Behavior of the Mo–Al2O3 system in a controlled reducing atmosphere

Abstract

Stochastic simulation (Monte Carlo method) has been used to evaluate the Mo–Al₂O₃ system at T = 2400 K and p = 1 × 10⁵ Pa in a controlled Ar + H₂ atmosphere. The results demonstrate that the qualitative and quantitative compositions of the system differ markedly from those in an inert (Ar) atmosphere: the presence of hydrogen in the system leads to the formation of hydrogen-containing vapor species (OH, H₂O, AlOH, AlOOH, AlH, AlH₂, and smaller amounts of H₂O₂, HO₂, and AlH₃). Increasing the hydrogen concentration in a controlled atmosphere leads to a reduction in the total concentration of oxygen and molybdenum oxides, accompanied by an increase in the concentration of elemental Al in the vapor phase. We have identified the main chemical processes that take place in the system and have shown that such processes have a cyclic nature and involve repeated interactions with the participation of the basic components of the system.