C. In the case of the powder on the basis of Gd, significant changes of phase composition were found. Phase composition analysis of powders after spraying with the APS method was also performed. The above analyses were performed on the basis of the previous differential thermal analysis (DTA) of powders, which made it possible to determine range of temperatures which phase transformations occur at.

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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Presentation: Poster at E-MRS Fall Meeting 2009, Symposium G, by Grzegorz J. Moskal
See On-line Journal of E-MRS Fall Meeting 2009

Submitted: 2009-04-17 14:05
Revised:   2009-08-19 13:21