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dc.contributor.authorMcLaughlin, Shona Raeen
dc.date2008-10-03 15:13:24.791
dc.date.accessioned2008-10-09T15:52:31Z
dc.date.available2008-10-09T15:52:31Z
dc.date.issued2008-10-09T15:52:31Z
dc.identifier.urihttp://hdl.handle.net/1974/1549
dc.descriptionThesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2008-10-03 15:13:24.791en
dc.description.abstractThree different B-site additives, Mg1/3Nb2/3, Zr4+, and Cu1/2W1/2, were added to BNT ceramics in varying concentrations. These were abbreviated as BNMN, BNZ, and BNCW, respectively. The compositions were calcined to form a perovskite structure, ground to a fine powder, pressed into tablets and sintered to form dense ceramics. XRD analysis confirmed the formation of the perovskite phase. The electro-mechanical properties of the ceramics were evaluated. There were improvements in the low-field room temperature dielectric constant of 30% with 25% BNMN, 13% with 10% BNZ, and 16% with 2% BNCW. Higher concentrations of the additives degraded the dielectric performance. The conductivity of the BNT ceramics was reduced with very small concentrations (0.25 to 0.5%) of each of the additives. This reduction was maintained at the higher concentrations of the additives, which allowed for higher electric fields to be applied during both the poling process and the strain measurements. Improvements of approximately 30% in the d33 values were found at concentrations of 0.5% of each of the additives, but higher concentrations of the additives degraded the d33 values. The coercive field was affected by the additions to BNT. Increasing concentrations of BNMN reduced the coercive field in bipolar strain measurements. This was accompanied by a reduction in the remanent strain. Small additions (0.5 to 1.5%) of BNZ resulted in an increase in the coercive field by about 12%, followed by a 25% decrease at 5% BNZ. The remanent strain followed the same pattern. All concentrations of BNCW studied reduced the coercive field by about 12%. The remanent strain increased by 25% at 0.5% BNCW, and decreased by 42% at 2.5% BNCW. The electro-mechanical results for the BNMN and BNZ additives were compared to the behaviours of their lead-based counterparts, PMN and PZ. There was no consistent trend in the response of the electromechanical properties to the additions between the current lead-free and the lead-based systems.en
dc.format.extent5047245 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoengen
dc.relation.ispartofseriesCanadian thesesen
dc.rightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.en
dc.subjectLead-free ferroelectricen
dc.subjectperovskiteen
dc.subjectBNTen
dc.subjectceramicsen
dc.titleFabrication and Properties of Bi1/2Na1/2TiO3 Based Ferroelectric Ceramics with Low Levels of B-site Additivesen
dc.typethesisen
dc.description.degreePhDen
dc.contributor.supervisorKrstic, Vladimiren
dc.contributor.departmentMechanical and Materials Engineeringen
dc.degree.grantorQueen's University at Kingstonen


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