Abstract: In this seminar, the microstructure and the dielectric properties of BaTiO3/BaTi1-xZrxO3 composites will be correlated. It will be showed that the Zr4+ substitution of Ti4+ changes the dilatometry behavior of the BaTi1-xZrxO3 compounds, therefore leading to residual two-dimensional stresses on the composites after ceramic processing. As BaTiO3´s dielectric properties are affected by two-dimensional stresses, their effects can be tracked by comparing the composites´ dielectric properties with predictions obtained by the simple mixture rule focused on BaTiO3 paraelectric/ferroelectric phase transition. The results show that the composites’ dielectric properties can be tuned through control of the microstructure and that it´s possible to achieve properties higher than the expectations. The BaTi1-xZrxO3 nanopowders were synthesized by the hydrothermal and by the polymeric precursors method. Ceramic composites with different grain sizes were obtained by tape casting and by the traditional ceramic processing route with sintering temperature of 1300 °C. Their structure, microstructure and dielectric properties were characterized and compared to those of homogeneous samples prepared under the same conditions.
Seminarista: Thiago Amaral – doutorando do Grupo de Pesquisa Crescimento de Cristais e Materiais Cerâmicos
Data: 12/05/2015
Local: Sala F-202 (Prédio dos Laboratórios de Ensino do IFSC)
Horário: Das 16h às 17h
