Phase Equilibria in Copper(I) Bromide-MBr Systems (M = Li, Na, K)

Abstract

The phase equilibria of CuBr-LiBr, CuBr-NaBr and CuBr-KBr were studied by difference scanning calorimetry (DSC) and X-ray powder diffraction. Extended solid solutions have been found in CuBr-LiBr, while mutual solid solubility of the components of CuBr-NaBr and CuBr-KBr seems to be negligible. It has been confirmed that K 2 CuBr 3 is stable at room temperature.

Precipitation of nanosized crystals CuBr and CuCl in potassium aluminoborate glasses

“…Thus, the obtained solidus temperature values are in a good agreement with those obtained in [8] when constructing the phase diagram for CuBr-KBr.…”

“…Thus, in the CuBr-KBr system there is 62% CuBr in the eutectic composition [8]. The liquidus temper ature in the CuBr-KBr system in the primary crystal lization field of CuBr is 220°C for the composition, containing ~68% CuBr.…”

“…At such sizes of the halide liquid volume, the process of phase separation reaches a coalescence stage. In this stage of the phase separation, the size dis tribution is described by the Lifshitz-Slyozov equa tion [8]. In the presence of a size distribution, effective radii determined from the SAXS data in the approxima tion of scattering from a monodisperse system of spher ical particles are somewhat higher than the mean size.…”

“…Sharp increases in the SAXS intensity upon cooling below ~80°C are caused by crystallization processes in the halide phase domains. According to the phase diagram of the CuBr−KBr system in a halide phase enriched with CuBr, crystals of CuBr and K 2 CuBr 3 should be present at tempera tures below the solidus temperature in equilibrium states [8]. Consequently, in heat treated glasses two crystal phases should be expected at room tempera ture, namely, CuBr and K 2 CuBr 3 .…”

“…According to the SAXS data, the solidus tempera ture of the halide phase in CuBr containing glass sam ples is equal to 170°C, while according to the data of [8], the solidus temperature of a particulate eutectic system CuBr-K 2 CuBr 3 is 179°C. Thus, the obtained solidus temperature values are in a good agreement with those obtained in [8] when constructing the phase diagram for CuBr-KBr.…”