Elaboration and characterization of barium titanate powders obtained by the mechanical activation of barium nitrate and titanate oxide, and electrical properties of the ceramics sintered by SPS
Résumé
The current work aims to reduce the energy required to obtain a high quality barium titanate nanocrystals via solid-state reaction. In order to achieve this challenge, Ba(NO3)2 and TiO2 were mechanically activated by high-energy ball milling, and then heat treated at moderate temperature (600 oC). When stoichiometric mixture was used, the formation of BT and minor BaCO3 and TiO2 impurities was observed. The use of Ba(NO3)2 excess leads to the formation of BT and a minor BaCO3 impurity. A simple acid wash treatment was used to remove the carbonate impurity and to provide a high purity BT. The powders were characterized by XRD, BET, Raman spectroscopy, and SEM-FEG. Spark Plasma Sintering (SPS) technique was used to get the dense nanoceramics. These materials show, at room temperature and at 1 kHz, colossal permittivity (ε = 105) associated with low dielectric loss (tg δ = 0.07).
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