Thermodynamic Parameters of Liquid Iron ― Tungsten Alloys

The activity of tungsten in liquid Fe ― W alloys has been examined over the concentration range 0.95 < x _Fe < 1.0 at 1870 K by the electro-motive force (EMF) method in concentration circuits, in which the reference electrode is W ― WO₂. That activity has very large positive deviations from ideal solution behavior, which decrease as the temperature rises. Calorimetry at 1900 K has given the enthalpies of solution and mixing for iron and tungsten for the composition range 0 < x _W ≤ 0.1. A small amount of heat is released when the alloys are formed. These characteristics of Fe ― W liquids agree with the most reliable published data.