Experimental investigations and thermodynamic descriptions of the Ni-Si and C-Ni-Si systems

The binary Ni-Si phase diagram is reassessed and a consistent set of thermodynamic parameters is obtained based on literature data which we could verify experimentally (15 samples involving are melting, annealing, water quenching, X-ray diffraction (XRD), and differential thermal analysis (DTA)). Applying this description of the Ni-Si system, as well as the descriptions of the Ni-C and Si-C systems available from the literature, preliminary calculations for the C-Ni-Si phase equilibria were made in order to provide guidance in selecting the compositions of decisive ternary alloys. These alloys were subjected to an experimental procedure similar to that employed for the Ni-Si alloys. The XRD and DTA measurements resulting from these ternary alloys provided accurate information on the invariant reaction temperatures in the C-Ni-Si system. Comprehensive comparisons between calculated and measured phase diagrams show that most of the experimental information is satisfactorily accounted for by the present description of the C-Ni-Si system. The liquidus projection and reaction scheme for the whole ternary system are presented.