Some Aspects of Interactions in the Mo–W–Al2O3–H2 System: Formation of Polyoxides

Abstract

The possibility of formation of molybdenum and tungsten polyoxides in the Mo–W–Al₂O₃–H₂ system at T = 2400 K and P = 1 bar in a controlled Ar + H₂ atmosphere has been investigated by the method of thermodynamic analysis. The formation of polyoxides is found to occur both due to the processes involving Al₂O₃ melt and in the absence of the latter. It is established that metals (Mo and W) and their mono-, di-, and even trioxides (in the latter case, mediated polymerization occurs) can be used as initial components to form polyoxides. It is shown that polyoxides themselves may interact with one of their main sources: Al₂O₃ melt.