Doctoral Dissertations

Abstract

"This work concerns the preparation of spherical, submicron, and unagglomerated lead-based ferroelectric powders by ultrasonic spray pyrolysis. Compositions investigated include: the relaxor ferroelectric lead magnesium niobate (Pb(Mg1/3Nb2/3)O3; PMN); an electrooptic composition of lanthanum doped lead zirconate titanate ((Pb1-xLax)(Zr1-yTiy)O3; PLZT); and samarium and manganese modified lead titanate (Pb1-xSmxTi0.98Mn0.02O3; PT).

Spray pyrolysis as a synthesis method for producing PMN was found to be non-ideal, as fully perovskite phase powders could not be produced directly by spray pyrolysis. Preparing powders with PbO or MgO additions in excess of stoichiometry was found to improve the perovskite content of as-sprayed powders. Fully perovskite powders could be prepared by calcining powders spray pyrolyzed with 5% excess PbO at 800° C for 15 minutes. These results suggested that the short residence time in the spray pyrolysis apparatus was insufficient for the kinetically-limited growth of the perovskite phase from the cubic pyrochlore phase.

Transparent PLZT was prepared by spray pyrolysis and two stage pressureless sintering. Unlike the studies on PMN, the correct stoichiometry and phase of the PLZT powders could be directly produced by spray pyrolysis.

Lead titanate was prepared by spray pyrolysis, mixed oxide, and a liquid mix technique. The spray pyrolysis prepared powders exhibited an ideal morphology and agglomeration state for preparation of ceramics. The formation of oxide particles by spray pyrolysis was modeled using equations by Lang and Messing. Controlling the powder properties by manipulation of solution concentration and surface tension are discussed"--Abstract, page iv.

Advisor(s)

Huebner, Wayne

Committee Member(s)

Anderson, H. U. (Harlan U.)
Switzer, Jay A., 1950-
Day, D. E.
Hagen, Donald E.

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Ceramic Engineering

Comments

Funding by the Office of Naval Research is gratefully acknowledged.

Publisher

University of Missouri--Rolla

Publication Date

Fall 1995

Journal article titles appearing in thesis/dissertation

  • Spray Pyrolysis Synthesis of Lead Magnesium Niobate
  • A Study of the Perovskite and Pyrochlore Phases in the PMN System
  • Spray Pyrolysis Synthesis and Atmosphere Sintering of Transparent Electrooptic PLZT Ceramics
  • Preparation of Samarium and Manganese Modified Lead Titanate by Ultrasonic Spray Pyrolysis
  • Spray Pyrolysis Synthesis of Lead Magnesium Niobate Relaxor Ferroelectric Powders

Pagination

xv, 158 pages

Note about bibliography

Includes bibliographical references.

Rights

© 1995 Jeffrey G. Marx, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Thesis Number

T 7053

Print OCLC #

35253700

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