Standard enthalpies of formation of some Mn-Y and Mn-Sc intermetallic compounds

The standard enthalpies of formation of Mn2Y, Mn23Y6 and Mn2Sc have been determined by aluminium drop solution calorimetry in an isothermal double cell Tian-Calvet high temperature microcalorimeter at 1123 K. The heats of dissolution of the elements and the intermetallic compounds have been measured at infinite dilution in liquid aluminium. Mn, Y and the three intermetallic compounds dissolved rapidly. It was not possible to determine the value for Sc directly due to the low solubility of this element in Al, which led to a precipitation of Al3Sc without further dissolution. The value has therefore been determined indirectly by the dissolution of two intermetallic compounds - Sc5Ge3 and Al2Sc - for which the enthalpies of formation are known from the literature. (C) 2001 Elsevier Science B.V. All rights reserved.