Preparation of Nanocomposite Ceramics by Sol-Gel Method in Canada

In July 2003, researchers at Simon Fraser University in Canada synthesized lead zirconate titanate ferroelectric nanopowders using an air-stable sol-gel method. The composition of lead zirconate titanate (PZT) was Pb (Zr0.53Ti0.47). O3. The fine powder produced by this method is of high purity and can be sintered at temperatures below 1000oC to produce ceramics with a density of 97% of the theoretical density. They also prepared PZT nanocomposite ceramics using high-purity PZT powders prepared by the sol-gel method, which was added with a small amount of [0.1-1.0 (Vol.)%] sol-gel prepared magnesium oxide (MgO).
The impedance spectrum was used to determine the frequency and temperature dependence of the dielectric properties of the ceramic nanocomposites in the range of 1 to 10 Hz at room temperature to 500oC. The Curie temperature (Tc) of a pure PZT ceramic is 400oC. The apparent frequency dispersion of the dielectric constant appears at Tc, which is believed to be due to the high conductivity grain boundary effect.
At room temperature, the dielectric constant (k) and dissipation factor are 820 and 0.025 at 1 kHz, respectively. The relationship between temperature and both ac and dc resistivity indicates that the activation energy is 1.1 eV. The conductivity of most pure PZT ceramics is about 0-12 S.m-1 at 40oC.