Journal of the American Ceramic Society, Vol.98, No.3, 1013-1018, 2015
Phase Structure Evolution and Thermo-Physical Properties of Nonstoichiometry Nd2-xZr2+xO7+x/2 Pyrochlore Ceramics
Nonstoichiometry pyrochlore composites of Nd2-xZr2+xO7+x/2 (x=0, 0.1, 0.2) were synthesized by chemical-coprecipitation and calcination method. The phase structure evolution and thermo-physical properties of Nd2-xZr2+xO7+x/2 were investigated. Structural analysis by Raman spectroscopy showed that Nd2-xZr2+xO7+x/2 underwent an ordering degree decrease and a lattice distortion increase with increasing x value. Nd1.9Zr2.1O7.05 and Nd1.8Zr2.2O7.1 exhibited lower thermal conductivities than Nd2Zr2O7, which might be related to the lower ordering degree and the enhanced phonon scattering due to lattice distortion. As ZrO2 content increasing, the thermal expansion coefficients of Nd2-xZr2+xO7+x/2 increased, which possibly arised from the decreased crystal energy due to reduced ordering degree.