Calorimetric studies of Ta-H system

Calorimetric studies of Ta-H system in the range of pressures n·10-3-2MPa and hydrogen contents 0.3<H/Ta<0.8 at 312 and 426.6 K have been carried out. For the experiment tantalum foil of 99.999 purity, prepared by means of LaNi5H∼6 decomposition, were used. The value of hydrogen dissolution enthalpy in tantalum to the composition TaH0.77±0.01, equal to (70.2±0.9)kJ/mol H2, has been obtained for the first time. The dependence of differental enthalpy of hydrogen dissolution in tantalum on the composition of solid solution formed in the range of compositions 0.3<H/T<0.8 has been studied