P-10 Solid state synthesis and characterization of La2Ce2O7 powder as a candidate material for thermal barrier coatings

Topic: Advances in solid state materials synthesis, new solids and compounds

I. Parchovianská^*, M. Parchovianský, A. Nowicka, A. Prnová, A. Pakseresht

FunGlass, A. Dubček University of Trenčín, Študentská 2, 911 50 Trenčín, Slovakia

 ^* E-mail: ivana.parchovianska@tnuni.sk

Keywords: solid-state reaction, lanthanum cerium oxide, TBC

Lanthanum cerium oxide, La₂Ce₂O₇ (LC), has attracted increasing interest as a promising material for thermal barrier coatings (TBC) because of its high phase stability and potential capability to be operated above 1250 °C [1]. Moreover, LC exhibits lower thermal conductivity and higher thermal expansion coefficient than the conventional yttria partially-stabilized zirconia [2]. In this work, LC powder was synthesized by solid-state reaction method using commercial La₂O₃ and CeO₂ binary oxides. The synthesized LC powder was heat treated at the temperatures of up to 1400 °C for 6 hours and investigated as a material for TBC applications: powder morphology, chemical composition, crystal structure and thermal stability were systematically studied. Scanning electron microscopy (SEM) of the prepared powder revealed agglomerated structure consisting of finely and uniformly distributed grains with size up to 10 µm. The fluorite structure of the LC powder after annealing at 1400 °C was confirmed by X-Ray diffraction analysis (XRD) showing intensive peaks corresponding to the pure La₂Ce₂O₇ phase. No additional peaks belonging to La₂O₃ were observed, confirming the formation of solid solution of La₂O₃ in CeO₂. The thermal behavior of the LC powder was analyzed by differential scanning calorimetry (DSC) in the temperature range of 25 °C – 1350 °C. Neither endothermic nor exothermic peaks were observed from the DSC curve at the tested temperature range, indicating high phase stability of the LC powder and its suitability for TBC applications.

References

[1]   Dehkharghani, A. M. F., Rahimipour, M. R., Zakeri, M. (2020). Crystal Structure and Lattice Parameter Investigation of La³⁺ Substituted CeO₂ in La_xCe_1-xO_2-X/2 Synthesized by Solid-State Method. Advanced Ceramics Progress, 6(1), 43–48.

[2]    Zhang, H., Sun, J., Duo, S., Zhou, X., Yuan, J., Dong, S., Yang, X., Zeng, J., Jiang, J., Deng, L., Cao, X. (2019). Thermal and mechanical properties of Ta₂O₅ doped La₂Ce₂O₇ thermal barrier coatings prepared by atmospheric plasma spraying. Journal of the European Ceramic Society, 39(7), 2379–2388.

Acknowledgments

This work was supported by the VEGA grant no. 1/0171/21. This work is a part of dissemination activities of project FunGlass. This project has received funding from the European Union´s Horizon 2020 research and innovation programme under grant agreement No 739566. This paper was also created in the frame of the project Centre for Functional and Surface Functionalized Glass (CEGLASS), ITMS code is 313011R453, operational program Research and innovation, co-funded from European Regional Development Fund.