### Thermodynamics Isotope Effects of LaNi4.25Al0.75 Absorbing Protium,Deuterium and Tritium

LIANG Bin-bin1;ZHAO Wei-wei1;HE Chang-shui1;QUE Ji2;YANG Hong-guang1

1. 1.China Institute of Atomic Energy, Beijing 102413, China;2.Nuclear and Radiation Safety Center, M. E. P, Beijing 100082, China
• Online:2016-05-20 Published:2016-06-03

### LaNi4.25Al0.75吸氕、氘、氚热力学同位素效应

1. 1.中国原子能科学研究院，北京102413；2.环境保护部 核与辐射安全中心，北京100082

Abstract:

The P-C-T curves of LaNi4.25Al0.75 alloy absorbing protium, deuterium and tritium were investigated at constant temperature and volume in our metal hydride research system. According to the Van’t Hoff Equation, the thermodynamics parameters of the hydride phase were determined. Enthalpy change and entropy change for protium, deuterium and tritium were -44.5, -45.0, -47.1 kJ/mol and -118.0, -121.8, -127.5 J•mol-1•K-1. The experiments indicated that the isotope effect did not obviously at low temperature, however, as the temperature increasing to 100  ℃, there were obvious thermodynamics isotope effect with hydrogen absorption by LaNi4.25Al0.75 alloy.  The order of equilibrium pressure absorbing gases was T2>D2>H2. However, the enthalpy and entropy appeared to be in verse order,  T2>D2>H2. The results showed that hydrogen isotope effect with LaNiAl alloys were depended on temperature.