An Assessment of Dopant Effects on Surface and Interfacial Properties in Alumina

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This project plans to study the dopant effects on surface and interfacial properties in alumina. It will examine the effects of dopants, such as Ca, Mg, and Ti on the relative energies and thermodynamica stabilities of different crstallographic planes through measurements of equilibrium pore shapes. It will also study the Rayleigh instability of lithographically introduced pore channels with preexistent finite amplitude perturbations of known but systematically varied wavelength. Finally, it will also study the grain growth, pore drag, amd pore-boundary separation, by varying pore size, shape, and spacing at the interface between undoped and doped single-crystal and polycrystalline alumina. %%% This proposal uses a lithography-based method for studying pore- boundary interactions. It studies the effects of dopants such Mg, Ca, and Ti on the pore-boundary separation conditions and on surface diffusion in alumina. Through this approach, the effect of these dopants on the surface energy anisotropy in alumina can be critically investigated. The role of anisotropy on the microstructural development can be ascertained, and it will be very helpful to the fabrication of in-situ composites such as those with elonagated grain structures.