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Sintering of piezoelectric PbNb²O⁶ with various dopants

University of British Columbia

The effect of temperature, dopants, dopant concentration, and processing procedure on the sintering kinetics of the piezoelectric ceramic PbNb₂O₆ has been investigated. The isothermal contraction behavior of PbNb2O6 over the temperature range 1050 - 1200 °C with various dopants (SrO, Bi₂0₃, LiNbO₃, and KNaNb₂O₆) at concentrations from 0 to 1 weight percent was studied. Because all mixing of the dopants with the PbNb2O6 powder was done by vibratory ball milling, the effect of milling on sintering kinetics was also studied. Vibratory ball milling of the undoped powder was found to produce specimens that contracted the most over the shortest period of time. A problem with 'milled' powder was the excessive grain growth resulting in fragile specimens. SEM micrographs of fractured specimens showed that milling with the addition of any dopant hindered grain growth. Shrinkage curves of these doped powders were found not to contract as fast as the 'milled' powder with no dopants. Of the 4 dopants tested, Bi₂0₃ was found to produce the largest grain size as well as exhibit the greatest contraction. This is in comparison to SrO additions which yielded the least contraction. The relative effectiveness between LiNbO₃ and KNaNb₂O₆ could not be determined with certainty but were found to be between SrO and Bi₂0₃. Micrographs suggest that increasing concentrations of SrO, LiNbO₃, and KNaNb₂O₆ decrease the grain size, unlike increasing additions of Bi₂0₃ which led to a larger grain size.

Thesis/Dissertation

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2008-12-19

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http://hdl.handle.net/2429/3223

Materials Engineering

University of British Columbia

UBCV

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