Enthalpy measurements of undercooled melts by levitation calorimetry: the pure metals nickel, iron, vanadium and niobium

A circulating gas cooling (CGC) system is added to a combination of an electromagnetic levitation apparatus and a drop calorimeter to measure the enthalpies of the pure metals nickel, iron, vanadium and niobium in the undercooled temperature range. The CGC system extends the experimental temperature range to lower temperatures. The effect of the CGC system on the heat losses during the drop of the sample is discussed and the evaluation procedure presented. The measured enthalpies of the metals in the undercooled range confirm the temperature dependences of the enthalpies of the liquid phase above their melting points.