Please use this identifier to cite or link to this item:
Title: Studies on (Ba₀.₉₅Sr₀.₀₅)(Zr₀.₀₅Ti₀.₉₅)O₃/polymer composites
Authors: Lee, Siu To Felix
Keywords: Barium compounds -- Electric properties.
Ceramic materials -- Electric properties.
Composite materials -- Electric properties.
Hong Kong Polytechnic University -- Dissertations
Issue Date: 2012
Publisher: The Hong Kong Polytechnic University
Abstract: The main objectives of the present work are to fabricate and study the properties of peroskite lead-free ceramic barium strontium zirconate titanate (abbreviated as BSZT) and its composites. BSZT with composition of Ba₀.₉₅Sr₀.₀₅Zr₀.₀₅Ti₀.₉₅O₃ is fabricated by a solid-state reaction method and studied in this project. The dielectric, piezoelectric and ferroelectric properties of this composition of BSZT have been measured. It is found that BSZT has piezoelectric constant of 270 pC/N, loss tangent tan δ of 1.5 % and thickness electromechanical coupling factor kt of 0.45. In this work, 2 different types of composites are fabricated, they include BSZT/polyvinylidene fluoridetrifluoroethylene [P(VDF-TrFE)] 0-3 composites and BSZT/epoxy 1-3 composites. High frequency ultrasonic transducers of 40 MHz have been fabricated using BSZT ceramics. Their bandwidth and two-way insertion loss are measured by the pulse-echo method. The bandwidth can reach up to 75 % with insertion loss of -26 dB. The transducers have been used for imaging and integrated into microfluidic channel to detect the acoustic velocity of the liquid under test. BSZT/P(VDF-TrFE) 0-3 composites with different ceramic volume fractions (Φ) ranging from 0.10 to 0.40 have been fabricated by dispersing fine BSZT powder evenly into the copolymer matrix. The pyroelectric coefficient and dielectric properties have been measured and compared with calculation using the Bruggeman's model. 0-3 composite with Φ = 0.30 has been found to have the best pyroelectric figure of merit. BSZT/epoxy 1-3 composites with ceramic volume fractions ranged from 0.55-0.85 have been fabricated by a dice-and-fill method. The resonance characteristics are measured and compared with the calculated results by the modified parallel and series model. Both measured and calculated results show that Φ = 0.65 has the best kt and it has been used to fabricate a low-frequency ultrasonic transducer.
Description: xix, 121 leaves : ill. ; 30 cm.
PolyU Library Call No.: [THS] LG51 .H577M AP 2012 Lee
Rights: All rights reserved.
Appears in Collections:Thesis

Files in This Item:
File Description SizeFormat 
b25300660_link.htmFor PolyU Users162 BHTMLView/Open
b25300660_ir.pdfFor All Users (Non-printable)5.12 MBAdobe PDFView/Open
Show full item record
PIRA download icon_1.1View/Download Contents

Page view(s)

Last Week
Last month
Citations as of Oct 8, 2018


Citations as of Oct 8, 2018

Google ScholarTM


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.