I.A. Tomilin

Enthalpies of formation for the AlY and AlYNi intermetallic compounds

Abstract A method of liquid-metal solution calorimetry has been applied for thermochemical research of intermetallic compounds in the Alue5f8Y and Alue5f8Yue5f8Ni systems. Heats of dissolution for the following intermetallics: Al 3 Y; Al 2 Y; Al 2 Y 3 and Al 4 YNi in liquid Al were measured with the help of a high-temperature isoperibol Calvet-type calorimeter. Using these values, standard molar enthalpies of formation for the listed compounds were calculated: Δ f,298 H o m (Al 3 Y) = −185.6 ± 7.2 kJ mol −1 ; Δ f,298 H o m (Al 2 Y) = −160.4 ± 7.5 kJ mol −1 ; Δ f,298 H o m (Al 2 Y 3 ) = −234.4 ± 19.5 kJ mol −1 ; Δ f,298 H o m (Al 4 Y ue5f8 Ni) = −361.5 ± 12.0 kJ mol −1 Comparisons have been made with some available experimental data and theoretical values calculated from the Miedema model with the help of parameters recommended in different papers.

Enthalpies of formation of liquid and amorphous Cu-Zr alloys

Abstract The enthalpies of formation of liquid Cu–Zr alloys were measured in an isoperibolic heat-flux calorimeter at 1573 K in the concentration range 0⩽xZr⩽0.53 and at 1873 K in the concentration range 0⩽xZr⩽0.55, respectively. The temperature dependence of the formation enthalpy of the liquid alloys was found. The enthalpies of formation of amorphous Cu–Zr alloys from pure crystalline elements were measured by means of a solution calorimeter based on liquid aluminium in the concentration range 0.3⩽xZr⩽0.7. Both enthalpies of formation are negative and analysed in terms of the ideal associate solution model.