Thermodynamic assessment of the Ge-Si-O-Cl-H system

Abstract

An assessed thermodynamic dataset for the Ge-Si-O-Cl- H system useful for application in the glass fiber industry is presented. The focus of the work is on the germanium-bearing species. Taking into account the available vapor pressure measurements on the Ge-O , Ge-Cl, Ge-Cl-H , and Ge-O-Cl Systems, modifications have been made to the recommended data for the important oxide and halide species. The GeO2-SiO2 and GeCl4-SiCl4 binary systems have been thermodynamically optimized using simple models. The current dataset, when combined with the data from the FactSage™ database for the other required species/phases, can be used to make useful calculations of glass vapor equilibria pertinent to the manufacture of germanium-doped silica glass fibers using vapor deposition methods.