Abstract No.:	4910
Title:	Synthesis and processing of gadolinum zirconate powder(Gd2Zr2O7)
Authors:	Marco Antonio Rivera-Gil* / Centro de Investigación y de Estudios Avanzados del Instituto Politecnico National, Mexico Cynthia Yanel Guijosa-García / Centro de Investigación y de Estudios Avanzados del IPN, Mexico Alma Gabriela Mora-Garcia/ Centro de Investigación y de Estudios Avanzados del IPN, Mexico Luis Gerardo Trapaga-Martinez/ Centro de Investigación y de Estudios Avanzados del IPN, Mexico Juan Muñoz-Saldaña/ Centro de Investigación y de Estudios Avanzados del IPN, Mexico
Abstract:	Gadolinium zirconate or GZO, Gd2Zr2O7 is actively being studied as candidate to replace YSZ ceramics for thermal barrier coating applications due to its phase stability at temperatures up to 1500 °C. GZO in a pyrochlore phase exhibits a low thermal expansion coefficient (11.6×10-6 C-1), a low thermal conductivity (1.6 W/mK), and a high density (7.0 g/cm3). These properties promote TBC sintering resistance, and also enhance its resistance to CMAS attack in harsh environments. However, under certain conditions, GZO exhibits a disordered fluorite-like structure. This structure is characterized by a higher thermal conductivity in comparison to the pyroclore-like structure. Clearly, this raise in conductivity negatively affects coating thermal insulation. This contribution reports on a synthesis route designed to obtain the pyroclore-like structure through solid-state reaction of mixed-oxides assisted by high-energy ball milling. The synthesis route is established from the analysis of the variation of time and temperature of the calcination process. Analysis of the structure is carried out by the Rietveld analysis of X-ray diffraction patterns and Raman spectroscopy. Thermal properties are determined from dilatometric curves, differential scanning calorimetry and thermogravimetric analyses. Once GZO synthesis route has been stablished, morphology conditioning is carried out to obtain spheroids by spray drying. Morphology properties are determined by scanning electron microscopy.

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