Phase-change sintering of BaCl2 transparent ceramics

摘要

We report on the compaction of anhydrous BaCl2 powders under severe plastic deformation and the conversion of their native orthorhombic cotunnite crystalline structure into a fine-grained cubic fluorite structure. This conversion, supported by x-ray diffraction and transmission electron microscopy data, and which enables the production of highly dense ceramics of BaCl2, occurs 500 degrees C below the known phase transition temperature of 925 degrees C for this material at 1 atm. We discuss this phase change in the context of a stress-induced polymorphic transformation and its implication on the fabrication of transparent ceramics for scintillator applications. (C) 2017 Elsevier B.V. All rights reserved.