|About this Abstract
||Materials Science & Technology 2009
||Characterization and Modeling of Ceramic-Ceramic and Metal-Ceramic Interfaces
||Quantitative Analysis of Grain Boundary Segregation in Oxides
||Elizabeth C. Dickey, Xin Li
|On-Site Speaker (Planned)
||Elizabeth C. Dickey
Segregation of dopant or impurity ions to grain boundaries can have marked effects on macroscopic electrical, optical or mechanical properties. Consequently, local quantification of dopant levels at grain boundaries is imperative for establishing processing-structure-property relationships for polycrystalline oxides. This talk reviews the driving forces for grain boundary segregation in ionic materials and presents two case studies in which impurity segregation is important for macroscopic material behavior: TiO<SUB>2</SUB> and YAG. For both systems, local dopant segregation levels and stoichiometry and measured by a combination of energy dispersive x-ray spectroscopy and electron energy loss spectroscopy (EELS) in a scanning transmission electron microscope. Interpretation of the EELS fine structure is guided by density functional theory calculations. The implications of the grain boundary chemistry for local electrical and optical properties are discussed.