Materials Research Bulletin, Vol.46, No.12, 2217-2221, 2011
Microstructures and dielectric properties of Ba0.6Sr0.4TiO3-MgO ceramics prepared by non-aqueous gelcasting and dry pressing
Non-aqueous gelcasting and dry pressing were used to prepare 45 wt% Ba0.6Sr0.4TiO3-55 wt% MgO (BSTM) ceramics. The effects of different forming methods on the microstructures and dielectric properties of the BSTM ceramics were investigated. The densities of the BSTM ceramics prepared by nonaqueous gelcasting are lower but more uniform than that of the BSTM ceramics prepared by dry pressing. The XRD analysis illustrates that phase compositions are completely the same no matter what forming method is adopted. The SEM results show that the BSTM green samples and sintered ceramics prepared by non-aqueous gelcasting are more uniform than that prepared by dry pressing. Furthermore, it is found that the BSTM ceramics prepared by non-aqueous gelcasting have higher and more uniform dielectric constant, tunability and loss tangent (measured at 10 kHz and 20 degrees C). Meanwhile, the BSTM ceramics prepared by non-aqueous gelcasting have higher dielectric constant and lower Q x f value (namely more loss) when they are measured at microwave frequencies. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.