铒二氢化物的氘、氚热力学同位素效应

在真空系统中对金属铒的氘活化特性进行了测试，测定了铒与氘、氚反应生成二氢化物及其可逆反应的压强-组成-温度（PCT）曲线。结果显示，铒的氘、氚化物α+β相平台区较宽且十分平坦，其二氘化物和二氚化物分解反应均未见明显滞后效应。基于PCT曲线获得了H/Er原子比在0.6～1.6区间的标准焓（ΔH°）和标准熵（ΔS°），其数值均随H/Er比的增大而减小，相同原子比下氚化物的ΔH°和ΔS°较氘化物的小，具有轻微的同位素效应。其中，ErD₁的ΔH°和ΔS°分别为（-199.7±7.3）kJ/mol和（-143.4±7.2） J/(mol?K)，ErT₁的ΔH°和ΔS°分别为（-209.3±3.3） kJ/mol和（-152.9±3.2）J/(mol?K)。

Isotope Effect on Thermodynamics of Erbium Dideuteride and Ditritide

In order to develop metal hydride technology for storing and processing tritium, the thermodynamics isotope effects of erbium dideuteride and ditritide were investigated. The pressure composition temperature (PCT) curves and activation characteristics of deuterium and tritium from erbium at different temperatures were measured. The isotherms show a wide and straight plateau, and with a unconspicuous hysteresis effect. And then relative partial molar enthalpy and entropy change for Er-D and Er-T reaction were calculated from the Van’t Hoff plots based on the measured PCT relations. In the region of atomic ratio H/Er from 0.6 up to 1.6, the enthalpy and entropy decrease with the increase of the hydrogen concentration. It can be seen that the enthalpy and entropy of ditritide are less than that of the dideuteride with the same atomic ratio, it shows slight thermodynamic isotope effects. The calculated enthalpy and entropy during the formation of the ErD₁ phase are (-199.7±7.3) kJ/mol and (-143.4±7.2) J/(mol?K), and the calculated enthalpy and entropy of ErT₁ phase are (-209.3±3.3) kJ/mol and (-152.9±3.2) J/(mol?K), respectively.