Abstract
Barium strontium titanate (Ba1-xSrxTiO3) ceramics were prepared by solid-state reaction method. XRD patterns showed that BT (x = 0) and BST2 (x = 0.2) ceramics presented tetragonal phase, while BST4 (0.4) and BST6 (0.6) ceramics showed cubic phase at room temperature. The relative permittivity and dissipation factor of Ba1-xSrxTiO3 ceramics with temperature of 125–425 K were characterized at 1–100 kHz by LCR meter. The Young's modulus and internal friction of Ba1-xSrxTiO3 ceramics in the range of 125 K–425 K at different vibration frequencies were tested by a Dynamic Mechanical Analysis (DMA) system. Compared with the dielectric measurement, mechanical analysis was more sensitive to reflect the phase transition and relaxation process. All Ba1-xSrxTiO3 samples showed three phase transitions, the transition temperatures decreased and the phase transition diffused as Sr content increased. Besides, a relaxation process caused by the interaction between domain walls and lattice defects emerged in pure BT ceramic, while it disappeared in all BST ceramics.
Funding
This work was supported by the National Key Technology R&D Program of China (2009BAG12A04) and the Scholarship Award for Excellent Doctoral Student granted by Ministry of Education (Nos. 0500219171).