Experimental study and thermodynamic calculation of Lu2O3-SiO2 binary system

As a binary system of BaO-Lu2O3-SiO2 ternary system, Lu2O3-SiO2 system was optimized and calculated by CALPHAD approach based on available phase diagram and relevant thermodynamic data of RE2O3-SiO2 (RE=Lu, Yb, Y) binary systems as well as our experimental data of Lu2O3-SiO2 system obtained by quenching experiment. The Gibbs free energy of high temperature solution was described by an ionic two-sublattice model as (Lu3+)P(O2–, SiO20)Q. The calculated phase diagram below 1873 K was in good agreement with experimental data at 1573, 1773 and 1873 K. The calculated Gibbs energies of two intermediate phases Lu2SiO5 and Lu2Si2O7, the activity of Lu2O3 and SiO2 and specific heat capacities of intermediate phases agreed well with experimental results of Y2O3-SiO2 system. This tentative study will offer help for the research of single-phase phosphor and related metallurgical slags, refractories, high-temperature superconductivity material systems.