Abstract
Nanocrystalline PbTiO3 in tetragonal form has been successfully prepared via a newly developed environmentally friendly coprecipitation process. The formation process of lead titanate from the PbC2O4 center dot TiO2 precursor was monitored using DTA-TG, XRD, FT-IR, and TEM techniques. XRD showed the phase transition of less stable tetragonal PbO decomposition intermediate to a more stable orthorhombic structure by raising the calcination temperature. For the precursor calcined at 600 degrees C, only XRD lines characteristic of nanocrystalline tetragonal PbTiO3 are detected. TEM of PbTiO3 nanocrystals showed agglomerates with diameters in the range 85-90 nm. Consistent with the TEM result, the grain size estimated using surface area measurements indicated a high degree of particle agglomeration. FT-IR measurements gave results which are in close agreement with those revealed by XRD technique. The ac conductivity of PbTiO3 depends on the dielectric property. The kinetics of the nonisothermal TG curves for the precursor decomposition was carried out assuming various solid-state-reaction models and applying three different computational methods. The data analysis showed that the presence of TiO2 during oxalate decomposition reaction does not alter the decomposition mechanism; it drastically affects the activation parameter values.