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GRAIN GROWTH RATE TRANSITIONS IN BARIUM STRONTIUM TITANATE

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posted on 15.08.2019 by Matthew J Michie
Understanding grain growth in dielectric ceramics is essential to controlling the electrical and mechanical properties necessary to produce ceramic capacitors and sensors. The effect of alloying barium titanate with strontium titanate on the equilibrium crystal shape was investigated in order to determine possible impacts on grain growth. The equilibrium crystal shape was studied through three experimental methods to identify possible changes in grain boundary energy or anisotropy with changing composition.
The first method was by imaging intergranular pores to observe faceting behavior and relative interfacial energies. Intergranular pores were reconstructed to determine the relative surface energies of the identified facets. The second method was to perform atomic force microscopy on surface facets to collect topography data. The topography data was combined with orientation data obtained by EBSD analysis from the same region, and used to calculate the normal vector of the surface facets. These datasets were plotted in a stereographic projection to study the faceting anisotropy. The third method involved collecting EBSD orientation data and images of surface faceting behavior. The surface faceting behavior of each grain was categorized by type of facet and plotted on a stereographic projection at the corresponding orientation. This allowed for the analysis of faceting transitions and the differentiation of faceted and continuous regions of the equilibrium crystal shape. The analysis of faceting behavior across compositions has implications on grain growth of the barium titanate/strontium titanate system.

Funding

DGE Grant #1144843

History

Degree Type

Doctor of Philosophy

Department

Materials Engineering

Campus location

West Lafayette

Advisor/Supervisor/Committee Chair

John Blendell

Advisor/Supervisor/Committee co-chair

Carol Handwerker

Additional Committee Member 2

Eric Kvam

Additional Committee Member 3

Wolfgang Rheinheimer

Additional Committee Member 4

Fu Zhao

Licence

Exports