Author/Authors :
KARGI, Birkız Dilek Afyon Kocatepe Üniversitesi - Mühendislik Fakültesi - Malzeme Bilimi ve Mühendisliği Bölümü, Turkey , TIKIZ, Serhat Afyon Kocatepe Üniversitesi - Teknoloji Uygulama ve Araştırma Merkezi, Turkey , ÖZGÜL, Metin Afyon Kocatepe Üniversitesi - Mühendislik Fakültesi, Teknoloji Uygulama ve Araştırma Merkezi - Malzeme Bilimi ve Mühendisliği Bölümü, Turkey
Title Of Article :
Electrical Aging in Lead-Free Piezoelectric Ceramics
Abstract :
Perovskite type lead-free piezoelectric Bi0.5(Na0.75K0.20Li0.05)0.5TiO3 (BNKLT), 0.948(K0.5Na0.5)NbO3-0.052LiSbO3(KNN-LS), and 0.948(K0.5Na0.5)NbO3-0.052LiSbO3+%1 mol Cu (KNN-LS-Cu) ceramics were synthesized by solid state method using high purity oxide and carbonate powders in this study. Following perovskite phase verification by X-ray diffraction (XRD) method, cold isostatic pressing was used to obtain disc shaped samples. Samples sintered at the range of 1040-1140°C depending on the composition were then sputter coated with gold (Au) and microstructural analyses were made in a scanning electron microscope (SEM). After the density measurements by Archimedes method, room temperature dielectric properties were measured by LCR-meter in gold electroded samples. For the piezoelectric measurements (d33), samples were poled in a hot (110°C) silicon oil bath by applying DC from 3 to 6 kV. After the poling, change in time was monitored both in dielectric (εr , tanδ) and piezoelectric (d33) properties up to 10^5 second. The stability of electrical properties is important for the reliability of ceramics for use in electronics. KNN-LS and Cu doped KNN-LS ceramics exhibits higher piezoelectric properties in comparison to BNKLT based ceramics. Even though no improvement in densification is achieved, dielectric constant and piezoelectric coefficient values remarkably increased in KNN-LS ceramics when doped with 1 % Cu. Aging of piezoelectric properties were also much less in KNN based ceramics.
NaturalLanguageKeyword :
Lead free Piezoelectric ceramics , Electrical aging , Dielectric properties
JournalTitle :
Afyon Kocatepe University Journal Of Science and Engineering
