Investigation of the Pyrolysis and Crystallization of Lead Zirconate Titanate Ceramics Prepared via the Sol Gel Process

The sol gel process for the preparation of lead zirconate, lead titanate and lead zirconate titanate is studied by various experimental techniques, comprising solid state NMR methods, FT IR spectroscopy, DTA/TG and XRD. Two temperature ranges are examined that cover (i) the pyrolysis step from the solid gel to the amorphous oxide mixture and (ii) the calcination step from the amorphous state to the crystalline ceramics. ¹³C NMR and FT IR spectroscopy studies primarily are used to monitor the structural changes during the pyrolysis step. ²⁰⁷Pb NMR spectroscopy is employed to examine the development of the short range order at the lead nuclei over the whole temperature range. The latter studies clearly show that the observed changes in the short range order are accompanied by alterations in the long range order, as derived from the XRD data. In addition, ²⁰⁷Pb NMR experiments are performed on ceramic samples that were obtained via the sol gel or the mixed oxide route. It is demonstrated that these samples exhibit significant differences in the short range order, although the long range order was found to be the same, being independent of the actual preparation route.