Measurement and modelling of high temperature thermodynamic properties of URh3 alloy

The high temperature phase stability of arc-melted cubic URh3 intermetallic compound has been investigated using high temperature inverse drop calorimetry in the temperature range of 300-1273 K. URh3 exists as a line compound with negligible solubility range. Room temperature XRD profile and elemental X-ray mapping experiments on 1273 K/3 h homogenized samples have confirmed the homogeneity and L12 (cF8; pm3m) crystal structure of URh3. The drop measurements yielded accurate values for the enthalpy increment ΔHT0 as a function of temperature, from which the specific heat CP has been estimated. The enthalpy data obtained in this study have been compared and combined with the reported data on low temperature CP and also with the ΔHT0 in the temperature range, 0-840 K, for a comprehensive theoretical analysis using quasiharmonic Debye-Grüneisen formalism. It is found that this model with due allowance for thermal expansion effects can successfully account for the experimentally measured thermal property data in the entire temperature region spanning 0-1273 K. Invoking a combination of measurement and modelling, a comprehensive set of thermodynamic quantities have been obtained for URh3.