Thermodynamic Properties of Ternary Refractory Carbides. Iii. Zirconium-Hafnium-Carbon

摘要

The thermodynamic properties of ternary zirconium-hafnium carbide, Zr(x)Hf(1-x)C(y), having the sodium-chloride type structure were studied, using the time-of-flight mass spectrometer. The ratios of the activities of the components were measured as a function of composition at 2440K. From the variation of the ratio of activities with composition, the pairwise interaction energies were obtained. The metal-metal interaction energy (E(12)-(E(11)+E(22))/2) = 1.9 plus or minus 0.3 kcal/mole, similar to that in the body-centered cubic zirconium-hafnium metallic system. The difference between the zirconium-carbon and hafnium-carbon interaction energy E(13)-E(23) is a function of composition and can be expressed as: E(13)-E(23) = (9.8 plus or minus 0.05)-(7.5 plus or minus 0.2)x in kcal/mole. (Author)