The phase relationships of the ternary system Eu 2 O 3 - La 2 O 3 - ZrO 2 and binary Eu 2 O 3 - La 2 O 3 subsystem were experimentally and thermodynamically studied. Six three-phase fields and nine two-phase ones in the Eu 2 O 3 - La 2 O 3 - ZrO 2 system were investigated by X-ray diffraction, scanning electron microscopy and electron probe microanalysis with wavelength dispersive spectrometer at 1873 K and 1673 K. Nevertheless, there only existed a two-phase region in the Eu 2 O 3 - La 2 O 3 system in the temperature range from 1873 K to 1673 K. After that, the ternary mixing parameters for the system Eu 2 O 3 - La 2 O 3 - ZrO 2 including the binary interaction parameters in the Eu 2 O 3 - La 2 O 3 subsystem are optimized with the CALPHAD (CALculation of PHAse Diagrams) method, based on obtained experimental results. The high-temperature phase relationships and the special type of continuous solid solutions (La 2-x Eu x Zr 2 O 7 ) investigated in present work will contribute to exploring new materials with specific properties such as optical transparency.
Weidong Han,Bin Ding,Mira Park,Fuhai Cui,Zafar Khan Ghouri,Prem Singh Saud,Hak-Yong Kim
Novel luminescent and amorphous La2O3–ZrO2:Eu3+ (LZE) nanofibrous membranes with robust softness are fabricated for the first time via a facile electrospinning technique. By incorporating zirconium oxide, the as-prepared lanthanum oxide nanofibrous membranes can be dramatically changed from extreme fragility to robust softness. Meanwhile, the softness and luminescent performance of LZE nanofibrous membranes can be finely controlled by regulating the doping concentration of zirconium oxide and europium in lanthanum oxide nanofibers. Additionally, the crystal structure analysis using X-ray diffractometer and high resolution transmission electron microscopy measurements have confirmed the correlation between the amorphous structure and softness. Furthermore, LZE membranes show the characteristic emission of Eu3+ corresponding to 5D0, 1, 2–7F0, 1, 2, 3, 4 transitions due to an efficient energy transfer from O2− to Eu3+. The LZE nanofibrous membranes with the optimum doping Eu3+ concentration of 3 mol% exhibit excellent softness and luminescent properties, which make the materials to have potential applications in fluorescent lamps and field emission displays.