[Zurück]

J.A. Diaz-Guillen, O. Dura, M.R. Diaz-Guillen, E. Bauer, M. Lopéz de la Torre, A.F. Fuentes:
"Thermophysical properties of Gd2Zr2O7 powders prepared by mechanical milling: Effect of homovalent Gd3+ substitution";
Journal of Alloys and Compounds, 649 (2015), S. 1145 - 1150.

This contribution analyzes the thermophysical properties of Gd1.6Ln0.4Zr2O7 (Ln ¼ La3þ,Nd3þ,Sm3þ,Dy3þ and Er3þ) ceramics synthesized at room temperature, by mechanically milling stoichiometric mixtures of high purity oxides. Regardless of chemical composition, powders milled for 27 h show XRD patterns similar to fluorite-type materials. Post-milling thermal treatments at 1500 􀀁C, facilitates the evolution to the ordered pyrochlore derivative for Gd2Zr2O7, and the La3þ-, Nd3þ-, and Sm3þ-containing materials. By contrast, samples containing the smaller lanthanides (Dy3þ or Er3þ), maintain the fluorite structure. Thermal conductivity of the as-prepared samples was obtained as a function of temperature, from thermal diffusivity, heat capacity and density values, using sintered pellets. We found that doping has an important effect in lowering Gd2Zr2O7 thermal conductivity, with final values ranging from 1.22 to 1.94 W m􀀀1 K􀀀1;Nd3þ- and Er3þ-containing samples represent an optimum combination of defects and disordering of oxygen vacancies that generate the lowest conductivity values of all samples tested.

http://dx.doi.org/10.1016/j.jallcom.2015.07.146