Thermodynamic Properties of Ternary Refractory Carbides: II . Zirconium‐Uranium‐Carbon and Zirconium‐Hafnium‐Carbon

Abstract

The thermodynamic properties of [ternary] zirconium‐uranium‐carbide and zirconium‐hafnium‐carbide both with a sodium‐chloride type structure were studied using the time‐of‐flight mass spectrometer. The ratio of the activities of the components was measured as a function of composition at 2440 °K, and from the variation of the ratio of activities with composition, the pairwise interaction energies were obtained. In the Zr‐U‐C system, the metal‐metal interaction energy, , was found to be , a value close to that obtained in the body‐centered cubic, zirconium‐uranium [metallic] system. The difference between the zirconium‐carbon and uranium‐carbon interaction energies, can be expressed as a function of composition by the equation In the Zr‐Hf‐C system, the metal‐metal interaction energy, was found to be , again a value close to that obtained in the body‐centered cubic, zirconium‐hafnium [metallic] system. The difference between the zirconium‐carbon and hafnium‐carbon interaction energies, , can be expressed as a function of composition by the equation