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

本课题拟研究掺杂剂对氧化铝表面和界面性能的影响。它将通过测量平衡孔隙形状来研究掺杂剂，如Ca， Mg和Ti对不同晶体平面的相对能量和热力学稳定性的影响。它还将研究光刻引入的具有已知但系统变化波长的有限振幅扰动的孔隙通道的瑞利不稳定性。最后，还将通过改变未掺杂和掺杂单晶和多晶氧化铝界面上的孔径、形状和间距来研究晶粒生长、孔隙阻力和孔隙边界分离。这个建议使用一种基于光刻的方法来研究孔隙边界的相互作用。研究了镁、钙、钛等掺杂剂对氧化铝孔边界分离条件和表面扩散的影响。通过这种方法，可以严谨地研究这些掺杂剂对氧化铝表面能各向异性的影响。研究了各向异性对微观组织发育的影响，为原位复合材料的制备提供了理论依据。

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.