Gas-to-soid condensation in a Mg-SiO-H_2OO_2 vapor:metastable eutectics in the MgO-SiO_2 phase diagram

摘要

Kinetically controlled gas-to-slid condensation in Mg-SiO-H_2-O_2 vapors resulted in the formation of amorphous,chemically orderd,solid compositions at 26+-7,46.56*2 and 87+-3.5 wt% MgO.The first two solid compositions match those of metastable eutectics in existing MgO-SiO_2 phase diagrams.An explanation for the highest-MgO metastable solid compositions requires a revision of this phase diagram to include a eutectic at approx 95wt.% MgO.