In-situ observations of high temperature surface processes on (alpha)-alumina bulk crystals

摘要

Reflection electron microscopy (REM) was applied to image in-situ the dynamic changes of atomic-height steps on the surfaces of (alpha)-alumina bulk crystals heated to high temperatures. Atomic diffusion, desorption and adsorption processes on cleaved (alpha)-alumina (012) surfaces were directly observed at temperatures of 1470 to 1670 K. The surface started to show visible structural changes at 1470--1520 K. The main surface process appears to be atomic desorption, which creates large, flat vacancy-type terraces on the surface. 7 refs., 6 figs.