In situ X–ray diffraction study of the phase boundary between diaspore and δ–AlOOH

Abstract

To determine the phase boundary between diaspore (α–AlOOH) and δ–AlOOH, in situ X–ray diffraction experiments were carried out using a multi–anvil high–pressure apparatus and synchrotron X–ray. The stability of each phase was determined by observing the change in powder X–ray diffraction patterns. The equilibrium phase boundary is described by the formula P (GPa) = 12.2 (±4.9) + 0.0027 (±0.0044) × T (K). The boundary determined in this study is located at a lower pressure than that estimated by previous quenching experimental studies.