Seifert, Klaus Thilo Paul
Lead-Free Piezoelectric Ceramics.
Technische Universität, Darmstadt
[Ph.D. Thesis], (2010)
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|Item Type:||Ph.D. Thesis|
|Title:||Lead-Free Piezoelectric Ceramics|
A number of new lead-free electroceramics have been developed based on the known lead-free ferroelectric system Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3 (BNT-20BKT) at the morphotropic phase boundary by introducing small amounts of K0.5Na0.5NbO3-Bi0.5K0.5TiO3 (KNN-03BKT). With increasing KNN-03BKT content, the materials show a reduction in the ferroelectric and piezoelectric properties. At the same time, the achievable maximum electrostrain peaks at a KNN-03BKT concentration of 1 mol% with 0.46 % at 8 kV/mm. A matrix of 10 compositions surrounding the composition with the highest electrostrain at room temperature was created with 0, 1 and 2 % KNN-03BKT for BNT-19BKT, BNT-20BKT and BNT-21BKT as well as BNT-20BKT-0.5(KNN-03BKT). The large-strain temperature and frequency dependence of these compositions was investigated between room temperature and 200 °C and 50 mHz and 500 Hz. While 8 compositions show typical ferroelectric behaviour, BNT-20BKT-1(KNN-03BKT) and BNT-20BKT-2(KNN-03BKT) both show a high strain at room temperature but very low remanent polarisation and strain. They also both show lower frequency and temperature dependant variation in the large-field strain than the ferroelectric compositions.
|Place of Publication:||Darmstadt|
|Uncontrolled Keywords:||Lead-Free Piezoceramics ferroelectric piezoelectric KNN BNT-BKT|
|Classification DDC:||600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften|
|Divisions:||11 Department of Materials and Earth Sciences > Material Science > Nonmetallic-Inorganic Materials|
|Date Deposited:||15 Dec 2010 06:38|
|Last Modified:||07 Dec 2012 11:58|
|Referees:||Rödel, Prof. Dr. Jürgen and Karsten, Prof. Dr. Albe|
|Refereed:||7 December 2010|