Thermodynamic properties of liquid alloys of gadolinium with silicon

Partial heats of mixing for gadolinium and silicon in the binary system Gd - Si are measured by means of a high-temperature isoperibolic calorimeter i n two concentration ranges: 0 <x(Gd) < 0.2 and 0.8 <X-Gd < 1 at 1760 K. The integral enthalpies of mixing are calculated from partial enthalpies by th e Darken method. Marked exothermic values of Delta (H) over bar(Gd(Si)) and Delta H were revealed for these binary alloys. Values of Delta H calculate d on the basis of model ideas of the "surrounding atom" theory are in good agreement with experimental values.