|About this Abstract
||Materials Science & Technology 2020
||Grain Boundaries, Interfaces, and Surfaces in Functional Materials: Fundamental Structure-Property-Performance Relationships
||Grain Boundary Engineering ZnAl2O4 via Rare Earth (RE) Doping with Varying Ionic Radii
||Luis Enrique Sotelo Martin, Ricardo H.R. Castro
|On-Site Speaker (Planned)
||Luis Enrique Sotelo Martin
Nanocrystalline ZnAl2O4 powder was synthesized with 0.5 mol% (RE)2O3 (RE=Nd, Y, Sc, In) using reverse-strike coprecipitation. RE dopants were chosen to span a range of crystal ionic radii (88.5 to 112.3 ppm) in order to study segregation behavior in ZnAl2O4. Resulting powders were analyzed with x-ray diffraction and electron microscopy where Nd exhibited the highest degree of grain boundary segregation. Microcalorimetry measurements were used to analyze the powders’ grain boundary and surface energies. The data showed a correlation between dopant characteristics and interfacial energies, with consequences to stability against coarsening for doped ZnAl2O4. Nanoindentation experiments on pellets sintered with high-pressure spark plasma sintering (HP-SPS) revealed Vickers hardness is dependent on doping chemistry which may be explained by the effects of dopants on grain boundaries. These results have implications for the future of grain boundary engineering as we continue to understand mechanical properties of nanocrystalline ceramics.