Author/Authors :
BERKSOY-YAVUZ, Ayşe Gebze Yüksek Teknoloji Enstitüsü - Mühendislik Fakültesi - Malzeme Bilimi ve Mühendisliği Bölümü, Turkey , BERKSOY-YAVUZ, Ayşe ENS Piezoaygıtlar Ltd., Turkey , ALKOY, Sedat ENS Piezoaygıtlar Ltd., Turkey , ALKOY, Sedat Gebze Yüksek Teknoloji Enstitüsü - Mühendislik Fakültesi - Malzeme Bilimi ve Mühendisliği Bölümü, Turkey , MENŞUR –ALKOY, Ebru Maltepe Üniversitesi - Mühendislik ve Doğa Bilimleri Fakültesi, Turkey
Title Of Article :
Electrical Properties and Impedance Spectroscopy of Lithium Doped Potassium Sodium Niobate (KNN) Based Ceramics
Abstract :
Among various lead-free piezoelectrics, (K0.5Na0.5)NbO3 (KNN) ceramics have been heavily investigated in recent years due to their high piezoelectric properties, high Curie temperature and their electromechanical properties. However, potassium leaves the structure easily during the sintering process of KNN ceramics. Thus, it becomes rather hard to densify KNN through conventional sintering methods due to potassium deficiency and good electrical properties cannot be achieved. The difficulties related to the densification of KNN ceramics must be overcome to achieve good properties. In this study, the structural and dielectric properties of 4 mol % Li (KL4) and 7 mol % Li (KL7) modified KNN ceramics were investigated. Furthermore, electrical behaviors of KNN ceramics were analyzed using AC impedance spectroscopy from 100 Hz to 10 MHz at various temperatures. The Curie temperatures of KL4 ve KL7 ceramics were measured as 468 °C ve 394 °C, respectively. The orthorombic-tetragonal phase transition shifted below room temperature with 7 mol % Li doping. The dielectric constants of KL4 and KL7 ceramics were measured as 345 and 615 at 100 kHz, respectively. The dielectric loss decreased with Li modification.
NaturalLanguageKeyword :
Piezoelectrics , Lead , Free ceramics , KNN , Impedance spectroscopy
JournalTitle :
Afyon Kocatepe University Journal Of Science and Engineering
