Author/Authors :
ÖZEREN, Yağız Gebze Yüksek Teknoloji Enstitüsü - Malzeme Bilimi ve Mühendisliği Bölümü, Turkey , BERKSOY-YAVUZ, Ayşe Gebze Yüksek Teknoloji Enstitüsü - Malzeme Bilimi ve Mühendisliği Bölümü, Turkey , BERKSOY-YAVUZ, Ayşe ENS Piezoaygıtlar Ltd., Turkey , ALKOY, Sedat Gebze Yüksek Teknoloji Enstitüsü - Malzeme Bilimi ve Mühendisliği Bölümü, Turkey , ALKOY, Sedat ENS Piezoaygıtlar Ltd., Turkey , MENŞUR ALKOY, Ebru ENS Piezoaygıtlar Ltd., Turkey , MENŞUR ALKOY, Ebru Maltepe Üniversitesi - Mühendislik ve Doğa Bilimleri Fakültesi, Turkey
Abstract :
Among lead-free based piezoelectric ceramics with perovskite structure, sodium bismuth titanate based ceramics [(Na0,5,Bi0,5)TiO3 ; (NBT)] have very important piezoelectric properties. However, the polling process of unmodified NBT ceramics is very difficult due to exhibiting high ionic conductivity and large coercive field at room temperature. Therefore, nowadays binary 0,94(Na0,5,Bi0,5)TiO3-0,06BaTiO3 and ternary (Na0,5,Bi0,5)TiO3-BaTiO3-(K0,5,Na0,5)NbO3 systems have been developed to alternative (Pb,Zr)TİO3 ceramics. In this study, the structural and dielectric properties of unmodified NBT ceramics as well as (Na0,5,Bi0,5)TiO3-BaTiO3 (NBT-BT) and 0,92(Na0,5,Bi0,5)TiO3-0,06BaTiO3-0,02(K0,5,Na0,5)NbO3 (NBT-BT-KNN) ceramics were investigated in detail. All ceramics were crystallized perovskite structure without any secondary phase which to be observed from X-ray analyzed. The electrical behavior of all ceramics was exhibited with an impedance spectroscopy as a function of frequency from 100 Hz up to 10 MHz. The relative density of NBT, NBT-BT and NBT-BT-KNN ceramics were 94%, 98% and 96%, respectively. The highest dielectric constant of measured temperatures (Tm) in NBT, NBT-BT and NBT-BT-KNN NBT, NBT-BT and NBT-BT-KNN ceramics were 328°C, 300°C and 287°C, respectively. Tm point was shifted to the lower temperatures with modification. The dielectric constants of NBT, NBT-BT and NBT-BT-KNN NBT were 646, 1451 and 1487 at room temperature, respectively.
NaturalLanguageKeyword :
Piezoelectrics , Lead , free , NBT , Impedance Spectroscopy
