Thermodynamic Assessment of the Mo–Si System

Abstract

The binary system Mo–Si is reassessed based on previously reported findings that the (Formula presented.) phase shows a deficiency in Si and to take into account experimental data on the heat capacities of the Mo silicides. The last aspect in particular has been neglected in previous assessments of the system. Experimental studies are carried out which confirm that the (Formula presented.) phase is deficient in Si in every alloy analyzed, with an average Si content of 23 at%. The thermodynamic description of this phase is adjusted accordingly and the parameters of the system are optimized. Two alternative possible descriptions are presented for the phase (Formula presented.). It is shown that the calculated binary phase diagram agrees well with experimental data, like liquidus and solidus temperatures as well as homogeneity ranges of the phases, where applicable, for both datasets. Likewise, thermophysical data like enthalpies of the formation of the silicides are adequately described.