Preparation and electrical characterisation of strontium titanate ceramic from titanyl acylate precursor in strong alkaline solution

Strontium titanate powder can be obtained from titanyl acylate precursor by using acetic acid chelating with titanium isopropoxide in a strong alkaline solution (pH > 1.3) at room temperature. Infrared spectroscopy, differential scanning calorimetry/thermogravimetric analysis and X-ray diffraction were used to investigate the effects of the size and properties of the precipitated precursor on the properties of the powder and the sinterability for ceramics. It was found that the strontium ion diffused into the gel made by the hydrolysis of the titanyl acylate precursor to form strontium titanate powder. The reaction rate of forming powder at higher temperature such as 100 degrees C and higher water content (the ratio of water to titanium alkoxide is 20) or higher acetic acid (the ratio of acetic acid to titanium alkoxide is 10), is rapid and the particle size is less than 0.1 mu m. Without adding any reagent the density of the sintered strontium titanate at 1300 degrees C from powder after freeze drying was over 95% of its theoretical density. The dielectric constant and dissipation factor of the strontium titanate body sintered at 1250, 1300, 1400 and 1450 degrees C, were also determined at a frequency of 1 kHz to 10 MHz at constant temperature.