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Title: Investigation of the structural and functional properties of lead-free barium calcium zirconate titanate piezoceramics
Author: Shu, Chang
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2018
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There is an urgent desire to move from lead-based piezoelectric materials to lead-free alternatives. One of the most promising lead-free materials has been reported to be zBao.7oCao.3oTi0J-(1-z) BaZro.2oTio.soOJ (abbreviated as zBCT-(1-z)BZT) system, which has comparable piezoelectric performance to lead-based materials. However, there is a lack of systematic research to investigate the effects of fabrication on the structural and functional properties of this zBCT -(1-z)BZT system. In this work, the end member Bai-xCaxTiOJ (x=0-0.30) and BaZryTii-y03 (ji=0-0.30) systems have been investigated. The phase transition diagrams of the two systems have been successfully established by measuring temperature dependent Raman spectroscopy and functional properties. The optimized fabrication procedure for forming single phased Bao.7oCao.3oTi0J and BaZro.2oTio.soOJ ceramics by solidstate methods, has been applied as a novel way to form zBCT-(1-z)BZT (O:Sz:~:J) ceramics by sintering the pre-calcined Bao.7oCao.3oTi0J and BaZro.2oTio.soOJ powders. A new phase diagram of the zBCT-(1-z)BZT (0$z:S1) has been constructed by combing structural and functional property measurements. It indicates a vertical orthorhombic phase region separating rhombohedral and tetragonal phases below the Curie temperature. The highest piezoelectric properties have been observed for z=0.5 ceramics at room temperature, due to the increased potential polarization directions in the vicinity of the orthorhombic to tetragonal phase boundary.
Supervisor: Not available Sponsor: University of Birmingham ; Brno University of Technology ; Erasmus Traineeship Program
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QD Chemistry ; TN Mining engineering. Metallurgy