Characterization and optical properties of m-Li2ZrO3 prepared by optimized solid-state reaction

Abstract

m-Li2ZrO3 powders were successfully prepared by solid-state reaction method using Li2CO3 and ZrO2 as raw materials. The synthesis was optimized by varying the ball-milling time (0?96 h); Li2CO3 excess (0 or 5 wt%), reaction temperature (700, 800, 900 or 1000 C), and reaction time (3, 6, 9 or 12 h). The structural, morphological and optical properties of m-Li2ZrO3 powders were examined by X-Ray Diffraction, Thermogravimetric and Differential-Thermal analysis, Scanning Electron Microscopy, High-Resolution Transmission Electron Microscopy, Laser Diffraction, Dynamic Light Scattering and UV?Vis Diffuse Reflectance Spectroscopy. The results show that precursors suitable for the synthesis of fine powders require ball-milling times longer than or equal to 6 h. Highly crystalline m-Li2ZrO3 was synthesized under two distinctive calcination conditions as follows: 900 C/6h without Li2CO3 excess or 1000 C/12 h using 5 wt% of Li2CO3 excess. Particle size of as-synthesized powders was found to be in the range from 200 nm to 1 mm. m-Li2ZrO3 was found to be a wide band gap material with apparent optical band gap of 5.5 eV (direct) and 5.1 eV (indirect), which can be used in UV-C applications.