Solubility of hydrogen and deuterium in ZrCo

This paper gives first results on the solubility of hydrogen and deuterium in ZrCo in the composition range 2 × 10 −3 < ( n H or n D )/ n ZrCo < 10 −1 as a function of temperature. Sieverts' constants ( K S ) D or H were obtained in the temperature range 473–773 K. The ratio ( K S) H (K S) D was found to be 1.182 ± 0.035. The relative partial molar enthalpies Δ H ̄ ∞ Q(Q = H, D) and the nonconfigurational or excess entropies ΔS nc Q at infinite dilution were calculated to be Δ H ̄ ∞ H = −28.2 kJ/mol H , Δ H ̄ ∞ D = −27.7 kJ/mol D , Δ S ̄ nc∞ H = −73.5 J/K mol H , and Δ S ̄ nc∞ D = −74.2 J/K mol D , respectively. Whereas the partial molar enthalpies Δ H ̄ Q were found to be largely independent of the x Q = n Q / n ZrCo ratio in the intermetallic compound, the negative partial molar entropies Δ S ̄ Q were observed to increase with x Q .