The microstructure of sillimanite with Al/Si-disordering at high temperature

Abstract

Synchrotron powder X-ray diffraction (XRD) and transmission electron microscope (TEM) experiments for annealed sillimanite have been carried out in the present study to examining the P-T conditions which form antiphase boundary (APB) in sillimanite. Our results show that the sillimanite which is expanded (by XRD) shows APB structures by TEM observation. We consider the causes of the volume expansion and APB are the same. The expansion is detected at sillimanite samples annealed above 1100°C. We concluded that APB in sillimanite is the evidence of being heated above 1100°C.