Thermochemistry of RPdAl (R = rare earth metal) intermetallics

The standard enthalpies of formation at 300 K of the RPdAl phases (R = Nd, Sm, Gd, Tb, Dy, Ho and Er) have been obtained by using a high-temperature direct reaction drop calorimeter. The reliability of the calorimetric results has been determined and supported by using different analytical techniques: light optical microscopy, scanning electron microscopy equipped with electron probe microanalysis (EPMA with EDS detector) and X-ray Powder Diffraction analysis. The high exothermal values observed for the RPdAl phases are discussed and compared with those available for the binary compounds of the R-Pd systems and for the ternary RNiAl phases. © 2010 Elsevier Ltd. All rights reserved.