Melting behavior of the Nowotny phase Mo4.8Si3C0.6

Abstract

Mixtures of the Mo₅Si₃ silicide with 1.1–2.4 wt % carbon were melted after reaction sintering and the formation of the Nowotny phase (Mo_4.8Si₃C_0.6), and the effect of various heat treatments on the phase composition of the samples was studied. The crystallization of the melted samples leads to a reduction of the volume fraction of the Nowotny phase relative to that after reaction sintering, but subsequent annealing below the liquid phase formation temperature allows the volume fraction of Mo_4.8Si₃C_0.6 to be again raised. We discuss possible causes of the observed phase transformations.