Microwave-hydrothermal synthesis of Nb-doped BaTiO3 nanoparticles under various conditions

Abstract

Tetragonal BaTiO3 powders were synthesized by the microwave-hydrothermal (MH) method. The effects of the reaction time and temperature on the MH synthesis were investigated. Typical experiments were performed with a solid state reaction for the system BaTiO3 + Nb2O3 at a high temperature. In the MH method, at a shorter time and lower temperature, the rate of the formation of tetragonal BaTiO3 and of the growth of particles went down substantially. The microwave heating can be very fast and uniform through a self-heating process that results from the direct absorption of the microwave energy in the reaction mixture. The synthesis of Nb-doped BaTiO3 has been investigated under MH conditions in the temperature range of 120–180°C for 1–3 hours using C16H36O4Ti, BaH2O2 · 8H2O, and NbCl5 as Ba, Ti and Nb sources, respectively. In the phase evolution studies, the X-ray diffraction measurements and Raman spectroscopy were employed. The Transmission Electron Microscope and the Field Emission Scanning Electron Microscopy images were taken for the detailed analysis of the grain size, surface, and morphology. The MH method was applied for the synthesis of Nb-doped BaTiO3 via provided advantages of the fast crystallization and decreased crystallite size. The nucleation rate should have been high because of a high heating rate in microwave heating processes.