화학공학소재연구정보센터
Materials Research Bulletin, Vol.115, 1-11, 2019
Order-Disorder transformation and its effect on the properties of (Lanthanide)(2)Zr1.5Hf0.5O7 functional nanoceramics
Order disorder transformations and its effect on the structural, optical and ionic transport properties of the cubic pyrochlore - defect fluorite structures are the prime focus of this study. Nanoceramics of Ln(2)Zr(1.5)Hf(0.5)O(7) (Ln = Pr, Nd, Sm, Gd, Dy and Er) are prepared through the modified combustion technique. X - ray diffraction analysis and electron microscopic studies show the cubic nano crystallite nature of the materials. Vibrational studies reveal the pyrochlore fluorite phase transformation in the series. Highly dense bulk ceramics are prepared from the nano particles at relatively low temperatures. The gradual replacement of Ln(3+) ions in Ln(2)Zr(1.5)Hf(0.5)O(7) changes the pyrochlores (Ln = Pr-Sm) to defect fluorite (Ln = Er) through the weakly ordered defect fluorites (Ln = Gd and Dy). Impedance spectroscopic analysis carried on the bulk ceramics shows the influence of phase transformation on the oxide ion conduction of bulk materials. The peak oxide ion conduction is observed for the Ln = Dy ceramic, which is at the pyrochlore fluorite phase boundary.