Synthesis of PbTiO3 ceramics using mechanical alloying and solid state sintering

The pressure-less sintering behavior of PbTiO3 powders synthesized by mechanical alloying TiO2 and PbO was investigated using dilatometry and Rietveld refinements of X-ray diffraction patterns. As-synthesized, the powders are nanocrystalline with a mean particle size of 20nm. Pressure-less sintering in the range 500-1050degreesC gives single phase ceramics with densities of 85-90% and crystallite sizes in the range 80-400 nm. Cracking due to the paraelectric-ferroelectric phase transition was not observed in samples sintered below 700degreesC due to the small crystallite size whereas macroscopic cracks formed in samples sintered above 700degreesC. Rietveld analysis indicates the formation of Pb vacancies in samples sintered and held for 24 h at intermediate temperatures (600-1000degreesC) which gives some insight into the mechanism of Pb loss and second phase formation in this system. (C) 2004 Elsevier Inc. All rights reserved.