Enthalpies of formation of liquid (copper + manganese) alloys

The enthalpies of formation of liquid (Cu + Mn) alloys were measured in the isoperibolic heat-flux calorimeter at 1573K in the entire range of compositions. The integral molar enthalpy of mixing was found to be negative in the range of molar fractions 0 < x sub Mn < 0.31, with Delta H(Min)=-0.69 plus/minus 0.27 kJ mol exp -1 at X sub Mn =0.12, and positive in the range 0.31 < X sub Mn < 1, with Delta H(max)=3.67 0.36 kJ mol exp -1 at X sub Mn =0.75. Limiting partial molar enthalpies of manganese and copper were calculated as Delta H sub Mn sub O =-18.0 plus/minus 6.6 kJ mol exp -1 and Delta =H sub Cu exp 0 =29.14.9 kJ mol exp -1 , respectively. The results are discussed in comparison with the thermodynamic data available in the literature and the equilibrium phase diagram.