Thermodynamic investigations of (Bi + Ni) system – Part II

The (Bi + Ni) system has two intermetallic compounds, Bi0.75Ni0.25 and Bi0.5Ni0.5, which melt peritectically, at temperatures 744 K and 927 K, respectively. The enthalpies of formation of these two compounds were measured by solution calorimetric method, successive precipitation method and were calculated from experimentally determined enthalpies of peritectic decomposition. For the solution calorimetric method, liquid ‘Bi’ was used as solvent and the enthalpy of solution of ‘Ni’ and intermetallic compounds in liquid ‘Bi’ bath was measured. Enthalpies of formation of Bi0.75Ni0.25 and Bi0.5Ni0.5 by solution calorimetry were −2 kJ · mol−1 and −3.7 kJ · mol−1, respectively, at T = 298.15 K. Enthalpies of mixing of liquid alloys, measured at different temperatures, were fit into a sub-regular solution model. Different theoretical models were used to calculate thermodynamic parameters of this system.

► Experimental enthalpies of formation of Bi–Ni and Bi3Ni by different methods. ► Measurement of enthalpy of mixing of Bi–Ni liquid solution. ► Theoretical models for estimation of thermodynamic parameters of the system. ► First time reporting of thermodynamic tables of the compounds.