Li2CO3와 B2O3를 첨가한 Bi1/2Na1/2TiO3-SrTiO3 무연 압전 세라믹스의 저온 소성 연구

Abstract

This study investigated microstructures, crystal structures, polarization, dielectric and electromechanical properties of 0.76Bi1/2Na1/2TiO3?0.24SrTiO3 (BNT-24ST)-based piezoceramcs by adding Li2CO3 and B2O3 (LB) as sintering aids for lowtemperature sintering. All samples were successfully synthesized using conventional solid-state reaction method and sintered at 950, 1,000, 1,050, 1,100 and 1,175℃ for 2 hours. Without LB, specimens required sintering temperatures over 1,175℃ for sufficient densification, while the addition of 0.10-mol LB decreased the sintering temperatures down to 950℃. The average grain size and dielectric properties of BNT-24ST-10LB ceramics were enhanced with increasing sintering temperature. We found that the low-temperature sintered BNT-24ST piezoceramics by adding LB showed the d33 *value of 402 pm/V at 4 kV/mm after sintering at 1,050℃, which was better than that of high-temperature fired specimens sintered at 1,175℃ without LB (242 pm/V). We believe that the results of this study promise a candidate for low-cost multilayer ceramic actuator applications.