Enthalpies of formation of Ni–Sn compounds

Enthalpies of formation (ΔfH) of nickel–tin compounds have been measured by direct reaction calorimetry: image (approximate value); image. Standard states are solid Ni and liquid Sn at the respective working temperatures: 728, 1288, 1389, 1332, 943 and 846 K. The enthalpy of formation of the Ni3Sn high-temperature form is measured for the first time, while that of Ni3Sn2_LT must be considered as approximate because the corresponding calorimetric reaction was incomplete. The chemical and phase compositions of the specimens have been verified by electron probe microanalyses and by high- and room-temperature X-ray diffraction analyses. Unidentified thermal effects have been observed in the Ni3Sn2 phases region.