Liquid-Phase Synthesis of Barium Acetatotitanyl and Barium Oxalatotitanyl as Intermediates for Preparing Nanosized Barium Titanate

摘要

Liquid-phase methods (an oxalate process in aqueous solution and a semialkoxide sol-gel process in anhydrous acetic acid) were used to prepare barium acetatotitanyl (BAT) and barium oxalatotitanyl (BOT), which are potential fillers for electrorheological liquids, and to prepare barium titanate during heat treatment of the aforementioned intermediates at 1200°C. The materials were characterized using electron microscopy, FTIR spectroscopy, and thermal analysis. The particle size was 80 to 100 nm for BAT powders and 20 to 50 nm for BOT powders. X-ray spectra of the powders dried at 120°C contain reflections from a barium titanate phase. The dielectric spectra of the materials synthesized were studied for suspensions in PMS-20 silicone oil over the frequency range from 25 to 106 Hz up to 4 kV/mm. The dielectric parameters of BOT suspensions decrease hyperbolically with rising alternate current frequency, whereas BAT suspensions give rise to a relaxation dielectric spectrum with relaxation times on the order of 10~(-3) s.