Chemical Processes in Al2O3-Mo and Al2O3-W systems in a weakly reducing atmosphere

Al₂O₃-Mo and Al₂O₃-W systems in a controlled Ar(95%) + H₂(5%) atmosphere at T = 2400 K and P = 1 bar have been calculated by the Monte Carlo method. It is established that the presence of hydrogen in these systems leads to the occurrence of OH, H₂O₂, HO₂, H₂O, AlOH, AlOOH, AlH, AlH₂, and AlH₃ components in the gas phase; aluminum hydrides are formed only through the interaction of hydrogen with melt evaporation products. The presence of reducing medium leads to a decrease in the free oxygen concentration by one to two orders of magnitude, which is expected to improve the quality of sapphire crystals.