High temperature phase transition behavior of schorl particles modified with rare earth

Abstract

In this study, rare earth/schorl composites were prepared using co-precipitation technique with Xinjiang schorl and cerium nitrate as raw materials. The phase transitions and the lattice parameters were investigated simultaneously during the heat treatment process utilizing a high temperature X-ray diffraction. The microstructures of the composites treated at 800, 850, 900 and 950 °C were characterized by scanning electron microscope, transmission electron microscope and high resolution transmission electron microscope. The results clearly indicate that the cerium ions exchanged the interfacial structure of schorl particles, which led to the reduction in phase transition temperature. The interfacial migration and mass transfer were promoted during the phase transformation, rendering a better transformation of mullite crystals from schorl.