This project was planned to be executed in 24 months during the master course of Mayra Dancini Golçaves, student of the PPGQ/UFSCar, CAPES level 7. Recently, a new wet chemical route known as "the oxidant peroxo method (OPM)" was developed to obtain lead based ferroelectric oxide powders of superior quality. This technique will be used in this project to synthesize new compositions of Pb(ZrTi)O3 and (PbRe)(ZrTi)O3, where Re means an rare earth element. The OPM route is based in the redox reaction between Pb(II) ions and some inorganic peroxo-complexes of titanium and rare earth ions in aqueous medium, forming an amorphous precipitate of nanometric particles with controlled composition. These particles can be crystallized into desired perovskite phase after a heat treatment at relatively low temperature (~600 ºC). The main advantages of this new method is the formation of uniform spherical particles with sharp size distribution that are completely free of any common contaminants, such as graphitic carbon or chlorine ion, and the use of water as solvent. It is well known that is fundamental to understand the transition from the amorphous to the crystalline state to better tailor the final physico-chemical properties of the dense ceramic bodies. Therefore, it is proposed in this project the use of spectroscopic techniques (Raman scattering and infrared absorption), the intensive use of powder X ray diffraction and electronic microscopies, with the objective of to determine the local structure of the amorphous precursors, to identify the crystallization mechanism that occurs during the synthesis of ceramic powders by the OPM route, and to characterize the structural and dielectric properties of the sintered ceramic bodies, using factorial planning and chemiometric techniques.
News published in Agência FAPESP Newsletter about the scholarship: