Pore Drag in Alumina.

摘要

A model experiment is introduced that allows the study of pore drag and pore-boundary separation under conditions of constant density. Photolithography, ion beam etching, and hot pressing were used to generate microdesigned interfacial pore arrays, consisting of pores of controlled size and spacing, in alumina. Results from an investigation of pore drag suggest that the surface diffusivity in MgO-doped alumina exceeds that in undoped alumina by a factor of 2--9 at 1600/degree/C. The condition for pore-boundary separation was found to depend strongly on pore spacing; the influence zone of pores is several microns wide. Concurrent studies of the grain boundary mobility show that the migration rate of basal plane sapphire into undoped alumina is lower than that into MgO-doped alumina. 22 refs., 10 figs. (ERA citation 14:008257)